From 2f556bdb9f2e3794722c0d9186db9799b35071c4 Mon Sep 17 00:00:00 2001 From: David Cohen Date: Wed, 21 Dec 2016 12:20:25 +0100 Subject: extcon: int3496: Add Intel INT3496 ACPI device extcon driver Add an extcon driver for USB OTG ports controlled by an Intel INT3496 ACPI device (e.g. Baytrail, Cherrytrail devices). Signed-off-by: David Cohen [hdgoede@redhat.com: Port to current kernel, cleanup, submit upstream] [hdgoede@redhat.com: Add Documentation/extcon/intel-int3496.txt] Signed-off-by: Hans de Goede Signed-off-by: Chanwoo Choi --- Documentation/extcon/intel-int3496.txt | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) create mode 100644 Documentation/extcon/intel-int3496.txt (limited to 'Documentation') diff --git a/Documentation/extcon/intel-int3496.txt b/Documentation/extcon/intel-int3496.txt new file mode 100644 index 000000000000..af0b366c25b7 --- /dev/null +++ b/Documentation/extcon/intel-int3496.txt @@ -0,0 +1,22 @@ +Intel INT3496 ACPI device extcon driver documentation +----------------------------------------------------- + +The Intel INT3496 ACPI device extcon driver is a driver for ACPI +devices with an acpi-id of INT3496, such as found for example on +Intel Baytrail and Cherrytrail tablets. + +This ACPI device describes how the OS can read the id-pin of the devices' +USB-otg port, as well as how it optionally can enable Vbus output on the +otg port and how it can optionally control the muxing of the data pins +between an USB host and an USB peripheral controller. + +The ACPI devices exposes this functionality by returning an array with up +to 3 gpio descriptors from its ACPI _CRS (Current Resource Settings) call: + +Index 0: The input gpio for the id-pin, this is always present and valid +Index 1: The output gpio for enabling Vbus output from the device to the otg + port, write 1 to enable the Vbus output (this gpio descriptor may + be absent or invalid) +Index 2: The output gpio for muxing of the data pins between the USB host and + the USB peripheral controller, write 1 to mux to the peripheral + controller -- cgit v1.2.3 From a0227cf344e2a33bd4454cf09e56a2a9a8fbfc1d Mon Sep 17 00:00:00 2001 From: Serge Semin Date: Fri, 13 Jan 2017 15:16:53 +0300 Subject: eeprom: Add IDT 89HPESx driver bindings file IDT 89HPESx PCIe-switches exposes SMBus interface to have an access to the device CSRs and EEPROM. So to properly utilize the interface functionality, developer should declare a valid dts-file node, which would refer to the corresponding 89HPESx device. Signed-off-by: Serge Semin Acked-by: Rob Herring Signed-off-by: Greg Kroah-Hartman --- .../devicetree/bindings/misc/idt_89hpesx.txt | 44 ++++++++++++++++++++++ 1 file changed, 44 insertions(+) create mode 100644 Documentation/devicetree/bindings/misc/idt_89hpesx.txt (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/misc/idt_89hpesx.txt b/Documentation/devicetree/bindings/misc/idt_89hpesx.txt new file mode 100644 index 000000000000..b9093b79ab7d --- /dev/null +++ b/Documentation/devicetree/bindings/misc/idt_89hpesx.txt @@ -0,0 +1,44 @@ +EEPROM / CSR SMBus-slave interface of IDT 89HPESx devices + +Required properties: + - compatible : should be "," + Basically there is only one manufacturer: idt, but some + compatible devices may be produced in future. Following devices + are supported: 89hpes8nt2, 89hpes12nt3, 89hpes24nt6ag2, + 89hpes32nt8ag2, 89hpes32nt8bg2, 89hpes12nt12g2, 89hpes16nt16g2, + 89hpes24nt24g2, 89hpes32nt24ag2, 89hpes32nt24bg2; + 89hpes12n3, 89hpes12n3a, 89hpes24n3, 89hpes24n3a; + 89hpes32h8, 89hpes32h8g2, 89hpes48h12, 89hpes48h12g2, + 89hpes48h12ag2, 89hpes16h16, 89hpes22h16, 89hpes22h16g2, + 89hpes34h16, 89hpes34h16g2, 89hpes64h16, 89hpes64h16g2, + 89hpes64h16ag2; + 89hpes12t3g2, 89hpes24t3g2, 89hpes16t4, 89hpes4t4g2, + 89hpes10t4g2, 89hpes16t4g2, 89hpes16t4ag2, 89hpes5t5, + 89hpes6t5, 89hpes8t5, 89hpes8t5a, 89hpes24t6, 89hpes6t6g2, + 89hpes24t6g2, 89hpes16t7, 89hpes32t8, 89hpes32t8g2, + 89hpes48t12, 89hpes48t12g2. + - reg : I2C address of the IDT 89HPESx device. + +Optionally there can be EEPROM-compatible subnode: + - compatible: There are five EEPROM devices supported: 24c32, 24c64, 24c128, + 24c256 and 24c512 differed by size. + - reg: Custom address of EEPROM device (If not specified IDT 89HPESx + (optional) device will try to communicate with EEPROM sited by default + address - 0x50) + - read-only : Parameterless property disables writes to the EEPROM + (optional) + +Example: + idt@60 { + compatible = "idt,89hpes32nt8ag2"; + reg = <0x74>; + #address-cells = <1>; + #size-cells = <0>; + + eeprom@50 { + compatible = "onsemi,24c64"; + reg = <0x50>; + read-only; + }; + }; + -- cgit v1.2.3 From 37afff0d87c9939843c664970af6c6d952f95712 Mon Sep 17 00:00:00 2001 From: Dave Gerlach Date: Thu, 12 Jan 2017 14:52:20 -0600 Subject: misc: sram: Integrate protect-exec reserved sram area type Introduce a new "protect-exec" reserved sram area type which is makes use of the the existing functionality provided for the "pool" sram region type for use with the genalloc framework and with the added requirement that it be maintained as read-only and executable while allowing for an arbitrary number of drivers to share the space. This introduces a common way to maintain a region of sram as read-only and executable and also introduces a helper function, sram_exec_copy, which allows for copying data to this protected region while maintaining locking to avoid conflicts between multiple users of the same space. A region of memory that is marked with the "protect-exec" flag in the device tree also has the requirement of providing a page aligned block of memory so that the page attribute manipulation does not affect surrounding regions. Also, selectively enable this only for builds that support set_memory_* calls, for now just ARM, through the use of Kconfig. Signed-off-by: Dave Gerlach Acked-by: Tony Lindgren Signed-off-by: Greg Kroah-Hartman --- Documentation/devicetree/bindings/sram/sram.txt | 6 ++++++ drivers/misc/Kconfig | 4 ++++ drivers/misc/Makefile | 1 + drivers/misc/sram.c | 21 +++++++++++++++++++-- drivers/misc/sram.h | 1 + 5 files changed, 31 insertions(+), 2 deletions(-) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/sram/sram.txt b/Documentation/devicetree/bindings/sram/sram.txt index 068c2c03c38f..267da4410aef 100644 --- a/Documentation/devicetree/bindings/sram/sram.txt +++ b/Documentation/devicetree/bindings/sram/sram.txt @@ -42,6 +42,12 @@ Optional properties in the area nodes: and in use by another device or devices - export : indicates that the reserved SRAM area may be accessed outside of the kernel, e.g. by bootloader or userspace +- protect-exec : Same as 'pool' above but with the additional + constraint that code wil be run from the region and + that the memory is maintained as read-only, executable + during code execution. NOTE: This region must be page + aligned on start and end in order to properly allow + manipulation of the page attributes. - label : the name for the reserved partition, if omitted, the label is taken from the node name excluding the unit address. diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig index 64971baf11fa..0444a8f9b094 100644 --- a/drivers/misc/Kconfig +++ b/drivers/misc/Kconfig @@ -474,11 +474,15 @@ config SRAM bool "Generic on-chip SRAM driver" depends on HAS_IOMEM select GENERIC_ALLOCATOR + select SRAM_EXEC if ARM help This driver allows you to declare a memory region to be managed by the genalloc API. It is supposed to be used for small on-chip SRAM areas found on many SoCs. +config SRAM_EXEC + bool + config VEXPRESS_SYSCFG bool "Versatile Express System Configuration driver" depends on VEXPRESS_CONFIG diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile index 31983366090a..7a3ea89339b4 100644 --- a/drivers/misc/Makefile +++ b/drivers/misc/Makefile @@ -47,6 +47,7 @@ obj-$(CONFIG_INTEL_MEI) += mei/ obj-$(CONFIG_VMWARE_VMCI) += vmw_vmci/ obj-$(CONFIG_LATTICE_ECP3_CONFIG) += lattice-ecp3-config.o obj-$(CONFIG_SRAM) += sram.o +obj-$(CONFIG_SRAM_EXEC) += sram-exec.o obj-y += mic/ obj-$(CONFIG_GENWQE) += genwqe/ obj-$(CONFIG_ECHO) += echo/ diff --git a/drivers/misc/sram.c b/drivers/misc/sram.c index 5a6e001845c2..d1185b78cf9a 100644 --- a/drivers/misc/sram.c +++ b/drivers/misc/sram.c @@ -122,6 +122,18 @@ static int sram_add_partition(struct sram_dev *sram, struct sram_reserve *block, if (ret) return ret; } + if (block->protect_exec) { + ret = sram_check_protect_exec(sram, block, part); + if (ret) + return ret; + + ret = sram_add_pool(sram, block, start, part); + if (ret) + return ret; + + sram_add_protect_exec(part); + } + sram->partitions++; return 0; @@ -207,7 +219,11 @@ static int sram_reserve_regions(struct sram_dev *sram, struct resource *res) if (of_find_property(child, "pool", NULL)) block->pool = true; - if ((block->export || block->pool) && block->size) { + if (of_find_property(child, "protect-exec", NULL)) + block->protect_exec = true; + + if ((block->export || block->pool || block->protect_exec) && + block->size) { exports++; label = NULL; @@ -269,7 +285,8 @@ static int sram_reserve_regions(struct sram_dev *sram, struct resource *res) goto err_chunks; } - if ((block->export || block->pool) && block->size) { + if ((block->export || block->pool || block->protect_exec) && + block->size) { ret = sram_add_partition(sram, block, res->start + block->start); if (ret) { diff --git a/drivers/misc/sram.h b/drivers/misc/sram.h index b268cd3f55bb..c181ce4c8fca 100644 --- a/drivers/misc/sram.h +++ b/drivers/misc/sram.h @@ -34,6 +34,7 @@ struct sram_reserve { u32 size; bool export; bool pool; + bool protect_exec; const char *label; }; -- cgit v1.2.3 From 1e928fff9a7444cbfbbb2420eb8cec79bfa53c6f Mon Sep 17 00:00:00 2001 From: Bai Ping Date: Sun, 22 Jan 2017 23:02:37 +0000 Subject: devicetree: bindings: nvmem: Add compatible string for imx6ul Add new compatible string for i.MX6UL SOC. Signed-off-by: Bai Ping Acked-by: Rob Herring Signed-off-by: Srinivas Kandagatla Signed-off-by: Greg Kroah-Hartman --- Documentation/devicetree/bindings/nvmem/imx-ocotp.txt | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/nvmem/imx-ocotp.txt b/Documentation/devicetree/bindings/nvmem/imx-ocotp.txt index 383d5889e95a..966a72ecc6bd 100644 --- a/Documentation/devicetree/bindings/nvmem/imx-ocotp.txt +++ b/Documentation/devicetree/bindings/nvmem/imx-ocotp.txt @@ -1,13 +1,15 @@ Freescale i.MX6 On-Chip OTP Controller (OCOTP) device tree bindings This binding represents the on-chip eFuse OTP controller found on -i.MX6Q/D, i.MX6DL/S, i.MX6SL, and i.MX6SX SoCs. +i.MX6Q/D, i.MX6DL/S, i.MX6SL, i.MX6SX and i.MX6UL SoCs. Required properties: - compatible: should be one of "fsl,imx6q-ocotp" (i.MX6Q/D/DL/S), "fsl,imx6sl-ocotp" (i.MX6SL), or - "fsl,imx6sx-ocotp" (i.MX6SX), followed by "syscon". + "fsl,imx6sx-ocotp" (i.MX6SX), + "fsl,imx6ul-ocotp" (i.MX6UL), + followed by "syscon". - reg: Should contain the register base and length. - clocks: Should contain a phandle pointing to the gated peripheral clock. -- cgit v1.2.3 From cadf8106661c061ab5041282a8e088de4e470526 Mon Sep 17 00:00:00 2001 From: Alexander Dahl Date: Sat, 28 Jan 2017 10:45:32 +0100 Subject: doc: convert UIO howto from docbook to sphinx MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Converted with tmplcvt. Only some tiny things needed manual fixing. Signed-off-by: Alexander Dahl Cc: Hans-Jürgen Koch Cc: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman --- Documentation/DocBook/Makefile | 2 +- Documentation/DocBook/uio-howto.tmpl | 1112 -------------------------------- Documentation/driver-api/index.rst | 1 + Documentation/driver-api/uio-howto.rst | 705 ++++++++++++++++++++ MAINTAINERS | 2 +- 5 files changed, 708 insertions(+), 1114 deletions(-) delete mode 100644 Documentation/DocBook/uio-howto.tmpl create mode 100644 Documentation/driver-api/uio-howto.rst (limited to 'Documentation') diff --git a/Documentation/DocBook/Makefile b/Documentation/DocBook/Makefile index a6eb7dcd4dd5..5fd8f5effd0c 100644 --- a/Documentation/DocBook/Makefile +++ b/Documentation/DocBook/Makefile @@ -11,7 +11,7 @@ DOCBOOKS := z8530book.xml \ writing_usb_driver.xml networking.xml \ kernel-api.xml filesystems.xml lsm.xml kgdb.xml \ gadget.xml libata.xml mtdnand.xml librs.xml rapidio.xml \ - genericirq.xml s390-drivers.xml uio-howto.xml scsi.xml \ + genericirq.xml s390-drivers.xml scsi.xml \ sh.xml regulator.xml w1.xml \ writing_musb_glue_layer.xml iio.xml diff --git a/Documentation/DocBook/uio-howto.tmpl b/Documentation/DocBook/uio-howto.tmpl deleted file mode 100644 index 5210f8a577c6..000000000000 --- a/Documentation/DocBook/uio-howto.tmpl +++ /dev/null @@ -1,1112 +0,0 @@ - - - - - -The Userspace I/O HOWTO - - - Hans-Jürgen - Koch - Linux developer, Linutronix - - - Linutronix - - -
- hjk@hansjkoch.de -
- - - - - 2006-2008 - Hans-Jürgen Koch. - - - 2009 - Red Hat Inc, Michael S. Tsirkin (mst@redhat.com) - - - - -This documentation is Free Software licensed under the terms of the -GPL version 2. - - - -2006-12-11 - - - This HOWTO describes concept and usage of Linux kernel's - Userspace I/O system. - - - - - 0.10 - 2016-10-17 - sch - Added generic hyperv driver - - - - 0.9 - 2009-07-16 - mst - Added generic pci driver - - - - 0.8 - 2008-12-24 - hjk - Added name attributes in mem and portio sysfs directories. - - - - 0.7 - 2008-12-23 - hjk - Added generic platform drivers and offset attribute. - - - 0.6 - 2008-12-05 - hjk - Added description of portio sysfs attributes. - - - 0.5 - 2008-05-22 - hjk - Added description of write() function. - - - 0.4 - 2007-11-26 - hjk - Removed section about uio_dummy. - - - 0.3 - 2007-04-29 - hjk - Added section about userspace drivers. - - - 0.2 - 2007-02-13 - hjk - Update after multiple mappings were added. - - - 0.1 - 2006-12-11 - hjk - First draft. - - - - - - -About this document - - - -Translations - -If you know of any translations for this document, or you are -interested in translating it, please email me -hjk@hansjkoch.de. - - - - -Preface - - For many types of devices, creating a Linux kernel driver is - overkill. All that is really needed is some way to handle an - interrupt and provide access to the memory space of the - device. The logic of controlling the device does not - necessarily have to be within the kernel, as the device does - not need to take advantage of any of other resources that the - kernel provides. One such common class of devices that are - like this are for industrial I/O cards. - - - To address this situation, the userspace I/O system (UIO) was - designed. For typical industrial I/O cards, only a very small - kernel module is needed. The main part of the driver will run in - user space. This simplifies development and reduces the risk of - serious bugs within a kernel module. - - - Please note that UIO is not an universal driver interface. Devices - that are already handled well by other kernel subsystems (like - networking or serial or USB) are no candidates for an UIO driver. - Hardware that is ideally suited for an UIO driver fulfills all of - the following: - - - - The device has memory that can be mapped. The device can be - controlled completely by writing to this memory. - - - The device usually generates interrupts. - - - The device does not fit into one of the standard kernel - subsystems. - - - - - -Acknowledgments - I'd like to thank Thomas Gleixner and Benedikt Spranger of - Linutronix, who have not only written most of the UIO code, but also - helped greatly writing this HOWTO by giving me all kinds of background - information. - - - -Feedback - Find something wrong with this document? (Or perhaps something - right?) I would love to hear from you. Please email me at - hjk@hansjkoch.de. - - - - - -About UIO - -If you use UIO for your card's driver, here's what you get: - - - - only one small kernel module to write and maintain. - - - develop the main part of your driver in user space, - with all the tools and libraries you're used to. - - - bugs in your driver won't crash the kernel. - - - updates of your driver can take place without recompiling - the kernel. - - - - -How UIO works - - Each UIO device is accessed through a device file and several - sysfs attribute files. The device file will be called - /dev/uio0 for the first device, and - /dev/uio1, /dev/uio2 - and so on for subsequent devices. - - - /dev/uioX is used to access the - address space of the card. Just use - mmap() to access registers or RAM - locations of your card. - - - - Interrupts are handled by reading from - /dev/uioX. A blocking - read() from - /dev/uioX will return as soon as an - interrupt occurs. You can also use - select() on - /dev/uioX to wait for an interrupt. The - integer value read from /dev/uioX - represents the total interrupt count. You can use this number - to figure out if you missed some interrupts. - - - For some hardware that has more than one interrupt source internally, - but not separate IRQ mask and status registers, there might be - situations where userspace cannot determine what the interrupt source - was if the kernel handler disables them by writing to the chip's IRQ - register. In such a case, the kernel has to disable the IRQ completely - to leave the chip's register untouched. Now the userspace part can - determine the cause of the interrupt, but it cannot re-enable - interrupts. Another cornercase is chips where re-enabling interrupts - is a read-modify-write operation to a combined IRQ status/acknowledge - register. This would be racy if a new interrupt occurred - simultaneously. - - - To address these problems, UIO also implements a write() function. It - is normally not used and can be ignored for hardware that has only a - single interrupt source or has separate IRQ mask and status registers. - If you need it, however, a write to /dev/uioX - will call the irqcontrol() function implemented - by the driver. You have to write a 32-bit value that is usually either - 0 or 1 to disable or enable interrupts. If a driver does not implement - irqcontrol(), write() will - return with -ENOSYS. - - - - To handle interrupts properly, your custom kernel module can - provide its own interrupt handler. It will automatically be - called by the built-in handler. - - - - For cards that don't generate interrupts but need to be - polled, there is the possibility to set up a timer that - triggers the interrupt handler at configurable time intervals. - This interrupt simulation is done by calling - uio_event_notify() - from the timer's event handler. - - - - Each driver provides attributes that are used to read or write - variables. These attributes are accessible through sysfs - files. A custom kernel driver module can add its own - attributes to the device owned by the uio driver, but not added - to the UIO device itself at this time. This might change in the - future if it would be found to be useful. - - - - The following standard attributes are provided by the UIO - framework: - - - - - name: The name of your device. It is - recommended to use the name of your kernel module for this. - - - - - version: A version string defined by your - driver. This allows the user space part of your driver to deal - with different versions of the kernel module. - - - - - event: The total number of interrupts - handled by the driver since the last time the device node was - read. - - - - - These attributes appear under the - /sys/class/uio/uioX directory. Please - note that this directory might be a symlink, and not a real - directory. Any userspace code that accesses it must be able - to handle this. - - - Each UIO device can make one or more memory regions available for - memory mapping. This is necessary because some industrial I/O cards - require access to more than one PCI memory region in a driver. - - - Each mapping has its own directory in sysfs, the first mapping - appears as /sys/class/uio/uioX/maps/map0/. - Subsequent mappings create directories map1/, - map2/, and so on. These directories will only - appear if the size of the mapping is not 0. - - - Each mapX/ directory contains four read-only files - that show attributes of the memory: - - - - - name: A string identifier for this mapping. This - is optional, the string can be empty. Drivers can set this to make it - easier for userspace to find the correct mapping. - - - - - addr: The address of memory that can be mapped. - - - - - size: The size, in bytes, of the memory - pointed to by addr. - - - - - offset: The offset, in bytes, that has to be - added to the pointer returned by mmap() to get - to the actual device memory. This is important if the device's memory - is not page aligned. Remember that pointers returned by - mmap() are always page aligned, so it is good - style to always add this offset. - - - - - - From userspace, the different mappings are distinguished by adjusting - the offset parameter of the - mmap() call. To map the memory of mapping N, you - have to use N times the page size as your offset: - - -offset = N * getpagesize(); - - - - Sometimes there is hardware with memory-like regions that can not be - mapped with the technique described here, but there are still ways to - access them from userspace. The most common example are x86 ioports. - On x86 systems, userspace can access these ioports using - ioperm(), iopl(), - inb(), outb(), and similar - functions. - - - Since these ioport regions can not be mapped, they will not appear under - /sys/class/uio/uioX/maps/ like the normal memory - described above. Without information about the port regions a hardware - has to offer, it becomes difficult for the userspace part of the - driver to find out which ports belong to which UIO device. - - - To address this situation, the new directory - /sys/class/uio/uioX/portio/ was added. It only - exists if the driver wants to pass information about one or more port - regions to userspace. If that is the case, subdirectories named - port0, port1, and so on, - will appear underneath - /sys/class/uio/uioX/portio/. - - - Each portX/ directory contains four read-only - files that show name, start, size, and type of the port region: - - - - - name: A string identifier for this port region. - The string is optional and can be empty. Drivers can set it to make it - easier for userspace to find a certain port region. - - - - - start: The first port of this region. - - - - - size: The number of ports in this region. - - - - - porttype: A string describing the type of port. - - - - - - - - - - -Writing your own kernel module - - Please have a look at uio_cif.c as an - example. The following paragraphs explain the different - sections of this file. - - - -struct uio_info - - This structure tells the framework the details of your driver, - Some of the members are required, others are optional. - - - - -const char *name: Required. The name of your driver as -it will appear in sysfs. I recommend using the name of your module for this. - - - -const char *version: Required. This string appears in -/sys/class/uio/uioX/version. - - - -struct uio_mem mem[ MAX_UIO_MAPS ]: Required if you -have memory that can be mapped with mmap(). For each -mapping you need to fill one of the uio_mem structures. -See the description below for details. - - - -struct uio_port port[ MAX_UIO_PORTS_REGIONS ]: Required -if you want to pass information about ioports to userspace. For each port -region you need to fill one of the uio_port structures. -See the description below for details. - - - -long irq: Required. If your hardware generates an -interrupt, it's your modules task to determine the irq number during -initialization. If you don't have a hardware generated interrupt but -want to trigger the interrupt handler in some other way, set -irq to UIO_IRQ_CUSTOM. -If you had no interrupt at all, you could set -irq to UIO_IRQ_NONE, though this -rarely makes sense. - - - -unsigned long irq_flags: Required if you've set -irq to a hardware interrupt number. The flags given -here will be used in the call to request_irq(). - - - -int (*mmap)(struct uio_info *info, struct vm_area_struct -*vma): Optional. If you need a special -mmap() function, you can set it here. If this -pointer is not NULL, your mmap() will be called -instead of the built-in one. - - - -int (*open)(struct uio_info *info, struct inode *inode) -: Optional. You might want to have your own -open(), e.g. to enable interrupts only when your -device is actually used. - - - -int (*release)(struct uio_info *info, struct inode *inode) -: Optional. If you define your own -open(), you will probably also want a custom -release() function. - - - -int (*irqcontrol)(struct uio_info *info, s32 irq_on) -: Optional. If you need to be able to enable or disable -interrupts from userspace by writing to /dev/uioX, -you can implement this function. The parameter irq_on -will be 0 to disable interrupts and 1 to enable them. - - - - -Usually, your device will have one or more memory regions that can be mapped -to user space. For each region, you have to set up a -struct uio_mem in the mem[] array. -Here's a description of the fields of struct uio_mem: - - - - -const char *name: Optional. Set this to help identify -the memory region, it will show up in the corresponding sysfs node. - - - -int memtype: Required if the mapping is used. Set this to -UIO_MEM_PHYS if you you have physical memory on your -card to be mapped. Use UIO_MEM_LOGICAL for logical -memory (e.g. allocated with kmalloc()). There's also -UIO_MEM_VIRTUAL for virtual memory. - - - -phys_addr_t addr: Required if the mapping is used. -Fill in the address of your memory block. This address is the one that -appears in sysfs. - - - -resource_size_t size: Fill in the size of the -memory block that addr points to. If size -is zero, the mapping is considered unused. Note that you -must initialize size with zero for -all unused mappings. - - - -void *internal_addr: If you have to access this memory -region from within your kernel module, you will want to map it internally by -using something like ioremap(). Addresses -returned by this function cannot be mapped to user space, so you must not -store it in addr. Use internal_addr -instead to remember such an address. - - - - -Please do not touch the map element of -struct uio_mem! It is used by the UIO framework -to set up sysfs files for this mapping. Simply leave it alone. - - - -Sometimes, your device can have one or more port regions which can not be -mapped to userspace. But if there are other possibilities for userspace to -access these ports, it makes sense to make information about the ports -available in sysfs. For each region, you have to set up a -struct uio_port in the port[] array. -Here's a description of the fields of struct uio_port: - - - - -char *porttype: Required. Set this to one of the predefined -constants. Use UIO_PORT_X86 for the ioports found in x86 -architectures. - - - -unsigned long start: Required if the port region is used. -Fill in the number of the first port of this region. - - - -unsigned long size: Fill in the number of ports in this -region. If size is zero, the region is considered unused. -Note that you must initialize size -with zero for all unused regions. - - - - -Please do not touch the portio element of -struct uio_port! It is used internally by the UIO -framework to set up sysfs files for this region. Simply leave it alone. - - - - - -Adding an interrupt handler - - What you need to do in your interrupt handler depends on your - hardware and on how you want to handle it. You should try to - keep the amount of code in your kernel interrupt handler low. - If your hardware requires no action that you - have to perform after each interrupt, - then your handler can be empty. If, on the other - hand, your hardware needs some action to - be performed after each interrupt, then you - must do it in your kernel module. Note - that you cannot rely on the userspace part of your driver. Your - userspace program can terminate at any time, possibly leaving - your hardware in a state where proper interrupt handling is - still required. - - - - There might also be applications where you want to read data - from your hardware at each interrupt and buffer it in a piece - of kernel memory you've allocated for that purpose. With this - technique you could avoid loss of data if your userspace - program misses an interrupt. - - - - A note on shared interrupts: Your driver should support - interrupt sharing whenever this is possible. It is possible if - and only if your driver can detect whether your hardware has - triggered the interrupt or not. This is usually done by looking - at an interrupt status register. If your driver sees that the - IRQ bit is actually set, it will perform its actions, and the - handler returns IRQ_HANDLED. If the driver detects that it was - not your hardware that caused the interrupt, it will do nothing - and return IRQ_NONE, allowing the kernel to call the next - possible interrupt handler. - - - - If you decide not to support shared interrupts, your card - won't work in computers with no free interrupts. As this - frequently happens on the PC platform, you can save yourself a - lot of trouble by supporting interrupt sharing. - - - - -Using uio_pdrv for platform devices - - In many cases, UIO drivers for platform devices can be handled in a - generic way. In the same place where you define your - struct platform_device, you simply also implement - your interrupt handler and fill your - struct uio_info. A pointer to this - struct uio_info is then used as - platform_data for your platform device. - - - You also need to set up an array of struct resource - containing addresses and sizes of your memory mappings. This - information is passed to the driver using the - .resource and .num_resources - elements of struct platform_device. - - - You now have to set the .name element of - struct platform_device to - "uio_pdrv" to use the generic UIO platform device - driver. This driver will fill the mem[] array - according to the resources given, and register the device. - - - The advantage of this approach is that you only have to edit a file - you need to edit anyway. You do not have to create an extra driver. - - - - -Using uio_pdrv_genirq for platform devices - - Especially in embedded devices, you frequently find chips where the - irq pin is tied to its own dedicated interrupt line. In such cases, - where you can be really sure the interrupt is not shared, we can take - the concept of uio_pdrv one step further and use a - generic interrupt handler. That's what - uio_pdrv_genirq does. - - - The setup for this driver is the same as described above for - uio_pdrv, except that you do not implement an - interrupt handler. The .handler element of - struct uio_info must remain - NULL. The .irq_flags element - must not contain IRQF_SHARED. - - - You will set the .name element of - struct platform_device to - "uio_pdrv_genirq" to use this driver. - - - The generic interrupt handler of uio_pdrv_genirq - will simply disable the interrupt line using - disable_irq_nosync(). After doing its work, - userspace can reenable the interrupt by writing 0x00000001 to the UIO - device file. The driver already implements an - irq_control() to make this possible, you must not - implement your own. - - - Using uio_pdrv_genirq not only saves a few lines of - interrupt handler code. You also do not need to know anything about - the chip's internal registers to create the kernel part of the driver. - All you need to know is the irq number of the pin the chip is - connected to. - - - - -Using uio_dmem_genirq for platform devices - - In addition to statically allocated memory ranges, they may also be - a desire to use dynamically allocated regions in a user space driver. - In particular, being able to access memory made available through the - dma-mapping API, may be particularly useful. The - uio_dmem_genirq driver provides a way to accomplish - this. - - - This driver is used in a similar manner to the - "uio_pdrv_genirq" driver with respect to interrupt - configuration and handling. - - - Set the .name element of - struct platform_device to - "uio_dmem_genirq" to use this driver. - - - When using this driver, fill in the .platform_data - element of struct platform_device, which is of type - struct uio_dmem_genirq_pdata and which contains the - following elements: - - - struct uio_info uioinfo: The same - structure used as the uio_pdrv_genirq platform - data - unsigned int *dynamic_region_sizes: - Pointer to list of sizes of dynamic memory regions to be mapped into - user space. - - unsigned int num_dynamic_regions: - Number of elements in dynamic_region_sizes array. - - - - The dynamic regions defined in the platform data will be appended to - the mem[] array after the platform device - resources, which implies that the total number of static and dynamic - memory regions cannot exceed MAX_UIO_MAPS. - - - The dynamic memory regions will be allocated when the UIO device file, - /dev/uioX is opened. - Similar to static memory resources, the memory region information for - dynamic regions is then visible via sysfs at - /sys/class/uio/uioX/maps/mapY/*. - The dynamic memory regions will be freed when the UIO device file is - closed. When no processes are holding the device file open, the address - returned to userspace is ~0. - - - - - - - -Writing a driver in userspace - - Once you have a working kernel module for your hardware, you can - write the userspace part of your driver. You don't need any special - libraries, your driver can be written in any reasonable language, - you can use floating point numbers and so on. In short, you can - use all the tools and libraries you'd normally use for writing a - userspace application. - - - -Getting information about your UIO device - - Information about all UIO devices is available in sysfs. The - first thing you should do in your driver is check - name and version to - make sure your talking to the right device and that its kernel - driver has the version you expect. - - - You should also make sure that the memory mapping you need - exists and has the size you expect. - - - There is a tool called lsuio that lists - UIO devices and their attributes. It is available here: - - - - http://www.osadl.org/projects/downloads/UIO/user/ - - - With lsuio you can quickly check if your - kernel module is loaded and which attributes it exports. - Have a look at the manpage for details. - - - The source code of lsuio can serve as an - example for getting information about an UIO device. - The file uio_helper.c contains a lot of - functions you could use in your userspace driver code. - - - - -mmap() device memory - - After you made sure you've got the right device with the - memory mappings you need, all you have to do is to call - mmap() to map the device's memory - to userspace. - - - The parameter offset of the - mmap() call has a special meaning - for UIO devices: It is used to select which mapping of - your device you want to map. To map the memory of - mapping N, you have to use N times the page size as - your offset: - - - offset = N * getpagesize(); - - - N starts from zero, so if you've got only one memory - range to map, set offset = 0. - A drawback of this technique is that memory is always - mapped beginning with its start address. - - - - -Waiting for interrupts - - After you successfully mapped your devices memory, you - can access it like an ordinary array. Usually, you will - perform some initialization. After that, your hardware - starts working and will generate an interrupt as soon - as it's finished, has some data available, or needs your - attention because an error occurred. - - - /dev/uioX is a read-only file. A - read() will always block until an - interrupt occurs. There is only one legal value for the - count parameter of - read(), and that is the size of a - signed 32 bit integer (4). Any other value for - count causes read() - to fail. The signed 32 bit integer read is the interrupt - count of your device. If the value is one more than the value - you read the last time, everything is OK. If the difference - is greater than one, you missed interrupts. - - - You can also use select() on - /dev/uioX. - - - - - - - -Generic PCI UIO driver - - The generic driver is a kernel module named uio_pci_generic. - It can work with any device compliant to PCI 2.3 (circa 2002) and - any compliant PCI Express device. Using this, you only need to - write the userspace driver, removing the need to write - a hardware-specific kernel module. - - - -Making the driver recognize the device - -Since the driver does not declare any device ids, it will not get loaded -automatically and will not automatically bind to any devices, you must load it -and allocate id to the driver yourself. For example: - - modprobe uio_pci_generic - echo "8086 10f5" > /sys/bus/pci/drivers/uio_pci_generic/new_id - - - -If there already is a hardware specific kernel driver for your device, the -generic driver still won't bind to it, in this case if you want to use the -generic driver (why would you?) you'll have to manually unbind the hardware -specific driver and bind the generic driver, like this: - - echo -n 0000:00:19.0 > /sys/bus/pci/drivers/e1000e/unbind - echo -n 0000:00:19.0 > /sys/bus/pci/drivers/uio_pci_generic/bind - - - -You can verify that the device has been bound to the driver -by looking for it in sysfs, for example like the following: - - ls -l /sys/bus/pci/devices/0000:00:19.0/driver - -Which if successful should print - - .../0000:00:19.0/driver -> ../../../bus/pci/drivers/uio_pci_generic - -Note that the generic driver will not bind to old PCI 2.2 devices. -If binding the device failed, run the following command: - - dmesg - -and look in the output for failure reasons - - - - -Things to know about uio_pci_generic - -Interrupts are handled using the Interrupt Disable bit in the PCI command -register and Interrupt Status bit in the PCI status register. All devices -compliant to PCI 2.3 (circa 2002) and all compliant PCI Express devices should -support these bits. uio_pci_generic detects this support, and won't bind to -devices which do not support the Interrupt Disable Bit in the command register. - - -On each interrupt, uio_pci_generic sets the Interrupt Disable bit. -This prevents the device from generating further interrupts -until the bit is cleared. The userspace driver should clear this -bit before blocking and waiting for more interrupts. - - - -Writing userspace driver using uio_pci_generic - -Userspace driver can use pci sysfs interface, or the -libpci libray that wraps it, to talk to the device and to -re-enable interrupts by writing to the command register. - - - -Example code using uio_pci_generic - -Here is some sample userspace driver code using uio_pci_generic: - -#include <stdlib.h> -#include <stdio.h> -#include <unistd.h> -#include <sys/types.h> -#include <sys/stat.h> -#include <fcntl.h> -#include <errno.h> - -int main() -{ - int uiofd; - int configfd; - int err; - int i; - unsigned icount; - unsigned char command_high; - - uiofd = open("/dev/uio0", O_RDONLY); - if (uiofd < 0) { - perror("uio open:"); - return errno; - } - configfd = open("/sys/class/uio/uio0/device/config", O_RDWR); - if (configfd < 0) { - perror("config open:"); - return errno; - } - - /* Read and cache command value */ - err = pread(configfd, &command_high, 1, 5); - if (err != 1) { - perror("command config read:"); - return errno; - } - command_high &= ~0x4; - - for(i = 0;; ++i) { - /* Print out a message, for debugging. */ - if (i == 0) - fprintf(stderr, "Started uio test driver.\n"); - else - fprintf(stderr, "Interrupts: %d\n", icount); - - /****************************************/ - /* Here we got an interrupt from the - device. Do something to it. */ - /****************************************/ - - /* Re-enable interrupts. */ - err = pwrite(configfd, &command_high, 1, 5); - if (err != 1) { - perror("config write:"); - break; - } - - /* Wait for next interrupt. */ - err = read(uiofd, &icount, 4); - if (err != 4) { - perror("uio read:"); - break; - } - - } - return errno; -} - - - - - - - - - -Generic Hyper-V UIO driver - - The generic driver is a kernel module named uio_hv_generic. - It supports devices on the Hyper-V VMBus similar to uio_pci_generic - on PCI bus. - - - -Making the driver recognize the device - -Since the driver does not declare any device GUID's, it will not get loaded -automatically and will not automatically bind to any devices, you must load it -and allocate id to the driver yourself. For example, to use the network device -GUID: - - modprobe uio_hv_generic - echo "f8615163-df3e-46c5-913f-f2d2f965ed0e" > /sys/bus/vmbus/drivers/uio_hv_generic/new_id - - - -If there already is a hardware specific kernel driver for the device, the -generic driver still won't bind to it, in this case if you want to use the -generic driver (why would you?) you'll have to manually unbind the hardware -specific driver and bind the generic driver, like this: - - echo -n vmbus-ed963694-e847-4b2a-85af-bc9cfc11d6f3 > /sys/bus/vmbus/drivers/hv_netvsc/unbind - echo -n vmbus-ed963694-e847-4b2a-85af-bc9cfc11d6f3 > /sys/bus/vmbus/drivers/uio_hv_generic/bind - - - -You can verify that the device has been bound to the driver -by looking for it in sysfs, for example like the following: - - ls -l /sys/bus/vmbus/devices/vmbus-ed963694-e847-4b2a-85af-bc9cfc11d6f3/driver - -Which if successful should print - - .../vmbus-ed963694-e847-4b2a-85af-bc9cfc11d6f3/driver -> ../../../bus/vmbus/drivers/uio_hv_generic - - - - - -Things to know about uio_hv_generic - -On each interrupt, uio_hv_generic sets the Interrupt Disable bit. -This prevents the device from generating further interrupts -until the bit is cleared. The userspace driver should clear this -bit before blocking and waiting for more interrupts. - - - - - -Further information - - - - OSADL homepage. - - - - Linutronix homepage. - - - - - diff --git a/Documentation/driver-api/index.rst b/Documentation/driver-api/index.rst index 5475a2807e7a..c5a1cd0a4ae7 100644 --- a/Documentation/driver-api/index.rst +++ b/Documentation/driver-api/index.rst @@ -30,6 +30,7 @@ available subsections can be seen below. miscellaneous vme 80211/index + uio-howto .. only:: subproject and html diff --git a/Documentation/driver-api/uio-howto.rst b/Documentation/driver-api/uio-howto.rst new file mode 100644 index 000000000000..f73d660b2956 --- /dev/null +++ b/Documentation/driver-api/uio-howto.rst @@ -0,0 +1,705 @@ +======================= +The Userspace I/O HOWTO +======================= + +:Author: Hans-Jürgen Koch Linux developer, Linutronix +:Date: 2006-12-11 + +About this document +=================== + +Translations +------------ + +If you know of any translations for this document, or you are interested +in translating it, please email me hjk@hansjkoch.de. + +Preface +------- + +For many types of devices, creating a Linux kernel driver is overkill. +All that is really needed is some way to handle an interrupt and provide +access to the memory space of the device. The logic of controlling the +device does not necessarily have to be within the kernel, as the device +does not need to take advantage of any of other resources that the +kernel provides. One such common class of devices that are like this are +for industrial I/O cards. + +To address this situation, the userspace I/O system (UIO) was designed. +For typical industrial I/O cards, only a very small kernel module is +needed. The main part of the driver will run in user space. This +simplifies development and reduces the risk of serious bugs within a +kernel module. + +Please note that UIO is not an universal driver interface. Devices that +are already handled well by other kernel subsystems (like networking or +serial or USB) are no candidates for an UIO driver. Hardware that is +ideally suited for an UIO driver fulfills all of the following: + +- The device has memory that can be mapped. The device can be + controlled completely by writing to this memory. + +- The device usually generates interrupts. + +- The device does not fit into one of the standard kernel subsystems. + +Acknowledgments +--------------- + +I'd like to thank Thomas Gleixner and Benedikt Spranger of Linutronix, +who have not only written most of the UIO code, but also helped greatly +writing this HOWTO by giving me all kinds of background information. + +Feedback +-------- + +Find something wrong with this document? (Or perhaps something right?) I +would love to hear from you. Please email me at hjk@hansjkoch.de. + +About UIO +========= + +If you use UIO for your card's driver, here's what you get: + +- only one small kernel module to write and maintain. + +- develop the main part of your driver in user space, with all the + tools and libraries you're used to. + +- bugs in your driver won't crash the kernel. + +- updates of your driver can take place without recompiling the kernel. + +How UIO works +------------- + +Each UIO device is accessed through a device file and several sysfs +attribute files. The device file will be called ``/dev/uio0`` for the +first device, and ``/dev/uio1``, ``/dev/uio2`` and so on for subsequent +devices. + +``/dev/uioX`` is used to access the address space of the card. Just use +:c:func:`mmap()` to access registers or RAM locations of your card. + +Interrupts are handled by reading from ``/dev/uioX``. A blocking +:c:func:`read()` from ``/dev/uioX`` will return as soon as an +interrupt occurs. You can also use :c:func:`select()` on +``/dev/uioX`` to wait for an interrupt. The integer value read from +``/dev/uioX`` represents the total interrupt count. You can use this +number to figure out if you missed some interrupts. + +For some hardware that has more than one interrupt source internally, +but not separate IRQ mask and status registers, there might be +situations where userspace cannot determine what the interrupt source +was if the kernel handler disables them by writing to the chip's IRQ +register. In such a case, the kernel has to disable the IRQ completely +to leave the chip's register untouched. Now the userspace part can +determine the cause of the interrupt, but it cannot re-enable +interrupts. Another cornercase is chips where re-enabling interrupts is +a read-modify-write operation to a combined IRQ status/acknowledge +register. This would be racy if a new interrupt occurred simultaneously. + +To address these problems, UIO also implements a write() function. It is +normally not used and can be ignored for hardware that has only a single +interrupt source or has separate IRQ mask and status registers. If you +need it, however, a write to ``/dev/uioX`` will call the +:c:func:`irqcontrol()` function implemented by the driver. You have +to write a 32-bit value that is usually either 0 or 1 to disable or +enable interrupts. If a driver does not implement +:c:func:`irqcontrol()`, :c:func:`write()` will return with +``-ENOSYS``. + +To handle interrupts properly, your custom kernel module can provide its +own interrupt handler. It will automatically be called by the built-in +handler. + +For cards that don't generate interrupts but need to be polled, there is +the possibility to set up a timer that triggers the interrupt handler at +configurable time intervals. This interrupt simulation is done by +calling :c:func:`uio_event_notify()` from the timer's event +handler. + +Each driver provides attributes that are used to read or write +variables. These attributes are accessible through sysfs files. A custom +kernel driver module can add its own attributes to the device owned by +the uio driver, but not added to the UIO device itself at this time. +This might change in the future if it would be found to be useful. + +The following standard attributes are provided by the UIO framework: + +- ``name``: The name of your device. It is recommended to use the name + of your kernel module for this. + +- ``version``: A version string defined by your driver. This allows the + user space part of your driver to deal with different versions of the + kernel module. + +- ``event``: The total number of interrupts handled by the driver since + the last time the device node was read. + +These attributes appear under the ``/sys/class/uio/uioX`` directory. +Please note that this directory might be a symlink, and not a real +directory. Any userspace code that accesses it must be able to handle +this. + +Each UIO device can make one or more memory regions available for memory +mapping. This is necessary because some industrial I/O cards require +access to more than one PCI memory region in a driver. + +Each mapping has its own directory in sysfs, the first mapping appears +as ``/sys/class/uio/uioX/maps/map0/``. Subsequent mappings create +directories ``map1/``, ``map2/``, and so on. These directories will only +appear if the size of the mapping is not 0. + +Each ``mapX/`` directory contains four read-only files that show +attributes of the memory: + +- ``name``: A string identifier for this mapping. This is optional, the + string can be empty. Drivers can set this to make it easier for + userspace to find the correct mapping. + +- ``addr``: The address of memory that can be mapped. + +- ``size``: The size, in bytes, of the memory pointed to by addr. + +- ``offset``: The offset, in bytes, that has to be added to the pointer + returned by :c:func:`mmap()` to get to the actual device memory. + This is important if the device's memory is not page aligned. + Remember that pointers returned by :c:func:`mmap()` are always + page aligned, so it is good style to always add this offset. + +From userspace, the different mappings are distinguished by adjusting +the ``offset`` parameter of the :c:func:`mmap()` call. To map the +memory of mapping N, you have to use N times the page size as your +offset:: + + offset = N * getpagesize(); + +Sometimes there is hardware with memory-like regions that can not be +mapped with the technique described here, but there are still ways to +access them from userspace. The most common example are x86 ioports. On +x86 systems, userspace can access these ioports using +:c:func:`ioperm()`, :c:func:`iopl()`, :c:func:`inb()`, +:c:func:`outb()`, and similar functions. + +Since these ioport regions can not be mapped, they will not appear under +``/sys/class/uio/uioX/maps/`` like the normal memory described above. +Without information about the port regions a hardware has to offer, it +becomes difficult for the userspace part of the driver to find out which +ports belong to which UIO device. + +To address this situation, the new directory +``/sys/class/uio/uioX/portio/`` was added. It only exists if the driver +wants to pass information about one or more port regions to userspace. +If that is the case, subdirectories named ``port0``, ``port1``, and so +on, will appear underneath ``/sys/class/uio/uioX/portio/``. + +Each ``portX/`` directory contains four read-only files that show name, +start, size, and type of the port region: + +- ``name``: A string identifier for this port region. The string is + optional and can be empty. Drivers can set it to make it easier for + userspace to find a certain port region. + +- ``start``: The first port of this region. + +- ``size``: The number of ports in this region. + +- ``porttype``: A string describing the type of port. + +Writing your own kernel module +============================== + +Please have a look at ``uio_cif.c`` as an example. The following +paragraphs explain the different sections of this file. + +struct uio_info +--------------- + +This structure tells the framework the details of your driver, Some of +the members are required, others are optional. + +- ``const char *name``: Required. The name of your driver as it will + appear in sysfs. I recommend using the name of your module for this. + +- ``const char *version``: Required. This string appears in + ``/sys/class/uio/uioX/version``. + +- ``struct uio_mem mem[ MAX_UIO_MAPS ]``: Required if you have memory + that can be mapped with :c:func:`mmap()`. For each mapping you + need to fill one of the ``uio_mem`` structures. See the description + below for details. + +- ``struct uio_port port[ MAX_UIO_PORTS_REGIONS ]``: Required if you + want to pass information about ioports to userspace. For each port + region you need to fill one of the ``uio_port`` structures. See the + description below for details. + +- ``long irq``: Required. If your hardware generates an interrupt, it's + your modules task to determine the irq number during initialization. + If you don't have a hardware generated interrupt but want to trigger + the interrupt handler in some other way, set ``irq`` to + ``UIO_IRQ_CUSTOM``. If you had no interrupt at all, you could set + ``irq`` to ``UIO_IRQ_NONE``, though this rarely makes sense. + +- ``unsigned long irq_flags``: Required if you've set ``irq`` to a + hardware interrupt number. The flags given here will be used in the + call to :c:func:`request_irq()`. + +- ``int (*mmap)(struct uio_info *info, struct vm_area_struct *vma)``: + Optional. If you need a special :c:func:`mmap()` + function, you can set it here. If this pointer is not NULL, your + :c:func:`mmap()` will be called instead of the built-in one. + +- ``int (*open)(struct uio_info *info, struct inode *inode)``: + Optional. You might want to have your own :c:func:`open()`, + e.g. to enable interrupts only when your device is actually used. + +- ``int (*release)(struct uio_info *info, struct inode *inode)``: + Optional. If you define your own :c:func:`open()`, you will + probably also want a custom :c:func:`release()` function. + +- ``int (*irqcontrol)(struct uio_info *info, s32 irq_on)``: + Optional. If you need to be able to enable or disable interrupts + from userspace by writing to ``/dev/uioX``, you can implement this + function. The parameter ``irq_on`` will be 0 to disable interrupts + and 1 to enable them. + +Usually, your device will have one or more memory regions that can be +mapped to user space. For each region, you have to set up a +``struct uio_mem`` in the ``mem[]`` array. Here's a description of the +fields of ``struct uio_mem``: + +- ``const char *name``: Optional. Set this to help identify the memory + region, it will show up in the corresponding sysfs node. + +- ``int memtype``: Required if the mapping is used. Set this to + ``UIO_MEM_PHYS`` if you you have physical memory on your card to be + mapped. Use ``UIO_MEM_LOGICAL`` for logical memory (e.g. allocated + with :c:func:`kmalloc()`). There's also ``UIO_MEM_VIRTUAL`` for + virtual memory. + +- ``phys_addr_t addr``: Required if the mapping is used. Fill in the + address of your memory block. This address is the one that appears in + sysfs. + +- ``resource_size_t size``: Fill in the size of the memory block that + ``addr`` points to. If ``size`` is zero, the mapping is considered + unused. Note that you *must* initialize ``size`` with zero for all + unused mappings. + +- ``void *internal_addr``: If you have to access this memory region + from within your kernel module, you will want to map it internally by + using something like :c:func:`ioremap()`. Addresses returned by + this function cannot be mapped to user space, so you must not store + it in ``addr``. Use ``internal_addr`` instead to remember such an + address. + +Please do not touch the ``map`` element of ``struct uio_mem``! It is +used by the UIO framework to set up sysfs files for this mapping. Simply +leave it alone. + +Sometimes, your device can have one or more port regions which can not +be mapped to userspace. But if there are other possibilities for +userspace to access these ports, it makes sense to make information +about the ports available in sysfs. For each region, you have to set up +a ``struct uio_port`` in the ``port[]`` array. Here's a description of +the fields of ``struct uio_port``: + +- ``char *porttype``: Required. Set this to one of the predefined + constants. Use ``UIO_PORT_X86`` for the ioports found in x86 + architectures. + +- ``unsigned long start``: Required if the port region is used. Fill in + the number of the first port of this region. + +- ``unsigned long size``: Fill in the number of ports in this region. + If ``size`` is zero, the region is considered unused. Note that you + *must* initialize ``size`` with zero for all unused regions. + +Please do not touch the ``portio`` element of ``struct uio_port``! It is +used internally by the UIO framework to set up sysfs files for this +region. Simply leave it alone. + +Adding an interrupt handler +--------------------------- + +What you need to do in your interrupt handler depends on your hardware +and on how you want to handle it. You should try to keep the amount of +code in your kernel interrupt handler low. If your hardware requires no +action that you *have* to perform after each interrupt, then your +handler can be empty. + +If, on the other hand, your hardware *needs* some action to be performed +after each interrupt, then you *must* do it in your kernel module. Note +that you cannot rely on the userspace part of your driver. Your +userspace program can terminate at any time, possibly leaving your +hardware in a state where proper interrupt handling is still required. + +There might also be applications where you want to read data from your +hardware at each interrupt and buffer it in a piece of kernel memory +you've allocated for that purpose. With this technique you could avoid +loss of data if your userspace program misses an interrupt. + +A note on shared interrupts: Your driver should support interrupt +sharing whenever this is possible. It is possible if and only if your +driver can detect whether your hardware has triggered the interrupt or +not. This is usually done by looking at an interrupt status register. If +your driver sees that the IRQ bit is actually set, it will perform its +actions, and the handler returns IRQ_HANDLED. If the driver detects +that it was not your hardware that caused the interrupt, it will do +nothing and return IRQ_NONE, allowing the kernel to call the next +possible interrupt handler. + +If you decide not to support shared interrupts, your card won't work in +computers with no free interrupts. As this frequently happens on the PC +platform, you can save yourself a lot of trouble by supporting interrupt +sharing. + +Using uio_pdrv for platform devices +----------------------------------- + +In many cases, UIO drivers for platform devices can be handled in a +generic way. In the same place where you define your +``struct platform_device``, you simply also implement your interrupt +handler and fill your ``struct uio_info``. A pointer to this +``struct uio_info`` is then used as ``platform_data`` for your platform +device. + +You also need to set up an array of ``struct resource`` containing +addresses and sizes of your memory mappings. This information is passed +to the driver using the ``.resource`` and ``.num_resources`` elements of +``struct platform_device``. + +You now have to set the ``.name`` element of ``struct platform_device`` +to ``"uio_pdrv"`` to use the generic UIO platform device driver. This +driver will fill the ``mem[]`` array according to the resources given, +and register the device. + +The advantage of this approach is that you only have to edit a file you +need to edit anyway. You do not have to create an extra driver. + +Using uio_pdrv_genirq for platform devices +------------------------------------------ + +Especially in embedded devices, you frequently find chips where the irq +pin is tied to its own dedicated interrupt line. In such cases, where +you can be really sure the interrupt is not shared, we can take the +concept of ``uio_pdrv`` one step further and use a generic interrupt +handler. That's what ``uio_pdrv_genirq`` does. + +The setup for this driver is the same as described above for +``uio_pdrv``, except that you do not implement an interrupt handler. The +``.handler`` element of ``struct uio_info`` must remain ``NULL``. The +``.irq_flags`` element must not contain ``IRQF_SHARED``. + +You will set the ``.name`` element of ``struct platform_device`` to +``"uio_pdrv_genirq"`` to use this driver. + +The generic interrupt handler of ``uio_pdrv_genirq`` will simply disable +the interrupt line using :c:func:`disable_irq_nosync()`. After +doing its work, userspace can reenable the interrupt by writing +0x00000001 to the UIO device file. The driver already implements an +:c:func:`irq_control()` to make this possible, you must not +implement your own. + +Using ``uio_pdrv_genirq`` not only saves a few lines of interrupt +handler code. You also do not need to know anything about the chip's +internal registers to create the kernel part of the driver. All you need +to know is the irq number of the pin the chip is connected to. + +Using uio_dmem_genirq for platform devices +------------------------------------------ + +In addition to statically allocated memory ranges, they may also be a +desire to use dynamically allocated regions in a user space driver. In +particular, being able to access memory made available through the +dma-mapping API, may be particularly useful. The ``uio_dmem_genirq`` +driver provides a way to accomplish this. + +This driver is used in a similar manner to the ``"uio_pdrv_genirq"`` +driver with respect to interrupt configuration and handling. + +Set the ``.name`` element of ``struct platform_device`` to +``"uio_dmem_genirq"`` to use this driver. + +When using this driver, fill in the ``.platform_data`` element of +``struct platform_device``, which is of type +``struct uio_dmem_genirq_pdata`` and which contains the following +elements: + +- ``struct uio_info uioinfo``: The same structure used as the + ``uio_pdrv_genirq`` platform data + +- ``unsigned int *dynamic_region_sizes``: Pointer to list of sizes of + dynamic memory regions to be mapped into user space. + +- ``unsigned int num_dynamic_regions``: Number of elements in + ``dynamic_region_sizes`` array. + +The dynamic regions defined in the platform data will be appended to the +`` mem[] `` array after the platform device resources, which implies +that the total number of static and dynamic memory regions cannot exceed +``MAX_UIO_MAPS``. + +The dynamic memory regions will be allocated when the UIO device file, +``/dev/uioX`` is opened. Similar to static memory resources, the memory +region information for dynamic regions is then visible via sysfs at +``/sys/class/uio/uioX/maps/mapY/*``. The dynamic memory regions will be +freed when the UIO device file is closed. When no processes are holding +the device file open, the address returned to userspace is ~0. + +Writing a driver in userspace +============================= + +Once you have a working kernel module for your hardware, you can write +the userspace part of your driver. You don't need any special libraries, +your driver can be written in any reasonable language, you can use +floating point numbers and so on. In short, you can use all the tools +and libraries you'd normally use for writing a userspace application. + +Getting information about your UIO device +----------------------------------------- + +Information about all UIO devices is available in sysfs. The first thing +you should do in your driver is check ``name`` and ``version`` to make +sure your talking to the right device and that its kernel driver has the +version you expect. + +You should also make sure that the memory mapping you need exists and +has the size you expect. + +There is a tool called ``lsuio`` that lists UIO devices and their +attributes. It is available here: + +http://www.osadl.org/projects/downloads/UIO/user/ + +With ``lsuio`` you can quickly check if your kernel module is loaded and +which attributes it exports. Have a look at the manpage for details. + +The source code of ``lsuio`` can serve as an example for getting +information about an UIO device. The file ``uio_helper.c`` contains a +lot of functions you could use in your userspace driver code. + +mmap() device memory +-------------------- + +After you made sure you've got the right device with the memory mappings +you need, all you have to do is to call :c:func:`mmap()` to map the +device's memory to userspace. + +The parameter ``offset`` of the :c:func:`mmap()` call has a special +meaning for UIO devices: It is used to select which mapping of your +device you want to map. To map the memory of mapping N, you have to use +N times the page size as your offset:: + + offset = N * getpagesize(); + +N starts from zero, so if you've got only one memory range to map, set +``offset = 0``. A drawback of this technique is that memory is always +mapped beginning with its start address. + +Waiting for interrupts +---------------------- + +After you successfully mapped your devices memory, you can access it +like an ordinary array. Usually, you will perform some initialization. +After that, your hardware starts working and will generate an interrupt +as soon as it's finished, has some data available, or needs your +attention because an error occurred. + +``/dev/uioX`` is a read-only file. A :c:func:`read()` will always +block until an interrupt occurs. There is only one legal value for the +``count`` parameter of :c:func:`read()`, and that is the size of a +signed 32 bit integer (4). Any other value for ``count`` causes +:c:func:`read()` to fail. The signed 32 bit integer read is the +interrupt count of your device. If the value is one more than the value +you read the last time, everything is OK. If the difference is greater +than one, you missed interrupts. + +You can also use :c:func:`select()` on ``/dev/uioX``. + +Generic PCI UIO driver +====================== + +The generic driver is a kernel module named uio_pci_generic. It can +work with any device compliant to PCI 2.3 (circa 2002) and any compliant +PCI Express device. Using this, you only need to write the userspace +driver, removing the need to write a hardware-specific kernel module. + +Making the driver recognize the device +-------------------------------------- + +Since the driver does not declare any device ids, it will not get loaded +automatically and will not automatically bind to any devices, you must +load it and allocate id to the driver yourself. For example:: + + modprobe uio_pci_generic + echo "8086 10f5" > /sys/bus/pci/drivers/uio_pci_generic/new_id + +If there already is a hardware specific kernel driver for your device, +the generic driver still won't bind to it, in this case if you want to +use the generic driver (why would you?) you'll have to manually unbind +the hardware specific driver and bind the generic driver, like this:: + + echo -n 0000:00:19.0 > /sys/bus/pci/drivers/e1000e/unbind + echo -n 0000:00:19.0 > /sys/bus/pci/drivers/uio_pci_generic/bind + +You can verify that the device has been bound to the driver by looking +for it in sysfs, for example like the following:: + + ls -l /sys/bus/pci/devices/0000:00:19.0/driver + +Which if successful should print:: + + .../0000:00:19.0/driver -> ../../../bus/pci/drivers/uio_pci_generic + +Note that the generic driver will not bind to old PCI 2.2 devices. If +binding the device failed, run the following command:: + + dmesg + +and look in the output for failure reasons. + +Things to know about uio_pci_generic +------------------------------------ + +Interrupts are handled using the Interrupt Disable bit in the PCI +command register and Interrupt Status bit in the PCI status register. +All devices compliant to PCI 2.3 (circa 2002) and all compliant PCI +Express devices should support these bits. uio_pci_generic detects +this support, and won't bind to devices which do not support the +Interrupt Disable Bit in the command register. + +On each interrupt, uio_pci_generic sets the Interrupt Disable bit. +This prevents the device from generating further interrupts until the +bit is cleared. The userspace driver should clear this bit before +blocking and waiting for more interrupts. + +Writing userspace driver using uio_pci_generic +------------------------------------------------ + +Userspace driver can use pci sysfs interface, or the libpci library that +wraps it, to talk to the device and to re-enable interrupts by writing +to the command register. + +Example code using uio_pci_generic +---------------------------------- + +Here is some sample userspace driver code using uio_pci_generic:: + + #include + #include + #include + #include + #include + #include + #include + + int main() + { + int uiofd; + int configfd; + int err; + int i; + unsigned icount; + unsigned char command_high; + + uiofd = open("/dev/uio0", O_RDONLY); + if (uiofd < 0) { + perror("uio open:"); + return errno; + } + configfd = open("/sys/class/uio/uio0/device/config", O_RDWR); + if (configfd < 0) { + perror("config open:"); + return errno; + } + + /* Read and cache command value */ + err = pread(configfd, &command_high, 1, 5); + if (err != 1) { + perror("command config read:"); + return errno; + } + command_high &= ~0x4; + + for(i = 0;; ++i) { + /* Print out a message, for debugging. */ + if (i == 0) + fprintf(stderr, "Started uio test driver.\n"); + else + fprintf(stderr, "Interrupts: %d\n", icount); + + /****************************************/ + /* Here we got an interrupt from the + device. Do something to it. */ + /****************************************/ + + /* Re-enable interrupts. */ + err = pwrite(configfd, &command_high, 1, 5); + if (err != 1) { + perror("config write:"); + break; + } + + /* Wait for next interrupt. */ + err = read(uiofd, &icount, 4); + if (err != 4) { + perror("uio read:"); + break; + } + + } + return errno; + } + +Generic Hyper-V UIO driver +========================== + +The generic driver is a kernel module named uio_hv_generic. It +supports devices on the Hyper-V VMBus similar to uio_pci_generic on +PCI bus. + +Making the driver recognize the device +-------------------------------------- + +Since the driver does not declare any device GUID's, it will not get +loaded automatically and will not automatically bind to any devices, you +must load it and allocate id to the driver yourself. For example, to use +the network device GUID:: + + modprobe uio_hv_generic + echo "f8615163-df3e-46c5-913f-f2d2f965ed0e" > /sys/bus/vmbus/drivers/uio_hv_generic/new_id + +If there already is a hardware specific kernel driver for the device, +the generic driver still won't bind to it, in this case if you want to +use the generic driver (why would you?) you'll have to manually unbind +the hardware specific driver and bind the generic driver, like this:: + + echo -n vmbus-ed963694-e847-4b2a-85af-bc9cfc11d6f3 > /sys/bus/vmbus/drivers/hv_netvsc/unbind + echo -n vmbus-ed963694-e847-4b2a-85af-bc9cfc11d6f3 > /sys/bus/vmbus/drivers/uio_hv_generic/bind + +You can verify that the device has been bound to the driver by looking +for it in sysfs, for example like the following:: + + ls -l /sys/bus/vmbus/devices/vmbus-ed963694-e847-4b2a-85af-bc9cfc11d6f3/driver + +Which if successful should print:: + + .../vmbus-ed963694-e847-4b2a-85af-bc9cfc11d6f3/driver -> ../../../bus/vmbus/drivers/uio_hv_generic + +Things to know about uio_hv_generic +----------------------------------- + +On each interrupt, uio_hv_generic sets the Interrupt Disable bit. This +prevents the device from generating further interrupts until the bit is +cleared. The userspace driver should clear this bit before blocking and +waiting for more interrupts. + +Further information +=================== + +- `OSADL homepage. `_ + +- `Linutronix homepage. `_ diff --git a/MAINTAINERS b/MAINTAINERS index be8de24fd6dd..6f6efd2e706a 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -12966,7 +12966,7 @@ USERSPACE I/O (UIO) M: Greg Kroah-Hartman S: Maintained T: git git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git -F: Documentation/DocBook/uio-howto.tmpl +F: Documentation/driver-api/uio-howto.rst F: drivers/uio/ F: include/linux/uio*.h -- cgit v1.2.3 From baa6d396635129d8a67793e884f3b2182c7354b3 Mon Sep 17 00:00:00 2001 From: Jason Gunthorpe Date: Wed, 1 Feb 2017 12:48:44 -0700 Subject: fpga: Add scatterlist based programming Requiring contiguous kernel memory is not a good idea, this is a limited resource and allocation can fail under normal work loads. This introduces a .write_sg op that supporting drivers can provide to DMA directly from dis-contiguous memory and a new entry point fpga_mgr_buf_load_sg that users can call to directly provide page lists. The full matrix of compatibility is provided, either the linear or sg interface can be used by the user with a driver supporting either interface. A notable change for drivers is that the .write op can now be called multiple times. Signed-off-by: Jason Gunthorpe Acked-by: Alan Tull Acked-by: Moritz Fischer Signed-off-by: Greg Kroah-Hartman --- Documentation/fpga/fpga-mgr.txt | 19 +++- drivers/fpga/fpga-mgr.c | 236 +++++++++++++++++++++++++++++++++++----- include/linux/fpga/fpga-mgr.h | 5 + 3 files changed, 227 insertions(+), 33 deletions(-) (limited to 'Documentation') diff --git a/Documentation/fpga/fpga-mgr.txt b/Documentation/fpga/fpga-mgr.txt index 86ee5078fd03..78f197fadfd1 100644 --- a/Documentation/fpga/fpga-mgr.txt +++ b/Documentation/fpga/fpga-mgr.txt @@ -22,7 +22,16 @@ To program the FPGA from a file or from a buffer: struct fpga_image_info *info, const char *buf, size_t count); -Load the FPGA from an image which exists as a buffer in memory. +Load the FPGA from an image which exists as a contiguous buffer in +memory. Allocating contiguous kernel memory for the buffer should be avoided, +users are encouraged to use the _sg interface instead of this. + + int fpga_mgr_buf_load_sg(struct fpga_manager *mgr, + struct fpga_image_info *info, + struct sg_table *sgt); + +Load the FPGA from an image from non-contiguous in memory. Callers can +construct a sg_table using alloc_page backed memory. int fpga_mgr_firmware_load(struct fpga_manager *mgr, struct fpga_image_info *info, @@ -166,7 +175,7 @@ success or negative error codes otherwise. The programming sequence is: 1. .write_init - 2. .write (may be called once or multiple times) + 2. .write or .write_sg (may be called once or multiple times) 3. .write_complete The .write_init function will prepare the FPGA to receive the image data. The @@ -176,7 +185,11 @@ buffer up at least this much before starting. The .write function writes a buffer to the FPGA. The buffer may be contain the whole FPGA image or may be a smaller chunk of an FPGA image. In the latter -case, this function is called multiple times for successive chunks. +case, this function is called multiple times for successive chunks. This interface +is suitable for drivers which use PIO. + +The .write_sg version behaves the same as .write except the input is a sg_table +scatter list. This interface is suitable for drivers which use DMA. The .write_complete function is called after all the image has been written to put the FPGA into operating mode. diff --git a/drivers/fpga/fpga-mgr.c b/drivers/fpga/fpga-mgr.c index f0a69d3e60a5..86d2cb203533 100644 --- a/drivers/fpga/fpga-mgr.c +++ b/drivers/fpga/fpga-mgr.c @@ -25,16 +25,106 @@ #include #include #include +#include +#include static DEFINE_IDA(fpga_mgr_ida); static struct class *fpga_mgr_class; +/* + * Call the low level driver's write_init function. This will do the + * device-specific things to get the FPGA into the state where it is ready to + * receive an FPGA image. The low level driver only gets to see the first + * initial_header_size bytes in the buffer. + */ +static int fpga_mgr_write_init_buf(struct fpga_manager *mgr, + struct fpga_image_info *info, + const char *buf, size_t count) +{ + int ret; + + mgr->state = FPGA_MGR_STATE_WRITE_INIT; + if (!mgr->mops->initial_header_size) + ret = mgr->mops->write_init(mgr, info, NULL, 0); + else + ret = mgr->mops->write_init( + mgr, info, buf, min(mgr->mops->initial_header_size, count)); + + if (ret) { + dev_err(&mgr->dev, "Error preparing FPGA for writing\n"); + mgr->state = FPGA_MGR_STATE_WRITE_INIT_ERR; + return ret; + } + + return 0; +} + +static int fpga_mgr_write_init_sg(struct fpga_manager *mgr, + struct fpga_image_info *info, + struct sg_table *sgt) +{ + struct sg_mapping_iter miter; + size_t len; + char *buf; + int ret; + + if (!mgr->mops->initial_header_size) + return fpga_mgr_write_init_buf(mgr, info, NULL, 0); + + /* + * First try to use miter to map the first fragment to access the + * header, this is the typical path. + */ + sg_miter_start(&miter, sgt->sgl, sgt->nents, SG_MITER_FROM_SG); + if (sg_miter_next(&miter) && + miter.length >= mgr->mops->initial_header_size) { + ret = fpga_mgr_write_init_buf(mgr, info, miter.addr, + miter.length); + sg_miter_stop(&miter); + return ret; + } + sg_miter_stop(&miter); + + /* Otherwise copy the fragments into temporary memory. */ + buf = kmalloc(mgr->mops->initial_header_size, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + len = sg_copy_to_buffer(sgt->sgl, sgt->nents, buf, + mgr->mops->initial_header_size); + ret = fpga_mgr_write_init_buf(mgr, info, buf, len); + + kfree(buf); + + return ret; +} + +/* + * After all the FPGA image has been written, do the device specific steps to + * finish and set the FPGA into operating mode. + */ +static int fpga_mgr_write_complete(struct fpga_manager *mgr, + struct fpga_image_info *info) +{ + int ret; + + mgr->state = FPGA_MGR_STATE_WRITE_COMPLETE; + ret = mgr->mops->write_complete(mgr, info); + if (ret) { + dev_err(&mgr->dev, "Error after writing image data to FPGA\n"); + mgr->state = FPGA_MGR_STATE_WRITE_COMPLETE_ERR; + return ret; + } + mgr->state = FPGA_MGR_STATE_OPERATING; + + return 0; +} + /** - * fpga_mgr_buf_load - load fpga from image in buffer + * fpga_mgr_buf_load_sg - load fpga from image in buffer from a scatter list * @mgr: fpga manager * @info: fpga image specific information - * @buf: buffer contain fpga image - * @count: byte count of buf + * @sgt: scatterlist table * * Step the low level fpga manager through the device-specific steps of getting * an FPGA ready to be configured, writing the image to it, then doing whatever @@ -42,54 +132,139 @@ static struct class *fpga_mgr_class; * mgr pointer from of_fpga_mgr_get() or fpga_mgr_get() and checked that it is * not an error code. * + * This is the preferred entry point for FPGA programming, it does not require + * any contiguous kernel memory. + * * Return: 0 on success, negative error code otherwise. */ -int fpga_mgr_buf_load(struct fpga_manager *mgr, struct fpga_image_info *info, - const char *buf, size_t count) +int fpga_mgr_buf_load_sg(struct fpga_manager *mgr, struct fpga_image_info *info, + struct sg_table *sgt) { - struct device *dev = &mgr->dev; int ret; - /* - * Call the low level driver's write_init function. This will do the - * device-specific things to get the FPGA into the state where it is - * ready to receive an FPGA image. The low level driver only gets to - * see the first initial_header_size bytes in the buffer. - */ - mgr->state = FPGA_MGR_STATE_WRITE_INIT; - ret = mgr->mops->write_init(mgr, info, buf, - min(mgr->mops->initial_header_size, count)); + ret = fpga_mgr_write_init_sg(mgr, info, sgt); + if (ret) + return ret; + + /* Write the FPGA image to the FPGA. */ + mgr->state = FPGA_MGR_STATE_WRITE; + if (mgr->mops->write_sg) { + ret = mgr->mops->write_sg(mgr, sgt); + } else { + struct sg_mapping_iter miter; + + sg_miter_start(&miter, sgt->sgl, sgt->nents, SG_MITER_FROM_SG); + while (sg_miter_next(&miter)) { + ret = mgr->mops->write(mgr, miter.addr, miter.length); + if (ret) + break; + } + sg_miter_stop(&miter); + } + if (ret) { - dev_err(dev, "Error preparing FPGA for writing\n"); - mgr->state = FPGA_MGR_STATE_WRITE_INIT_ERR; + dev_err(&mgr->dev, "Error while writing image data to FPGA\n"); + mgr->state = FPGA_MGR_STATE_WRITE_ERR; return ret; } + return fpga_mgr_write_complete(mgr, info); +} +EXPORT_SYMBOL_GPL(fpga_mgr_buf_load_sg); + +static int fpga_mgr_buf_load_mapped(struct fpga_manager *mgr, + struct fpga_image_info *info, + const char *buf, size_t count) +{ + int ret; + + ret = fpga_mgr_write_init_buf(mgr, info, buf, count); + if (ret) + return ret; + /* * Write the FPGA image to the FPGA. */ mgr->state = FPGA_MGR_STATE_WRITE; ret = mgr->mops->write(mgr, buf, count); if (ret) { - dev_err(dev, "Error while writing image data to FPGA\n"); + dev_err(&mgr->dev, "Error while writing image data to FPGA\n"); mgr->state = FPGA_MGR_STATE_WRITE_ERR; return ret; } + return fpga_mgr_write_complete(mgr, info); +} + +/** + * fpga_mgr_buf_load - load fpga from image in buffer + * @mgr: fpga manager + * @flags: flags setting fpga confuration modes + * @buf: buffer contain fpga image + * @count: byte count of buf + * + * Step the low level fpga manager through the device-specific steps of getting + * an FPGA ready to be configured, writing the image to it, then doing whatever + * post-configuration steps necessary. This code assumes the caller got the + * mgr pointer from of_fpga_mgr_get() and checked that it is not an error code. + * + * Return: 0 on success, negative error code otherwise. + */ +int fpga_mgr_buf_load(struct fpga_manager *mgr, struct fpga_image_info *info, + const char *buf, size_t count) +{ + struct page **pages; + struct sg_table sgt; + const void *p; + int nr_pages; + int index; + int rc; + /* - * After all the FPGA image has been written, do the device specific - * steps to finish and set the FPGA into operating mode. + * This is just a fast path if the caller has already created a + * contiguous kernel buffer and the driver doesn't require SG, non-SG + * drivers will still work on the slow path. */ - mgr->state = FPGA_MGR_STATE_WRITE_COMPLETE; - ret = mgr->mops->write_complete(mgr, info); - if (ret) { - dev_err(dev, "Error after writing image data to FPGA\n"); - mgr->state = FPGA_MGR_STATE_WRITE_COMPLETE_ERR; - return ret; + if (mgr->mops->write) + return fpga_mgr_buf_load_mapped(mgr, info, buf, count); + + /* + * Convert the linear kernel pointer into a sg_table of pages for use + * by the driver. + */ + nr_pages = DIV_ROUND_UP((unsigned long)buf + count, PAGE_SIZE) - + (unsigned long)buf / PAGE_SIZE; + pages = kmalloc_array(nr_pages, sizeof(struct page *), GFP_KERNEL); + if (!pages) + return -ENOMEM; + + p = buf - offset_in_page(buf); + for (index = 0; index < nr_pages; index++) { + if (is_vmalloc_addr(p)) + pages[index] = vmalloc_to_page(p); + else + pages[index] = kmap_to_page((void *)p); + if (!pages[index]) { + kfree(pages); + return -EFAULT; + } + p += PAGE_SIZE; } - mgr->state = FPGA_MGR_STATE_OPERATING; - return 0; + /* + * The temporary pages list is used to code share the merging algorithm + * in sg_alloc_table_from_pages + */ + rc = sg_alloc_table_from_pages(&sgt, pages, index, offset_in_page(buf), + count, GFP_KERNEL); + kfree(pages); + if (rc) + return rc; + + rc = fpga_mgr_buf_load_sg(mgr, info, &sgt); + sg_free_table(&sgt); + + return rc; } EXPORT_SYMBOL_GPL(fpga_mgr_buf_load); @@ -291,8 +466,9 @@ int fpga_mgr_register(struct device *dev, const char *name, struct fpga_manager *mgr; int id, ret; - if (!mops || !mops->write_init || !mops->write || - !mops->write_complete || !mops->state) { + if (!mops || !mops->write_complete || !mops->state || + !mops->write_init || (!mops->write && !mops->write_sg) || + (mops->write && mops->write_sg)) { dev_err(dev, "Attempt to register without fpga_manager_ops\n"); return -EINVAL; } diff --git a/include/linux/fpga/fpga-mgr.h b/include/linux/fpga/fpga-mgr.h index 16551d5eac36..57beb5d09bfc 100644 --- a/include/linux/fpga/fpga-mgr.h +++ b/include/linux/fpga/fpga-mgr.h @@ -22,6 +22,7 @@ #define _LINUX_FPGA_MGR_H struct fpga_manager; +struct sg_table; /** * enum fpga_mgr_states - fpga framework states @@ -88,6 +89,7 @@ struct fpga_image_info { * @state: returns an enum value of the FPGA's state * @write_init: prepare the FPGA to receive confuration data * @write: write count bytes of configuration data to the FPGA + * @write_sg: write the scatter list of configuration data to the FPGA * @write_complete: set FPGA to operating state after writing is done * @fpga_remove: optional: Set FPGA into a specific state during driver remove * @@ -102,6 +104,7 @@ struct fpga_manager_ops { struct fpga_image_info *info, const char *buf, size_t count); int (*write)(struct fpga_manager *mgr, const char *buf, size_t count); + int (*write_sg)(struct fpga_manager *mgr, struct sg_table *sgt); int (*write_complete)(struct fpga_manager *mgr, struct fpga_image_info *info); void (*fpga_remove)(struct fpga_manager *mgr); @@ -129,6 +132,8 @@ struct fpga_manager { int fpga_mgr_buf_load(struct fpga_manager *mgr, struct fpga_image_info *info, const char *buf, size_t count); +int fpga_mgr_buf_load_sg(struct fpga_manager *mgr, struct fpga_image_info *info, + struct sg_table *sgt); int fpga_mgr_firmware_load(struct fpga_manager *mgr, struct fpga_image_info *info, -- cgit v1.2.3 From 47512cfd0d7a8bd6ab71d01cd89fca19eb2093eb Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 15 Feb 2017 11:11:50 +0100 Subject: x86/platform/goldfish: Prevent unconditional loading The goldfish platform code registers the platform device unconditionally which causes havoc in several ways if the goldfish_pdev_bus driver is enabled: - Access to the hardcoded physical memory region, which is either not available or contains stuff which is completely unrelated. - Prevents that the interrupt of the serial port can be requested - In case of a spurious interrupt it goes into a infinite loop in the interrupt handler of the pdev_bus driver (which needs to be fixed seperately). Add a 'goldfish' command line option to make the registration opt-in when the platform is compiled in. I'm seriously grumpy about this engineering trainwreck, which has seven SOBs from Intel developers for 50 lines of code. And none of them figured out that this is broken. Impressive fail! Fixes: ddd70cf93d78 ("goldfish: platform device for x86") Reported-by: Gabriel C Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org Acked-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- Documentation/admin-guide/kernel-parameters.txt | 4 ++++ arch/x86/platform/goldfish/goldfish.c | 14 +++++++++++++- 2 files changed, 17 insertions(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index be7c0d9506b1..18eefa860f76 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1201,6 +1201,10 @@ When zero, profiling data is discarded and associated debugfs files are removed at module unload time. + goldfish [X86] Enable the goldfish android emulator platform. + Don't use this when you are not running on the + android emulator + gpt [EFI] Forces disk with valid GPT signature but invalid Protective MBR to be treated as GPT. If the primary GPT is corrupted, it enables the backup/alternate diff --git a/arch/x86/platform/goldfish/goldfish.c b/arch/x86/platform/goldfish/goldfish.c index 1693107a518e..0d17c0aafeb1 100644 --- a/arch/x86/platform/goldfish/goldfish.c +++ b/arch/x86/platform/goldfish/goldfish.c @@ -42,10 +42,22 @@ static struct resource goldfish_pdev_bus_resources[] = { } }; +static bool goldfish_enable __initdata; + +static int __init goldfish_setup(char *str) +{ + goldfish_enable = true; + return 0; +} +__setup("goldfish", goldfish_setup); + static int __init goldfish_init(void) { + if (!goldfish_enable) + return -ENODEV; + platform_device_register_simple("goldfish_pdev_bus", -1, - goldfish_pdev_bus_resources, 2); + goldfish_pdev_bus_resources, 2); return 0; } device_initcall(goldfish_init); -- cgit v1.2.3