diff options
Diffstat (limited to 'Documentation/driver-api')
-rw-r--r-- | Documentation/driver-api/basics.rst | 27 | ||||
-rw-r--r-- | Documentation/driver-api/infrastructure.rst | 18 | ||||
-rw-r--r-- | Documentation/driver-api/media/dtv-common.rst | 9 | ||||
-rw-r--r-- | Documentation/driver-api/s390-drivers.rst | 4 | ||||
-rw-r--r-- | Documentation/driver-api/tty/tty_buffer.rst | 7 | ||||
-rw-r--r-- | Documentation/driver-api/usb/usb.rst | 9 | ||||
-rw-r--r-- | Documentation/driver-api/vfio.rst | 147 |
7 files changed, 194 insertions, 27 deletions
diff --git a/Documentation/driver-api/basics.rst b/Documentation/driver-api/basics.rst index 7671b531ba1a..d78b7c328ff7 100644 --- a/Documentation/driver-api/basics.rst +++ b/Documentation/driver-api/basics.rst @@ -15,8 +15,8 @@ Driver device table :no-identifiers: pci_device_id -Delaying, scheduling, and timer routines ----------------------------------------- +Delaying and scheduling routines +-------------------------------- .. kernel-doc:: include/linux/sched.h :internal: @@ -33,16 +33,16 @@ Delaying, scheduling, and timer routines .. kernel-doc:: include/linux/completion.h :internal: -.. kernel-doc:: kernel/time/timer.c - :export: - -Wait queues and Wake events ---------------------------- +Time and timer routines +----------------------- -.. kernel-doc:: include/linux/wait.h +.. kernel-doc:: include/linux/jiffies.h :internal: -.. kernel-doc:: kernel/sched/wait.c +.. kernel-doc:: kernel/time/time.c + :export: + +.. kernel-doc:: kernel/time/timer.c :export: High-resolution timers @@ -57,6 +57,15 @@ High-resolution timers .. kernel-doc:: kernel/time/hrtimer.c :export: +Wait queues and Wake events +--------------------------- + +.. kernel-doc:: include/linux/wait.h + :internal: + +.. kernel-doc:: kernel/sched/wait.c + :export: + Internal Functions ------------------ diff --git a/Documentation/driver-api/infrastructure.rst b/Documentation/driver-api/infrastructure.rst index 683bd460e222..3d52dfdfa9fd 100644 --- a/Documentation/driver-api/infrastructure.rst +++ b/Documentation/driver-api/infrastructure.rst @@ -8,12 +8,24 @@ The Basic Device Driver-Model Structures :internal: :no-identifiers: device_link_state +.. kernel-doc:: include/linux/device/bus.h + :identifiers: bus_type bus_notifier_event + +.. kernel-doc:: include/linux/device/class.h + :identifiers: class + +.. kernel-doc:: include/linux/device/driver.h + :identifiers: probe_type device_driver + Device Drivers Base ------------------- .. kernel-doc:: drivers/base/init.c :internal: +.. kernel-doc:: include/linux/device/driver.h + :no-identifiers: probe_type device_driver + .. kernel-doc:: drivers/base/driver.c :export: @@ -23,6 +35,9 @@ Device Drivers Base .. kernel-doc:: drivers/base/syscore.c :export: +.. kernel-doc:: include/linux/device/class.h + :no-identifiers: class + .. kernel-doc:: drivers/base/class.c :export: @@ -41,6 +56,9 @@ Device Drivers Base .. kernel-doc:: drivers/base/platform.c :export: +.. kernel-doc:: include/linux/device/bus.h + :no-identifiers: bus_type bus_notifier_event + .. kernel-doc:: drivers/base/bus.c :export: diff --git a/Documentation/driver-api/media/dtv-common.rst b/Documentation/driver-api/media/dtv-common.rst index f8b2c4dc8170..207a22bcaf4a 100644 --- a/Documentation/driver-api/media/dtv-common.rst +++ b/Documentation/driver-api/media/dtv-common.rst @@ -3,15 +3,6 @@ Digital TV Common functions --------------------------- -Math functions -~~~~~~~~~~~~~~ - -Provide some commonly-used math functions, usually required in order to -estimate signal strength and signal to noise measurements in dB. - -.. kernel-doc:: include/media/dvb_math.h - - DVB devices ~~~~~~~~~~~ diff --git a/Documentation/driver-api/s390-drivers.rst b/Documentation/driver-api/s390-drivers.rst index 5158577bc29b..8c0845c4eee7 100644 --- a/Documentation/driver-api/s390-drivers.rst +++ b/Documentation/driver-api/s390-drivers.rst @@ -27,7 +27,7 @@ not strictly considered I/O devices. They are considered here as well, although they are not the focus of this document. Some additional information can also be found in the kernel source under -Documentation/s390/driver-model.rst. +Documentation/arch/s390/driver-model.rst. The css bus =========== @@ -38,7 +38,7 @@ into several categories: * Standard I/O subchannels, for use by the system. They have a child device on the ccw bus and are described below. * I/O subchannels bound to the vfio-ccw driver. See - Documentation/s390/vfio-ccw.rst. + Documentation/arch/s390/vfio-ccw.rst. * Message subchannels. No Linux driver currently exists. * CHSC subchannels (at most one). The chsc subchannel driver can be used to send asynchronous chsc commands. diff --git a/Documentation/driver-api/tty/tty_buffer.rst b/Documentation/driver-api/tty/tty_buffer.rst index a39d4781e0d2..4b5ca1776d4f 100644 --- a/Documentation/driver-api/tty/tty_buffer.rst +++ b/Documentation/driver-api/tty/tty_buffer.rst @@ -15,10 +15,13 @@ Flip Buffer Management ====================== .. kernel-doc:: drivers/tty/tty_buffer.c - :identifiers: tty_prepare_flip_string tty_insert_flip_string_fixed_flag - tty_insert_flip_string_flags __tty_insert_flip_char + :identifiers: tty_prepare_flip_string tty_flip_buffer_push tty_ldisc_receive_buf +.. kernel-doc:: include/linux/tty_flip.h + :identifiers: tty_insert_flip_string_fixed_flag tty_insert_flip_string_flags + tty_insert_flip_char + ---- Other Functions diff --git a/Documentation/driver-api/usb/usb.rst b/Documentation/driver-api/usb/usb.rst index 2c94ff2f4385..fb41768696ec 100644 --- a/Documentation/driver-api/usb/usb.rst +++ b/Documentation/driver-api/usb/usb.rst @@ -420,6 +420,12 @@ USBDEVFS_CONNECTINFO know the devnum value already, it's the DDD value of the device file name. +USBDEVFS_GET_SPEED + Returns the speed of the device. The speed is returned as a + nummerical value in accordance with enum usb_device_speed + + File modification time is not updated by this request. + USBDEVFS_GETDRIVER Returns the name of the kernel driver bound to a given interface (a string). Parameter is a pointer to this structure, which is @@ -771,8 +777,7 @@ Speed may be: ======= ====================================================== 1.5 Mbit/s for low speed USB 12 Mbit/s for full speed USB - 480 Mbit/s for high speed USB (added for USB 2.0); - also used for Wireless USB, which has no fixed speed + 480 Mbit/s for high speed USB (added for USB 2.0) 5000 Mbit/s for SuperSpeed USB (added for USB 3.0) ======= ====================================================== diff --git a/Documentation/driver-api/vfio.rst b/Documentation/driver-api/vfio.rst index 68abc089d6dd..633d11c7fa71 100644 --- a/Documentation/driver-api/vfio.rst +++ b/Documentation/driver-api/vfio.rst @@ -239,6 +239,137 @@ group and can access them as follows:: /* Gratuitous device reset and go... */ ioctl(device, VFIO_DEVICE_RESET); +IOMMUFD and vfio_iommu_type1 +---------------------------- + +IOMMUFD is the new user API to manage I/O page tables from userspace. +It intends to be the portal of delivering advanced userspace DMA +features (nested translation [5]_, PASID [6]_, etc.) while also providing +a backwards compatibility interface for existing VFIO_TYPE1v2_IOMMU use +cases. Eventually the vfio_iommu_type1 driver, as well as the legacy +vfio container and group model is intended to be deprecated. + +The IOMMUFD backwards compatibility interface can be enabled two ways. +In the first method, the kernel can be configured with +CONFIG_IOMMUFD_VFIO_CONTAINER, in which case the IOMMUFD subsystem +transparently provides the entire infrastructure for the VFIO +container and IOMMU backend interfaces. The compatibility mode can +also be accessed if the VFIO container interface, ie. /dev/vfio/vfio is +simply symlink'd to /dev/iommu. Note that at the time of writing, the +compatibility mode is not entirely feature complete relative to +VFIO_TYPE1v2_IOMMU (ex. DMA mapping MMIO) and does not attempt to +provide compatibility to the VFIO_SPAPR_TCE_IOMMU interface. Therefore +it is not generally advisable at this time to switch from native VFIO +implementations to the IOMMUFD compatibility interfaces. + +Long term, VFIO users should migrate to device access through the cdev +interface described below, and native access through the IOMMUFD +provided interfaces. + +VFIO Device cdev +---------------- + +Traditionally user acquires a device fd via VFIO_GROUP_GET_DEVICE_FD +in a VFIO group. + +With CONFIG_VFIO_DEVICE_CDEV=y the user can now acquire a device fd +by directly opening a character device /dev/vfio/devices/vfioX where +"X" is the number allocated uniquely by VFIO for registered devices. +cdev interface does not support noiommu devices, so user should use +the legacy group interface if noiommu is wanted. + +The cdev only works with IOMMUFD. Both VFIO drivers and applications +must adapt to the new cdev security model which requires using +VFIO_DEVICE_BIND_IOMMUFD to claim DMA ownership before starting to +actually use the device. Once BIND succeeds then a VFIO device can +be fully accessed by the user. + +VFIO device cdev doesn't rely on VFIO group/container/iommu drivers. +Hence those modules can be fully compiled out in an environment +where no legacy VFIO application exists. + +So far SPAPR does not support IOMMUFD yet. So it cannot support device +cdev either. + +vfio device cdev access is still bound by IOMMU group semantics, ie. there +can be only one DMA owner for the group. Devices belonging to the same +group can not be bound to multiple iommufd_ctx or shared between native +kernel and vfio bus driver or other driver supporting the driver_managed_dma +flag. A violation of this ownership requirement will fail at the +VFIO_DEVICE_BIND_IOMMUFD ioctl, which gates full device access. + +Device cdev Example +------------------- + +Assume user wants to access PCI device 0000:6a:01.0:: + + $ ls /sys/bus/pci/devices/0000:6a:01.0/vfio-dev/ + vfio0 + +This device is therefore represented as vfio0. The user can verify +its existence:: + + $ ls -l /dev/vfio/devices/vfio0 + crw------- 1 root root 511, 0 Feb 16 01:22 /dev/vfio/devices/vfio0 + $ cat /sys/bus/pci/devices/0000:6a:01.0/vfio-dev/vfio0/dev + 511:0 + $ ls -l /dev/char/511\:0 + lrwxrwxrwx 1 root root 21 Feb 16 01:22 /dev/char/511:0 -> ../vfio/devices/vfio0 + +Then provide the user with access to the device if unprivileged +operation is desired:: + + $ chown user:user /dev/vfio/devices/vfio0 + +Finally the user could get cdev fd by:: + + cdev_fd = open("/dev/vfio/devices/vfio0", O_RDWR); + +An opened cdev_fd doesn't give the user any permission of accessing +the device except binding the cdev_fd to an iommufd. After that point +then the device is fully accessible including attaching it to an +IOMMUFD IOAS/HWPT to enable userspace DMA:: + + struct vfio_device_bind_iommufd bind = { + .argsz = sizeof(bind), + .flags = 0, + }; + struct iommu_ioas_alloc alloc_data = { + .size = sizeof(alloc_data), + .flags = 0, + }; + struct vfio_device_attach_iommufd_pt attach_data = { + .argsz = sizeof(attach_data), + .flags = 0, + }; + struct iommu_ioas_map map = { + .size = sizeof(map), + .flags = IOMMU_IOAS_MAP_READABLE | + IOMMU_IOAS_MAP_WRITEABLE | + IOMMU_IOAS_MAP_FIXED_IOVA, + .__reserved = 0, + }; + + iommufd = open("/dev/iommu", O_RDWR); + + bind.iommufd = iommufd; + ioctl(cdev_fd, VFIO_DEVICE_BIND_IOMMUFD, &bind); + + ioctl(iommufd, IOMMU_IOAS_ALLOC, &alloc_data); + attach_data.pt_id = alloc_data.out_ioas_id; + ioctl(cdev_fd, VFIO_DEVICE_ATTACH_IOMMUFD_PT, &attach_data); + + /* Allocate some space and setup a DMA mapping */ + map.user_va = (int64_t)mmap(0, 1024 * 1024, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, 0, 0); + map.iova = 0; /* 1MB starting at 0x0 from device view */ + map.length = 1024 * 1024; + map.ioas_id = alloc_data.out_ioas_id;; + + ioctl(iommufd, IOMMU_IOAS_MAP, &map); + + /* Other device operations as stated in "VFIO Usage Example" */ + VFIO User API ------------------------------------------------------------------------------- @@ -279,6 +410,7 @@ similar to a file operations structure:: struct iommufd_ctx *ictx, u32 *out_device_id); void (*unbind_iommufd)(struct vfio_device *vdev); int (*attach_ioas)(struct vfio_device *vdev, u32 *pt_id); + void (*detach_ioas)(struct vfio_device *vdev); int (*open_device)(struct vfio_device *vdev); void (*close_device)(struct vfio_device *vdev); ssize_t (*read)(struct vfio_device *vdev, char __user *buf, @@ -315,9 +447,10 @@ container_of(). - The [un]bind_iommufd callbacks are issued when the device is bound to and unbound from iommufd. - - The attach_ioas callback is issued when the device is attached to an - IOAS managed by the bound iommufd. The attached IOAS is automatically - detached when the device is unbound from iommufd. + - The [de]attach_ioas callback is issued when the device is attached to + and detached from an IOAS managed by the bound iommufd. However, the + attached IOAS can also be automatically detached when the device is + unbound from iommufd. - The read/write/mmap callbacks implement the device region access defined by the device's own VFIO_DEVICE_GET_REGION_INFO ioctl. @@ -564,3 +697,11 @@ This implementation has some specifics: \-0d.1 00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev 90) + +.. [5] Nested translation is an IOMMU feature which supports two stage + address translations. This improves the address translation efficiency + in IOMMU virtualization. + +.. [6] PASID stands for Process Address Space ID, introduced by PCI + Express. It is a prerequisite for Shared Virtual Addressing (SVA) + and Scalable I/O Virtualization (Scalable IOV). |