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-rw-r--r--Documentation/admin-guide/kernel-parameters.rst1
-rw-r--r--Documentation/admin-guide/kernel-parameters.txt6
-rw-r--r--Documentation/driver-api/device_link.rst3
-rw-r--r--Documentation/driver-api/driver-model/devres.rst4
-rw-r--r--Documentation/driver-api/driver-model/driver.rst43
-rw-r--r--Documentation/filesystems/debugfs.txt50
6 files changed, 85 insertions, 22 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.rst b/Documentation/admin-guide/kernel-parameters.rst
index d05d531b4ec9..6d421694d98e 100644
--- a/Documentation/admin-guide/kernel-parameters.rst
+++ b/Documentation/admin-guide/kernel-parameters.rst
@@ -127,6 +127,7 @@ parameter is applicable::
NET Appropriate network support is enabled.
NUMA NUMA support is enabled.
NFS Appropriate NFS support is enabled.
+ OF Devicetree is enabled.
OSS OSS sound support is enabled.
PV_OPS A paravirtualized kernel is enabled.
PARIDE The ParIDE (parallel port IDE) subsystem is enabled.
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 1fda057434c3..b25b47a47acd 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3240,6 +3240,12 @@
This can be set from sysctl after boot.
See Documentation/admin-guide/sysctl/vm.rst for details.
+ of_devlink [OF, KNL] Create device links between consumer and
+ supplier devices by scanning the devictree to infer the
+ consumer/supplier relationships. A consumer device
+ will not be probed until all the supplier devices have
+ probed successfully.
+
ohci1394_dma=early [HW] enable debugging via the ohci1394 driver.
See Documentation/debugging-via-ohci1394.txt for more
info.
diff --git a/Documentation/driver-api/device_link.rst b/Documentation/driver-api/device_link.rst
index 1b5020ec6517..bc2d89af88ce 100644
--- a/Documentation/driver-api/device_link.rst
+++ b/Documentation/driver-api/device_link.rst
@@ -281,7 +281,8 @@ State machine
:c:func:`driver_bound()`.)
* Before a consumer device is probed, presence of supplier drivers is
- verified by checking that links to suppliers are in ``DL_STATE_AVAILABLE``
+ verified by checking the consumer device is not in the wait_for_suppliers
+ list and by checking that links to suppliers are in ``DL_STATE_AVAILABLE``
state. The state of the links is updated to ``DL_STATE_CONSUMER_PROBE``.
(Call to :c:func:`device_links_check_suppliers()` from
:c:func:`really_probe()`.)
diff --git a/Documentation/driver-api/driver-model/devres.rst b/Documentation/driver-api/driver-model/devres.rst
index a100bef54952..4ab193319d8c 100644
--- a/Documentation/driver-api/driver-model/devres.rst
+++ b/Documentation/driver-api/driver-model/devres.rst
@@ -316,6 +316,10 @@ IOMAP
devm_ioremap_nocache()
devm_ioremap_wc()
devm_ioremap_resource() : checks resource, requests memory region, ioremaps
+ devm_ioremap_resource_wc()
+ devm_platform_ioremap_resource() : calls devm_ioremap_resource() for platform device
+ devm_platform_ioremap_resource_wc()
+ devm_platform_ioremap_resource_byname()
devm_iounmap()
pcim_iomap()
pcim_iomap_regions() : do request_region() and iomap() on multiple BARs
diff --git a/Documentation/driver-api/driver-model/driver.rst b/Documentation/driver-api/driver-model/driver.rst
index 11d281506a04..baa6a85c8287 100644
--- a/Documentation/driver-api/driver-model/driver.rst
+++ b/Documentation/driver-api/driver-model/driver.rst
@@ -169,6 +169,49 @@ A driver's probe() may return a negative errno value to indicate that
the driver did not bind to this device, in which case it should have
released all resources it allocated::
+ void (*sync_state)(struct device *dev);
+
+sync_state is called only once for a device. It's called when all the consumer
+devices of the device have successfully probed. The list of consumers of the
+device is obtained by looking at the device links connecting that device to its
+consumer devices.
+
+The first attempt to call sync_state() is made during late_initcall_sync() to
+give firmware and drivers time to link devices to each other. During the first
+attempt at calling sync_state(), if all the consumers of the device at that
+point in time have already probed successfully, sync_state() is called right
+away. If there are no consumers of the device during the first attempt, that
+too is considered as "all consumers of the device have probed" and sync_state()
+is called right away.
+
+If during the first attempt at calling sync_state() for a device, there are
+still consumers that haven't probed successfully, the sync_state() call is
+postponed and reattempted in the future only when one or more consumers of the
+device probe successfully. If during the reattempt, the driver core finds that
+there are one or more consumers of the device that haven't probed yet, then
+sync_state() call is postponed again.
+
+A typical use case for sync_state() is to have the kernel cleanly take over
+management of devices from the bootloader. For example, if a device is left on
+and at a particular hardware configuration by the bootloader, the device's
+driver might need to keep the device in the boot configuration until all the
+consumers of the device have probed. Once all the consumers of the device have
+probed, the device's driver can synchronize the hardware state of the device to
+match the aggregated software state requested by all the consumers. Hence the
+name sync_state().
+
+While obvious examples of resources that can benefit from sync_state() include
+resources such as regulator, sync_state() can also be useful for complex
+resources like IOMMUs. For example, IOMMUs with multiple consumers (devices
+whose addresses are remapped by the IOMMU) might need to keep their mappings
+fixed at (or additive to) the boot configuration until all its consumers have
+probed.
+
+While the typical use case for sync_state() is to have the kernel cleanly take
+over management of devices from the bootloader, the usage of sync_state() is
+not restricted to that. Use it whenever it makes sense to take an action after
+all the consumers of a device have probed.
+
int (*remove) (struct device *dev);
remove is called to unbind a driver from a device. This may be
diff --git a/Documentation/filesystems/debugfs.txt b/Documentation/filesystems/debugfs.txt
index 9e27c843d00e..dc497b96fa4f 100644
--- a/Documentation/filesystems/debugfs.txt
+++ b/Documentation/filesystems/debugfs.txt
@@ -68,41 +68,49 @@ actually necessary; the debugfs code provides a number of helper functions
for simple situations. Files containing a single integer value can be
created with any of:
- struct dentry *debugfs_create_u8(const char *name, umode_t mode,
- struct dentry *parent, u8 *value);
- struct dentry *debugfs_create_u16(const char *name, umode_t mode,
- struct dentry *parent, u16 *value);
+ void debugfs_create_u8(const char *name, umode_t mode,
+ struct dentry *parent, u8 *value);
+ void debugfs_create_u16(const char *name, umode_t mode,
+ struct dentry *parent, u16 *value);
struct dentry *debugfs_create_u32(const char *name, umode_t mode,
struct dentry *parent, u32 *value);
- struct dentry *debugfs_create_u64(const char *name, umode_t mode,
- struct dentry *parent, u64 *value);
+ void debugfs_create_u64(const char *name, umode_t mode,
+ struct dentry *parent, u64 *value);
These files support both reading and writing the given value; if a specific
file should not be written to, simply set the mode bits accordingly. The
values in these files are in decimal; if hexadecimal is more appropriate,
the following functions can be used instead:
- struct dentry *debugfs_create_x8(const char *name, umode_t mode,
- struct dentry *parent, u8 *value);
- struct dentry *debugfs_create_x16(const char *name, umode_t mode,
- struct dentry *parent, u16 *value);
- struct dentry *debugfs_create_x32(const char *name, umode_t mode,
- struct dentry *parent, u32 *value);
- struct dentry *debugfs_create_x64(const char *name, umode_t mode,
- struct dentry *parent, u64 *value);
+ void debugfs_create_x8(const char *name, umode_t mode,
+ struct dentry *parent, u8 *value);
+ void debugfs_create_x16(const char *name, umode_t mode,
+ struct dentry *parent, u16 *value);
+ void debugfs_create_x32(const char *name, umode_t mode,
+ struct dentry *parent, u32 *value);
+ void debugfs_create_x64(const char *name, umode_t mode,
+ struct dentry *parent, u64 *value);
These functions are useful as long as the developer knows the size of the
value to be exported. Some types can have different widths on different
-architectures, though, complicating the situation somewhat. There is a
-function meant to help out in one special case:
+architectures, though, complicating the situation somewhat. There are
+functions meant to help out in such special cases:
- struct dentry *debugfs_create_size_t(const char *name, umode_t mode,
- struct dentry *parent,
- size_t *value);
+ void debugfs_create_size_t(const char *name, umode_t mode,
+ struct dentry *parent, size_t *value);
As might be expected, this function will create a debugfs file to represent
a variable of type size_t.
+Similarly, there are helpers for variables of type unsigned long, in decimal
+and hexadecimal:
+
+ struct dentry *debugfs_create_ulong(const char *name, umode_t mode,
+ struct dentry *parent,
+ unsigned long *value);
+ void debugfs_create_xul(const char *name, umode_t mode,
+ struct dentry *parent, unsigned long *value);
+
Boolean values can be placed in debugfs with:
struct dentry *debugfs_create_bool(const char *name, umode_t mode,
@@ -114,8 +122,8 @@ lower-case values, or 1 or 0. Any other input will be silently ignored.
Also, atomic_t values can be placed in debugfs with:
- struct dentry *debugfs_create_atomic_t(const char *name, umode_t mode,
- struct dentry *parent, atomic_t *value)
+ void debugfs_create_atomic_t(const char *name, umode_t mode,
+ struct dentry *parent, atomic_t *value)
A read of this file will get atomic_t values, and a write of this file
will set atomic_t values.