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r: 375576
b: refs/heads/master
c: a2c7a54
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v: v3
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Linus Torvalds committed May 14, 2013
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2 changes: 1 addition & 1 deletion [refs]
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---
refs/heads/master: e34166ad63eac4d0fa98b4c4ed7a98202a18faef
refs/heads/master: a2c7a54fcc36dc3d0d461e883d9535f8f52f5a3f
156 changes: 156 additions & 0 deletions trunk/Documentation/ABI/testing/sysfs-block-bcache
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What: /sys/block/<disk>/bcache/unregister
Date: November 2010
Contact: Kent Overstreet <kent.overstreet@gmail.com>
Description:
A write to this file causes the backing device or cache to be
unregistered. If a backing device had dirty data in the cache,
writeback mode is automatically disabled and all dirty data is
flushed before the device is unregistered. Caches unregister
all associated backing devices before unregistering themselves.

What: /sys/block/<disk>/bcache/clear_stats
Date: November 2010
Contact: Kent Overstreet <kent.overstreet@gmail.com>
Description:
Writing to this file resets all the statistics for the device.

What: /sys/block/<disk>/bcache/cache
Date: November 2010
Contact: Kent Overstreet <kent.overstreet@gmail.com>
Description:
For a backing device that has cache, a symlink to
the bcache/ dir of that cache.

What: /sys/block/<disk>/bcache/cache_hits
Date: November 2010
Contact: Kent Overstreet <kent.overstreet@gmail.com>
Description:
For backing devices: integer number of full cache hits,
counted per bio. A partial cache hit counts as a miss.

What: /sys/block/<disk>/bcache/cache_misses
Date: November 2010
Contact: Kent Overstreet <kent.overstreet@gmail.com>
Description:
For backing devices: integer number of cache misses.

What: /sys/block/<disk>/bcache/cache_hit_ratio
Date: November 2010
Contact: Kent Overstreet <kent.overstreet@gmail.com>
Description:
For backing devices: cache hits as a percentage.

What: /sys/block/<disk>/bcache/sequential_cutoff
Date: November 2010
Contact: Kent Overstreet <kent.overstreet@gmail.com>
Description:
For backing devices: Threshold past which sequential IO will
skip the cache. Read and written as bytes in human readable
units (i.e. echo 10M > sequntial_cutoff).

What: /sys/block/<disk>/bcache/bypassed
Date: November 2010
Contact: Kent Overstreet <kent.overstreet@gmail.com>
Description:
Sum of all reads and writes that have bypassed the cache (due
to the sequential cutoff). Expressed as bytes in human
readable units.

What: /sys/block/<disk>/bcache/writeback
Date: November 2010
Contact: Kent Overstreet <kent.overstreet@gmail.com>
Description:
For backing devices: When on, writeback caching is enabled and
writes will be buffered in the cache. When off, caching is in
writethrough mode; reads and writes will be added to the
cache but no write buffering will take place.

What: /sys/block/<disk>/bcache/writeback_running
Date: November 2010
Contact: Kent Overstreet <kent.overstreet@gmail.com>
Description:
For backing devices: when off, dirty data will not be written
from the cache to the backing device. The cache will still be
used to buffer writes until it is mostly full, at which point
writes transparently revert to writethrough mode. Intended only
for benchmarking/testing.

What: /sys/block/<disk>/bcache/writeback_delay
Date: November 2010
Contact: Kent Overstreet <kent.overstreet@gmail.com>
Description:
For backing devices: In writeback mode, when dirty data is
written to the cache and the cache held no dirty data for that
backing device, writeback from cache to backing device starts
after this delay, expressed as an integer number of seconds.

What: /sys/block/<disk>/bcache/writeback_percent
Date: November 2010
Contact: Kent Overstreet <kent.overstreet@gmail.com>
Description:
For backing devices: If nonzero, writeback from cache to
backing device only takes place when more than this percentage
of the cache is used, allowing more write coalescing to take
place and reducing total number of writes sent to the backing
device. Integer between 0 and 40.

What: /sys/block/<disk>/bcache/synchronous
Date: November 2010
Contact: Kent Overstreet <kent.overstreet@gmail.com>
Description:
For a cache, a boolean that allows synchronous mode to be
switched on and off. In synchronous mode all writes are ordered
such that the cache can reliably recover from unclean shutdown;
if disabled bcache will not generally wait for writes to
complete but if the cache is not shut down cleanly all data
will be discarded from the cache. Should not be turned off with
writeback caching enabled.

What: /sys/block/<disk>/bcache/discard
Date: November 2010
Contact: Kent Overstreet <kent.overstreet@gmail.com>
Description:
For a cache, a boolean allowing discard/TRIM to be turned off
or back on if the device supports it.

What: /sys/block/<disk>/bcache/bucket_size
Date: November 2010
Contact: Kent Overstreet <kent.overstreet@gmail.com>
Description:
For a cache, bucket size in human readable units, as set at
cache creation time; should match the erase block size of the
SSD for optimal performance.

What: /sys/block/<disk>/bcache/nbuckets
Date: November 2010
Contact: Kent Overstreet <kent.overstreet@gmail.com>
Description:
For a cache, the number of usable buckets.

What: /sys/block/<disk>/bcache/tree_depth
Date: November 2010
Contact: Kent Overstreet <kent.overstreet@gmail.com>
Description:
For a cache, height of the btree excluding leaf nodes (i.e. a
one node tree will have a depth of 0).

What: /sys/block/<disk>/bcache/btree_cache_size
Date: November 2010
Contact: Kent Overstreet <kent.overstreet@gmail.com>
Description:
Number of btree buckets/nodes that are currently cached in
memory; cache dynamically grows and shrinks in response to
memory pressure from the rest of the system.

What: /sys/block/<disk>/bcache/written
Date: November 2010
Contact: Kent Overstreet <kent.overstreet@gmail.com>
Description:
For a cache, total amount of data in human readable units
written to the cache, excluding all metadata.

What: /sys/block/<disk>/bcache/btree_written
Date: November 2010
Contact: Kent Overstreet <kent.overstreet@gmail.com>
Description:
For a cache, sum of all btree writes in human readable units.
20 changes: 0 additions & 20 deletions trunk/Documentation/ABI/testing/sysfs-bus-rbd
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Expand Up @@ -66,27 +66,7 @@ current_snap

The current snapshot for which the device is mapped.

snap_*

A directory per each snapshot

parent

Information identifying the pool, image, and snapshot id for
the parent image in a layered rbd image (format 2 only).

Entries under /sys/bus/rbd/devices/<dev-id>/snap_<snap-name>
-------------------------------------------------------------

snap_id

The rados internal snapshot id assigned for this snapshot

snap_size

The size of the image when this snapshot was taken.

snap_features

A hexadecimal encoding of the feature bits for this snapshot.

6 changes: 2 additions & 4 deletions trunk/Documentation/ABI/testing/sysfs-class-mtd
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Expand Up @@ -14,17 +14,15 @@ Description:
The /sys/class/mtd/mtd{0,1,2,3,...} directories correspond
to each /dev/mtdX character device. These may represent
physical/simulated flash devices, partitions on a flash
device, or concatenated flash devices. They exist regardless
of whether CONFIG_MTD_CHAR is actually enabled.
device, or concatenated flash devices.

What: /sys/class/mtd/mtdXro/
Date: April 2009
KernelVersion: 2.6.29
Contact: linux-mtd@lists.infradead.org
Description:
These directories provide the corresponding read-only device
nodes for /sys/class/mtd/mtdX/ . They are only created
(for the benefit of udev) if CONFIG_MTD_CHAR is enabled.
nodes for /sys/class/mtd/mtdX/ .

What: /sys/class/mtd/mtdX/dev
Date: April 2009
Expand Down
109 changes: 108 additions & 1 deletion trunk/Documentation/acpi/enumeration.txt
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Expand Up @@ -66,6 +66,83 @@ the ACPI device explicitly to acpi_platform_device_ids list defined in
drivers/acpi/acpi_platform.c. This limitation is only for the platform
devices, SPI and I2C devices are created automatically as described below.

DMA support
~~~~~~~~~~~
DMA controllers enumerated via ACPI should be registered in the system to
provide generic access to their resources. For example, a driver that would
like to be accessible to slave devices via generic API call
dma_request_slave_channel() must register itself at the end of the probe
function like this:

err = devm_acpi_dma_controller_register(dev, xlate_func, dw);
/* Handle the error if it's not a case of !CONFIG_ACPI */

and implement custom xlate function if needed (usually acpi_dma_simple_xlate()
is enough) which converts the FixedDMA resource provided by struct
acpi_dma_spec into the corresponding DMA channel. A piece of code for that case
could look like:

#ifdef CONFIG_ACPI
struct filter_args {
/* Provide necessary information for the filter_func */
...
};

static bool filter_func(struct dma_chan *chan, void *param)
{
/* Choose the proper channel */
...
}

static struct dma_chan *xlate_func(struct acpi_dma_spec *dma_spec,
struct acpi_dma *adma)
{
dma_cap_mask_t cap;
struct filter_args args;

/* Prepare arguments for filter_func */
...
return dma_request_channel(cap, filter_func, &args);
}
#else
static struct dma_chan *xlate_func(struct acpi_dma_spec *dma_spec,
struct acpi_dma *adma)
{
return NULL;
}
#endif

dma_request_slave_channel() will call xlate_func() for each registered DMA
controller. In the xlate function the proper channel must be chosen based on
information in struct acpi_dma_spec and the properties of the controller
provided by struct acpi_dma.

Clients must call dma_request_slave_channel() with the string parameter that
corresponds to a specific FixedDMA resource. By default "tx" means the first
entry of the FixedDMA resource array, "rx" means the second entry. The table
below shows a layout:

Device (I2C0)
{
...
Method (_CRS, 0, NotSerialized)
{
Name (DBUF, ResourceTemplate ()
{
FixedDMA (0x0018, 0x0004, Width32bit, _Y48)
FixedDMA (0x0019, 0x0005, Width32bit, )
})
...
}
}

So, the FixedDMA with request line 0x0018 is "tx" and next one is "rx" in
this example.

In robust cases the client unfortunately needs to call
acpi_dma_request_slave_chan_by_index() directly and therefore choose the
specific FixedDMA resource by its index.

SPI serial bus support
~~~~~~~~~~~~~~~~~~~~~~
Slave devices behind SPI bus have SpiSerialBus resource attached to them.
Expand Down Expand Up @@ -199,17 +276,29 @@ the device to the driver. For example:
{
Name (SBUF, ResourceTemplate()
{
...
// Used to power on/off the device
GpioIo (Exclusive, PullDefault, 0x0000, 0x0000,
IoRestrictionOutputOnly, "\\_SB.PCI0.GPI0",
0x00, ResourceConsumer,,)
{
// Pin List
0x0055
}

// Interrupt for the device
GpioInt (Edge, ActiveHigh, ExclusiveAndWake, PullNone,
0x0000, "\\_SB.PCI0.GPI0", 0x00, ResourceConsumer,,)
{
// Pin list
0x0058
}

...

Return (SBUF)
}

Return (SBUF)
}

These GPIO numbers are controller relative and path "\\_SB.PCI0.GPI0"
Expand All @@ -220,6 +309,24 @@ The driver can do this by including <linux/acpi_gpio.h> and then calling
acpi_get_gpio(path, gpio). This will return the Linux GPIO number or
negative errno if there was no translation found.

In a simple case of just getting the Linux GPIO number from device
resources one can use acpi_get_gpio_by_index() helper function. It takes
pointer to the device and index of the GpioIo/GpioInt descriptor in the
device resources list. For example:

int gpio_irq, gpio_power;
int ret;

gpio_irq = acpi_get_gpio_by_index(dev, 1, NULL);
if (gpio_irq < 0)
/* handle error */

gpio_power = acpi_get_gpio_by_index(dev, 0, NULL);
if (gpio_power < 0)
/* handle error */

/* Now we can use the GPIO numbers */

Other GpioIo parameters must be converted first by the driver to be
suitable to the gpiolib before passing them.

Expand Down
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