Many devices support a child block device (e.g. MMC, USB). Add a
convenient way to get this device given the parent device.
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
Sometimes it is useful to be able to find a block device without also
probing it. Add a function for this as well as the associated test.
Signed-off-by: Simon Glass <sjg@chromium.org>
The block device uclass does not currently support selecting a particular
hardware partition but this is needed for MMC. Add it so that the blk API
can support MMC properly.
Signed-off-by: Simon Glass <sjg@chromium.org>
Add a function that automatically builds the device name given the parent
and a supplied string. Most callers will want to do this, so putting this
functionality in one place makes more sense.
Signed-off-by: Simon Glass <sjg@chromium.org>
Allow a devnum parameter of -1 to indicate that the device number should be
alocated automatically. The next highest available device number for that
interface type is used.
Signed-off-by: Simon Glass <sjg@chromium.org>
There is quite a bit of duplicated common code related to block devices
in the IDE and SCSI implementations.
Create some helper functions that can be used to reduce the duplication.
These rely on a linker list of interface-type drivers
Signed-off-by: Simon Glass <sjg@chromium.org>
Add a block device cache to speed up repeated reads of block devices by
various filesystems.
This small amount of cache can dramatically speed up filesystem
operations by skipping repeated reads of common areas of a block
device (typically directory structures).
This has shown to have some benefit on FAT filesystem operations of
loading a kernel and RAM disk, but more dramatic benefits on ext4
filesystems when the kernel and/or RAM disk are spread across
multiple extent header structures as described in commit fc0fc50.
The cache is implemented through a minimal list (block_cache) maintained
in most-recently-used order and count of the current number of entries
(cache_count). It uses a maximum block count setting to prevent copies
of large block reads and an upper bound on the number of cached areas.
The maximum number of entries in the cache defaults to 32 and the maximum
number of blocks per cache entry has a default of 2, which has shown to
produce the best results on testing of ext4 and FAT filesystems.
The 'blkcache' command (enabled through CONFIG_CMD_BLOCK_CACHE) allows
changing these values and can be used to tune for a particular filesystem
layout.
Signed-off-by: Eric Nelson <eric@nelint.com>
Add a uclass for block devices. These provide block-oriented data access,
supporting reading, writing and erasing of whole blocks.
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Stephen Warren <swarren@nvidia.com>
To ease conversion to driver model, add helper functions which deal with
calling each block device method. With driver model we can reimplement these
functions with the same arguments.
Use inline functions to avoid increasing code size on some boards.
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Stephen Warren <swarren@nvidia.com>
This is a device number, and we want to use 'dev' to mean a driver model
device. Rename the member.
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Stephen Warren <swarren@nvidia.com>
Since these are sequentially numbered it makes sense to use an enum. It
avoids having to maintain the maximum value, and provides a type we can use
if it is useful.
In fact the maximum value is not used. Rename it to COUNT, since MAX suggests
it is the maximum valid value, but it is not.
Signed-off-by: Simon Glass <sjg@chromium.org>
Tested-by: Stephen Warren <swarren@nvidia.com>
At present block devices are tied up with partitions. But not all block
devices have partitions within them. They are in fact separate concepts.
Create a separate blk.h header file for block devices.
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Stephen Warren <swarren@nvidia.com>
