[U-Boot] [PATCH v4 2/5] devres: introduce Devres (Managed Device Resource) framework

[Simon Glass]

On 28 July 2015 at 12:07, Simon Glass <sjg at chromium.org> wrote:
> On 25 July 2015 at 06:52, Masahiro Yamada <yamada.masahiro at socionext.com> wrote:
>> In U-Boot's driver model, memory is basically allocated and freed
>> in the core framework.  So, low level drivers generally only have
>> to specify the size of needed memory with .priv_auto_alloc_size,
>> .platdata_auto_alloc_size, etc.  Nevertheless, some drivers still
>> need to allocate/free memory on their own in case they cannot
>> statically know the necessary memory size.  So, I believe it is
>> reasonable enough to port Devres into U-boot.
>>
>> Devres, which originates in Linux, manages device resources for each
>> device and automatically releases them on driver detach.  With devres,
>> device resources are guaranteed to be freed whether initialization
>> fails half-way or the device gets detached.
>>
>> The basic idea is totally the same to that of Linux, but I tweaked
>> it a bit so that it fits in U-Boot's driver model.
>>
>> In U-Boot, drivers are activated in two steps: binding and probing.
>> Binding puts a driver and a device together.  It is just data
>> manipulation on the system memory, so nothing has happened on the
>> hardware device at this moment.  When the device is really used, it
>> is probed.  Probing initializes the real hardware device to make it
>> really ready for use.
>>
>> So, the resources acquired during the probing process must be freed
>> when the device is removed.  Likewise, what has been allocated in
>> binding should be released when the device is unbound.  The struct
>> devres has a member "probe" to remember when the resource was
>> allocated.
>>
>> CONFIG_DEBUG_DEVRES is also supported for easier debugging.
>> If enabled, debug messages are printed each time a resource is
>> allocated/freed.
>>
>> Signed-off-by: Masahiro Yamada <yamada.masahiro at socionext.com>
>> ---
>>
>> Changes in v4:
>>   - Comment struct devres
>>
>> Changes in v3:
>>   - Update git-description.  Do not mention about the DM core part.
>>
>> Changes in v2:
>>   - Add more APIs: _free, _find, _get, _remove, _destroy, _release
>>   - Move devres_release_probe() and devres_release_all() decrlarations
>>     to dm/device-internal.h
>>   - Move comments to headers
>>
>>  drivers/core/Kconfig         |  10 +++
>>  drivers/core/Makefile        |   2 +-
>>  drivers/core/device-remove.c |   5 ++
>>  drivers/core/device.c        |   3 +
>>  drivers/core/devres.c        | 196 +++++++++++++++++++++++++++++++++++++++++++
>>  include/dm/device-internal.h |  19 +++++
>>  include/dm/device.h          | 140 +++++++++++++++++++++++++++++++
>>  7 files changed, 374 insertions(+), 1 deletion(-)
>
> Acked-by: Simon Glass <sjg at chromium.org>

Applied to u-boot-dm, thanks!