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

[Simon Glass]

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>