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@socionext.com>
Acked-by: Simon Glass <sjg@chromium.org>
Not all boards use garbage collection in their link step, so we should avoid
adding options that rely on this for prevention of code bloat. Add separate
Kconfig options for syscon and regmap uclasses.
Signed-off-by: Simon Glass <sjg@chromium.org>
Document that mixing DM_DEVICE_REMOVE and DM_USB is a bad idea, and also why
this is a bad idea.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Simon Glass <sjg@chromium.org>
In many cases SPL only uses a single serial port and there is no need for
alias sequence support. We will just use the serial port pointed to by
stdout-path in the /chosen node.
Signed-off-by: Simon Glass <sjg@chromium.org>
Now CONFIG_SPL_BUILD is not defined in Kconfig, so
"!depends on SPL_BUILD" and "if !SPL_BUILD" are redundant.
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Expand the help messages for each driver. Add missing Kconfig for I2C,
SPI flash and thermal.
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
This would be useful to start moving various config options.
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>
