mailbox: bcm2835: Make use of the helper function devm_platform_ioremap_resource()

Use the devm_platform_ioremap_resource() helper instead of
calling platform_get_resource() and devm_ioremap_resource()
separately

Signed-off-by: Cai Huoqing <caihuoqing@baidu.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

mailbox: bcm2835: Remove redundant dev_err call in bcm2835_mbox_probe()

There is a error message within devm_ioremap_resource
already, so remove the dev_err call to avoid redundant
error message.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

mailbox: bcm2835: Use device-managed registration API

Get rid of some boilerplate driver removal code by using the newly added
device-managed registration API.

Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

mailbox: bcm2835: Switch to SPDX identifier

Adopt the SPDX license identifier headers to ease license compliance
management.

Cc: Lubomir Rintel <lkundrak@v3.sk>
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Acked-by: Lubomir Rintel <lkundrak@v3.sk>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

mailbox: bcm2835: Fix of_xlate return value

The bcm2835-mailbox returns NULL instead of an error pointer, which could
result in a NULL ptr dereference in mbox_request_channel. So fix this
by returning a proper error pointer.

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Fixes: 0bae6af6d704 ("mailbox: Enable BCM2835 mailbox support")
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

mailbox: Drop owner assignment from platform_driver

platform_driver does not need to set an owner because
platform_driver_register() will set it.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: Lee Jones <lee@kernel.org>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

mailbox/bcm2835: Fix mailbox full detection.

With the VC reader blocked and the ARM writing, MAIL0_STA reads empty
permanently while MAIL1_STA goes from empty (0x40000000) to non-empty
(0x00000001-0x00000007) to full (0x80000008).

This bug ended up having no effect on us, because all of our
transactions in the client driver were synchronous and under a mutex.

Suggested-by: Phil Elwell <phil@raspberrypi.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

mailbox: Enable BCM2835 mailbox support

This mailbox driver provides a single mailbox channel to write 32-bit
values to the VPU and get a 32-bit response. The Raspberry Pi
firmware uses this mailbox channel to implement firmware calls, while
Roku 2 (despite being derived from the same firmware tree) doesn't.

The driver was originally submitted by Lubomir, based on the
out-of-tree 2708 mailbox driver. Eric Anholt fixed it up for
upstreaming, with the major functional change being that it now has no
notion of multiple channels (since that is a firmware-dependent
concept) and instead the raspberrypi-firmware driver will do that
bit-twiddling in its own messages.
[Jassi: made the 'mbox_chan_ops' struct as const and removed a redundant
variable]

Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Signed-off-by: Craig McGeachie <slapdau@yahoo.com.au>
Signed-off-by: Eric Anholt <eric@anholt.net>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>