mailbox: stm32-ipcc: Convert to platform remove callback returning void

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.

To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new(), which already returns void. Eventually after all drivers
are converted, .remove_new() will be renamed to .remove().

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

mailbox: Explicitly include correct DT includes

The DT of_device.h and of_platform.h date back to the separate
of_platform_bus_type before it as merged into the regular platform bus.
As part of that merge prepping Arm DT support 13 years ago, they
"temporarily" include each other. They also include platform_device.h
and of.h. As a result, there's a pretty much random mix of those include
files used throughout the tree. In order to detangle these headers and
replace the implicit includes with struct declarations, users need to
explicitly include the correct includes.

Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

mailbox: stm32-ipcc: 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: stm32-ipcc: cast void pointers to unsigned long

Now that the driver can be enabled by COMPILE_TEST, we see warnings on
64bit platforms when void pointers are cast to unsigned int (and
vice versa).

warning: cast to smaller integer type 'unsigned int' from 'void *'
unsigned int chan = (unsigned int)link->con_priv;
...
warning: cast to 'void *' from smaller integer type 'unsigned int'
ipcc->controller.chans[i].con_priv = (void *)i;

Update these casts to use unsigned long variables, which are the same
size as pointers on all platforms.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Reviewed-by: Fabien Dessenne <fabien.dessenne@st.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

mailbox: stm32-ipcc: remove duplicate error message

platform_get_irq_byname already prints an error message if the requested
irq was not found. Don't print another message in the driver.

Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Reviewed-by: Fabien Dessenne <fabien.dessenne@st.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

mailbox: stm32-ipcc: Update wakeup management

The wakeup specific IRQ management is no more needed to wake up the
stm32 platform. A relationship has been established between the EXTI and
the RX IRQ, just need to declare the EXTI interrupt instead of the
IPCC RX IRQ.

Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>
Signed-off-by: Fabien Dessenne <fabien.dessenne@st.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

mailbox: stm32_ipcc: add spinlock to fix channels concurrent access

Add spinlock protection on IPCC register update to avoid race condition.
Without this fix, stm32_ipcc_set_bits and stm32_ipcc_clr_bits can be
called in parallel for different channels. This results in register
corruptions.

Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
Reviewed-by: Fabien Dessenne <fabien.dessenne@st.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

mailbox: stm32-ipcc: check invalid irq

On failure of_irq_get() returns a negative value or zero, which is
not handled as an error in the existing implementation.
Instead of using this API, use platform_get_irq() that returns
exclusively a negative value on failure.
Also, do not output an error log in case of defer probe error.

Signed-off-by: Fabien Dessenne <fabien.dessenne@st.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

mailbox: stm32-ipcc: remove useless device_init_wakeup call

If the "wakeup-source" property does not exist there is no need to call
device_init_wakeup("false") at probe.

Signed-off-by: Fabien Dessenne <fabien.dessenne@st.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

mailbox: stm32-ipcc: do not enable wakeup source by default

By default do not enable the wakeup source.
This lets the userspace application decide whether the wakeup source
shall be enabled or not.

Signed-off-by: Fabien Dessenne <fabien.dessenne@st.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

mailbox: stm32-ipcc: Use device-managed registration API

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

Reviewed-by: Ludovic Barre <ludovic.barre@st.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

mailbox: add STMicroelectronics STM32 IPCC driver

The STMicroelectronics STM32 Inter-Processor Communication Controller
(IPCC) is used for communicating data between two processors.
It provides a non blocking signaling mechanism to post and retrieve
communication data in an atomic way.

Signed-off-by: Fabien Dessenne <fabien.dessenne@st.com>
Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>