hwspinlock: stm32: Use struct_size() helper in devm_kzalloc()

Make use of the struct_size() helper instead of an open-coded version,
in order to avoid any potential type mistakes or integer overflows that,
in the worst scenario, could lead to heap overflows.

Also, address the following sparse warnings:
drivers/hwspinlock/stm32_hwspinlock.c:84:32: warning: using sizeof on a flexible structure

Link: https://github.com/KSPP/linux/issues/174
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Baolin Wang <baolin.wang7@gmail.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220125021353.GA29777@embeddedor

hwspinlock: stm32: enable clock at probe

Set the clock during probe and keep its control during suspend / resume
operations.
This fixes an issue when CONFIG_PM is not set and where the clock is
never enabled.

Make use of devm_ functions to simplify the code.

Signed-off-by: Fabien Dessenne <fabien.dessenne@foss.st.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20211011135836.1045437-1-fabien.dessenne@foss.st.com

hwspinlock: stm32: convert to devm_platform_ioremap_resource

Use devm_platform_ioremap_resource() to simplify code.

Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Link: https://lore.kernel.org/r/20191228191541.26999-1-tiny.windzz@gmail.com
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

hwspinlock: stm32: implement the relax() ops

Implement this optional ops, called by hwspinlock core while spinning on
a lock, between two successive invocations of trylock().

Reviewed-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: Fabien Dessenne <fabien.dessenne@st.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

hwspinlock: fix return value check in stm32_hwspinlock_probe()

In case of error, the function devm_ioremap_resource() returns ERR_PTR()
and never returns NULL. The NULL test in the return value check should
be replaced with IS_ERR().

Fixes: f24fcff1d267 ("hwspinlock: add STM32 hwspinlock device")
Acked-by: Benjamin Gaignard <benjamin.gaignard@gmail.com>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

hwspinlock: add STM32 hwspinlock device

This patch adds support of hardware semaphores for stm32mp1 SoC.
The hardware block provides 32 semaphores.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>