remoteproc: stm32: add an ST stm32_rproc driver

This patch introduces a new remoteproc driver to control Cortex-M4
co-processor of the STM32 family.
It provides with the following features:
- start and stop
- dedicated co-processor memory regions registration
- coredump and recovery

Signed-off-by: Fabien Dessenne <fabien.dessenne@st.com>
Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
Signed-off-by: Loic Pallardy <loic.pallardy@st.com>
Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
[bjorn: Fixup of dev_dbg types and cast of int to pointer in mbox send]
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

drivers/remoteproc/Kconfig

@@ -197,6 +197,21 @@ config ST_REMOTEPROC
 config ST_SLIM_REMOTEPROC
 	tristate
 
+config STM32_RPROC
+	tristate "STM32 remoteproc support"
+	depends on ARCH_STM32
+	depends on REMOTEPROC
+	select MAILBOX
+	help
+	  Say y here to support STM32 MCU processors via the
+	  remote processor framework.
+
+	  You want to say y here in order to enable AMP
+	  use-cases to run on your platform (dedicated firmware could be
+	  offloaded to remote MCU processors using this framework).
+
+	  This can be either built-in or a loadable module.
+
 endif # REMOTEPROC
 
 endmenu

drivers/remoteproc/Makefile

@@ -26,3 +26,4 @@ qcom_wcnss_pil-y			+= qcom_wcnss.o
 qcom_wcnss_pil-y			+= qcom_wcnss_iris.o
 obj-$(CONFIG_ST_REMOTEPROC)		+= st_remoteproc.o
 obj-$(CONFIG_ST_SLIM_REMOTEPROC)	+= st_slim_rproc.o
+obj-$(CONFIG_STM32_RPROC)		+= stm32_rproc.o