mailbox: Add driver for Broadcom FlexRM ring manager

Some of the Broadcom iProc SoCs have FlexRM ring manager
which provides a ring-based programming interface to various
offload engines (e.g. RAID, Crypto, etc).

This patch adds a common mailbox driver for Broadcom FlexRM
ring manager which can be shared by various offload engine
drivers (implemented as mailbox clients).

Reviewed-by: Ray Jui <ray.jui@broadcom.com>
Reviewed-by: Scott Branden <scott.branden@broadcom.com>
Reviewed-by: Pramod KUMAR <pramod.kumar@broadcom.com>
Signed-off-by: Anup Patel <anup.patel@broadcom.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

drivers/mailbox/Kconfig

@@ -151,4 +151,15 @@ config BCM_PDC_MBOX
 	  Mailbox implementation for the Broadcom FlexSparx DMA ring manager,
 	  which provides access to various offload engines on Broadcom
 	  SoCs, including FA2/FA+ on Northstar Plus and PDC on Northstar 2.
+
+config BCM_FLEXRM_MBOX
+	tristate "Broadcom FlexRM Mailbox"
+	depends on ARM64 || COMPILE_TEST
+	depends on HAS_DMA
+	select GENERIC_MSI_IRQ_DOMAIN
+	default ARCH_BCM_IPROC
+	help
+	  Mailbox implementation of the Broadcom FlexRM ring manager,
+	  which provides access to various offload engines on Broadcom
+	  SoCs. Say Y here if you want to use the Broadcom FlexRM.
 endif

drivers/mailbox/Makefile

@@ -30,4 +30,6 @@ obj-$(CONFIG_HI6220_MBOX)	+= hi6220-mailbox.o
 
 obj-$(CONFIG_BCM_PDC_MBOX)	+= bcm-pdc-mailbox.o
 
+obj-$(CONFIG_BCM_FLEXRM_MBOX)	+= bcm-flexrm-mailbox.o
+
 obj-$(CONFIG_TEGRA_HSP_MBOX)	+= tegra-hsp.o