[PATCH v5 07/23] FWU: STM32MP1: Add support to read boot index from backup register

[Sughosh Ganu]

The FWU Multi Bank Update feature allows the platform to boot the
firmware images from one of the partitions(banks). The first stage
bootloader(fsbl) passes the value of the boot index, i.e. the bank
from which the firmware images were booted from to U-Boot. On the
STM32MP157C-DK2 board, this value is passed through one of the SoC's
backup register. Add a function to read the boot index value from the
backup register.

Signed-off-by: Sughosh Ganu <sughosh.ganu at linaro.org>
---
 arch/arm/mach-stm32mp/include/mach/stm32.h | 4 ++++
 board/st/stm32mp1/stm32mp1.c               | 7 +++++++
 include/fwu.h                              | 2 +-
 3 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mach-stm32mp/include/mach/stm32.h b/arch/arm/mach-stm32mp/include/mach/stm32.h
index 47e88fc3dc..40995ee142 100644
--- a/arch/arm/mach-stm32mp/include/mach/stm32.h
+++ b/arch/arm/mach-stm32mp/include/mach/stm32.h
@@ -100,6 +100,7 @@ enum boot_device {
 #define TAMP_BACKUP_REGISTER(x)		(STM32_TAMP_BASE + 0x100 + 4 * x)
 #define TAMP_BACKUP_MAGIC_NUMBER	TAMP_BACKUP_REGISTER(4)
 #define TAMP_BACKUP_BRANCH_ADDRESS	TAMP_BACKUP_REGISTER(5)
+#define TAMP_FWU_BOOT_INFO_REG		TAMP_BACKUP_REGISTER(10)
 #define TAMP_COPRO_RSC_TBL_ADDRESS	TAMP_BACKUP_REGISTER(17)
 #define TAMP_COPRO_STATE		TAMP_BACKUP_REGISTER(18)
 #define TAMP_BOOT_CONTEXT		TAMP_BACKUP_REGISTER(20)
@@ -118,6 +119,9 @@ enum boot_device {
 #define TAMP_BOOT_INSTANCE_MASK		GENMASK(3, 0)
 #define TAMP_BOOT_FORCED_MASK		GENMASK(7, 0)
 #define TAMP_BOOT_DEBUG_ON		BIT(16)
+#define TAMP_FWU_BOOT_IDX_MASK		GENMASK(3, 0)
+
+#define TAMP_FWU_BOOT_IDX_OFFSET	0
 
 enum forced_boot_mode {
 	BOOT_NORMAL = 0x00,
diff --git a/board/st/stm32mp1/stm32mp1.c b/board/st/stm32mp1/stm32mp1.c
index e68bf09955..dff41ed6f6 100644
--- a/board/st/stm32mp1/stm32mp1.c
+++ b/board/st/stm32mp1/stm32mp1.c
@@ -1081,4 +1081,11 @@ int fwu_plat_get_update_index(u32 *update_idx)
 	return ret;
 }
 
+void fwu_plat_get_bootidx(void *boot_idx)
+{
+	u32 *bootidx = boot_idx;
+
+	*bootidx = (readl(TAMP_FWU_BOOT_INFO_REG) >>
+		    TAMP_FWU_BOOT_IDX_OFFSET) & TAMP_FWU_BOOT_IDX_MASK;
+}
 #endif /* CONFIG_FWU_MULTI_BANK_UPDATE */
diff --git a/include/fwu.h b/include/fwu.h
index 36e58afa29..41774ff9e2 100644
--- a/include/fwu.h
+++ b/include/fwu.h
@@ -46,7 +46,7 @@ int fwu_revert_boot_index(void);
 int fwu_accept_image(efi_guid_t *img_type_id, u32 bank);
 int fwu_clear_accept_image(efi_guid_t *img_type_id, u32 bank);
 
-
+void fwu_plat_get_bootidx(void *boot_idx);
 int fwu_plat_get_alt_num(struct udevice *dev, efi_guid_t *image_guid,
 			 int *alt_num);
 int fwu_plat_get_update_index(u32 *update_idx);
-- 
2.25.1