[PATCH v10 07/15] 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>
Reviewed-by: Patrick Delaunay <patrick.delaunay at foss.st.com>
Acked-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>
---
Changes since V9:
* Change the fwu_plat_get_bootidx() function to take an uint * as the
  function parameter instead of the void * as suggested by Etienne.

 arch/arm/mach-stm32mp/include/mach/stm32.h |  5 +++++
 board/st/stm32mp1/stm32mp1.c               | 23 ++++++++++++++++++++++
 include/fwu.h                              | 12 +++++++++++
 3 files changed, 40 insertions(+)

diff --git a/arch/arm/mach-stm32mp/include/mach/stm32.h b/arch/arm/mach-stm32mp/include/mach/stm32.h
index c70375a723..c85ae6a34e 100644
--- a/arch/arm/mach-stm32mp/include/mach/stm32.h
+++ b/arch/arm/mach-stm32mp/include/mach/stm32.h
@@ -112,11 +112,16 @@ enum boot_device {
 #ifdef CONFIG_STM32MP15x
 #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)
 #define TAMP_BOOTCOUNT			TAMP_BACKUP_REGISTER(21)
 
+#define TAMP_FWU_BOOT_IDX_MASK		GENMASK(3, 0)
+
+#define TAMP_FWU_BOOT_IDX_OFFSET	0
+
 #define TAMP_COPRO_STATE_OFF		0
 #define TAMP_COPRO_STATE_INIT		1
 #define TAMP_COPRO_STATE_CRUN		2
diff --git a/board/st/stm32mp1/stm32mp1.c b/board/st/stm32mp1/stm32mp1.c
index 6562bcf95b..54b9535405 100644
--- a/board/st/stm32mp1/stm32mp1.c
+++ b/board/st/stm32mp1/stm32mp1.c
@@ -960,3 +960,26 @@ static void board_copro_image_process(ulong fw_image, size_t fw_size)
 }
 
 U_BOOT_FIT_LOADABLE_HANDLER(IH_TYPE_COPRO, board_copro_image_process);
+
+#if defined(CONFIG_FWU_MULTI_BANK_UPDATE)
+
+#include <fwu.h>
+
+/**
+ * fwu_plat_get_bootidx() - Get the value of the boot index
+ * @boot_idx: Boot index value
+ *
+ * Get the value of the bank(partition) from which the platform
+ * has booted. This value is passed to U-Boot from the earlier
+ * stage bootloader which loads and boots all the relevant
+ * firmware images
+ *
+ */
+void fwu_plat_get_bootidx(uint *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 3ff37c628b..484289ed4f 100644
--- a/include/fwu.h
+++ b/include/fwu.h
@@ -244,4 +244,16 @@ int fwu_plat_get_alt_num(struct udevice *dev, efi_guid_t *image_guid,
  *
  */
 int fwu_plat_get_update_index(uint *update_idx);
+
+/**
+ * fwu_plat_get_bootidx() - Get the value of the boot index
+ * @boot_idx: Boot index value
+ *
+ * Get the value of the bank(partition) from which the platform
+ * has booted. This value is passed to U-Boot from the earlier
+ * stage bootloader which loads and boots all the relevant
+ * firmware images
+ *
+ */
+void fwu_plat_get_bootidx(uint *boot_idx);
 #endif /* _FWU_H_ */
-- 
2.34.1