[PATCH] xilinx: versal: add firmware access to PMC multi Boot mode register

[Prasad Kummari]

Added extended support for retrieving the PMC muti boot mode
register via the firmware interface, which is preferred when
U-Boot runs in EL2 and cannot directly access PMC registers
via raw reads. Ideally, all secure registers should be accessed
via xilinx_pm_request(). Introduced the secure
zynqmp_pm_get_pmc_multi_boot_reg() call, which uses
xilinx_pm_request() to read the PMC multi boot mode register.

BootROM increments the MultiBoot register (PMC_MULTI_BOOT) read
address offset by 32 KB and retries. For SD and eMMC boot modes,
it can search up to 8191 FAT files for the identification string.
A 13-bit mask (0x1FFF) is applied to PMC_MULTI_BOOT_MASK to obtain
the correct values in BootROM.

Signed-off-by: Prasad Kummari <prasad.kummari at amd.com>
---
 arch/arm/mach-versal/include/mach/hardware.h |  2 ++
 board/xilinx/versal/board.c                  |  8 ++++++-
 drivers/firmware/firmware-zynqmp.c           | 23 ++++++++++++++++++++
 include/zynqmp_firmware.h                    |  4 ++++
 4 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mach-versal/include/mach/hardware.h b/arch/arm/mach-versal/include/mach/hardware.h
index 9d1c2f0dcfc..b5f80a8e3a9 100644
--- a/arch/arm/mach-versal/include/mach/hardware.h
+++ b/arch/arm/mach-versal/include/mach/hardware.h
@@ -87,6 +87,8 @@ struct crp_regs {
 #define JTAG_MODE	0x00000000
 #define BOOT_MODE_USE_ALT	0x100
 #define BOOT_MODE_ALT_SHIFT	12
+#define PMC_MULTI_BOOT_REG	0xF1110004
+#define PMC_MULTI_BOOT_MASK	0x1FFF
 
 #define FLASH_RESET_GPIO	0xc
 #define WPROT_CRP	0xF126001C
diff --git a/board/xilinx/versal/board.c b/board/xilinx/versal/board.c
index 3046fd7e5f0..6c4a2f5ead6 100644
--- a/board/xilinx/versal/board.c
+++ b/board/xilinx/versal/board.c
@@ -60,12 +60,18 @@ static u8 versal_get_bootmode(void)
 static u32 versal_multi_boot(void)
 {
 	u8 bootmode = versal_get_bootmode();
+	u32 reg = 0;
 
 	/* Mostly workaround for QEMU CI pipeline */
 	if (bootmode == JTAG_MODE)
 		return 0;
 
-	return readl(0xF1110004);
+	if (IS_ENABLED(CONFIG_ZYNQMP_FIRMWARE) && current_el() != 3)
+		reg = zynqmp_pm_get_pmc_multi_boot_reg();
+	else
+		reg = readl(PMC_MULTI_BOOT_REG);
+
+	return reg & PMC_MULTI_BOOT_MASK;
 }
 
 int board_init(void)
diff --git a/drivers/firmware/firmware-zynqmp.c b/drivers/firmware/firmware-zynqmp.c
index 2adc132b4cc..584397ba29a 100644
--- a/drivers/firmware/firmware-zynqmp.c
+++ b/drivers/firmware/firmware-zynqmp.c
@@ -218,6 +218,29 @@ u32 zynqmp_pm_get_bootmode_reg(void)
 	return ret_payload[1];
 }
 
+u32 zynqmp_pm_get_pmc_multi_boot_reg(void)
+{
+	int ret;
+	u32 ret_payload[PAYLOAD_ARG_CNT];
+
+	ret = zynqmp_pm_is_function_supported(PM_IOCTL, IOCTL_READ_REG);
+	if (ret) {
+		printf("%s: IOCTL_READ_REG is not supported failed with error code: %d\n"
+		       , __func__, ret);
+		return 0;
+	}
+
+	ret = xilinx_pm_request(PM_IOCTL, PM_REG_PMC_GLOBAL_NODE, IOCTL_READ_REG,
+				PMC_MULTI_BOOT_MODE_REG_OFFSET, 0, ret_payload);
+	if (ret) {
+		printf("%s: node 0x%x: get_bootmode 0x%x failed\n",
+		       __func__, PM_REG_PMC_GLOBAL_NODE, PMC_MULTI_BOOT_MODE_REG_OFFSET);
+		return 0;
+	}
+
+	return ret_payload[1];
+}
+
 int zynqmp_pm_feature(const u32 api_id)
 {
 	int ret;
diff --git a/include/zynqmp_firmware.h b/include/zynqmp_firmware.h
index e7275f72fac..5474f66078c 100644
--- a/include/zynqmp_firmware.h
+++ b/include/zynqmp_firmware.h
@@ -458,6 +458,7 @@ int zynqmp_mmio_read(const u32 address, u32 *value);
 int zynqmp_mmio_write(const u32 address, const u32 mask, const u32 value);
 int zynqmp_pm_feature(const u32 api_id);
 u32 zynqmp_pm_get_bootmode_reg(void);
+u32 zynqmp_pm_get_pmc_multi_boot_reg(void);
 
 /* Type of Config Object */
 #define PM_CONFIG_OBJECT_TYPE_BASE	0x1U
@@ -504,4 +505,7 @@ struct zynqmp_ipi_msg {
 #define CRP_BOOT_MODE_REG_NODE		0x30000001
 #define CRP_BOOT_MODE_REG_OFFSET	0x200
 
+#define PM_REG_PMC_GLOBAL_NODE	0x30000004
+#define PMC_MULTI_BOOT_MODE_REG_OFFSET	0x4
+
 #endif /* _ZYNQMP_FIRMWARE_H_ */
-- 
2.25.1