[PATCH v5 10/21] board: mach-k3: r5: common: Store wakeup reason on scratchpad memory

["Richard Genoud (TI)" <richard.genoud@bootlin.com>]

From: Abhash Kumar Jha <a-kumar2@ti.com>

While resuming from suspend, the wakeup reason need to be stored
and this will be used by the Linux kernel once its up.

Use the 32 bytes of MCU_PSRAM0_RAM area (addr = 0x40280000) to
store the wakeup reason.

Read the value as soon as it starts and store it internally.

Signed-off-by: Abhash Kumar Jha <a-kumar2@ti.com>
Co-developed-by: Richard Genoud (TI) <richard.genoud@bootlin.com>
Signed-off-by: Richard Genoud (TI) <richard.genoud@bootlin.com>
---
 arch/arm/mach-k3/Kconfig         | 10 ++++++++++
 arch/arm/mach-k3/r5/lpm-common.c | 24 ++++++++++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/arch/arm/mach-k3/Kconfig b/arch/arm/mach-k3/Kconfig
index a32ed3a9683f..bbb62fa617fc 100644
--- a/arch/arm/mach-k3/Kconfig
+++ b/arch/arm/mach-k3/Kconfig
@@ -101,6 +101,16 @@ config SYS_K3_BOOT_CORE_ID
 	int
 	default 16
 
+config SYS_K3_SCRATCH_LPM_ADDR
+	hex
+	default 0x40280000 if SOC_K3_J721E || SOC_K3_J7200 || SOC_K3_J784S4
+	default 0x0
+	help
+	  Address where the wake-up reason is stored at resume (32 bits).
+	  It will be read by the Linux kernel once its up.
+	  On J7200/J784s4 the MCU_PSRAM0_RAM is used by default.
+	  Set it to 0 if unused.
+
 config K3_EARLY_CONS
 	bool "Activate to allow for an early console during SPL"
 	depends on SPL
diff --git a/arch/arm/mach-k3/r5/lpm-common.c b/arch/arm/mach-k3/r5/lpm-common.c
index 559e1b5f681a..0e5feae6d12d 100644
--- a/arch/arm/mach-k3/r5/lpm-common.c
+++ b/arch/arm/mach-k3/r5/lpm-common.c
@@ -29,6 +29,11 @@
 /* PMIC register where the magic value resides */
 #define K3_LPM_SCRATCH_PAD_REG_3 0xcb
 
+/* Wake-up source IDs */
+#define K3_LPM_WAKE_SOURCE_MAIN_IO 0x80
+#define K3_LPM_WAKE_SOURCE_MCU_IO 0x81
+#define K3_LPM_WAKE_SOURCE_PMIC_GPIO 0xB0
+
 #define IO_ISO_STATUS BIT(25)
 #define FW_IMAGE_SIZE 0x80000
 
@@ -40,6 +45,11 @@ struct lpm_addr_info {
 	u32 size;
 };
 
+struct lpm_scratch_space {
+	u16 wake_src;
+	u16 reserved;
+} __packed;
+
 __weak void clear_isolation(void) { }
 
 /* This is used by J722s */
@@ -75,6 +85,7 @@ void k3_deassert_ddr_ret(const char *pmic_name, unsigned int ddr_ret_val,
 /* in board_init_f(), there's no BSS, so we can't use global/static variables */
 bool j7xx_board_is_resuming(void)
 {
+	struct lpm_scratch_space *lpm_scratch;
 	struct udevice *pmic, *i2c;
 	u32 pmctrl_val = 0;
 	int ret, magic;
@@ -85,7 +96,18 @@ bool j7xx_board_is_resuming(void)
 #ifdef PMCTRL_IO_LPM
 	pmctrl_val = readl(PMCTRL_IO_LPM);
 #endif
+	lpm_scratch = (struct lpm_scratch_space *)CONFIG_SYS_K3_SCRATCH_LPM_ADDR;
+	if (lpm_scratch) {
+		lpm_scratch->wake_src = 0;
+		lpm_scratch->reserved = 0;
+	}
 	if ((pmctrl_val & IO_ISO_STATUS) == IO_ISO_STATUS) {
+		if (lpm_scratch) {
+			if (IS_ENABLED(CONFIG_SOC_K3_J784S4))
+				lpm_scratch->wake_src = K3_LPM_WAKE_SOURCE_MCU_IO;
+			else
+				lpm_scratch->wake_src = K3_LPM_WAKE_SOURCE_MAIN_IO;
+		}
 		clear_isolation();
 		gd_set_k3_resuming(K3_RESUME_STATE_RESUMING);
 		debug("board is resuming from IO_DDR mode\n");
@@ -127,6 +149,8 @@ bool j7xx_board_is_resuming(void)
 
 	if (magic == K3_LPM_MAGIC_SUSPEND) {
 		debug("%s: board is resuming\n", __func__);
+		if (lpm_scratch)
+			lpm_scratch->wake_src = K3_LPM_WAKE_SOURCE_PMIC_GPIO;
 		gd_set_k3_resuming(K3_RESUME_STATE_RESUMING);
 
 		/* clean magic suspend */