[PATCH 15/20] arm: mach-k3: j721s2: Enable LPM resume flow

[Richard Genoud (TI)]

From: "Thomas Richard (TI)" <thomas.richard at bootlin.com>

Add the board specific part of the exit retention sequence for k3-ddrss:
- exit DDR from retention
- de-assert the DDR_RET pin
- restore DDR max frequency
- exit DDR from low power
Then generic resume path is run.

Signed-off-by: Thomas Richard (TI) <thomas.richard at bootlin.com>
---
 arch/arm/mach-k3/j721s2/j721s2_init.c | 73 +++++++++++++++++++++++++--
 1 file changed, 69 insertions(+), 4 deletions(-)

diff --git a/arch/arm/mach-k3/j721s2/j721s2_init.c b/arch/arm/mach-k3/j721s2/j721s2_init.c
index b5453d8895d4..0dcdc817e5a5 100644
--- a/arch/arm/mach-k3/j721s2/j721s2_init.c
+++ b/arch/arm/mach-k3/j721s2/j721s2_init.c
@@ -16,12 +16,17 @@
 #include <dm/uclass-internal.h>
 #include <dm/pinctrl.h>
 #include <dm/root.h>
+#include <mach/k3-ddr.h>
 #include <mmc.h>
+#include <power/pmic.h>
 #include <remoteproc.h>
 
 #include "../sysfw-loader.h"
+#include "../lpm-common.h"
 #include "../common.h"
 
+#define MAX_DDR_CONTROLLERS	2
+
 /* NAVSS North Bridge (NB) */
 #define NAVSS0_NBSS_NB0_CFG_MMRS		0x03702000
 #define NAVSS0_NBSS_NB1_CFG_MMRS		0x03703000
@@ -250,12 +255,42 @@ bool check_rom_loaded_sysfw(void)
 	return is_rom_loaded_sysfw(&bootdata);
 }
 
+#define GPIO_OUT_1 0x3D
+#define DDR_RET_VAL BIT(3)
+#define PMIC_NSLEEP_REG 0x86
+
+static void k3_deassert_ddr_ret(void)
+{
+	struct udevice *pmic;
+	int regval;
+	int err;
+
+	err = uclass_get_device_by_name(UCLASS_PMIC,
+					"pmic at 4c", &pmic);
+	if (err) {
+		printf("Getting PMIC at 4c init failed: %d\n", err);
+		return;
+	}
+	/* Set DDR_RET Signal Low on PMIC B */
+	regval = pmic_reg_read(pmic, GPIO_OUT_1) & ~DDR_RET_VAL;
+	regval &= ~(1 << (4 - 1));
+	pmic_reg_write(pmic, GPIO_OUT_1, regval);
+}
+
+__weak bool j7xx_board_is_resuming(void)
+{
+	return false;
+}
+
 void k3_mem_init(void)
 {
 	struct udevice *dev;
-	int ret;
+	int ret, ctrl = 0;
 
 	if (IS_ENABLED(CONFIG_K3_J721E_DDRSS)) {
+		struct udevice *devs[MAX_DDR_CONTROLLERS];
+		struct k3_ddrss_regs regs[MAX_DDR_CONTROLLERS];
+
 		ret = uclass_get_device_by_name(UCLASS_MISC, "msmc", &dev);
 		if (ret)
 			panic("Probe of msmc failed: %d\n", ret);
@@ -263,10 +298,40 @@ void k3_mem_init(void)
 		ret = uclass_get_device(UCLASS_RAM, 0, &dev);
 		if (ret)
 			panic("DRAM 0 init failed: %d\n", ret);
+		devs[0] = dev;
+		ctrl++;
 
-		ret = uclass_next_device_err(&dev);
-		if (ret && ret != -ENODEV)
-			panic("DRAM 1 init failed: %d\n", ret);
+		while (ctrl < MAX_DDR_CONTROLLERS) {
+			ret = uclass_next_device_err(&dev);
+			if (ret == -ENODEV)
+				break;
+
+			if (ret)
+				panic("DRAM %d init failed: %d\n", ctrl, ret);
+			devs[ctrl] = dev;
+			ctrl++;
+		}
+
+		if (j7xx_board_is_resuming()) {
+			/* exit DDRs from retention */
+			for (ctrl = 0; ctrl < MAX_DDR_CONTROLLERS; ctrl++)
+				k3_ddrss_lpddr4_exit_retention(devs[ctrl],
+							       &regs[ctrl]);
+
+			/* de-assert DDR_RET pin */
+			k3_deassert_ddr_ret();
+
+			/* restore DDR max frequency */
+			for (ctrl = 0; ctrl < MAX_DDR_CONTROLLERS; ctrl++)
+				k3_ddrss_lpddr4_change_freq(devs[ctrl]);
+
+			/* exit DDR from low power */
+			for (ctrl = 0; ctrl < MAX_DDR_CONTROLLERS; ctrl++)
+				k3_ddrss_lpddr4_exit_low_power(devs[ctrl],
+							       &regs[ctrl]);
+
+			do_resume();
+		}
 	}
 	spl_enable_cache();
 }