[PATCH v4 14/19] arm: mach-k3: j784s4: Enable LPM resume flow for J784s4/J742s2 SOCs

[Richard Genoud (TI)]

Add support for resuming from suspend in board_init_f.
The resume state of the SOC is identified and lpm resume
sequence is followed accordingly.

First, add the board specific part of the exit retention sequence for
k3-ddrss following the DDR resume sequence:
   - exit DDR from retention
   - de-assert the DDR_RET pin
   - restore DDR max frequency
   - exit DDR from low power

The self-refresh exit sequence is performed in a loop for each DDR
controller. (J784S4 has 4 DDR controllers and J742S2 has only 2)

Select the number of ddr controllers on the basis of
CONFIG_TARGET_J742S2_R5_EVM build flag.

Then:
   - Extract context address from devicetree and send to TIFS.
   - Power on the rproc cluster.
   - Replay the certificates attached to saved images of ATF and OPTEE.
   - Resume sequence for context restore and rproc resume.
   - Image entry to DM firmware.
(All those steps are done in do_resume())

The context address area is firewalled by TIFS to protect it from
other hosts.

Co-developed-by: Gregory CLEMENT (TI) <gregory.clement at bootlin.com>
Signed-off-by: Gregory CLEMENT (TI) <gregory.clement at bootlin.com>
Signed-off-by: Thomas Richard (TI) <thomas.richard at bootlin.com>
Co-developed-by: Prasanth Babu Mantena <p-mantena at ti.com>
Signed-off-by: Prasanth Babu Mantena <p-mantena at ti.com>
Co-developed-by: Abhash Kumar Jha <a-kumar2 at ti.com>
Signed-off-by: Abhash Kumar Jha <a-kumar2 at ti.com>
Signed-off-by: Richard Genoud (TI) <richard.genoud at bootlin.com>
---
 arch/arm/mach-k3/j784s4/j784s4_init.c | 44 +++++++++++++++++++++++++--
 board/ti/j784s4/evm.c                 |  3 +-
 2 files changed, 44 insertions(+), 3 deletions(-)

diff --git a/arch/arm/mach-k3/j784s4/j784s4_init.c b/arch/arm/mach-k3/j784s4/j784s4_init.c
index 507b7ab685ad..d49249fa233a 100644
--- a/arch/arm/mach-k3/j784s4/j784s4_init.c
+++ b/arch/arm/mach-k3/j784s4/j784s4_init.c
@@ -18,11 +18,21 @@
 #include <mmc.h>
 #include <remoteproc.h>
 #include <k3_bist.h>
+#include <power/pmic.h>
+#include <mach/k3-ddr.h>
 
 #include "../sysfw-loader.h"
 #include "../common.h"
+#include "../lpm-common.h"
 
-#define J784S4_MAX_DDR_CONTROLLERS	4
+#if IS_ENABLED(CONFIG_TARGET_J742S2_R5_EVM)
+#define MAX_DDR_CONTROLLERS	2
+#else
+#define MAX_DDR_CONTROLLERS	4
+#endif
+
+/* DDR retention bits */
+#define DDR_RET_VAL BIT(5)
 
 #define CTRL_MMR_CFG0_AUDIO_REFCLK1_CTRL	0x001082e4
 #define AUDIO_REFCLK1_DEFAULT			0x1c
@@ -279,20 +289,50 @@ void k3_mem_init(void)
 	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(UCLASS_RAM, 0, &dev);
 		if (ret)
 			panic("DRAM 0 init failed: %d\n", ret);
+
+		devs[0] = dev;
 		ctrl++;
 
-		while (ctrl < J784S4_MAX_DDR_CONTROLLERS) {
+		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("pmic at 48", DDR_RET_VAL, 0, false);
+
+			/* 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]);
+			}
+			printf("Initialized %d DRAM controllers\n", ctrl);
+
+			do_resume();
+		}
 		printf("Initialized %d DRAM controllers\n", ctrl);
 	}
 
diff --git a/board/ti/j784s4/evm.c b/board/ti/j784s4/evm.c
index 179a26d570fd..3b345528be5f 100644
--- a/board/ti/j784s4/evm.c
+++ b/board/ti/j784s4/evm.c
@@ -61,7 +61,8 @@ int board_late_init(void)
 }
 #endif
 
-#if (IS_ENABLED(CONFIG_SPL_BUILD) && IS_ENABLED(CONFIG_TARGET_J784S4_R5_EVM))
+#if (IS_ENABLED(CONFIG_SPL_BUILD) && (IS_ENABLED(CONFIG_TARGET_J784S4_R5_EVM) || \
+				      IS_ENABLED(CONFIG_TARGET_J742S2_R5_EVM)))
 void clear_isolation(void)
 {
 	int ret;