[TOPIC] Implement reset to EDL for qcs9100

arch/arm/cpu/armv8/fwcall.c

@@ -129,3 +129,18 @@ void __noreturn psci_system_off(void)
 	while (1)
 		;
 }
+
+int psci_features(u32 psci_func_id)
+{
+	struct pt_regs regs;
+
+	regs.regs[0] = ARM_PSCI_1_0_FN_PSCI_FEATURES;
+	regs.regs[1] = psci_func_id;
+
+	if (use_smc_for_psci)
+		smc_call(&regs);
+	else
+		hvc_call(&regs);
+
+	return regs.regs[0];
+}

arch/arm/include/asm/system.h

@@ -342,6 +342,7 @@ void smc_call(struct pt_regs *args);
 void __noreturn psci_system_reset(void);
 void __noreturn psci_system_reset2(u32 reset_level, u32 cookie);
 void __noreturn psci_system_off(void);
+int psci_features(u32 psci_func_id);
 
 #ifdef CONFIG_ARMV8_PSCI
 extern char __secure_start[];

cmd/boot.c

@@ -60,6 +60,9 @@ U_BOOT_CMD(
 	reset, 2, 0,	do_reset,
 	"Perform RESET of the CPU",
 	"- cold boot without level specifier\n"
+#ifdef CONFIG_SYSRESET_QCOM_PSCI
+	"reset -edl - Boot to Emergency DownLoad mode\n"
+#endif
 	"reset -w - warm reset if implemented"
 );
 

configs/qcom_defconfig

@@ -130,7 +130,9 @@ CONFIG_QCOM_RPMH=y
 CONFIG_SPMI_MSM=y
 CONFIG_SYSINFO=y
 CONFIG_SYSINFO_SMBIOS=y
+CONFIG_SYSRESET_CMD_RESET_ARGS=y
 CONFIG_SYSRESET_QCOM_PSHOLD=y
+CONFIG_SYSRESET_QCOM_PSCI=y
 CONFIG_USB=y
 CONFIG_USB_XHCI_HCD=y
 CONFIG_USB_XHCI_DWC3=y

doc/usage/cmd/reset.rst

@@ -22,6 +22,8 @@ DDR and peripherals, on some boards also resets external PMIC.
 -w
     Do warm WARM, reset CPU but keep peripheral/DDR/PMIC active.
 
+-edl
+    Boot to Emergency DownLoad mode on supported Qualcomm platforms.
 
 Return value
 ------------

drivers/firmware/psci.c

@@ -186,6 +186,10 @@ static int psci_bind(struct udevice *dev)
 					 NULL);
 		if (ret)
 			pr_debug("PSCI System Reset was not bound.\n");
+		if (IS_ENABLED(CONFIG_SYSRESET_QCOM_PSCI) &&
+		    device_bind_driver(dev, "qcom_psci-sysreset",
+				       "qcom_psci-sysreset", NULL))
+			pr_debug("QCOM PSCI System Reset was not bound.\n");
 	}
 
 	/* From PSCI v1.0 onward we can discover services through ARM_SMCCC_FEATURE */

drivers/sysreset/Kconfig

@@ -49,6 +49,14 @@ config SYSRESET_CMD_RESET
 	help
 	  Enable sysreset implementation of the reset command.
 
+config SYSRESET_CMD_RESET_ARGS
+	bool "Enable reset command to take arguments"
+	help
+	  Pass on the arguments received by the 'reset' command to the
+	  sysreset driver(s). The sysreset driver(s) may make use of the
+	  additional arguments for implementing arch/board specific
+	  functionality.
+
 if CMD_POWEROFF
 
 config SYSRESET_CMD_POWEROFF
@@ -293,6 +301,12 @@ config SYSRESET_RAA215300
 	help
 	  Add support for the system reboot via the Renesas RAA215300 PMIC.
 
+config SYSRESET_QCOM_PSCI
+	bool "Support reset to EDL for Qualcomm SoCs via PSCI"
+	help
+	  Add support for the reset to EDL (Emergency Download) on Qualcomm
+	  SoCs via PSCI.
+
 config SYSRESET_QCOM_PSHOLD
 	bool "Support sysreset for Qualcomm SoCs via PSHOLD"
 	help

drivers/sysreset/Makefile

@@ -30,6 +30,7 @@ obj-$(CONFIG_SYSRESET_RESETCTL) += sysreset_resetctl.o
 obj-$(CONFIG_$(PHASE_)SYSRESET_AT91) += sysreset_at91.o
 obj-$(CONFIG_$(PHASE_)SYSRESET_X86) += sysreset_x86.o
 obj-$(CONFIG_SYSRESET_RAA215300) += sysreset_raa215300.o
+obj-$(CONFIG_SYSRESET_QCOM_PSCI) += sysreset_qcom-psci.o
 obj-$(CONFIG_SYSRESET_QCOM_PSHOLD) += sysreset_qcom-pshold.o
 obj-$(CONFIG_TARGET_XTFPGA) += sysreset_xtfpga.o
 obj-$(CONFIG_SYSRESET_QEMU_VIRT_CTRL) += sysreset_qemu_virt_ctrl.o

drivers/sysreset/sysreset-uclass.c

@@ -32,6 +32,18 @@ int sysreset_request(struct udevice *dev, enum sysreset_t type)
 	return ops->request(dev, type);
 }
 
+#if IS_ENABLED(CONFIG_SYSRESET_CMD_RESET_ARGS)
+int sysreset_request_arg(struct udevice *dev, int argc, char * const argv[])
+{
+	struct sysreset_ops *ops = sysreset_get_ops(dev);
+
+	if (!ops->request_arg)
+		return -ENOSYS;
+
+	return ops->request_arg(dev, argc, argv);
+}
+#endif /* CONFIG_SYSRESET_CMD_RESET_ARGS */
+
 int sysreset_get_status(struct udevice *dev, char *buf, int size)
 {
 	struct sysreset_ops *ops = sysreset_get_ops(dev);
@@ -71,6 +83,26 @@ int sysreset_walk(enum sysreset_t type)
 	return ret;
 }
 
+#if IS_ENABLED(CONFIG_SYSRESET_CMD_RESET_ARGS)
+int sysreset_walk_arg(int argc, char * const argv[])
+{
+	struct udevice *dev;
+	int ret = -ENOSYS;
+
+	while (ret != -EINPROGRESS && ret != -EPROTONOSUPPORT) {
+		for (uclass_first_device(UCLASS_SYSRESET, &dev);
+		     dev;
+		     uclass_next_device(&dev)) {
+			ret = sysreset_request_arg(dev, argc, argv);
+			if (ret == -EINPROGRESS || ret == -EPROTONOSUPPORT)
+				break;
+		}
+	}
+
+	return ret;
+}
+#endif /* CONFIG_SYSRESET_CMD_RESET_ARGS */
+
 int sysreset_get_last_walk(void)
 {
 	struct udevice *dev;
@@ -132,6 +164,11 @@ int do_reset(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
 	printf("resetting ...\n");
 	mdelay(100);
 
+#if IS_ENABLED(CONFIG_SYSRESET_CMD_RESET_ARGS)
+	if (argc > 1 && sysreset_walk_arg(argc, argv) == -EINPROGRESS)
+		return 0;
+#endif
+
 	sysreset_walk_halt(reset_type);
 
 	return 0;

drivers/sysreset/sysreset_qcom-psci.c

@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2017 Masahiro Yamada <yamada.masahiro@socionext.com>
+ * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
+ */
+
+#include <dm.h>
+#include <sysreset.h>
+#include <asm/system.h>
+#include <linux/errno.h>
+#include <linux/psci.h>
+#include <asm/psci.h>
+
+static int qcom_psci_sysreset_get_status(struct udevice *dev, char *buf, int size)
+{
+	return -EOPNOTSUPP;
+}
+
+static int qcom_psci_sysreset_request_arg(struct udevice *dev, int argc,
+					  char * const argv[])
+{
+	if (!strncasecmp(argv[1], "-edl", 4)) {
+		/* Supported in qcs9100, qcs8300, sc7280, qcs615 */
+		if (psci_features(ARM_PSCI_1_1_FN64_SYSTEM_RESET2) ==
+							ARM_PSCI_RET_SUCCESS) {
+			psci_system_reset2(0, 1);
+			return -EINPROGRESS;
+		}
+		printf("PSCI SYSTEM_RESET2 not supported\n");
+	}
+
+	return -EPROTONOSUPPORT;
+}
+
+static struct sysreset_ops qcom_psci_sysreset_ops = {
+	.request_arg = qcom_psci_sysreset_request_arg,
+	.get_status = qcom_psci_sysreset_get_status,
+};
+
+U_BOOT_DRIVER(qcom_psci_sysreset) = {
+	.name = "qcom_psci-sysreset",
+	.id = UCLASS_SYSRESET,
+	.ops = &qcom_psci_sysreset_ops,
+	.flags = DM_FLAG_PRE_RELOC,
+};

include/sysreset.h

@@ -43,6 +43,24 @@ struct sysreset_ops {
 	 * (in which case this method will not actually return)
 	 */
 	int (*request)(struct udevice *dev, enum sysreset_t type);
+
+	/**
+	 * @request_arg: Reset handler implementations that might need to process
+	 *		 arguments given to the 'reset' command.
+	 *
+	 * Note that this function may return before the reset takes effect.
+	 *
+	 * @dev:	Device to be used for system reset
+	 * @argc:	No. of items in @argv
+	 * @argv:	Arguments given to 'reset' command
+	 * Return:
+	 * -EINPROGRESS		if the reset has started and will complete soon
+	 * -EPROTONOSUPPORT	if not supported by this device
+	 * 0			if the reset has already happened
+	 * (in which case this method will not actually return)
+	 */
+	int (*request_arg)(struct udevice *dev, int argc, char * const argv[]);
+
 	/**
 	 * @get_status:	get printable reset status information
 	 *