[PATCH v2 1/2] sysreset: Implement PSCI based reset to EDL mode for QCOM SoCs

[Varadarajan Narayanan]

The SYSRESET_PSCI interface presently available doesn't support booting
into Emergency DownLoad (EDL) mode. The EDL mode is used to flash the
board with different firmware.

Since EDL is Qcom specific, implement a Qcom specific SYSRESET_PSCI
handler that handles resetting to EDL in addition to the usual cold/warm
reset and poweroff.

Signed-off-by: Varadarajan Narayanan <quic_varada at quicinc.com>
---
v2: * Update commit message
    * Elaborate Kconfig help text
    * Use '-edl' instead of 'edl' for consistency with other arguments of reset
      command
    * Remove 'weak' for qcom_psci_sysreset_get_status() and make it static
    * Mention 'SYSRESET_EDL' is Qcom specific in the enum's comments
---
 drivers/firmware/psci.c               |  4 +++
 drivers/sysreset/Kconfig              |  7 ++++
 drivers/sysreset/Makefile             |  1 +
 drivers/sysreset/sysreset-uclass.c    |  7 ++--
 drivers/sysreset/sysreset_qcom-psci.c | 48 +++++++++++++++++++++++++++
 include/sysreset.h                    |  7 ++++
 6 files changed, 72 insertions(+), 2 deletions(-)
 create mode 100644 drivers/sysreset/sysreset_qcom-psci.c

diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c
index 2e3223e1c32..b6838a244d2 100644
--- a/drivers/firmware/psci.c
+++ b/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 */
diff --git a/drivers/sysreset/Kconfig b/drivers/sysreset/Kconfig
index 4972905482a..d407c322bdb 100644
--- a/drivers/sysreset/Kconfig
+++ b/drivers/sysreset/Kconfig
@@ -285,6 +285,13 @@ config SYSRESET_RAA215300
 	help
 	  Add support for the system reboot via the Renesas RAA215300 PMIC.
 
+config SYSRESET_QCOM_PSCI
+	bool "Support sysreset for Qualcomm SoCs via PSCI"
+	help
+	  Add support for the system reboot on Qualcomm SoCs via PSCI.
+	  This allows warm/cold reset, poweroff and reset to EDL (Emergency
+	  Download)
+
 config SYSRESET_QCOM_PSHOLD
 	bool "Support sysreset for Qualcomm SoCs via PSHOLD"
 	help
diff --git a/drivers/sysreset/Makefile b/drivers/sysreset/Makefile
index ded91a4d325..58eb0e356e1 100644
--- a/drivers/sysreset/Makefile
+++ b/drivers/sysreset/Makefile
@@ -29,5 +29,6 @@ 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
diff --git a/drivers/sysreset/sysreset-uclass.c b/drivers/sysreset/sysreset-uclass.c
index 536ac727142..ff9bc962ec0 100644
--- a/drivers/sysreset/sysreset-uclass.c
+++ b/drivers/sysreset/sysreset-uclass.c
@@ -125,8 +125,11 @@ int do_reset(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
 	if (argc > 2)
 		return CMD_RET_USAGE;
 
-	if (argc == 2 && argv[1][0] == '-' && argv[1][1] == 'w') {
-		reset_type = SYSRESET_WARM;
+	if (argc == 2) {
+		if (argv[1][0] == '-' && argv[1][1] == 'w')
+			reset_type = SYSRESET_WARM;
+		else if (!strncmp("-edl", argv[1], 4))
+			reset_type = SYSRESET_EDL;
 	}
 
 	printf("resetting ...\n");
diff --git a/drivers/sysreset/sysreset_qcom-psci.c b/drivers/sysreset/sysreset_qcom-psci.c
new file mode 100644
index 00000000000..9d0606c059b
--- /dev/null
+++ b/drivers/sysreset/sysreset_qcom-psci.c
@@ -0,0 +1,48 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2017 Masahiro Yamada <yamada.masahiro at 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>
+
+static int qcom_psci_sysreset_get_status(struct udevice *dev, char *buf, int size)
+{
+	return -EOPNOTSUPP;
+}
+
+static int qcom_psci_sysreset_request(struct udevice *dev, enum sysreset_t type)
+{
+	switch (type) {
+	case SYSRESET_WARM:
+	case SYSRESET_COLD:
+		psci_sys_reset(type);
+		break;
+	case SYSRESET_POWER_OFF:
+		psci_sys_poweroff();
+		break;
+	case SYSRESET_EDL:
+		psci_system_reset2(0, 1);
+		break;
+	default:
+		return -EPROTONOSUPPORT;
+	}
+
+	return -EINPROGRESS;
+}
+
+static struct sysreset_ops qcom_psci_sysreset_ops = {
+	.request = qcom_psci_sysreset_request,
+	.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,
+};
diff --git a/include/sysreset.h b/include/sysreset.h
index ff20abdeed3..d0f60ed2456 100644
--- a/include/sysreset.h
+++ b/include/sysreset.h
@@ -21,6 +21,13 @@ enum sysreset_t {
 	SYSRESET_POWER,
 	/** @SYSRESET_POWER_OFF: turn off power */
 	SYSRESET_POWER_OFF,
+#if IS_ENABLED(CONFIG_SYSRESET_QCOM_PSCI)
+	/**
+	 * @SYSRESET_EDL: Reset and boot into Emergency DownLoader.
+	 *		  This is supported only in recent Qcom SoCs.
+	 */
+	SYSRESET_EDL,
+#endif
 	/** @SYSRESET_COUNT: number of available reset types */
 	SYSRESET_COUNT,
 };
-- 
2.34.1