soc: qcom: Add snapshot of reboot reason driver

This is a snapshot of the reboot reason driver as of msm-5.15
commit <908a517b050d> ("Merge "sched/walt: remove duplicate
definitions of rt_task_arrival_time"").

Change-Id: I7cf898ac8d4232d1e00a58f97091ebc2e52fcb5b
Signed-off-by: Huang Yiwei <quic_hyiwei@quicinc.com>

drivers/power/reset/Kconfig

@@ -134,6 +134,15 @@ config POWER_RESET_QCOM_PON
 	  power-on and reboot reason, Say Y.
 	  If unsure, Say N.
 
+config POWER_RESET_QCOM_REBOOT_REASON
+        tristate "MSM reboot mode driver"
+        depends on ARCH_QCOM
+        help
+          Support for setting reboot reason on MSM boards.
+          This feature supports commands such as "reboot bootloader"
+          to boot the MSM board to fastboot mode.
+          If unsure, say Y.
+
 config POWER_RESET_OCELOT_RESET
 	bool "Microsemi Ocelot reset driver"
 	depends on MSCC_OCELOT || ARCH_SPARX5 || COMPILE_TEST

drivers/power/reset/Makefile

@@ -16,6 +16,7 @@ obj-$(CONFIG_POWER_RESET_MSM) += msm-poweroff.o
 obj-$(CONFIG_POWER_RESET_MT6323) += mt6323-poweroff.o
 obj-$(CONFIG_POWER_RESET_OXNAS) += oxnas-restart.o
 obj-$(CONFIG_POWER_RESET_QCOM_PON) += qcom-pon.o
+obj-$(CONFIG_POWER_RESET_QCOM_REBOOT_REASON) += qcom-reboot-reason.o
 obj-$(CONFIG_POWER_RESET_OCELOT_RESET) += ocelot-reset.o
 obj-$(CONFIG_POWER_RESET_PIIX4_POWEROFF) += piix4-poweroff.o
 obj-$(CONFIG_POWER_RESET_LTC2952) += ltc2952-poweroff.o

drivers/power/reset/qcom-reboot-reason.c

@@ -0,0 +1,111 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2019, 2021 The Linux Foundation. All rights reserved.
+ */
+
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/reboot.h>
+#include <linux/pm.h>
+#include <linux/of_address.h>
+#include <linux/nvmem-consumer.h>
+
+struct qcom_reboot_reason {
+	struct device *dev;
+	struct notifier_block reboot_nb;
+	struct nvmem_cell *nvmem_cell;
+};
+
+struct poweroff_reason {
+	const char *cmd;
+	unsigned char pon_reason;
+};
+
+static struct poweroff_reason reasons[] = {
+	{ "recovery",			0x01 },
+	{ "bootloader",			0x02 },
+	{ "rtc",			0x03 },
+	{ "dm-verity device corrupted",	0x04 },
+	{ "dm-verity enforcing",	0x05 },
+	{ "keys clear",			0x06 },
+	{}
+};
+
+static int qcom_reboot_reason_reboot(struct notifier_block *this,
+				     unsigned long event, void *ptr)
+{
+	char *cmd = ptr;
+	struct qcom_reboot_reason *reboot = container_of(this,
+		struct qcom_reboot_reason, reboot_nb);
+	struct poweroff_reason *reason;
+
+	if (!cmd)
+		return NOTIFY_OK;
+	for (reason = reasons; reason->cmd; reason++) {
+		if (!strcmp(cmd, reason->cmd)) {
+			nvmem_cell_write(reboot->nvmem_cell,
+					 &reason->pon_reason,
+					 sizeof(reason->pon_reason));
+			break;
+		}
+	}
+
+	return NOTIFY_OK;
+}
+
+static int qcom_reboot_reason_probe(struct platform_device *pdev)
+{
+	struct qcom_reboot_reason *reboot;
+
+	reboot = devm_kzalloc(&pdev->dev, sizeof(*reboot), GFP_KERNEL);
+	if (!reboot)
+		return -ENOMEM;
+
+	reboot->dev = &pdev->dev;
+
+	reboot->nvmem_cell = nvmem_cell_get(reboot->dev, "restart_reason");
+
+	if (IS_ERR(reboot->nvmem_cell))
+		return PTR_ERR(reboot->nvmem_cell);
+
+	reboot->reboot_nb.notifier_call = qcom_reboot_reason_reboot;
+	reboot->reboot_nb.priority = 255;
+	register_reboot_notifier(&reboot->reboot_nb);
+
+	platform_set_drvdata(pdev, reboot);
+
+	return 0;
+}
+
+static int qcom_reboot_reason_remove(struct platform_device *pdev)
+{
+	struct qcom_reboot_reason *reboot = platform_get_drvdata(pdev);
+
+	unregister_reboot_notifier(&reboot->reboot_nb);
+
+	return 0;
+}
+
+static const struct of_device_id of_qcom_reboot_reason_match[] = {
+	{ .compatible = "qcom,reboot-reason", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, of_qcom_reboot_reason_match);
+
+static struct platform_driver qcom_reboot_reason_driver = {
+	.probe = qcom_reboot_reason_probe,
+	.remove = qcom_reboot_reason_remove,
+	.driver = {
+		.name = "qcom-reboot-reason",
+		.of_match_table = of_match_ptr(of_qcom_reboot_reason_match),
+	},
+};
+
+module_platform_driver(qcom_reboot_reason_driver);
+
+MODULE_DESCRIPTION("MSM Reboot Reason Driver");
+MODULE_LICENSE("GPL v2");