power: reset: Add snapshot of vm power off driver

Add snapshot of vm power off driver as of msm-4.14
'commit 77a20e0a50e1
("power: reset: cache flush before VM restart")'.

Change-Id: I380b16f46429711284bb6717847a1eef5d8ee9b1
Signed-off-by: Ping Jiang <scottjiang@codeaurora.org>

drivers/power/reset/Kconfig

@@ -105,6 +105,14 @@ config POWER_RESET_MSM
 	help
 	  Power off and restart support for Qualcomm boards.
 
+config POWER_RESET_QCOM_VM
+	tristate "Qualcomm Technologies, Inc. MSM VM power-off driver"
+	help
+	  Power off and restart support for Qualcomm Technologies, Inc. virtual
+	  machine. This driver supports virtual machine power down and restart.
+	  Say Y here if you have a MSM virtual machine and wish to enable
+	  restart driver.
+
 config POWER_RESET_QCOM_DOWNLOAD_MODE
 	tristate "MSM download mode driver"
 	depends on ARCH_QCOM

drivers/power/reset/Makefile

@@ -11,6 +11,7 @@ obj-$(CONFIG_POWER_RESET_GPIO) += gpio-poweroff.o
 obj-$(CONFIG_POWER_RESET_GPIO_RESTART) += gpio-restart.o
 obj-$(CONFIG_POWER_RESET_HISI) += hisi-reboot.o
 obj-$(CONFIG_POWER_RESET_MSM) += msm-poweroff.o
+obj-$(CONFIG_POWER_RESET_QCOM_VM) += msm-vm-poweroff.o
 obj-$(CONFIG_POWER_RESET_QCOM_DOWNLOAD_MODE) += qcom-dload-mode.o
 obj-$(CONFIG_POWER_RESET_QCOM_PON) += qcom-pon.o
 obj-$(CONFIG_POWER_RESET_QCOM_REBOOT_REASON) += qcom-reboot-reason.o

drivers/power/reset/msm-vm-poweroff.c

@@ -0,0 +1,94 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2019-2021, The Linux Foundation. All rights reserved.
+ */
+
+#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/delay.h>
+#include <linux/of_address.h>
+
+#include <asm/cacheflush.h>
+#include <asm/system_misc.h>
+#include <soc/qcom/watchdog.h>
+
+static int in_panic;
+static struct notifier_block restart_nb;
+
+static int panic_prep_restart(struct notifier_block *this,
+			      unsigned long event, void *ptr)
+{
+	in_panic = 1;
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block panic_blk = {
+	.notifier_call	= panic_prep_restart,
+};
+
+static int do_vm_restart(struct notifier_block *unused, unsigned long action,
+						void *arg)
+{
+	pr_notice("Going down for vm restart now\n");
+
+	flush_cache_all();
+
+	/*outer_flush_all is not supported by 64bit kernel*/
+#ifndef CONFIG_ARM64
+	outer_flush_all();
+#endif
+
+	if (in_panic)
+		qcom_wdt_trigger_bite();
+
+	return NOTIFY_DONE;
+}
+
+static int vm_restart_probe(struct platform_device *pdev)
+{
+	atomic_notifier_chain_register(&panic_notifier_list, &panic_blk);
+
+	restart_nb.notifier_call = do_vm_restart;
+	restart_nb.priority = 200;
+	register_restart_handler(&restart_nb);
+
+	return 0;
+}
+
+static const struct of_device_id of_vm_restart_match[] = {
+	{ .compatible = "qcom,vm-restart", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, of_vm_restart_match);
+
+static struct platform_driver vm_restart_driver = {
+	.probe = vm_restart_probe,
+	.driver = {
+		.name = "msm-vm-restart",
+		.of_match_table = of_match_ptr(of_vm_restart_match),
+	},
+};
+
+static int __init vm_restart_init(void)
+{
+	return platform_driver_register(&vm_restart_driver);
+}
+
+#if IS_MODULE(CONFIG_POWER_RESET_QCOM_VM)
+module_init(vm_restart_init);
+#else
+pure_initcall(vm_restart_init);
+#endif
+
+static __exit void vm_restart_exit(void)
+{
+	platform_driver_unregister(&vm_restart_driver);
+}
+module_exit(vm_restart_exit);
+
+MODULE_DESCRIPTION("MSM VM Poweroff Driver");
+MODULE_LICENSE("GPL v2");