DNM: psci-mfd driver for review

drivers/power/reset/Kconfig

@@ -348,6 +348,16 @@ config NVMEM_REBOOT_MODE
 	  then the bootloader can read it and take different
 	  action according to the mode.
 
+config PSCI_REBOOT_MODE
+	bool "PSCI reboot mode driver"
+	depends on OF && ARM_PSCI_FW
+	select REBOOT_MODE
+	help
+	  Say y here will enable PSCI reboot mode driver. This gets
+          the PSCI reboot mode arguments and passes them to psci
+	  driver. psci driver uses these arguments for issuing
+	  device reset into different boot states.
+
 config POWER_MLXBF
 	tristate "Mellanox BlueField power handling driver"
 	depends on (GPIO_MLXBF2 || GPIO_MLXBF3) && ACPI

drivers/power/reset/Makefile

@@ -40,4 +40,5 @@ obj-$(CONFIG_REBOOT_MODE) += reboot-mode.o
 obj-$(CONFIG_SYSCON_REBOOT_MODE) += syscon-reboot-mode.o
 obj-$(CONFIG_POWER_RESET_SC27XX) += sc27xx-poweroff.o
 obj-$(CONFIG_NVMEM_REBOOT_MODE) += nvmem-reboot-mode.o
+obj-$(CONFIG_PSCI_REBOOT_MODE) += psci-reboot-mode.o
 obj-$(CONFIG_POWER_MLXBF) += pwr-mlxbf.o

drivers/power/reset/psci-reboot-mode.c

@@ -0,0 +1,92 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
+ */
+
+#include <linux/device/faux.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/of.h>
+#include <linux/psci.h>
+#include <linux/reboot.h>
+#include <linux/reboot-mode.h>
+#include <linux/types.h>
+#include <linux/platform_device.h>
+#include <linux/module.h>
+
+/*
+ * Predefined reboot-modes are defined as per the values
+ * of enum reboot_mode defined in the kernel: reboot.c.
+ */
+static struct mode_info psci_resets[] = {
+	{ .mode = "warm", .magic = REBOOT_WARM},
+	{ .mode = "soft", .magic = REBOOT_SOFT},
+	{ .mode = "cold", .magic = REBOOT_COLD},
+};
+
+static void psci_reboot_mode_set_predefined_modes(struct reboot_mode_driver *reboot)
+{
+	INIT_LIST_HEAD(&reboot->predefined_modes);
+	for (u32 i = 0; i < ARRAY_SIZE(psci_resets); i++) {
+		/* Prepare the magic with arg1 as 0 and arg2 as per pre-defined mode */
+		psci_resets[i].magic = REBOOT_MODE_MAGIC(0, psci_resets[i].magic);
+		INIT_LIST_HEAD(&psci_resets[i].list);
+		list_add_tail(&psci_resets[i].list, &reboot->predefined_modes);
+	}
+}
+
+/*
+ * arg1 is reset_type(Low 32 bit of magic).
+ * arg2 is cookie(High 32 bit of magic).
+ * If reset_type is 0, cookie will be used to decide the reset command.
+ */
+static int psci_reboot_mode_write(struct reboot_mode_driver *reboot, u64 magic)
+{
+	u32 reset_type = REBOOT_MODE_ARG1(magic);
+	u32 cookie = REBOOT_MODE_ARG2(magic);
+
+	pr_err("DEBUG: PSCI write called");
+	pr_err("DEBUG: PSCI write called");
+	pr_err("DEBUG: PSCI write called");
+	if (reset_type == 0) {
+		if (cookie == REBOOT_WARM || cookie == REBOOT_SOFT)
+			psci_set_reset_cmd(true, 0, 0);
+		else
+			psci_set_reset_cmd(false, 0, 0);
+	} else {
+		psci_set_reset_cmd(true, reset_type, cookie);
+	}
+
+	return NOTIFY_DONE;
+}
+
+static int psci_reboot_mode_probe(struct platform_device *pdev)
+{
+	struct reboot_mode_driver *reboot;
+	int ret;
+
+	reboot = devm_kzalloc(&pdev->dev, sizeof(*reboot), GFP_KERNEL);
+	if (!reboot)
+		return -ENOMEM;
+
+	psci_reboot_mode_set_predefined_modes(reboot);
+	reboot->write = psci_reboot_mode_write;
+	reboot->dev = &pdev->dev;
+
+	ret = devm_reboot_mode_register(&pdev->dev, reboot);
+	if (ret) {
+		dev_err_probe(&pdev->dev, ret, "devm_reboot_mode_register failed %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static struct platform_driver psci_reboot_mode_driver = {
+	.probe  = psci_reboot_mode_probe,
+	.driver = {
+		.name	= "psci-reboot-mode",
+	},
+};
+
+module_platform_driver(psci_reboot_mode_driver);