1 files changed, 107 insertions, 0 deletions
diff --git a/drivers/firmware/reboot_reason_sram.c b/drivers/firmware/reboot_reason_sram.c
new file mode 100644
index 000000000000..af87b6d34f77
--- /dev/null
+++ b/drivers/firmware/reboot_reason_sram.c
@@ -0,0 +1,107 @@
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/spinlock.h>
+#include <linux/reboot.h>
+
+/* Types of reasons */
+enum {
+	NONE,
+	BOOTLOADER,
+	RECOVERY,
+	OEM,
+	MAX_REASONS
+};
+
+static u32			reasons[MAX_REASONS];
+static void __iomem		*reboot_reason_val_addr;
+static struct notifier_block	reboot_nb;
+
+static int reboot_reason(struct notifier_block *nb, unsigned long action,
+								void *data)
+{
+	char *cmd = (char *)data;
+	u32 reason = reasons[NONE];
+
+	if (!reboot_reason_val_addr)
+		return NOTIFY_DONE;
+
+	if (cmd != NULL) {
+		if (!strncmp(cmd, "bootloader", 10))
+			reason = reasons[BOOTLOADER];
+		else if (!strncmp(cmd, "recovery", 8))
+			reason = reasons[RECOVERY];
+		else if (!strncmp(cmd, "oem-", 4)) {
+			unsigned long code;
+
+			if (!kstrtoul(cmd+4, 0, &code))
+				reason = reasons[OEM] | (code & 0xff);
+		}
+	}
+
+	if (reason != -1)
+		writel(reason, reboot_reason_val_addr);
+	return NOTIFY_DONE;
+}
+
+static int reboot_reason_probe(struct platform_device *pdev)
+{
+	struct resource *res;
+	u32 val;
+	int i;
+
+	/* initialize the reasons */
+	for (i = 0; i < MAX_REASONS; i++)
+		reasons[i] = -1;
+
+	/* Try to grab the reason io address */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	reboot_reason_val_addr = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(reboot_reason_val_addr))
+		return PTR_ERR(reboot_reason_val_addr);
+
+	/* initialize specified reasons from DT */
+	if (!of_property_read_u32(pdev->dev.of_node, "reason,none", &val))
+		reasons[NONE] = val;
+	if (!of_property_read_u32(pdev->dev.of_node, "reason,bootloader", &val))
+		reasons[BOOTLOADER] = val;
+	if (!of_property_read_u32(pdev->dev.of_node, "reason,recovery", &val))
+		reasons[RECOVERY] = val;
+	if (!of_property_read_u32(pdev->dev.of_node, "reason,oem", &val))
+		reasons[OEM] = val;
+
+	/* Install the notifier */
+	reboot_nb.notifier_call = reboot_reason;
+	reboot_nb.priority = 256;
+	if (register_reboot_notifier(&reboot_nb)) {
+		dev_err(&pdev->dev,
+			"failed to setup restart handler.\n");
+	}
+	return 0;
+}
+
+int reboot_reason_remove(struct platform_device *pdev)
+{
+	unregister_reboot_notifier(&reboot_nb);
+	return 0;
+}
+
+static const struct of_device_id reboot_reason_of_match[] = {
+	{ .compatible = "linux,reboot-reason-sram", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, reboot_reason_of_match);
+
+static struct platform_driver reboot_reason_driver = {
+	.driver = {
+		.name = "reboot-reason-sram",
+		.of_match_table = reboot_reason_of_match,
+	},
+	.probe = reboot_reason_probe,
+	.remove = reboot_reason_remove,
+};
+module_platform_driver(reboot_reason_driver);