@@ -136,6 +136,15 @@ config QCOM_SCM
bool
depends on ARM || ARM64
+config REBOOT_REASON_SRAM
+ bool "Pass reboot reason to bootloader via SRAM"
+ default n
+ help
+ On many systems there is a desire to provide a reboot reason to
+ the bootloader, so that the bootloader can boot into a desired
+ mode on the next boot. This option enables support for communicating
+ this reason to the bootloader via SRAM
+
source "drivers/firmware/google/Kconfig"
source "drivers/firmware/efi/Kconfig"
@@ -13,6 +13,7 @@ obj-$(CONFIG_ISCSI_IBFT) += iscsi_ibft.o
obj-$(CONFIG_FIRMWARE_MEMMAP) += memmap.o
obj-$(CONFIG_QCOM_SCM) += qcom_scm.o
CFLAGS_qcom_scm.o :=$(call as-instr,.arch_extension sec,-DREQUIRES_SEC=1)
+obj-$(CONFIG_REBOOT_REASON_SRAM)+= reboot_reason_sram.o
obj-$(CONFIG_GOOGLE_FIRMWARE) += google/
obj-$(CONFIG_EFI) += efi/
new file mode 100644
@@ -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);
This patch adds a basic driver to allow for commands like "reboot bootloader" and "reboot recovery" to communicate this reboot-reason to the bootloader. This is commonly done on Android devices, in order to reboot the device into fastboot or recovery mode. It also supports custom OEM specific commands, via "reboot oem-<value>". This driver pulls the phys memory address from DT as well as the magic reason values that are written to the address for each mode. Cc: Vishal Bhoj <vishal.bhoj@linaro.org> Cc: haojian.zhuang@linaro.org Cc: guodong.xu@linaro.org Signed-off-by: John Stultz <john.stultz@linaro.org> --- drivers/firmware/Kconfig | 9 +++ drivers/firmware/Makefile | 1 + drivers/firmware/reboot_reason_sram.c | 107 ++++++++++++++++++++++++++++++++++ 3 files changed, 117 insertions(+) create mode 100644 drivers/firmware/reboot_reason_sram.c -- 1.9.1