reboot-mode: read the boot mode from RTC memory
RTC devices could provide battery-backed memory that can be used for
storing the reboot mode magic value.
Add a new reboot-mode back-end that uses RTC to store the reboot-mode
magic value. The driver also supports both endianness modes.
Signed-off-by: Nandor Han <nandor.han@vaisala.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/reboot-mode/Kconfig b/drivers/reboot-mode/Kconfig
index ff65e20..ac67bfc 100644
--- a/drivers/reboot-mode/Kconfig
+++ b/drivers/reboot-mode/Kconfig
@@ -24,4 +24,13 @@
a device in a specific mode by using a GPIO that can be controlled
outside U-Boot.
+config DM_REBOOT_MODE_RTC
+ bool "Use RTC as reboot mode backend"
+ depends on DM_REBOOT_MODE
+ default n
+ help
+ Use RTC non volatile memory to control the reboot mode. This will allow users to boot
+ a device in a specific mode by using a register(s) that can be controlled
+ outside U-Boot (e.g. Kernel).
+
endmenu
diff --git a/drivers/reboot-mode/Makefile b/drivers/reboot-mode/Makefile
index 04917be..2c13780 100644
--- a/drivers/reboot-mode/Makefile
+++ b/drivers/reboot-mode/Makefile
@@ -6,3 +6,4 @@
obj-$(CONFIG_DM_REBOOT_MODE) += reboot-mode-uclass.o
obj-$(CONFIG_DM_REBOOT_MODE_GPIO) += reboot-mode-gpio.o
+obj-$(CONFIG_DM_REBOOT_MODE_RTC) += reboot-mode-rtc.o
diff --git a/drivers/reboot-mode/reboot-mode-rtc.c b/drivers/reboot-mode/reboot-mode-rtc.c
new file mode 100644
index 0000000..972d0cd
--- /dev/null
+++ b/drivers/reboot-mode/reboot-mode-rtc.c
@@ -0,0 +1,127 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c), Vaisala Oyj
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <dm/device_compat.h>
+#include <reboot-mode/reboot-mode-rtc.h>
+#include <reboot-mode/reboot-mode.h>
+#include <rtc.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+static int reboot_mode_get(struct udevice *dev, u32 *buf)
+{
+ if (!buf)
+ return -EINVAL;
+
+ int ret;
+ u8 *val = (u8 *)buf;
+ struct reboot_mode_rtc_platdata *plat_data;
+
+ plat_data = dev_get_plat(dev);
+ if (!plat_data)
+ return -EINVAL;
+
+ for (int i = 0; i < plat_data->size; i++) {
+ ret = rtc_read8(plat_data->rtc, plat_data->addr + i);
+ if (ret < 0)
+ return ret;
+
+ val[i] = ret;
+ }
+
+ if (plat_data->is_big_endian)
+ *buf = __be32_to_cpu(*buf);
+ else
+ *buf = __le32_to_cpu(*buf);
+
+ return 0;
+}
+
+static int reboot_mode_set(struct udevice *dev, u32 buf)
+{
+ int ret;
+ u8 *val;
+ struct reboot_mode_rtc_platdata *plat_data;
+
+ plat_data = dev_get_plat(dev);
+ if (!plat_data)
+ return -EINVAL;
+
+ if (plat_data->is_big_endian)
+ buf = __cpu_to_be32(buf);
+ else
+ buf = __cpu_to_le32(buf);
+
+ val = (u8 *)&buf;
+
+ for (int i = 0; i < plat_data->size; i++) {
+ ret = rtc_write8(plat_data->rtc, (plat_data->addr + i), val[i]);
+ if (ret < 0)
+ return ret;
+ }
+
+ return 0;
+}
+
+#if CONFIG_IS_ENABLED(OF_CONTROL)
+static int reboot_mode_ofdata_to_platdata(struct udevice *dev)
+{
+ struct ofnode_phandle_args phandle_args;
+ struct reboot_mode_rtc_platdata *plat_data;
+
+ plat_data = dev_get_plat(dev);
+ if (!plat_data)
+ return -EINVAL;
+
+ if (dev_read_phandle_with_args(dev, "rtc", NULL, 0, 0, &phandle_args)) {
+ dev_err(dev, "RTC device not specified\n");
+ return -ENOENT;
+ }
+
+ if (uclass_get_device_by_ofnode(UCLASS_RTC, phandle_args.node,
+ &plat_data->rtc)) {
+ dev_err(dev, "could not get the RTC device\n");
+ return -ENODEV;
+ }
+
+ plat_data->addr =
+ dev_read_addr_size_index(dev, 0, (fdt_size_t *)&plat_data->size);
+ if (plat_data->addr == FDT_ADDR_T_NONE) {
+ dev_err(dev, "Invalid RTC address\n");
+ return -EINVAL;
+ }
+ if (plat_data->size > sizeof(u32)) {
+ dev_err(dev, "Invalid reg size\n");
+ return -EINVAL;
+ }
+
+ plat_data->is_big_endian = ofnode_read_bool(dev_ofnode(dev), "big-endian");
+
+ return 0;
+}
+
+static const struct udevice_id reboot_mode_ids[] = {
+ { .compatible = "reboot-mode-rtc", 0 },
+ {}
+};
+#endif
+
+static const struct reboot_mode_ops reboot_mode_rtc_ops = {
+ .get = reboot_mode_get,
+ .set = reboot_mode_set,
+};
+
+U_BOOT_DRIVER(reboot_mode_rtc) = {
+ .name = "reboot-mode-rtc",
+ .id = UCLASS_REBOOT_MODE,
+#if CONFIG_IS_ENABLED(OF_CONTROL)
+ .of_match = reboot_mode_ids,
+ .of_to_plat = reboot_mode_ofdata_to_platdata,
+#endif
+ .plat_auto = sizeof(struct reboot_mode_rtc_platdata),
+ .ops = &reboot_mode_rtc_ops,
+};