reboot-mode: add support for reboot mode control

A new driver uclass is created to handle the reboot mode control.

The new uclass driver is updating an environment variable with the
configured reboot mode. The mode is extracted from a map provided
at initialization time. The map contains a list of modes
and associated ids.

Signed-off-by: Nandor Han <nandor.han@vaisala.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

drivers/reboot-mode/reboot-mode-uclass.c

@@ -0,0 +1,134 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c), Vaisala Oyj
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <dm/device_compat.h>
+#include <dm/devres.h>
+#include <exports.h>
+#include <reboot-mode/reboot-mode.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+int dm_reboot_mode_update(struct udevice *dev)
+{
+	struct reboot_mode_ops *ops = reboot_mode_get_ops(dev);
+	u32 rebootmode;
+	int ret, i;
+
+	assert(ops);
+
+	if (!ops->get)
+		return -ENOSYS;
+
+	ret = ops->get(dev, &rebootmode);
+	if (ret < 0) {
+		dev_err(dev, "Failed to retrieve the reboot mode value\n");
+		return ret;
+	}
+
+	const struct reboot_mode_uclass_platdata *plat_data =
+		dev_get_uclass_plat(dev);
+
+	for (i = 0; i < plat_data->count; i++) {
+		if (plat_data->modes[i].mode_id == rebootmode) {
+			ret = env_set(plat_data->env_variable,
+				      plat_data->modes[i].mode_name);
+			if (ret) {
+				dev_err(dev, "Failed to set env: %s\n",
+					plat_data->env_variable);
+				return ret;
+			}
+		}
+	}
+
+	if (ops->set) {
+		/* Clear the value */
+		rebootmode = 0;
+		ret = ops->set(dev, rebootmode);
+		if (ret) {
+			dev_err(dev, "Failed to clear the reboot mode\n");
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+int dm_reboot_mode_pre_probe(struct udevice *dev)
+{
+	struct reboot_mode_uclass_platdata *plat_data;
+
+	plat_data = dev_get_uclass_plat(dev);
+	if (!plat_data)
+		return -EINVAL;
+
+#if CONFIG_IS_ENABLED(OF_CONTROL)
+	const int node = dev_of_offset(dev);
+	const char *mode_prefix = "mode-";
+	const int mode_prefix_len = strlen(mode_prefix);
+	int property;
+	const u32 *propvalue;
+	const char *propname;
+
+	plat_data->env_variable = fdt_getprop(gd->fdt_blob,
+					      node,
+					      "u-boot,env-variable",
+					      NULL);
+	if (!plat_data->env_variable)
+		plat_data->env_variable = "reboot-mode";
+
+	plat_data->count = 0;
+
+	fdt_for_each_property_offset(property, gd->fdt_blob, node) {
+		propvalue = fdt_getprop_by_offset(gd->fdt_blob,
+						  property, &propname, NULL);
+		if (!propvalue) {
+			dev_err(dev, "Could not get the value for property %s\n",
+				propname);
+			return -EINVAL;
+		}
+
+		if (!strncmp(propname, mode_prefix, mode_prefix_len))
+			plat_data->count++;
+	}
+
+	plat_data->modes = devm_kcalloc(dev, plat_data->count,
+					sizeof(struct reboot_mode_mode), 0);
+
+	struct reboot_mode_mode *next = plat_data->modes;
+
+	fdt_for_each_property_offset(property, gd->fdt_blob, node) {
+		propvalue = fdt_getprop_by_offset(gd->fdt_blob,
+						  property, &propname, NULL);
+		if (!propvalue) {
+			dev_err(dev, "Could not get the value for property %s\n",
+				propname);
+			return -EINVAL;
+		}
+
+		if (!strncmp(propname, mode_prefix, mode_prefix_len)) {
+			next->mode_name = &propname[mode_prefix_len];
+			next->mode_id = fdt32_to_cpu(*propvalue);
+
+			next++;
+		}
+	}
+#else
+	if (!plat_data->env_variable)
+		plat_data->env_variable = "reboot-mode";
+
+#endif
+
+	return 0;
+}
+
+UCLASS_DRIVER(reboot_mode) = {
+	.name	= "reboot-mode",
+	.id	= UCLASS_REBOOT_MODE,
+	.pre_probe	= dm_reboot_mode_pre_probe,
+	.per_device_plat_auto =
+		sizeof(struct reboot_mode_uclass_platdata),
+};