Merge "boot: Add a boot_control HAL"
diff --git a/include/hardware/boot_control.h b/include/hardware/boot_control.h
new file mode 100644
index 0000000..62d6918
--- /dev/null
+++ b/include/hardware/boot_control.h
@@ -0,0 +1,125 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_INCLUDE_HARDWARE_BOOT_CONTROL_H
+#define ANDROID_INCLUDE_HARDWARE_BOOT_CONTROL_H
+
+#include <hardware/hardware.h>
+
+__BEGIN_DECLS
+
+#define BOOT_CONTROL_MODULE_API_VERSION_0_1 HARDWARE_MODULE_API_VERSION(0, 1)
+
+/**
+ * The id of this module
+ */
+#define BOOT_CONTROL_HARDWARE_MODULE_ID "bootctrl"
+
+/*
+ * The Boot Control HAL is designed to allow for managing sets of redundant
+ * partitions, called slots, that can be booted from independantly. Slots
+ * are sets of partitions whose names differ only by a given suffix.
+ * They are identified here by a 0 indexed number, and associated with their
+ * suffix, which can be appended to the base name for any particular partition
+ * to find the one associated with that slot. The bootloader must pass the suffix
+ * of the currently active slot either through a kernel command line property at
+ * androidboot.slot_suffix, or the device tree at /firmware/android/slot_suffix.
+ * The primary use of this set up is to allow for background updates while the
+ * device is running, and to provide a fallback in the event that the update fails.
+ */
+
+
+/**
+ * Every hardware module must have a data structure named HAL_MODULE_INFO_SYM
+ * and the fields of this data structure must begin with hw_module_t
+ * followed by module specific information.
+ */
+typedef struct boot_control_module {
+ struct hw_module_t common;
+
+ /*
+ * (*init)() perform any initialization tasks needed for the HAL.
+ * This is called only once.
+ */
+ void (*init)(struct boot_control_module *module);
+
+ /*
+ * (*getNumberSlots)() returns the number of available slots.
+ * For instance, a system with a single set of partitions would return
+ * 1, a system with A/B would return 2, A/B/C -> 3...
+ */
+ unsigned (*getNumberSlots)(struct boot_control_module *module);
+
+ /*
+ * (*getCurrentSlot)() returns the value letting the system know
+ * whether the current slot is A or B. The meaning of A and B is
+ * left up to the implementer. It is assumed that if the current slot
+ * is A, then the block devices underlying B can be accessed directly
+ * without any risk of corruption.
+ * The returned value is always guaranteed to be strictly less than the
+ * value returned by getNumberSlots. Slots start at 0 and
+ * finish at getNumberSlots() - 1
+ */
+ unsigned (*getCurrentSlot)(struct boot_control_module *module);
+
+ /*
+ * (*markBootSuccessful)() marks the current slot
+ * as having booted successfully
+ *
+ * Returns 0 on success, -errno on error.
+ */
+ int (*markBootSuccessful)(struct boot_control_module *module);
+
+ /*
+ * (*setActiveBootSlot)() marks the slot passed in parameter as
+ * the active boot slot (see getCurrentSlot for an explanation
+ * of the "slot" parameter). This overrides any previous call to
+ * setSlotAsUnbootable.
+ * Returns 0 on success, -errno on error.
+ */
+ int (*setActiveBootSlot)(struct boot_control_module *module, unsigned slot);
+
+ /*
+ * (*setSlotAsUnbootable)() marks the slot passed in parameter as
+ * an unbootable. This can be used while updating the contents of the slot's
+ * partitions, so that the system will not attempt to boot a known bad set up.
+ * Returns 0 on success, -errno on error.
+ */
+ int (*setSlotAsUnbootable)(struct boot_control_module *module, unsigned slot);
+
+ /*
+ * (*isSlotBootable)() returns if the slot passed in parameter has
+ * booted successfully in the past.
+ * Returns 1 if the slot has booted successfully, 0 if it has not,
+ * and -errno on error.
+ */
+ int (*isSlotBootable)(struct boot_control_module *module, unsigned slot);
+
+ /*
+ * (*getSuffix)() returns the string suffix used by partitions that
+ * correspond to the slot number passed in parameter. The returned string
+ * is expected to be statically allocated and not need to be freed.
+ * Returns NULL if slot does not match an existing slot.
+ */
+ const char* (*getSuffix)(struct boot_control_module *module, unsigned slot);
+
+ void* reserved[32];
+} boot_control_module_t;
+
+
+__END_DECLS
+
+#endif // ANDROID_INCLUDE_HARDWARE_BOOT_CONTROL_H