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/* Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
/* Non-volatile storage routines.
*/
#ifndef VBOOT_REFERENCE_NVSTORAGE_H_
#define VBOOT_REFERENCE_NVSTORAGE_H_
#define NV_BLOCK_SIZE 16 /* Size of NV storage block in bytes */
typedef struct VbNvContext {
/* Raw NV data. Caller must fill this before calling VbNvSetup(). */
uint8_t raw[NV_BLOCK_SIZE];
/* Flag indicating whether raw data has changed. Set by VbNvTeardown() if
* the raw data has changed and needs to be stored to the underlying
* non-volatile data store. */
int raw_changed;
/* Internal data for NV storage routines. Caller should not touch
* these fields. */
int regenerate_crc;
} VbNvContext;
/* Parameter type for VbNvGet(), VbNvSet(). */
typedef enum VbNvParam {
VBNV_FIRMWARE_SETTINGS_RESET = 0,
VBNV_KERNEL_SETTINGS_RESET,
VBNV_DEBUG_RESET_MODE,
VBNV_TRY_B_COUNT,
VBNV_RECOVERY_REQUEST,
VBNV_LOCALIZATION_INDEX,
VBNV_KERNEL_FIELD,
} VbNvParam;
/* Initialize the NV storage library. This must be called before any
* other functions in this library. Returns 0 if success, non-zero if
* error.
*
* If you have access to global variables, you may want to wrap this
* in your own VbNvOpen() function which allocates a context, acquires
* a lock to prevent race conditions accessing the underlying storage,
* reads the raw data from underlying storage, and calls VbNvSetup().
* We don't do that in here because there are no global variables in
* UEFI BIOS during PEI phase. */
int VbNvSetup(VbNvContext* context);
/* Clean up and flush changes back to the raw data. This must be
* called after other functions in this library. Caller must check
* context.raw_changed after calling this function. Returns 0 if
* success, non-zero if error.
*
* If you have access to global variables, you may want to wrap this
* in your own VbNvClose() function which calls VbNvTeardown(), writes
* the underlying storage if context.raw_changed, releases the lock
* acquired in VbNvOpen, and frees the context. */
int VbNvTeardown(VbNvContext* context);
/* Read a NV storage parameter into *dest. Returns 0 if success,
* non-zero if error. */
int VbNvGet(VbNvContext* context, VbNvParam param, uint32_t* dest);
/* Set a NV storage param to a new value. Returns 0 if success,
* non-zero if error. */
int VbNvSet(VbNvContext* context, VbNvParam param, uint32_t value);
#endif /* VBOOT_REFERENCE_NVSTORAGE_H_ */
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