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/* Copyright 2016 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.
*/
#include "common.h"
#include "console.h"
#include "flash.h"
#include "nvmem.h"
#include "shared_mem.h"
#include "task.h"
#include "timer.h"
#include "util.h"
#define CPRINTF(format, args...) cprintf(CC_COMMAND, format, ## args)
#define CPRINTS(format, args...) cprints(CC_COMMAND, format, ## args)
#define NVMEM_ACQUIRE_CACHE_SLEEP_MS 25
#define NVMEM_ACQUIRE_CACHE_MAX_ATTEMPTS (250 / NVMEM_ACQUIRE_CACHE_SLEEP_MS)
#define NVMEM_NOT_INITIALIZED (-1)
/* Table of start addresses for each partition */
static const uintptr_t nvmem_base_addr[NVMEM_NUM_PARTITIONS] = {
CONFIG_FLASH_NVMEM_BASE_A,
CONFIG_FLASH_NVMEM_BASE_B
};
/* NvMem user buffer start offset table */
static uint32_t nvmem_user_start_offset[NVMEM_NUM_USERS];
/* A/B partion that is most up to date */
static int nvmem_act_partition;
/* NvMem cache memory structure */
struct nvmem_cache {
uint8_t *base_ptr;
task_id_t task;
struct mutex mtx;
};
struct nvmem_cache cache;
static uint8_t commits_enabled;
static uint8_t commits_skipped;
/* NvMem error state */
static int nvmem_error_state;
/* Flag to track if an Nv write/move is not completed */
static int nvmem_write_error;
static int nvmem_save(uint8_t tag_generation, size_t partition)
{
struct nvmem_tag *tag;
size_t nvmem_offset;
/* Flash offset of the partition to save. */
nvmem_offset = nvmem_base_addr[partition] - CONFIG_PROGRAM_MEMORY_BASE;
/* Erase partition */
if (flash_physical_erase(nvmem_offset,
NVMEM_PARTITION_SIZE)) {
CPRINTF("%s:%d\n", __func__, __LINE__);
return EC_ERROR_UNKNOWN;
}
tag = (struct nvmem_tag *)cache.base_ptr;
tag->generation = tag_generation;
/* Calculate sha of the whole thing. */
nvmem_compute_sha(&tag->generation,
NVMEM_PARTITION_SIZE -
offsetof(struct nvmem_tag, generation),
tag->sha,
sizeof(tag->sha));
/* Write partition */
if (flash_physical_write(nvmem_offset,
NVMEM_PARTITION_SIZE,
cache.base_ptr)) {
CPRINTF("%s:%d\n", __func__, __LINE__);
return EC_ERROR_UNKNOWN;
}
return EC_SUCCESS;
}
static int nvmem_partition_sha_match(int index)
{
uint8_t sha_comp[NVMEM_SHA_SIZE];
struct nvmem_partition *p_part;
p_part = (struct nvmem_partition *)nvmem_base_addr[index];
nvmem_compute_sha(&p_part->tag.generation,
(NVMEM_PARTITION_SIZE - NVMEM_SHA_SIZE),
sha_comp, sizeof(sha_comp));
/* Check if computed value matches stored value. */
return !memcmp(p_part->tag.sha, sha_comp, NVMEM_SHA_SIZE);
}
/* Called with the semaphore locked. */
static int nvmem_acquire_cache(void)
{
int attempts = 0;
int ret;
if (shared_mem_size() < NVMEM_PARTITION_SIZE) {
CPRINTF("Not enough shared mem! avail = 0x%x < reqd = 0x%x\n",
shared_mem_size(), NVMEM_PARTITION_SIZE);
return EC_ERROR_OVERFLOW;
}
while (attempts < NVMEM_ACQUIRE_CACHE_MAX_ATTEMPTS) {
ret = shared_mem_acquire(NVMEM_PARTITION_SIZE,
(char **)&cache.base_ptr);
if (ret == EC_SUCCESS) {
/* Copy partiion contents from flash into cache */
memcpy(cache.base_ptr,
(void *)nvmem_base_addr[nvmem_act_partition],
NVMEM_PARTITION_SIZE);
return EC_SUCCESS;
} else if (ret == EC_ERROR_BUSY) {
CPRINTF("Shared Mem not avail! Attempt %d\n", attempts);
/* wait NVMEM_ACQUIRE_CACHE_SLEEP_MS msec */
/* TODO: what time really makes sense? */
msleep(NVMEM_ACQUIRE_CACHE_SLEEP_MS);
}
attempts++;
}
/* Timeout Error condition */
CPRINTF("%s:%d\n", __func__, __LINE__);
cache.base_ptr = NULL; /* Just in case. */
return EC_ERROR_TIMEOUT;
}
static int nvmem_lock_cache(void)
{
/*
* Need to protect the cache contents and pointer value from other tasks
* attempting to do nvmem write operations. However, since this function
* may be called mutliple times prior to the mutex lock being released,
* there is a check first to see if the current task holds the lock. If
* it does then the task number will equal the value in cache.task. If
* the lock is held by a different task then mutex_lock function will
* operate as normal.
*/
if (cache.task != task_get_current()) {
mutex_lock(&cache.mtx);
cache.task = task_get_current();
} else
/* Lock is held by current task, nothing else to do. */
return EC_SUCCESS;
/*
* Acquire the shared memory buffer and copy the full
* partition size from flash into the cache buffer.
*/
if (nvmem_acquire_cache() != EC_SUCCESS) {
/* Shared memory not available, need to release lock */
/* Set task number to value that can't match a valid task */
cache.task = TASK_ID_COUNT;
/* Release lock */
mutex_unlock(&cache.mtx);
return EC_ERROR_TIMEOUT;
}
return EC_SUCCESS;
}
static void nvmem_release_cache(void)
{
/* Done with shared memory buffer, release it. */
shared_mem_release(cache.base_ptr);
/* Inidicate cache is not available */
cache.base_ptr = NULL;
/* Reset task number to max value */
cache.task = TASK_ID_COUNT;
/* Release mutex lock here */
mutex_unlock(&cache.mtx);
}
static int nvmem_reinitialize(void)
{
int ret;
/*
* NvMem is not properly itialized. Let's just erase everything and
* start over, so that at least 1 partition is ready to be used.
*/
nvmem_act_partition = 0;
/* Need to acquire the shared memory buffer */
ret = nvmem_lock_cache();
if (ret != EC_SUCCESS)
return ret;
memset(cache.base_ptr, 0xff, NVMEM_PARTITION_SIZE);
/* Start with generation zero in the current active partition. */
ret = nvmem_save(0, nvmem_act_partition);
nvmem_release_cache();
if (ret) {
CPRINTF("%s:%d\n", __func__, __LINE__);
return ret;
}
return EC_SUCCESS;
}
static int nvmem_compare_generation(void)
{
struct nvmem_partition *p_part;
uint16_t ver0, ver1;
uint32_t delta;
p_part = (struct nvmem_partition *)nvmem_base_addr[0];
ver0 = p_part->tag.generation;
p_part = (struct nvmem_partition *)nvmem_base_addr[1];
ver1 = p_part->tag.generation;
/* Compute generation difference accounting for wrap condition */
delta = (ver0 - ver1 + (1<<NVMEM_GENERATION_BITS)) &
NVMEM_GENERATION_MASK;
/*
* If generation number delta is positive in a circular sense then
* partition 0 has the newest generation number. Otherwise, it's
* partition 1.
*/
return delta < (1<<(NVMEM_GENERATION_BITS-1)) ? 0 : 1;
}
static int nvmem_find_partition(void)
{
int n;
/* Don't know which partition to use yet */
nvmem_act_partition = NVMEM_NOT_INITIALIZED;
/*
* Check each partition to determine if the sha is good. If both
* partitions have valid sha(s), then compare generation numbers to
* select the most recent one.
*/
for (n = 0; n < NVMEM_NUM_PARTITIONS; n++)
if (nvmem_partition_sha_match(n)) {
if (nvmem_act_partition == NVMEM_NOT_INITIALIZED)
nvmem_act_partition = n;
else
nvmem_act_partition =
nvmem_compare_generation();
} else {
ccprintf("%s:%d partiton %d verification FAILED\n",
__func__, __LINE__, n);
}
if (nvmem_act_partition != NVMEM_NOT_INITIALIZED)
return EC_SUCCESS;
/*
* If active_partition is still not selected, then neither partition
* is valid. Let's reinitialize the NVMEM - there is nothing else we
* can do.
*/
CPRINTS("%s: No Valid Parition found, have to reinitialize!");
if (nvmem_reinitialize() != EC_SUCCESS) {
CPRINTS("%s: Reinitialization failed!!");
return EC_ERROR_UNKNOWN;
}
return EC_SUCCESS;
}
static int nvmem_generate_offset_table(void)
{
int n;
uint32_t start_offset;
/*
* Create table of starting offsets within partition for each user
* buffer that's been defined.
*/
start_offset = sizeof(struct nvmem_tag);
for (n = 0; n < NVMEM_NUM_USERS; n++) {
nvmem_user_start_offset[n] = start_offset;
start_offset += nvmem_user_sizes[n];
}
/* Verify that all defined user buffers fit within the partition */
if (start_offset > NVMEM_PARTITION_SIZE)
return EC_ERROR_OVERFLOW;
return EC_SUCCESS;
}
static int nvmem_get_partition_off(int user, uint32_t offset,
uint32_t len, uint32_t *p_buf_offset)
{
uint32_t start_offset;
/* Sanity check for user */
if (user >= NVMEM_NUM_USERS)
return EC_ERROR_OVERFLOW;
/* Get offset within the partition for the start of user buffer */
start_offset = nvmem_user_start_offset[user];
/*
* Ensure that read/write operation that is calling this function
* doesn't exceed the end of its buffer.
*/
if (offset + len > nvmem_user_sizes[user])
return EC_ERROR_OVERFLOW;
/* Compute offset within the partition for the rd/wr operation */
*p_buf_offset = start_offset + offset;
return EC_SUCCESS;
}
int nvmem_setup(uint8_t starting_generation)
{
struct nvmem_partition *p_part;
int part;
int ret;
CPRINTS("Configuring NVMEM FLash Partition");
/*
* Initialize NVmem partition. This function will only be called
* if during nvmem_init() fails which implies that NvMem is not fully
* erased and neither partion tag contains a valid sha meaning they are
* both corrupted
*/
for (part = 0; part < NVMEM_NUM_PARTITIONS; part++) {
/* Set active partition variable */
nvmem_act_partition = part;
/* Get the cache buffer */
if (nvmem_lock_cache() != EC_SUCCESS) {
CPRINTF("NvMem: Cache ram not available!\n");
return EC_ERROR_TIMEOUT;
}
/* Fill entire partition to 0xFFs */
memset(cache.base_ptr, 0xff, NVMEM_PARTITION_SIZE);
/* Get pointer to start of partition */
p_part = (struct nvmem_partition *)cache.base_ptr;
/* Commit function will increment generation number */
p_part->tag.generation = starting_generation + part - 1;
/* Compute sha for the partition */
nvmem_compute_sha(&cache.base_ptr[NVMEM_SHA_SIZE],
NVMEM_PARTITION_SIZE -
NVMEM_SHA_SIZE,
p_part->tag.sha,
NVMEM_SHA_SIZE);
/* Partition is now ready, write it to flash. */
ret = nvmem_commit();
if (ret != EC_SUCCESS)
return ret;
}
return EC_SUCCESS;
}
int nvmem_init(void)
{
int ret;
/* Generate start offsets within partiion for user buffers */
ret = nvmem_generate_offset_table();
if (ret) {
CPRINTF("%s:%d\n", __func__, __LINE__);
return ret;
}
/* Initialize error state, assume everything is good */
nvmem_error_state = EC_SUCCESS;
nvmem_write_error = 0;
/* Default state for cache base_ptr and task number */
cache.base_ptr = NULL;
cache.task = TASK_ID_COUNT;
ret = nvmem_find_partition();
if (ret != EC_SUCCESS) {
/* Write NvMem partitions to 0xff and setup new tags */
nvmem_setup(0);
/* Should find valid partiion now */
ret = nvmem_find_partition();
if (ret) {
/* Change error state to non-zero */
nvmem_error_state = EC_ERROR_UNKNOWN;
CPRINTF("%s:%d\n", __func__, __LINE__);
return ret;
}
}
CPRINTS("Active NVram partition set to %d", nvmem_act_partition);
commits_enabled = 1;
commits_skipped = 0;
return EC_SUCCESS;
}
int nvmem_get_error_state(void)
{
return nvmem_error_state;
}
int nvmem_is_different(uint32_t offset, uint32_t size, void *data,
enum nvmem_users user)
{
int ret;
uint8_t *p_src;
uintptr_t src_addr;
uint32_t src_offset;
/* Point to either NvMem flash or ram if that's active */
if (cache.base_ptr == NULL)
src_addr = nvmem_base_addr[nvmem_act_partition];
else
src_addr = (uintptr_t)cache.base_ptr;
/* Get partition offset for this read operation */
ret = nvmem_get_partition_off(user, offset, size, &src_offset);
if (ret != EC_SUCCESS)
return ret;
/* Advance to the correct byte within the data buffer */
src_addr += src_offset;
p_src = (uint8_t *)src_addr;
/* Compare NvMem with data */
return memcmp(p_src, data, size);
}
int nvmem_read(uint32_t offset, uint32_t size,
void *data, enum nvmem_users user)
{
int ret;
uint8_t *p_src;
uintptr_t src_addr;
uint32_t src_offset;
/* Point to either NvMem flash or ram if that's active */
if (cache.base_ptr == NULL)
src_addr = nvmem_base_addr[nvmem_act_partition];
else
src_addr = (uintptr_t)cache.base_ptr;
/* Get partition offset for this read operation */
ret = nvmem_get_partition_off(user, offset, size, &src_offset);
if (ret != EC_SUCCESS)
return ret;
/* Advance to the correct byte within the data buffer */
src_addr += src_offset;
p_src = (uint8_t *)src_addr;
/* Copy from src into the caller's destination buffer */
memcpy(data, p_src, size);
return EC_SUCCESS;
}
int nvmem_write(uint32_t offset, uint32_t size,
void *data, enum nvmem_users user)
{
int ret;
uint8_t *p_dest;
uintptr_t dest_addr;
uint32_t dest_offset;
/* Make sure that the cache buffer is active */
ret = nvmem_lock_cache();
if (ret) {
nvmem_write_error = 1;
return ret;
}
/* Compute partition offset for this write operation */
ret = nvmem_get_partition_off(user, offset, size, &dest_offset);
if (ret != EC_SUCCESS) {
nvmem_write_error = 1;
return ret;
}
/* Advance to correct offset within data buffer */
dest_addr = (uintptr_t)cache.base_ptr;
dest_addr += dest_offset;
p_dest = (uint8_t *)dest_addr;
/* Copy data from caller into destination buffer */
memcpy(p_dest, data, size);
return EC_SUCCESS;
}
int nvmem_move(uint32_t src_offset, uint32_t dest_offset, uint32_t size,
enum nvmem_users user)
{
int ret;
uint8_t *p_src, *p_dest;
uintptr_t base_addr;
uint32_t s_buff_offset, d_buff_offset;
/* Make sure that the cache buffer is active */
ret = nvmem_lock_cache();
if (ret) {
nvmem_write_error = 1;
return ret;
}
/* Compute partition offset for source */
ret = nvmem_get_partition_off(user, src_offset, size, &s_buff_offset);
if (ret != EC_SUCCESS) {
nvmem_write_error = 1;
return ret;
}
/* Compute partition offset for destination */
ret = nvmem_get_partition_off(user, dest_offset, size, &d_buff_offset);
if (ret != EC_SUCCESS) {
nvmem_write_error = 1;
return ret;
}
base_addr = (uintptr_t)cache.base_ptr;
/* Create pointer to src location within partition */
p_src = (uint8_t *)(base_addr + s_buff_offset);
/* Create pointer to dest location within partition */
p_dest = (uint8_t *)(base_addr + d_buff_offset);
/* Move the data block in NvMem */
memmove(p_dest, p_src, size);
return EC_SUCCESS;
}
void nvmem_enable_commits(void)
{
if (commits_enabled)
return;
commits_enabled = 1;
if (!commits_skipped)
return;
CPRINTS("Committing NVMEM changes.");
nvmem_commit();
commits_skipped = 0;
}
void nvmem_disable_commits(void)
{
commits_enabled = 0;
commits_skipped = 0;
}
int nvmem_commit(void)
{
int new_active_partition;
uint16_t generation;
struct nvmem_partition *p_part;
if (!commits_enabled) {
commits_skipped = 1;
CPRINTS("Skipping commit");
return EC_SUCCESS;
}
/* Ensure that all writes/moves prior to commit call succeeded */
if (nvmem_write_error) {
CPRINTS("NvMem: Write Error, commit abandoned");
/* Clear error state */
nvmem_write_error = 0;
nvmem_release_cache();
return EC_ERROR_UNKNOWN;
}
/*
* All scratch buffer blocks must be written to physical flash
* memory. In addition, the scratch block buffer index table
* entries must be reset along with the index itself.
*/
/* Update generation number */
if (cache.base_ptr == NULL) {
CPRINTF("%s:%d\n", __func__, __LINE__);
return EC_ERROR_UNKNOWN;
}
p_part = (struct nvmem_partition *)cache.base_ptr;
generation = p_part->tag.generation + 1;
/* Check for restricted generation number */
if (generation == NVMEM_GENERATION_MASK)
generation = 0;
/* Toggle parition being used (always write to current spare) */
new_active_partition = nvmem_act_partition ^ 1;
/* Write active partition to NvMem */
if (nvmem_save(generation, new_active_partition) != EC_SUCCESS) {
/* Free up scratch buffers */
nvmem_release_cache();
return EC_ERROR_UNKNOWN;
}
/* Update newest partition index */
nvmem_act_partition = new_active_partition;
/* Free up scratch buffers */
nvmem_release_cache();
return EC_SUCCESS;
}
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