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/*
* Copyright (C) 2016 Pengutronix, Markus Pargmann <mpa@pengutronix.de>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#include <common.h>
#include "state.h"
struct state_backend_storage_bucket_cache {
struct state_backend_storage_bucket bucket;
struct state_backend_storage_bucket *raw;
u8 *data;
ssize_t data_len;
bool force_write;
/* For outputs */
struct device_d *dev;
};
static inline struct state_backend_storage_bucket_cache
*get_bucket_cache(struct state_backend_storage_bucket *bucket)
{
return container_of(bucket,
struct state_backend_storage_bucket_cache,
bucket);
}
static inline void state_backend_bucket_cache_drop(
struct state_backend_storage_bucket_cache *cache)
{
if (cache->data) {
free(cache->data);
cache->data = NULL;
cache->data_len = 0;
}
}
static int state_backend_bucket_cache_fill(
struct state_backend_storage_bucket_cache *cache)
{
int ret;
ret = cache->raw->read(cache->raw, &cache->data, &cache->data_len);
if (ret == -EUCLEAN)
cache->force_write = true;
else if (ret)
return ret;
return 0;
}
static int state_backend_bucket_cache_read(struct state_backend_storage_bucket *bucket,
uint8_t ** buf_out,
ssize_t * len_hint)
{
struct state_backend_storage_bucket_cache *cache =
get_bucket_cache(bucket);
int ret;
if (!cache->data) {
ret = state_backend_bucket_cache_fill(cache);
if (ret)
return ret;
}
if (cache->data) {
*buf_out = xmemdup(cache->data, cache->data_len);
if (!*buf_out)
return -ENOMEM;
*len_hint = cache->data_len;
}
return 0;
}
static int state_backend_bucket_cache_write(struct state_backend_storage_bucket *bucket,
const uint8_t * buf, ssize_t len)
{
struct state_backend_storage_bucket_cache *cache =
get_bucket_cache(bucket);
int ret;
if (!cache->force_write) {
if (!cache->data)
ret = state_backend_bucket_cache_fill(cache);
if (cache->data_len == len && !memcmp(cache->data, buf, len))
return 0;
}
state_backend_bucket_cache_drop(cache);
ret = cache->raw->write(cache->raw, buf, len);
if (ret)
return ret;
cache->data = xmemdup(buf, len);
cache->data_len = len;
return 0;
}
static int state_backend_bucket_cache_init(
struct state_backend_storage_bucket *bucket)
{
struct state_backend_storage_bucket_cache *cache =
get_bucket_cache(bucket);
if (cache->raw->init) {
return cache->raw->init(cache->raw);
}
return 0;
}
static void state_backend_bucket_cache_free(
struct state_backend_storage_bucket *bucket)
{
struct state_backend_storage_bucket_cache *cache =
get_bucket_cache(bucket);
state_backend_bucket_cache_drop(cache);
cache->raw->free(cache->raw);
free(cache);
}
int state_backend_bucket_cached_create(struct device_d *dev,
struct state_backend_storage_bucket *raw,
struct state_backend_storage_bucket **out)
{
struct state_backend_storage_bucket_cache *cache;
cache = xzalloc(sizeof(*cache));
cache->raw = raw;
cache->dev = dev;
cache->bucket.free = state_backend_bucket_cache_free;
cache->bucket.read = state_backend_bucket_cache_read;
cache->bucket.write = state_backend_bucket_cache_write;
cache->bucket.init = state_backend_bucket_cache_init;
*out = &cache->bucket;
return 0;
}
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