u-boot/drivers/block/blkcache.c
Tom Rini 83d290c56f SPDX: Convert all of our single license tags to Linux Kernel style
When U-Boot started using SPDX tags we were among the early adopters and
there weren't a lot of other examples to borrow from.  So we picked the
area of the file that usually had a full license text and replaced it
with an appropriate SPDX-License-Identifier: entry.  Since then, the
Linux Kernel has adopted SPDX tags and they place it as the very first
line in a file (except where shebangs are used, then it's second line)
and with slightly different comment styles than us.

In part due to community overlap, in part due to better tag visibility
and in part for other minor reasons, switch over to that style.

This commit changes all instances where we have a single declared
license in the tag as both the before and after are identical in tag
contents.  There's also a few places where I found we did not have a tag
and have introduced one.

Signed-off-by: Tom Rini <trini@konsulko.com>
2018-05-07 09:34:12 -04:00

172 lines
3.7 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) Nelson Integration, LLC 2016
* Author: Eric Nelson<eric@nelint.com>
*
*/
#include <config.h>
#include <common.h>
#include <malloc.h>
#include <part.h>
#include <linux/ctype.h>
#include <linux/list.h>
struct block_cache_node {
struct list_head lh;
int iftype;
int devnum;
lbaint_t start;
lbaint_t blkcnt;
unsigned long blksz;
char *cache;
};
static LIST_HEAD(block_cache);
static struct block_cache_stats _stats = {
.max_blocks_per_entry = 2,
.max_entries = 32
};
static struct block_cache_node *cache_find(int iftype, int devnum,
lbaint_t start, lbaint_t blkcnt,
unsigned long blksz)
{
struct block_cache_node *node;
list_for_each_entry(node, &block_cache, lh)
if ((node->iftype == iftype) &&
(node->devnum == devnum) &&
(node->blksz == blksz) &&
(node->start <= start) &&
(node->start + node->blkcnt >= start + blkcnt)) {
if (block_cache.next != &node->lh) {
/* maintain MRU ordering */
list_del(&node->lh);
list_add(&node->lh, &block_cache);
}
return node;
}
return 0;
}
int blkcache_read(int iftype, int devnum,
lbaint_t start, lbaint_t blkcnt,
unsigned long blksz, void *buffer)
{
struct block_cache_node *node = cache_find(iftype, devnum, start,
blkcnt, blksz);
if (node) {
const char *src = node->cache + (start - node->start) * blksz;
memcpy(buffer, src, blksz * blkcnt);
debug("hit: start " LBAF ", count " LBAFU "\n",
start, blkcnt);
++_stats.hits;
return 1;
}
debug("miss: start " LBAF ", count " LBAFU "\n",
start, blkcnt);
++_stats.misses;
return 0;
}
void blkcache_fill(int iftype, int devnum,
lbaint_t start, lbaint_t blkcnt,
unsigned long blksz, void const *buffer)
{
lbaint_t bytes;
struct block_cache_node *node;
/* don't cache big stuff */
if (blkcnt > _stats.max_blocks_per_entry)
return;
if (_stats.max_entries == 0)
return;
bytes = blksz * blkcnt;
if (_stats.max_entries <= _stats.entries) {
/* pop LRU */
node = (struct block_cache_node *)block_cache.prev;
list_del(&node->lh);
_stats.entries--;
debug("drop: start " LBAF ", count " LBAFU "\n",
node->start, node->blkcnt);
if (node->blkcnt * node->blksz < bytes) {
free(node->cache);
node->cache = 0;
}
} else {
node = malloc(sizeof(*node));
if (!node)
return;
node->cache = 0;
}
if (!node->cache) {
node->cache = malloc(bytes);
if (!node->cache) {
free(node);
return;
}
}
debug("fill: start " LBAF ", count " LBAFU "\n",
start, blkcnt);
node->iftype = iftype;
node->devnum = devnum;
node->start = start;
node->blkcnt = blkcnt;
node->blksz = blksz;
memcpy(node->cache, buffer, bytes);
list_add(&node->lh, &block_cache);
_stats.entries++;
}
void blkcache_invalidate(int iftype, int devnum)
{
struct list_head *entry, *n;
struct block_cache_node *node;
list_for_each_safe(entry, n, &block_cache) {
node = (struct block_cache_node *)entry;
if ((node->iftype == iftype) &&
(node->devnum == devnum)) {
list_del(entry);
free(node->cache);
free(node);
--_stats.entries;
}
}
}
void blkcache_configure(unsigned blocks, unsigned entries)
{
struct block_cache_node *node;
if ((blocks != _stats.max_blocks_per_entry) ||
(entries != _stats.max_entries)) {
/* invalidate cache */
while (!list_empty(&block_cache)) {
node = (struct block_cache_node *)block_cache.next;
list_del(&node->lh);
free(node->cache);
free(node);
}
_stats.entries = 0;
}
_stats.max_blocks_per_entry = blocks;
_stats.max_entries = entries;
_stats.hits = 0;
_stats.misses = 0;
}
void blkcache_stats(struct block_cache_stats *stats)
{
memcpy(stats, &_stats, sizeof(*stats));
_stats.hits = 0;
_stats.misses = 0;
}