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mtd core: call driver write function with complete buffer 

mtd->write is supposed to loop around pages internally, no need
to do this in mtd_write. This fixes a huge write performance drop
with the m25p80 driver when it was converted to a mtd driver recently.
Since mtd->writesize is 1 for this driver mtd_write ended up doing
single byte writes on the flash.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
This commit is contained in:
Sascha Hauer 2012-11-29 11:16:40 +01:00
parent 381fd6f56e
commit 3139c3e9a6
1 changed files with 3 additions and 53 deletions
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56
drivers/mtd/core.c
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@ -62,65 +62,15 @@ static ssize_t mtd_read(struct cdev *cdev, void* buf, size_t count,
#define MTDPGALG(x) ((x) & ~(mtd->writesize - 1))
#ifdef CONFIG_MTD_WRITE
static int all_ff(const void *buf, int len)
{
int i;
const uint8_t *p = buf;
for (i = 0; i < len; i++)
if (p[i] != 0xFF)
return 0;
return 1;
}
static ssize_t mtd_write(struct cdev* cdev, const void *buf, size_t _count,
loff_t _offset, ulong flags)
{
struct mtd_info *mtd = cdev->priv;
size_t retlen, now;
int ret = 0;
void *wrbuf = NULL;
size_t count = _count;
unsigned long offset = _offset;
size_t retlen;
int ret;
if (NOTALIGNED(offset)) {
printf("offset 0x%0lx not page aligned\n", offset);
return -EINVAL;
}
ret = mtd->write(mtd, _offset, _count, &retlen, buf);
dev_dbg(cdev->dev, "write: offset: 0x%08lx count: 0x%zx\n", offset, count);
while (count) {
now = count > mtd->writesize ? mtd->writesize : count;
if (NOTALIGNED(now)) {
dev_dbg(cdev->dev, "not aligned: %d %ld\n",
mtd->writesize,
(offset % mtd->writesize));
wrbuf = xmalloc(mtd->writesize);
memset(wrbuf, 0xff, mtd->writesize);
memcpy(wrbuf + (offset % mtd->writesize), buf, now);
if (!all_ff(wrbuf, mtd->writesize))
ret = mtd->write(mtd, MTDPGALG(offset),
mtd->writesize, &retlen,
wrbuf);
free(wrbuf);
} else {
if (!all_ff(buf, mtd->writesize))
ret = mtd->write(mtd, offset, now, &retlen,
buf);
dev_dbg(cdev->dev,
"offset: 0x%08lx now: 0x%zx retlen: 0x%zx\n",
offset, now, retlen);
}
if (ret)
goto out;
offset += now;
count -= now;
buf += now;
}
out:
return ret ? ret : _count;
}
#endif