[PATCH 17/17] mtd: m25p80: change the m25p80_read to reading page to page
Wenyou Yang
wenyou.yang at atmel.com
Mon Nov 12 03:52:37 EST 2012
When run "flashcp /bin/busybox /dev/mtdX", it arised a OOPS. changing to fix the [BUG].
Signed-off-by: Wenyou Yang <wenyou.yang at atmel.com>
Cc: dwmw2 at infradead.org
Cc: linux-mtd at lists.infradead.org
---
drivers/mtd/devices/m25p80.c | 44 +++++++++++++++++++++++++++++++++++++++---
1 file changed, 41 insertions(+), 3 deletions(-)
diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
index 03838ba..73e5fea 100644
--- a/drivers/mtd/devices/m25p80.c
+++ b/drivers/mtd/devices/m25p80.c
@@ -340,6 +340,7 @@ static int m25p80_read(struct mtd_info *mtd, loff_t from, size_t len,
size_t *retlen, u_char *buf)
{
struct m25p *flash = mtd_to_m25p(mtd);
+ u32 page_offset, page_size;
struct spi_transfer t[2];
struct spi_message m;
@@ -358,7 +359,6 @@ static int m25p80_read(struct mtd_info *mtd, loff_t from, size_t len,
spi_message_add_tail(&t[0], &m);
t[1].rx_buf = buf;
- t[1].len = len;
spi_message_add_tail(&t[1], &m);
mutex_lock(&flash->lock);
@@ -379,9 +379,47 @@ static int m25p80_read(struct mtd_info *mtd, loff_t from, size_t len,
flash->command[0] = OPCODE_READ;
m25p_addr2cmd(flash, from, flash->command);
- spi_sync(flash->spi, &m);
+ page_offset = from & (flash->page_size - 1);
+
+ /* do all the bytes fit onto one page? */
+ if (page_offset + len <= flash->page_size) {
+ t[1].len = len;
+
+ spi_sync(flash->spi, &m);
+
+ *retlen = m.actual_length - m25p_cmdsz(flash)
+ - FAST_READ_DUMMY_BYTE;
+
+ } else {
+ u32 i;
+
+ /* the size of data remaining on the first page */
+ page_size = flash->page_size - page_offset;
+
+ t[1].len = page_size;
+ spi_sync(flash->spi, &m);
+
+ *retlen = m.actual_length - m25p_cmdsz(flash)
+ - FAST_READ_DUMMY_BYTE;
+
+ /* write everything in flash->page_size chunks */
+ for (i = page_size; i < len; i += page_size) {
+ page_size = len - i;
+ if (page_size > flash->page_size)
+ page_size = flash->page_size;
+
+ /* write the next page to flash */
+ m25p_addr2cmd(flash, from + i, flash->command);
+
+ t[1].rx_buf = buf + i;
+ t[1].len = page_size;
+
+ spi_sync(flash->spi, &m);
- *retlen = m.actual_length - m25p_cmdsz(flash) - FAST_READ_DUMMY_BYTE;
+ *retlen += m.actual_length - m25p_cmdsz(flash)
+ - FAST_READ_DUMMY_BYTE;
+ }
+ }
mutex_unlock(&flash->lock);
--
1.7.9.5
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