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authorKamal Dasu <kdasu.kdev@gmail.com>2014-05-01 20:51:19 -0400
committerBrian Norris <computersforpeace@gmail.com>2014-05-20 16:35:32 -0700
commit66507c7bc8895f0da6b4ad87e96d61a9f7d7a118 (patch)
treea011e33764deec5b848280f3f2ed386f60967929 /drivers/mtd
parent6e5221558d35563dc656833a021543fba8185c41 (diff)
downloadop-kernel-dev-66507c7bc8895f0da6b4ad87e96d61a9f7d7a118.zip
op-kernel-dev-66507c7bc8895f0da6b4ad87e96d61a9f7d7a118.tar.gz
mtd: nand: Add support to use nand_base poi databuf as bounce buffer
nand_base can be passed a kmap()'d buffers from highmem by filesystems like jffs2. This results in failure to map the physical address of the DMA buffer on various contoller driver on different platforms. This change adds a chip option to use preallocated databuf as bounce buffers used in nand_do_read_ops() and nand_do_write_ops(). This allows for specific nand controller driver to set this option as needed. Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com> Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Diffstat (limited to 'drivers/mtd')
-rw-r--r--drivers/mtd/nand/nand_base.c37
1 files changed, 31 insertions, 6 deletions
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 7853b9b..1b844b8 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -37,6 +37,7 @@
#include <linux/err.h>
#include <linux/sched.h>
#include <linux/slab.h>
+#include <linux/mm.h>
#include <linux/types.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/nand.h>
@@ -1500,6 +1501,7 @@ static int nand_do_read_ops(struct mtd_info *mtd, loff_t from,
mtd->oobavail : mtd->oobsize;
uint8_t *bufpoi, *oob, *buf;
+ int use_bufpoi;
unsigned int max_bitflips = 0;
int retry_mode = 0;
bool ecc_fail = false;
@@ -1522,9 +1524,20 @@ static int nand_do_read_ops(struct mtd_info *mtd, loff_t from,
bytes = min(mtd->writesize - col, readlen);
aligned = (bytes == mtd->writesize);
+ if (!aligned)
+ use_bufpoi = 1;
+ else if (chip->options & NAND_USE_BOUNCE_BUFFER)
+ use_bufpoi = !virt_addr_valid(buf);
+ else
+ use_bufpoi = 0;
+
/* Is the current page in the buffer? */
if (realpage != chip->pagebuf || oob) {
- bufpoi = aligned ? buf : chip->buffers->databuf;
+ bufpoi = use_bufpoi ? chip->buffers->databuf : buf;
+
+ if (use_bufpoi && aligned)
+ pr_debug("%s: using read bounce buffer for buf@%p\n",
+ __func__, buf);
read_retry:
chip->cmdfunc(mtd, NAND_CMD_READ0, 0x00, page);
@@ -1546,7 +1559,7 @@ read_retry:
ret = chip->ecc.read_page(mtd, chip, bufpoi,
oob_required, page);
if (ret < 0) {
- if (!aligned)
+ if (use_bufpoi)
/* Invalidate page cache */
chip->pagebuf = -1;
break;
@@ -1555,7 +1568,7 @@ read_retry:
max_bitflips = max_t(unsigned int, max_bitflips, ret);
/* Transfer not aligned data */
- if (!aligned) {
+ if (use_bufpoi) {
if (!NAND_HAS_SUBPAGE_READ(chip) && !oob &&
!(mtd->ecc_stats.failed - ecc_failures) &&
(ops->mode != MTD_OPS_RAW)) {
@@ -2375,11 +2388,23 @@ static int nand_do_write_ops(struct mtd_info *mtd, loff_t to,
int bytes = mtd->writesize;
int cached = writelen > bytes && page != blockmask;
uint8_t *wbuf = buf;
+ int use_bufpoi;
+ int part_pagewr = (column || writelen < (mtd->writesize - 1));
+
+ if (part_pagewr)
+ use_bufpoi = 1;
+ else if (chip->options & NAND_USE_BOUNCE_BUFFER)
+ use_bufpoi = !virt_addr_valid(buf);
+ else
+ use_bufpoi = 0;
- /* Partial page write? */
- if (unlikely(column || writelen < (mtd->writesize - 1))) {
+ /* Partial page write?, or need to use bounce buffer */
+ if (use_bufpoi) {
+ pr_debug("%s: using write bounce buffer for buf@%p\n",
+ __func__, buf);
cached = 0;
- bytes = min_t(int, bytes - column, (int) writelen);
+ if (part_pagewr)
+ bytes = min_t(int, bytes - column, writelen);
chip->pagebuf = -1;
memset(chip->buffers->databuf, 0xff, mtd->writesize);
memcpy(&chip->buffers->databuf[column], buf, bytes);
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