Some nand controllers (eg. omap2) need to have their buffers u32 aligned
to use high speed transfer mechanisms.
This commit provides a way to plug in an alignment function and provides a
32-bit algnment function.
Signed-off-by: Charles Manning <cdhmanning@xxxxxxxxx>
---
drivers/mtd/nand/nand_base.c | 22 +++++++++++++++++++++-
include/linux/mtd/nand.h | 5 +++--
2 files changed, 24 insertions(+), 3 deletions(-)
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 1f75a1b..e8c2432 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -1156,6 +1156,22 @@ static int nand_read_page_swecc(struct mtd_info *mtd, struct nand_chip *chip,
}
/**
+ * nand_align_subpage32 - function to align subpage read to 32-bits
+ * @mtd: mtd info structure
+ * @buf: pointer to pointer of buffer that needs to be aligned
+ * @len: pointer to length that needs to be aligned.
+ */
+
+void nand_align_subpage32(uint8_t **buf, int *len)
+{
+ int diff = (int)(*buf) & 3;
+ *buf = *buf - diff;
+ *len = *len + diff;
+ *len = (*len + 3) & ~3;
+}
+EXPORT_SYMBOL(nand_align_subpage32);
+
+/**
* nand_read_subpage - [REPLACABLE] software ecc based sub-page read function
* @mtd: mtd info structure
* @chip: nand chip info structure
@@ -1169,6 +1185,7 @@ static int nand_read_subpage(struct mtd_info *mtd, struct nand_chip *chip,
int start_step, end_step, num_steps;
uint32_t *eccpos = chip->ecc.layout->eccpos;
uint8_t *p;
+ uint8_t *b;
int data_col_addr, i, gaps = 0;
int datafrag_len, eccfrag_len, aligned_len, aligned_pos;
int busw = (chip->options & NAND_BUSWIDTH_16) ? 2 : 1;
@@ -1222,7 +1239,10 @@ static int nand_read_subpage(struct mtd_info *mtd, struct nand_chip *chip,
chip->cmdfunc(mtd, NAND_CMD_RNDOUT,
mtd->writesize + aligned_pos, -1);
- chip->read_buf(mtd, &chip->oob_poi[aligned_pos], aligned_len);
+ b = &chip->oob_poi[aligned_pos];
+ if(chip->align_subpage)
+ chip->align_subpage(&b, &aligned_len);
+ chip->read_buf(mtd, b, aligned_len);
}
for (i = 0; i < eccfrag_len; i++)
diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
index 63e17d0..6ea6177 100644
--- a/include/linux/mtd/nand.h
+++ b/include/linux/mtd/nand.h
@@ -474,6 +474,7 @@ struct nand_buffers {
* additional error status checks (determine if errors are
* correctable).
* @write_page: [REPLACEABLE] High-level page write function
+ * @align_subpage: [OPTIONAL] Aligns subpage read buffer.
*/
struct nand_chip {
@@ -501,7 +502,7 @@ struct nand_chip {
int status, int page);
int (*write_page)(struct mtd_info *mtd, struct nand_chip *chip,
const uint8_t *buf, int page, int cached, int raw);
-
+ void (*align_subpage)(uint8_t **buf, int *len);
int chip_delay;
unsigned int options;
@@ -597,7 +598,7 @@ extern int nand_erase_nand(struct mtd_info *mtd, struct erase_info *instr,
int allowbbt);
extern int nand_do_read(struct mtd_info *mtd, loff_t from, size_t len,
size_t *retlen, uint8_t *buf);
-
+extern void nand_align_subpage32(uint8_t **buf, int *len);
/**
* struct platform_nand_chip - chip level device structure
* @nr_chips: max. number of chips to scan for
--
1.7.1.5.g49342
--
To unsubscribe from this list: send the line "unsubscribe linux-omap" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
