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authorArtem Bityutskiy <artem.bityutskiy@linux.intel.com>2012-02-02 13:54:25 +0200
committerDavid Woodhouse <David.Woodhouse@intel.com>2012-02-04 08:04:57 +0000
commit500823195d0c9eec2a4637484f30cc93ec633d4a (patch)
tree9fa140cfce10567d10f5e7e708f71193ff9ec228 /drivers
parent1a30871fe635d3e92972e6b93e39ff65bb57e52d (diff)
Revert "mtd: atmel_nand: optimize read/write buffer functions"
This reverts commit fb5427508abbd635e877fabdf55795488119c2d6. The reason is that it breaks 16 bits NAND flash as it was reported by Nikolaus Voss and confirmed by Eric BĂ©nard. Nicolas Ferre <nicolas.ferre@atmel.com> alco confirmed: "After double checking with designers, I must admit that I misunderstood the way of optimizing accesses to SMC. 16 bit nand is not so common those days..." Reported-by: Nikolaus Voss <n.voss@weinmann.de> Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com> Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com> Cc: stable@kernel.org [3.1+]
Diffstat (limited to 'drivers')
-rw-r--r--drivers/mtd/nand/atmel_nand.c45
1 files changed, 41 insertions, 4 deletions
diff --git a/drivers/mtd/nand/atmel_nand.c b/drivers/mtd/nand/atmel_nand.c
index 4dd056e2e16a..35b4fb55dbd6 100644
--- a/drivers/mtd/nand/atmel_nand.c
+++ b/drivers/mtd/nand/atmel_nand.c
@@ -161,6 +161,37 @@ static int atmel_nand_device_ready(struct mtd_info *mtd)
!!host->board->rdy_pin_active_low;
}
+/*
+ * Minimal-overhead PIO for data access.
+ */
+static void atmel_read_buf8(struct mtd_info *mtd, u8 *buf, int len)
+{
+ struct nand_chip *nand_chip = mtd->priv;
+
+ __raw_readsb(nand_chip->IO_ADDR_R, buf, len);
+}
+
+static void atmel_read_buf16(struct mtd_info *mtd, u8 *buf, int len)
+{
+ struct nand_chip *nand_chip = mtd->priv;
+
+ __raw_readsw(nand_chip->IO_ADDR_R, buf, len / 2);
+}
+
+static void atmel_write_buf8(struct mtd_info *mtd, const u8 *buf, int len)
+{
+ struct nand_chip *nand_chip = mtd->priv;
+
+ __raw_writesb(nand_chip->IO_ADDR_W, buf, len);
+}
+
+static void atmel_write_buf16(struct mtd_info *mtd, const u8 *buf, int len)
+{
+ struct nand_chip *nand_chip = mtd->priv;
+
+ __raw_writesw(nand_chip->IO_ADDR_W, buf, len / 2);
+}
+
static void dma_complete_func(void *completion)
{
complete(completion);
@@ -235,27 +266,33 @@ err_buf:
static void atmel_read_buf(struct mtd_info *mtd, u8 *buf, int len)
{
struct nand_chip *chip = mtd->priv;
+ struct atmel_nand_host *host = chip->priv;
if (use_dma && len > mtd->oobsize)
/* only use DMA for bigger than oob size: better performances */
if (atmel_nand_dma_op(mtd, buf, len, 1) == 0)
return;
- /* if no DMA operation possible, use PIO */
- memcpy_fromio(buf, chip->IO_ADDR_R, len);
+ if (host->board->bus_width_16)
+ atmel_read_buf16(mtd, buf, len);
+ else
+ atmel_read_buf8(mtd, buf, len);
}
static void atmel_write_buf(struct mtd_info *mtd, const u8 *buf, int len)
{
struct nand_chip *chip = mtd->priv;
+ struct atmel_nand_host *host = chip->priv;
if (use_dma && len > mtd->oobsize)
/* only use DMA for bigger than oob size: better performances */
if (atmel_nand_dma_op(mtd, (void *)buf, len, 0) == 0)
return;
- /* if no DMA operation possible, use PIO */
- memcpy_toio(chip->IO_ADDR_W, buf, len);
+ if (host->board->bus_width_16)
+ atmel_write_buf16(mtd, buf, len);
+ else
+ atmel_write_buf8(mtd, buf, len);
}
/*