On Tue, Jul 20, 2010 at 10:08:23AM +0800, Mingkai Hu wrote:
> For Freescale's eSPI controller, the max transaction length one time
> is limitted by the SPCOM[TRANSLEN] field which is 0x10000. When used
> mkfs.ext2 command to create ext2 filesystem on the flash, the read
> length will exceed the max value of the SPCOM[TRANSLEN] field, so
> change the read function to read page by page.
>
> For other SPI flash driver, also needed to change the read function
> if used the eSPI controller.
>
> Signed-off-by: Mingkai Hu <mingkai...@freescale.com>
> ---
> drivers/mtd/devices/m25p80.c | 18 ++++++++++++++----
> 1 files changed, 14 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
> index 81e49a9..6cbe6b1 100644
> --- a/drivers/mtd/devices/m25p80.c
> +++ b/drivers/mtd/devices/m25p80.c
> @@ -317,6 +317,7 @@ static int m25p80_read(struct mtd_info *mtd, loff_t from,
> size_t len,
> struct m25p *flash = mtd_to_m25p(mtd);
> struct spi_transfer t[2];
> struct spi_message m;
> + u32 i, page_size = 0;
>
> DEBUG(MTD_DEBUG_LEVEL2, "%s: %s %s 0x%08x, len %zd\n",
> dev_name(&flash->spi->dev), __func__, "from",
> @@ -341,7 +342,6 @@ 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);
>
> /* Byte count starts at zero. */
> @@ -364,11 +364,21 @@ static int m25p80_read(struct mtd_info *mtd, loff_t
> from, size_t len,
>
> /* Set up the write data buffer. */
> flash->command[0] = OPCODE_READ;
> - m25p_addr2cmd(flash, from, flash->command);
>
> - spi_sync(flash->spi, &m);
> + for (i = page_size; i < len; i += page_size) {
> + page_size = len - i;
> + if (page_size > flash->page_size)
> + page_size = flash->page_size;
>
> - *retlen = m.actual_length - m25p_cmdsz(flash) - FAST_READ_DUMMY_BYTE;
> + m25p_addr2cmd(flash, from + i, flash->command);
> + t[1].len = page_size;
> + t[1].rx_buf = buf + i;
> +
> + spi_sync(flash->spi, &m);
> +
> + *retlen += m.actual_length - m25p_cmdsz(flash)
> + - FAST_READ_DUMMY_BYTE;
> + }
This patch seems to cripple all users just because eSPI cannot handle it. Am I
reading it wrong?
>
> mutex_unlock(&flash->lock);
>
> --
> 1.6.4
>
>
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