[PATCH 17/17] mtd: m25p80: change the m25p80_read to reading page to page

[Baruch Siach]

Hi Wenyou Yang,

On Mon, Nov 12, 2012 at 04:52:37PM +0800, Wenyou Yang wrote:
> When run "flashcp /bin/busybox /dev/mtdX", it arised a OOPS. changing to fix the [BUG].

Please post the BUG printout, and include it with the commit log.

baruch

> 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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