[OpenWrt-Devel] [PATCH] ar71xx: fix spi ath79 fast read (for 3.10 kernel)

[John Crispin]

can someone who knows m25p80 better than me figure out if this is
correct please ?



On 26/07/2014 04:52, Zhao, Gang wrote:
> Fast read adds a dummy byte in tx buffer if the transfer type is 
> SPI_TRANSFER_FLASH_READ_CMD. The dummy byte should be ignored when 
> calculating read address. This is done by adding a bool variable
> dummy in struct spi_transfer to indicate whether this transfer
> includes the dummy byte.
> 
> Signed-off-by: Zhao, Gang <gang.zhao.42 at gmail.com> --- 
> .../464-spi-ath79-fix-fast-flash-read.patch        | 36
> ++++++++++++++++++++++ 1 file changed, 36 insertions(+) create mode
> 100644
> target/linux/ar71xx/patches-3.10/464-spi-ath79-fix-fast-flash-read.patch
>
>  diff --git
> a/target/linux/ar71xx/patches-3.10/464-spi-ath79-fix-fast-flash-read.patch
> b/target/linux/ar71xx/patches-3.10/464-spi-ath79-fix-fast-flash-read.patch
>
> 
new file mode 100644
> index 0000000..6567755 --- /dev/null +++
> b/target/linux/ar71xx/patches-3.10/464-spi-ath79-fix-fast-flash-read.patch
>
> 
@@ -0,0 +1,36 @@
> +--- a/drivers/mtd/devices/m25p80.c ++++
> b/drivers/mtd/devices/m25p80.c +@@ -360,6 +360,10 @@ static int
> m25p80_read(struct mtd_info * + 	t[0].type =
> SPI_TRANSFER_FLASH_READ_CMD; + 	t[0].tx_buf = flash->command; +
> t[0].len = m25p_cmdsz(flash) + (flash->fast_read ? 1 : 0); ++ ++	if
> (flash->fast_read) ++		t[0].dummy = true; ++ +
> spi_message_add_tail(&t[0], &m); + + 	t[1].type =
> SPI_TRANSFER_FLASH_READ_DATA; +--- a/drivers/spi/spi-ath79.c ++++
> b/drivers/spi/spi-ath79.c +@@ -268,6 +268,10 @@ static int
> ath79_spi_do_read_flash_cmd(s + 	sp->read_addr = 0; + + 	len =
> t->len - 1; ++ ++	if (t->dummy) ++		len -= 1; ++ + 	p = t->tx_buf; 
> + + 	while (len--) { +--- a/include/linux/spi/spi.h ++++
> b/include/linux/spi/spi.h +@@ -531,6 +531,7 @@ struct spi_transfer
> { + 	u16		delay_usecs; + 	u32		speed_hz; + 	enum spi_transfer_type
> type; ++	bool dummy; + + 	struct list_head transfer_list; + };
> 
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