Philip,
Thanks for your comment. And have sent out "[PATCH v2] mmc:sdio:guarantee
setting card data bus width as 4-bit " which uses the below printk.
printk(KERN_WARNING("%s: SDIO_CCCR_IF is invalid: 0x%02X\n",
mmc_hostname(card->host), ctrl);
Best Wishes,
Yong Ding
Operating Systems Engineering,
Application Processor Systems Engineering
-----Original Message-----
From: Philip Rakity
Sent: Monday, May 14, 2012 10:09 PM
To: Yong Ding
Cc: c...@laptop.org; linux-mmc@vger.kernel.org; o...@wizery.com;
linus.wall...@linaro.org; ulf.hans...@stericsson.com;
linux-ker...@vger.kernel.org
Subject: Re: [PATCH] mmc:sdio:guarantee setting card data bus width as 4-bit
ACK
but see below for printk change
On May 14, 2012, at 1:35 AM, yongd wrote:
> SDIO_CCCR_IF[1:0] in SDIO card is used for card data bus width
> setting as below,
> 00b: 1-bit bus
> 01b: Reserved
> 10b: 4-bit bus
> 11b: 8-bit bus(only for embedded SDIO)
> And sdio_enable_wide is for setting data bus width as 4-bit. But
> currently, it 1stly read the register, 2ndly OR' 1b with SDIO_CCCR_IF[1],
> and then write it back.
> As we can see, such way is based on such assumption that the
> SDIO_CCCR_IF[0] is always 0. Apparently, this is not right.
>
> Signed-off-by: yongd <yo...@marvell.com>
> ---
> drivers/mmc/core/sdio.c | 6 ++++++
> include/linux/mmc/sdio.h | 2 ++
> 2 files changed, 8 insertions(+)
>
> diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c
> index 13d0e95..6b6f902 100644
> --- a/drivers/mmc/core/sdio.c
> +++ b/drivers/mmc/core/sdio.c
> @@ -218,6 +218,12 @@ static int sdio_enable_wide(struct mmc_card *card)
> if (ret)
> return ret;
>
> + if ((ctrl & SDIO_BUS_WIDTH_MASK)
> + == SDIO_BUS_WIDTH_RESERVED)
> + printk(KERN_WARNING"SDIO_CCCR_IF is invalid: %d\n", ctrl);
printk(KERN_WARNING("%s: SDIO_CCCR_IF is invalid: %02X\n",
mmc_hostname(card->host), ctrl);
please double check mmc_hostname argument.
> +
> + /* set as 4-bit bus width */
> + ctrl &= ~SDIO_BUS_WIDTH_MASK;
> ctrl |= SDIO_BUS_WIDTH_4BIT;
>
> ret = mmc_io_rw_direct(card, 1, 0, SDIO_CCCR_IF, ctrl, NULL);
> diff --git a/include/linux/mmc/sdio.h b/include/linux/mmc/sdio.h
> index c9fe66c..17446d3 100644
> --- a/include/linux/mmc/sdio.h
> +++ b/include/linux/mmc/sdio.h
> @@ -98,7 +98,9 @@
>
> #define SDIO_CCCR_IF 0x07 /* bus interface controls */
>
> +#define SDIO_BUS_WIDTH_MASK 0x03 /* data bus width setting */
> #define SDIO_BUS_WIDTH_1BIT 0x00
> +#define SDIO_BUS_WIDTH_RESERVED 0x01
> #define SDIO_BUS_WIDTH_4BIT 0x02
> #define SDIO_BUS_ECSI 0x20 /* Enable continuous SPI
> interrupt */
> #define SDIO_BUS_SCSI 0x40 /* Support continuous SPI
> interrupt */
> --
> 1.7.9.5
>
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