LinuxLists.cc - [PATCH v2] mmc:sdio:guarantee setting card data bus width as 4-bit

2012-05-15 05:11:11

Subject: [PATCH v2] mmc:sdio:guarantee setting card data bus width as 4-bit

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 <[email protected]>
---
drivers/mmc/core/sdio.c | 7 +++++++
include/linux/mmc/sdio.h | 2 ++
2 files changed, 9 insertions(+)

diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c
index 13d0e95..7b528cf 100644
--- a/drivers/mmc/core/sdio.c
+++ b/drivers/mmc/core/sdio.c
@@ -218,6 +218,13 @@ 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"%s: SDIO_CCCR_IF is invalid: 0x%02X\n",
+ mmc_hostname(card->host), ctrl);
+
+ /* 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

2012-05-15 05:12:25

by Philip Rakity

[permalink] [raw]

Subject: Re: [PATCH v2] mmc:sdio:guarantee setting card data bus width as 4-bit

ACK

On May 14, 2012, at 10:09 PM, 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 <[email protected]>
> ---
> drivers/mmc/core/sdio.c | 7 +++++++
> include/linux/mmc/sdio.h | 2 ++
> 2 files changed, 9 insertions(+)
>
> diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c
> index 13d0e95..7b528cf 100644
> --- a/drivers/mmc/core/sdio.c
> +++ b/drivers/mmc/core/sdio.c
> @@ -218,6 +218,13 @@ 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"%s: SDIO_CCCR_IF is invalid: 0x%02X\n",
> + mmc_hostname(card->host), ctrl);
> +
> + /* 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
>

2012-05-17 12:37:50

by Chris Ball

[permalink] [raw]

Subject: Re: [PATCH v2] mmc:sdio:guarantee setting card data bus width as 4-bit

2012-05-18 01:50:44

by yongd

[permalink] [raw]

Subject: RE: [PATCH v2] mmc:sdio:guarantee setting card data bus width as 4-bit

Chris,
Thanks. And my full name is Yong Ding.

Best Wishes,

Yong Ding
Operating Systems Engineering,
Application Processor Systems Engineering

-----Original Message-----
From: Chris Ball [mailto:[email protected]]
Sent: Thursday, May 17, 2012 8:38 PM
To: Yong Ding
Cc: [email protected]; Philip Rakity; [email protected]; [email protected]; [email protected]; [email protected]
Subject: Re: [PATCH v2] mmc:sdio:guarantee setting card data bus width as 4-bit

Hi,

On Tue, May 15 2012, 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 <[email protected]>

Thanks. Can we have your full name, for the copyright record?

- Chris.
--
Chris Ball <[email protected]> <http://printf.net/>
One Laptop Per Child

2012-06-06 13:23:42

by Chris Ball

[permalink] [raw]

Subject: Re: [PATCH v2] mmc:sdio:guarantee setting card data bus width as 4-bit

Hi,

On Tue, May 15 2012, 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 <[email protected]>
> ---
> drivers/mmc/core/sdio.c | 7 +++++++
> include/linux/mmc/sdio.h | 2 ++
> 2 files changed, 9 insertions(+)
>
> diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c
> index 13d0e95..7b528cf 100644
> --- a/drivers/mmc/core/sdio.c
> +++ b/drivers/mmc/core/sdio.c
> @@ -218,6 +218,13 @@ 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"%s: SDIO_CCCR_IF is invalid: 0x%02X\n",
> + mmc_hostname(card->host), ctrl);
> +
> + /* 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 */

Thanks, pushed to mmc-next for 3.5.

- Chris.
--
Chris Ball <[email protected]> <http://printf.net/>
One Laptop Per Child

2012-06-07 01:32:43

by yongd

[permalink] [raw]

Subject: RE: [PATCH v2] mmc:sdio:guarantee setting card data bus width as 4-bit

Chris,
Thanks, and very glad to hear this:-)

Best Wishes,

Yong Ding
Operating Systems Engineering,
Application Processor Systems Engineering

-----Original Message-----
From: Chris Ball [mailto:[email protected]]
Sent: Wednesday, June 06, 2012 9:24 PM
To: Yong Ding
Cc: [email protected]; Philip Rakity; [email protected]; [email protected]; [email protected]; [email protected]
Subject: Re: [PATCH v2] mmc:sdio:guarantee setting card data bus width as 4-bit

Hi,

On Tue, May 15 2012, 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 <[email protected]>
> ---
> drivers/mmc/core/sdio.c | 7 +++++++
> include/linux/mmc/sdio.h | 2 ++
> 2 files changed, 9 insertions(+)
>
> diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c
> index 13d0e95..7b528cf 100644
> --- a/drivers/mmc/core/sdio.c
> +++ b/drivers/mmc/core/sdio.c
> @@ -218,6 +218,13 @@ 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"%s: SDIO_CCCR_IF is invalid: 0x%02X\n",
> + mmc_hostname(card->host), ctrl);
> +
> + /* 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 */

Thanks, pushed to mmc-next for 3.5.

- Chris.
--
Chris Ball <[email protected]> <http://printf.net/>
One Laptop Per Child