[U-Boot] [PATCH][v3] fsl_esdhc: Correcting esdhc timeout counter calculation
- Timeout counter value is set as DTOCV bits in SYSCTL register For counter value set as timeout, Timeout period = (2^(timeout + 13)) SD Clock cycles
- As per 4.6.2.2 section of SD Card specification v2.00, host should cofigure timeout period value to minimum 0.25 sec.
- Number of SD Clock cycles for 0.25sec should be minimum (SD Clock/sec * 0.25 sec) SD Clock cycles = (mmc->tran_speed * 1/4) SD Clock cycles
- Calculating timeout based on (2^(timeout + 13)) >= mmc->tran_speed * 1/4 Taking log2 both the sides and rounding up to next power of 2 => timeout + 13 = log2(mmc->tran_speed/4) + 1
Signed-off-by: Priyanka Jain Priyanka.Jain@freescale.com Signed-off-by: Andy Fleming afleming@freescale.com Signed-off-by: Kumar Gala galak@kernel.crashing.org Acked-by: Mingkai Hu Mingkai.Hu@freescale.com --- Changes for v3: Including code changes of v1 as suggested by Stefano Babic
Changes for v2: Added proper description as suggested by Wolfgang Denk
drivers/mmc/fsl_esdhc.c | 16 +++++++++++++++- 1 files changed, 15 insertions(+), 1 deletions(-)
diff --git a/drivers/mmc/fsl_esdhc.c b/drivers/mmc/fsl_esdhc.c index a368fe6..359d939 100644 --- a/drivers/mmc/fsl_esdhc.c +++ b/drivers/mmc/fsl_esdhc.c @@ -207,7 +207,21 @@ static int esdhc_setup_data(struct mmc *mmc, struct mmc_data *data) esdhc_write32(®s->blkattr, data->blocks << 16 | data->blocksize);
/* Calculate the timeout period for data transactions */ - timeout = fls(mmc->tran_speed/10) - 1; + /* + * 1)Timeout period = (2^(timeout+13)) SD Clock cycles + * 2)Timeout period should be minimum 0.250sec as per SD Card spec + * So, Number of SD Clock cycles for 0.25sec should be minimum + * (SD Clock/sec * 0.25 sec) SD Clock cycles + * = (mmc->tran_speed * 1/4) SD Clock cycles + * As 1) >= 2) + * => (2^(timeout+13)) >= mmc->tran_speed * 1/4 + * Taking log2 both the sides + * => timeout + 13 >= log2(mmc->tran_speed/4) + * Rounding up to next power of 2 + * => timeout + 13 = log2(mmc->tran_speed/4) + 1 + * => timeout + 13 = fls(mmc->tran_speed/4) + */ + timeout = fls(mmc->tran_speed/4); timeout -= 13;
if (timeout > 14)
On Mar 2, 2011, at 9:48 PM, Priyanka Jain wrote:
- Timeout counter value is set as DTOCV bits in SYSCTL register
For counter value set as timeout, Timeout period = (2^(timeout + 13)) SD Clock cycles
- As per 4.6.2.2 section of SD Card specification v2.00, host should
cofigure timeout period value to minimum 0.25 sec.
Number of SD Clock cycles for 0.25sec should be minimum (SD Clock/sec * 0.25 sec) SD Clock cycles = (mmc->tran_speed * 1/4) SD Clock cycles
Calculating timeout based on (2^(timeout + 13)) >= mmc->tran_speed * 1/4 Taking log2 both the sides and rounding up to next power of 2 => timeout + 13 = log2(mmc->tran_speed/4) + 1
Signed-off-by: Priyanka Jain Priyanka.Jain@freescale.com Signed-off-by: Andy Fleming afleming@freescale.com Signed-off-by: Kumar Gala galak@kernel.crashing.org Acked-by: Mingkai Hu Mingkai.Hu@freescale.com
Changes for v3: Including code changes of v1 as suggested by Stefano Babic
Changes for v2: Added proper description as suggested by Wolfgang Denk
drivers/mmc/fsl_esdhc.c | 16 +++++++++++++++- 1 files changed, 15 insertions(+), 1 deletions(-)
Stefano,
Got a chance to test on imx? Would like this fix in v2011.03
- k
On 03/03/2011 04:48 AM, Priyanka Jain wrote:
Timeout counter value is set as DTOCV bits in SYSCTL register For counter value set as timeout, Timeout period = (2^(timeout + 13)) SD Clock cycles
As per 4.6.2.2 section of SD Card specification v2.00, host should cofigure timeout period value to minimum 0.25 sec.
Number of SD Clock cycles for 0.25sec should be minimum (SD Clock/sec * 0.25 sec) SD Clock cycles = (mmc->tran_speed * 1/4) SD Clock cycles
Calculating timeout based on (2^(timeout + 13)) >= mmc->tran_speed * 1/4 Taking log2 both the sides and rounding up to next power of 2 => timeout + 13 = log2(mmc->tran_speed/4) + 1
Signed-off-by: Priyanka Jain Priyanka.Jain@freescale.com Signed-off-by: Andy Fleming afleming@freescale.com Signed-off-by: Kumar Gala galak@kernel.crashing.org Acked-by: Mingkai Hu Mingkai.Hu@freescale.com
Tested on a i.MX51 board.
Tested-by: Stefano Babic sbabic@denx.de
Best regards, Stefano Babic
On Mar 7, 2011, at 3:41 AM, Stefano Babic wrote:
On 03/03/2011 04:48 AM, Priyanka Jain wrote:
- Timeout counter value is set as DTOCV bits in SYSCTL register
For counter value set as timeout, Timeout period = (2^(timeout + 13)) SD Clock cycles
- As per 4.6.2.2 section of SD Card specification v2.00, host should
cofigure timeout period value to minimum 0.25 sec.
Number of SD Clock cycles for 0.25sec should be minimum (SD Clock/sec * 0.25 sec) SD Clock cycles = (mmc->tran_speed * 1/4) SD Clock cycles
Calculating timeout based on (2^(timeout + 13)) >= mmc->tran_speed * 1/4 Taking log2 both the sides and rounding up to next power of 2 => timeout + 13 = log2(mmc->tran_speed/4) + 1
Signed-off-by: Priyanka Jain Priyanka.Jain@freescale.com Signed-off-by: Andy Fleming afleming@freescale.com Signed-off-by: Kumar Gala galak@kernel.crashing.org Acked-by: Mingkai Hu Mingkai.Hu@freescale.com
Tested on a i.MX51 board.
Tested-by: Stefano Babic sbabic@denx.de
Best regards, Stefano Babic
thanks
applied.
- k
participants (3)
-
Kumar Gala -
Priyanka Jain -
Stefano Babic