2019-10-10 10:53:18

by Faiz Abbas

Subject: [PATCH] mmc: sdhci-omap: Fix Tuning procedure for temperatures < -20C

According to the App note[1] detailing the tuning algorithm, for
temperatures < -20C, the initial tuning value should be min(largest
value in LPW - 24, ceil(13/16 ratio of LPW)). The largest value in
LPW is (max_window + 4 * (max_len - 1)) and not (max_window + 4 * max_len)
itself. Fix this implementation.

[1] http://www.ti.com/lit/an/spraca9b/spraca9b.pdf

Fixes: 961de0a856e3 ("mmc: sdhci-omap: Workaround errata regarding
SDR104/HS200 tuning failures (i929)")
Cc: [email protected]
Signed-off-by: Faiz Abbas <[email protected]>
---
drivers/mmc/host/sdhci-omap.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mmc/host/sdhci-omap.c b/drivers/mmc/host/sdhci-omap.c
index 41c2677c587f..083e7e053c95 100644
--- a/drivers/mmc/host/sdhci-omap.c
+++ b/drivers/mmc/host/sdhci-omap.c
@@ -372,7 +372,7 @@ static int sdhci_omap_execute_tuning(struct mmc_host *mmc, u32 opcode)
* on temperature
*/
if (temperature < -20000)
- phase_delay = min(max_window + 4 * max_len - 24,
+ phase_delay = min(max_window + 4 * (max_len - 1) - 24,
max_window +
DIV_ROUND_UP(13 * max_len, 16) * 4);
else if (temperature < 20000)
--
2.19.2

2019-10-19 08:17:21

by Ulf Hansson

Subject: Re: [PATCH] mmc: sdhci-omap: Fix Tuning procedure for temperatures < -20C

On Thu, 10 Oct 2019 at 12:51, Faiz Abbas <[email protected]> wrote:
>
> According to the App note[1] detailing the tuning algorithm, for
> temperatures < -20C, the initial tuning value should be min(largest
> value in LPW - 24, ceil(13/16 ratio of LPW)). The largest value in
> LPW is (max_window + 4 * (max_len - 1)) and not (max_window + 4 * max_len)
> itself. Fix this implementation.
>
> [1] http://www.ti.com/lit/an/spraca9b/spraca9b.pdf
>
> Fixes: 961de0a856e3 ("mmc: sdhci-omap: Workaround errata regarding
> SDR104/HS200 tuning failures (i929)")
> Cc: [email protected]
> Signed-off-by: Faiz Abbas <[email protected]>

Applied for fixes, thanks!

Kind regards
Uffe


> ---
> drivers/mmc/host/sdhci-omap.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/sdhci-omap.c b/drivers/mmc/host/sdhci-omap.c
> index 41c2677c587f..083e7e053c95 100644
> --- a/drivers/mmc/host/sdhci-omap.c
> +++ b/drivers/mmc/host/sdhci-omap.c
> @@ -372,7 +372,7 @@ static int sdhci_omap_execute_tuning(struct mmc_host *mmc, u32 opcode)
> * on temperature
> */
> if (temperature < -20000)
> - phase_delay = min(max_window + 4 * max_len - 24,
> + phase_delay = min(max_window + 4 * (max_len - 1) - 24,
> max_window +
> DIV_ROUND_UP(13 * max_len, 16) * 4);
> else if (temperature < 20000)
> --
> 2.19.2
>