2015-08-25 20:05 GMT+08:00 Ulf Hansson <[email protected]>:
> On 20 August 2015 at 02:16, Barry Song <[email protected]> wrote:
>> 2015-08-18 1:11 GMT+08:00 Ulf Hansson <[email protected]>:
>>> On 11 August 2015 at 10:41, Barry Song <[email protected]> wrote:
>>>> From: Weijun Yang <[email protected]>
>>>>
>>>> As SD Specifications Part1 Physical Layer Specification Version
>>>> 3.01 says, CMD19 tuning is available for unlocked cards in transfer
>>>> state of 1.8V signaling mode. The small difference between v3.00
>>>> and 3.01 spec means that CMD19 tuning is also available for DDR50
>>>> mode.
>>>
>>> So what happens with cards following the 3.0 spec version, those
>>> doesn't need to support the tuning CMD right? Perhaps that needs to be
>>> addressed in this patch well!?
>>
>> from HW registers of the card, we cann't know whether the HW needs
>> tuning. it is said 3.0.x need tuning, but 3.0 doesn't need. @weijun,
>> pls fix me if i am wrong.
>> if so, it seems we need a static flag somewhere to indicate whether
>> the tuning is needed. we can't detect to find the tuning requirement.
>
> Another way is to always try doing the tuning for DDR50, but in case
> of errors just ignore them and print a debug/info message!?
Uffe, do you mean something like below:
diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index 4e7366a..d4df9f0 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -629,8 +629,23 @@ static int mmc_sd_init_uhs_card(struct mmc_card *card)
*/
if (!mmc_host_is_spi(card->host) &&
(card->sd_bus_speed == UHS_SDR50_BUS_SPEED ||
- card->sd_bus_speed == UHS_SDR104_BUS_SPEED))
+ card->sd_bus_speed == UHS_DDR50_BUS_SPEED ||
+ card->sd_bus_speed == UHS_SDR104_BUS_SPEED)) {
err = mmc_execute_tuning(card);
+
+ /*
+ * As SD Specifications Part1 Physical Layer Specification Version
+ * 3.01 says, CMD19 tuning is available for unlocked cards in transfer
+ * state of 1.8V signaling mode. The small difference between v3.00
+ * and 3.01 spec means that CMD19 tuning is also available for DDR50
+ * mode.
+ */
+ if (err && (card->sd_bus_speed == UHS_DDR50_BUS_SPEED))
+ pr_err("%s: ddr50 tuning failed\n", mmc_hostname(card->host));
+ kfree(status);
+ return 0;
+ }
+ }
out:
kfree(status);
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 64b7fdb..382810d 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1915,6 +1915,7 @@ static int sdhci_execute_tuning(struct mmc_host
*mmc, u32 opcode)
break;
case MMC_TIMING_UHS_SDR104:
+ case MMC_TIMING_UHS_DDR50:
break;
case MMC_TIMING_UHS_SDR50:
>
> Kind regards
> Uffe
-barry
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