Hi Philip, Can you please confirm what should be the correct implementation? Thanks, Arindam > -----Original Message----- > From: subhashj@xxxxxxxxxxxxxx [mailto:subhashj@xxxxxxxxxxxxxx] > Sent: Wednesday, June 15, 2011 5:28 AM > To: Nath, Arindam > Cc: 'Philip Rakity'; 'zhangfei gao'; cjb@xxxxxxxxxx; linux- > mmc@xxxxxxxxxxxxxxx; Lu, Aaron > Subject: RE: UHS-I bus speed mode should be set last in UHS > initialization > > Hi Arindam, > > > -----Original Message----- > > From: linux-mmc-owner@xxxxxxxxxxxxxxx [mailto:linux-mmc- > > owner@xxxxxxxxxxxxxxx] On Behalf Of Nath, Arindam > > Sent: Tuesday, June 14, 2011 12:00 AM > > To: subhashj@xxxxxxxxxxxxxx > > Cc: Philip Rakity; zhangfei gao; cjb@xxxxxxxxxx; linux- > > mmc@xxxxxxxxxxxxxxx; Lu, Aaron > > Subject: RE: UHS-I bus speed mode should be set last in UHS > > initialization > > > > Adding Philip and Zhangfei. > > > > Hi Subhash, > > > > Does your controller follow some non-standard steps for > initialization? > > I referred to Figure 3-14, section 3.9.4 of Physical Layer Spec > v3.01, > > and it shows the order, setting Driver Strength Select, Bus Speed > Mode, > > and then Current Limit. So please confirm back. > > Sorry, I don't know what do you mean by non standard steps for > initialization. Nowhere in v3.01 spec, it is mentioned that Bus speed > mode > **must** be set before current limit. Figure 3-14 also doesn't indicate > this. > > If you set the bus speed mode in sd_set_bus_speed_mode(), you are > changing > the host controller timings as well and if it's SDR50/SDR104 mode, then > immediately after setting the host controller timing mode, we have to > execute tuning sequence but here before executing tuning sequence, you > are > sending the CMD6 which involves the read data transfer from card which > is > bound to fail without tuning and it does fail with our host controller. > > Do let me know if this explanation make sense. > > Regards, > Subhash > > > > > Thanks, > > Arindam > > > > > -----Original Message----- > > > From: subhashj@xxxxxxxxxxxxxx [mailto:subhashj@xxxxxxxxxxxxxx] > > > Sent: Tuesday, June 14, 2011 1:27 AM > > > To: Nath, Arindam > > > Subject: FW: UHS-I bus speed mode should be set last in UHS > > > initialization > > > > > > Hi Arindam, > > > > > > Does this change make sense for you? If yes, then I can go ahead > and > > > post a > > > patch for this. > > > > > > Regards, > > > Subhash > > > > > > -----Original Message----- > > > From: linux-mmc-owner@xxxxxxxxxxxxxxx > > > [mailto:linux-mmc-owner@xxxxxxxxxxxxxxx] On Behalf Of Subhash > > Jadavani > > > Sent: Monday, June 06, 2011 3:44 PM > > > To: linux-mmc@xxxxxxxxxxxxxxx > > > Subject: UHS-I bus speed mode should be set last in UHS > > initialization > > > > > > Hi Chris, Arindam, > > > > > > mmc_sd_init_uhs_card function sets the driver type, current limit > and > > > bus > > > speed mode on card as well as on host controller side. Currently > bus > > > speed > > > mode is set by sending CMD6 to card and setting timing mode in host > > > controller and then before initiating tuning sequence, it also > tries > > to > > > set current limit by sending CMD6 to card which fails on our host > > > controller (due to data CRC or timeout errors) if bus speed mode is > > > SDR50/SDR104 mode. > > > > > > So basically bus speed mode should be set only after current limit > is > > > set > > > in the card and immediately after setting the bus speed mode, > tuning > > > sequence should be initiated. So following changes is needed. If it > > > looks > > > fine then I can send you this change in patch. > > > > > > diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c index > > > 0da37eb..19634d5 100644 > > > --- a/drivers/mmc/core/sd.c > > > +++ b/drivers/mmc/core/sd.c > > > @@ -610,13 +610,13 @@ static int mmc_sd_init_uhs_card(struct > mmc_card > > > *card) > > > if (err) > > > goto out; > > > > > > - /* Set bus speed mode of the card */ > > > - err = sd_set_bus_speed_mode(card, status); > > > + /* Set current limit for the card */ > > > + err = sd_set_current_limit(card, status); > > > if (err) > > > goto out; > > > > > > - /* Set current limit for the card */ > > > - err = sd_set_current_limit(card, status); > > > + /* Set bus speed mode of the card */ > > > + err = sd_set_bus_speed_mode(card, status); > > > if (err) > > > goto out; > > > > > > Regards, > > > Subhash > > > > > > -- > > > Sent by a consultant of the Qualcomm Innovation Center, Inc. > > > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora > > > Forum. > > > > > > > > > -- > > > To unsubscribe from this list: send the line "unsubscribe linux- > mmc" > > in > > > the body of a message to majordomo@xxxxxxxxxxxxxxx > > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > > > > > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-mmc" > in > > the body of a message to majordomo@xxxxxxxxxxxxxxx > > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
