Hi Subhash, > -----Original Message----- > From: subhashj@xxxxxxxxxxxxxx [mailto:subhashj@xxxxxxxxxxxxxx] > Sent: Wednesday, March 09, 2011 7:39 PM > To: Nath, Arindam; cjb@xxxxxxxxxx > Cc: zhangfei.gao@xxxxxxxxx; prakity@xxxxxxxxxxx; linux- > mmc@xxxxxxxxxxxxxxx; Su, Henry; Lu, Aaron; anath.amd@xxxxxxxxx > Subject: RE: [PATCH v2 03/12] mmc: sd: query function modes for uhs > cards > > > > > -----Original Message----- > > From: linux-mmc-owner@xxxxxxxxxxxxxxx [mailto:linux-mmc- > > owner@xxxxxxxxxxxxxxx] On Behalf Of Arindam Nath > > Sent: Friday, March 04, 2011 5:03 PM > > To: cjb@xxxxxxxxxx > > Cc: zhangfei.gao@xxxxxxxxx; prakity@xxxxxxxxxxx; > > subhashj@xxxxxxxxxxxxxx; linux-mmc@xxxxxxxxxxxxxxx; henry.su@xxxxxxx; > > aaron.lu@xxxxxxx; anath.amd@xxxxxxxxx; Arindam Nath > > Subject: [PATCH v2 03/12] mmc: sd: query function modes for uhs cards > > > > SD cards which conform to Physical Layer Spec v3.01 can support > > additional Bus Speed Modes, Driver Strength, and Current Limit > > other than the default values. We use CMD6 mode 0 to read these > > additional card functions. The values read here will be used > > during UHS-I initialization steps. > > > > Signed-off-by: Arindam Nath <arindam.nath@xxxxxxx> > > --- > > drivers/mmc/core/sd.c | 99 > > +++++++++++++++++++++++++++++++++++++++------- > > include/linux/mmc/card.h | 3 + > > 2 files changed, 87 insertions(+), 15 deletions(-) > > > > diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c > > index 3e82599..a63956b 100644 > > --- a/drivers/mmc/core/sd.c > > +++ b/drivers/mmc/core/sd.c > > @@ -283,25 +283,94 @@ static int mmc_read_switch(struct mmc_card > *card) > > return -ENOMEM; > > } > > > > - err = mmc_sd_switch(card, 0, 0, 1, status); > > - if (err) { > > - /* If the host or the card can't do the switch, > > - * fail more gracefully. */ > > - if ((err != -EINVAL) > > - && (err != -ENOSYS) > > - && (err != -EFAULT)) > > + if (card->scr.sda_spec3) { > > + /* First find out the supported Bus Speed Modes. */ > > + err = mmc_sd_switch(card, 0, 0, 1, status); > Reading function-group-1 status applies for both SD3.0 and SD2.0 cards > as > well. With card->scr.sda_spec check, you are duplicating the same code > in > else part of it as well. You can optimize it to only one call to > mmc_sd_switch() to read function-group-1. Yes, there is a duplication of the code. I will try to minimize it in the next version. > > > + if (err) { > > + /* > > + * If the host or the card can't do the switch, > > + * fail more gracefully. > > + */ > > + if ((err != -EINVAL) > > + && (err != -ENOSYS) > > + && (err != -EFAULT)) > > + goto out; > > + > > + printk(KERN_WARNING "%s: problem reading " > > + "Bus Speed modes.\n", > > + mmc_hostname(card->host)); > > + err = 0; > > + > > goto out; > > + } > > > > - printk(KER N_WARNING "%s: problem reading switch " > > - "capabilities, performance might suffer.\n", > > - mmc_hostname(card->host)); > > - err = 0; > > + card->sw_caps.uhs_bus_mode = status[13]; > Is adding uhs* prefix is appropriate? If card supports SD3.0 spec means > card > have to support UHS modes? Can we have cards (SDXC?) which sets SD3.0 > spec > bit in SCR but does not support any of the UHS modes. So in this case > putting uhs* prefix might not be appropriate. As per Physical Layer Spec v3.01, UHS-I can be applied to SDHC and SDXC cards. Cards which support UHS-I should have sda_spec3 set in the SCR register. Since we need to set the data rate depending on the exact UHS-I speed mode, I have prefixed the variable with uhs_ to make things clear. Thanks, Arindam > > > > + > > + /* Find out Driver Strengths supported by the card */ > > + err = mmc_sd_switch(card, 0, 2, 1, status); > > + if (err) { > > + /* > > + * If the host or the card can't do the switch, > > + * fail more gracefully. > > + */ > > + if ((err != -EINVAL) > > + && (err != -ENOSYS) > > + && (err != -EFAULT)) > > + goto out; > > + > > + printk(KERN_WARNING "%s: problem reading " > > + "Driver Strength.\n", > > + mmc_hostname(card->host)); > > + err = 0; > > > > - goto out; > > - } > > + goto out; > > + } > > > > - if (status[13] & 0x02) > > - card->sw_caps.hs_max_dtr = 50000000; > > + card->sw_caps.uhs_drv_type = status[9]; > > + > > + /* Find out Current Limits supported by the card */ > > + err = mmc_sd_switch(card, 0, 3, 1, status); > > + if (err) { > > + /* > > + * If the host or the card can't do the switch, > > + * fail more gracefully. > > + */ > > + if ((err != -EINVAL) > > + && (err != -ENOSYS) > > + && (err != -EFAULT)) > > + goto out; > > + > > + printk(KERN_WARNING "%s: problem reading " > > + "Current Limit.\n", > > + mmc_hostname(card->host)); > > + err = 0; > > + > > + goto out; > > + } > > + > > + card->sw_caps.uhs_curr_limit = status[7]; > > + } else { > > + err = mmc_sd_switch(card, 0, 0, 1, status); > > + if (err) { > > + /* > > + * If the host or the card can't do the switch, > > + * fail more gracefully. > > + */ > > + if ((err != -EINVAL) > > + && (err != -ENOSYS) > > + && (err != -EFAULT)) > > + goto out; > > + > > + printk(KERN_WARNING "%s: problem reading switch " > > + "capabilities, performance might suffer.\n", > > + mmc_hostname(card->host)); > > + err = 0; > > + goto out; > > + } > > + > > + if (status[13] & 0x02) > > + card->sw_caps.hs_max_dtr = 50000000; > > + } > > > > out: > > kfree(status); > > diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h > > index 22b0335..7080f22 100644 > > --- a/include/linux/mmc/card.h > > +++ b/include/linux/mmc/card.h > > @@ -75,6 +75,9 @@ struct sd_ssr { > > > > struct sd_switch_caps { > > unsigned int hs_max_dtr; > > + unsigned int uhs_bus_mode; > > + unsigned int uhs_drv_type; > > + unsigned int uhs_curr_limit; > > }; > > > > struct sdio_cccr { > > -- > > 1.7.1 > > > > -- > > 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
