> -----Original Message----- > From: Nath, Arindam [mailto:Arindam.Nath@xxxxxxx] > Sent: Thursday, March 10, 2011 2:13 PM > To: subhashj@xxxxxxxxxxxxxx; cjb@xxxxxxxxxx > Cc: zhangfei.gao@xxxxxxxxx; prakity@xxxxxxxxxxx; linux- > mmc@xxxxxxxxxxxxxxx; Su, Henry; Lu, Aaron; anath.amd@xxxxxxxxx > Subject: RE: [PATCH v2 07/12] mmc: sd: set current limit for uhs cards > > Hi Subhash, > > > > -----Original Message----- > > From: subhashj@xxxxxxxxxxxxxx [mailto:subhashj@xxxxxxxxxxxxxx] > > Sent: Thursday, March 10, 2011 1:46 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 07/12] mmc: sd: set current limit for uhs > cards > > > > > > > > > -----Original Message----- > > > From: Arindam Nath [mailto:anath.amd@xxxxxxxxx] 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 07/12] mmc: sd: set current limit for uhs cards > > > > > > We decide on the current limit to be set for the card based on the > > > Capability of Host Controller to provide current at 1.8V > signalling, > > > and the maximum current limit of the card as indicated by CMD6 > > > mode 0. We then set the current limit for the card using CMD6 mode > 1. > > > > > > Signed-off-by: Arindam Nath <arindam.nath@xxxxxxx> > > > --- > > > drivers/mmc/core/sd.c | 45 > > > +++++++++++++++++++++++++++++++++++++++++++++ > > > drivers/mmc/host/sdhci.c | 24 ++++++++++++++++++++++++ > > > include/linux/mmc/card.h | 9 +++++++++ > > > include/linux/mmc/host.h | 1 + > > > 4 files changed, 79 insertions(+), 0 deletions(-) > > > > > > diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c > > > index ec0d8e6..df98a2c 100644 > > > --- a/drivers/mmc/core/sd.c > > > +++ b/drivers/mmc/core/sd.c > > > @@ -550,6 +550,46 @@ static int sd_set_bus_speed_mode(struct > mmc_card > > > *card, u8 *status) > > > return 0; > > > } > > > > > > +static int sd_set_current_limit(struct mmc_card *card, u8 *status) > > > +{ > > > + struct mmc_host *host = card->host; > > > + int mmc_host_max_current_180, current_limit; > > > + int err; > > > + > > > + /* sanity check */ > > > + if (!host->ops->get_max_current_180) > > > + return 0; > > > + > > > + /* Maximum current supported by host at 1.8V */ > > > + mmc_host_max_current_180 = host->ops->get_max_current_180(host); > > > > I don't think this should be mmc_ops. Max. current limit supported by > > host > > should be one of the MMC_CAP*. > > In your case you can read the "SDHCI_MAX_CURRENT" register during the > > probe > > and can set the appropriate MMC_CAP* from below: > > #define MMC_CAP_MAX_CURRENT_200 (1 << xx) > > #define MMC_CAP_MAX_CURRENT_400 (1 << (xx+1)) > > #define MMC_CAP_MAX_CURRENT_600 (1 << (xx+2)) > > #define MMC_CAP_MAX_CURRENT_800 (1 << (xx+3)) > > Good suggestion. Thanks. I will make the changes. > > > > > > + > > > + if (mmc_host_max_current_180 >= 800) { > > > + if (card->sw_caps.uhs_curr_limit & SD_MAX_CURRENT_800) > > > + current_limit = SD_SET_CURRENT_LIMIT_800; > > > + else if (card->sw_caps.uhs_curr_limit & SD_MAX_CURRENT_600) > > > + current_limit = SD_SET_CURRENT_LIMIT_600; > > > + else if (card->sw_caps.uhs_curr_limit & SD_MAX_CURRENT_400) > > > + current_limit = SD_SET_CURRENT_LIMIT_400; > > > + } else if (mmc_host_max_current_180 >= 600) { > > > + if (card->sw_caps.uhs_curr_limit & SD_MAX_CURRENT_600) > > > + current_limit = SD_SET_CURRENT_LIMIT_600; > > > + else if (card->sw_caps.uhs_curr_limit & SD_MAX_CURRENT_400) > > > + current_limit = SD_SET_CURRENT_LIMIT_400; > > > + } else if (mmc_host_max_current_180 >= 400) > > > + if (card->sw_caps.uhs_curr_limit & SD_MAX_CURRENT_400) > > > + current_limit = SD_SET_CURRENT_LIMIT_400; > > > + > > > > What will be value of current_limit if (mmc_host_max_current_180 < > 400) > > I referred to table 4-11 of Physical Layer specv3.01. < 400mA should > fall under the default current limit. Ok. this is fine. > > Thanks, > Arindam > > > > > > + err = mmc_sd_switch(card, 1, 3, current_limit, status); > > > + if (err) > > > + return err; > > > + > > > + if (((status[15] >> 4) & 0x0F) != current_limit) > > > + printk(KERN_WARNING "%s: Problem setting current limit!\n", > > > + mmc_hostname(card->host)); > > > + > > > + return 0; > > > +} > > > + > > > /* > > > * UHS-I specific initialization procedure > > > */ > > > @@ -590,6 +630,11 @@ static int mmc_sd_init_uhs_card(struct > mmc_card > > > *card) > > > > > > /* Set bus speed mode of the card */ > > > err = sd_set_bus_speed_mode(card, status); > > > + if (err) > > > + goto out; > > > + > > > + /* Set current limit for the card */ > > > + err = sd_set_current_limit(card, status); > > > > > > out: > > > kfree(status); > > > diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c > > > index f127fa2..245cc39 100644 > > > --- a/drivers/mmc/host/sdhci.c > > > +++ b/drivers/mmc/host/sdhci.c > > > @@ -1462,12 +1462,36 @@ static int > > > sdhci_start_signal_voltage_switch(struct mmc_host *mmc) > > > return -EAGAIN; > > > } > > > > > > +static int sdhci_get_max_current_180(struct mmc_host *mmc) > > > +{ > > > + struct sdhci_host *host; > > > + u32 max_current_caps; > > > + unsigned long flags; > > > + int max_current_180; > > > + > > > + host = mmc_priv(mmc); > > > + > > > + spin_lock_irqsave(&host->lock, flags); > > > + > > > + max_current_caps = sdhci_readl(host, SDHCI_MAX_CURRENT); > > > + > > > + spin_unlock_irqrestore(&host->lock, flags); > > > + > > > + /* Maximum current is 4 times the register value for 1.8V */ > > > + max_current_180 = ((max_current_caps & > > > SDHCI_MAX_CURRENT_180_MASK) >> > > > + SDHCI_MAX_CURRENT_180_SHIFT) * > > > + SDHCI_MAX_CURRENT_MULTIPLIER; > > > + > > > + return max_current_180; > > > +} > > > + > > > static const struct mmc_host_ops sdhci_ops = { > > > .request = sdhci_request, > > > .set_ios = sdhci_set_ios, > > > .get_ro = sdhci_get_ro, > > > .enable_sdio_irq = sdhci_enable_sdio_irq, > > > .start_signal_voltage_switch = > > > sdhci_start_signal_voltage_switch, > > > + .get_max_current_180 = sdhci_get_max_current_180, > > > }; > > > > > > > > > > > > /********************************************************************** > > > *******\ > > > diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h > > > index 0b24c41..a6811ae 100644 > > > --- a/include/linux/mmc/card.h > > > +++ b/include/linux/mmc/card.h > > > @@ -98,6 +98,15 @@ struct sd_switch_caps { > > > #define SD_DRIVER_TYPE_C 0x04 > > > #define SD_DRIVER_TYPE_D 0x08 > > > unsigned int uhs_curr_limit; > > > +#define SD_SET_CURRENT_LIMIT_200 0 > > > +#define SD_SET_CURRENT_LIMIT_400 1 > > > +#define SD_SET_CURRENT_LIMIT_600 2 > > > +#define SD_SET_CURRENT_LIMIT_800 3 > > > + > > > +#define SD_MAX_CURRENT_200 (1 << SD_SET_CURRENT_LIMIT_200) > > > +#define SD_MAX_CURRENT_400 (1 << SD_SET_CURRENT_LIMIT_400) > > > +#define SD_MAX_CURRENT_600 (1 << SD_SET_CURRENT_LIMIT_600) > > > +#define SD_MAX_CURRENT_800 (1 << SD_SET_CURRENT_LIMIT_800) > > > }; > > > > > > struct sdio_cccr { > > > diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h > > > index 4dfff6d..e84cd05 100644 > > > --- a/include/linux/mmc/host.h > > > +++ b/include/linux/mmc/host.h > > > @@ -128,6 +128,7 @@ struct mmc_host_ops { > > > void (*init_card)(struct mmc_host *host, struct mmc_card *card); > > > > > > int (*start_signal_voltage_switch)(struct mmc_host *host); > > > + int (*get_max_current_180)(struct mmc_host *mmc); > > > }; > > > > > > struct mmc_card; > > > -- > > > 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
