> -----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)) > + > + 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) > + 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
