Arindam, Thanks, There are a few other functions in the same file that should also be changed for the same reason. Philip On Mar 16, 2011, at 8:24 AM, Nath, Arindam wrote: > Hi Philip, > > >> -----Original Message----- >> From: Philip Rakity [mailto:prakity@xxxxxxxxxxx] >> Sent: Wednesday, March 16, 2011 8:48 PM >> To: Nath, Arindam >> Cc: cjb@xxxxxxxxxx; zhangfei.gao@xxxxxxxxx; subhashj@xxxxxxxxxxxxxx; >> linux-mmc@xxxxxxxxxxxxxxx; Su, Henry; Lu, Aaron; anath.amd@xxxxxxxxx >> Subject: Re: [PATCH v2 07/12] mmc: sd: set current limit for uhs cards >> >> >> On Mar 16, 2011, at 8:00 AM, Nath, Arindam wrote: >> >>> Hi Philip, >>> >>> >>>> -----Original Message----- >>>> From: Philip Rakity [mailto:prakity@xxxxxxxxxxx] >>>> Sent: Wednesday, March 16, 2011 8:22 PM >>>> To: Nath, Arindam >>>> Cc: cjb@xxxxxxxxxx; zhangfei.gao@xxxxxxxxx; subhashj@xxxxxxxxxxxxxx; >>>> linux-mmc@xxxxxxxxxxxxxxx; Su, Henry; Lu, Aaron; anath.amd@xxxxxxxxx >>>> Subject: Re: [PATCH v2 07/12] mmc: sd: set current limit for uhs >> cards >>>> >>>> >>>> On Mar 16, 2011, at 7:32 AM, Nath, Arindam wrote: >>>> >>>>> Hi Philip, >>>>> >>>>> >>>>>> -----Original Message----- >>>>>> From: Philip Rakity [mailto:prakity@xxxxxxxxxxx] >>>>>> Sent: Wednesday, March 16, 2011 7:56 PM >>>>>> To: Nath, Arindam >>>>>> Cc: cjb@xxxxxxxxxx; zhangfei.gao@xxxxxxxxx; >> subhashj@xxxxxxxxxxxxxx; >>>>>> linux-mmc@xxxxxxxxxxxxxxx; Su, Henry; Lu, Aaron; >> anath.amd@xxxxxxxxx >>>>>> Subject: Re: [PATCH v2 07/12] mmc: sd: set current limit for uhs >>>> cards >>>>>> >>>>>> >>>>>> On Mar 4, 2011, at 3:32 AM, Arindam Nath wrote: >>>>>> >>>>>>> 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; >>>>>> >>>>>> a better name would be get_max_current rather than >>>> get_max_current_180 >>>>> >>>>> The Max Current Capabilities register reports maximum currents for >>>> 1.8V, 3.0V and 3.3V. Since we are only interested in the maximum >>>> current at 1.8V, so I have added *_180 to the variable names to make >> it >>>> explicit. >>>> >>>> understand but that is the usage now and if we need to extend the >> code >>>> the name becomes misleading. >>> >>> Okay. I will remove *_180 in next version. >>> >>>>> >>>>>> >>>>>> do you want a test for get_max_current_180 < 400 ? and return 0 >>>> have >>>>>> it do the switch >>>>>> by setting the value ? >>>>> >>>>> As mentioned in the Physical Layer spec v3.01, <400mA falls under >> the >>>> default current limit, so we don't need to set it in case any or all >> of >>>> the above conditions fail. >>>> >>>> if future cards have memory or power is not removed they will they >>>> retain the old setting ? if so better to explicitly initialize. >>> >>> Can you please elaborate this a little further? >> >> Power to the sd slot is supplied via a regulator. This is turned on at >> power on. >> sometime in the future a reboot is done. power is NOT removed. The >> device does not reset >> into the default state. Have seen this on some boards. > > Thanks for the explanation. I will modify code to set the default current limit for the card. > > Regards, > Arindam > >> >>> >>> Thanks, >>> Arindam >>> >>>> >>>>> >>>>> Thanks, >>>>> Arindam >>>>> >>>>>>> + >>>>>>> + /* Maximum current supported by host at 1.8V */ >>>>>>> + mmc_host_max_current_180 = host->ops- >>> get_max_current_180(host); >>>>>>> + >>>>>>> + 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; >>>>>> >>>>>> or >>>>>> else >>>>>> current_limit = SD_SET_CURRENT_LIMIT_200; >>>>>>> + >>>>>>> + 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; >>>>>>> } >>>>>>> >>>>>> >>>>>> better name is sdhci_get_max_current >>>>>> >>>>>>> +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; >>>>>> >>>>>> SDHCI_MAX_CURRENT_SHIFT is better name. >>>>>> >>>>>>> + >>>>>>> + 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, >>>>>> >>>>>> .get_max_current = sdhci_get_max_current; >>>>>>> }; >>>>>>> >>>>>>> >>>>>> >>>> >> /********************************************************************** >>>>>> *******\ >>>>>>> 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
