On Mar 16, 2011, at 8:33 AM, Nath, Arindam wrote: > Hi Philip, > > >> -----Original Message----- >> From: Philip Rakity [mailto:prakity@xxxxxxxxxxx] >> Sent: Wednesday, March 16, 2011 9:01 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 >> >> >> Arindam, >> >> Thanks, >> >> There are a few other functions in the same file that should also be >> changed for the same reason. > > I hope you mean by setting default bus speed mode and driver type for the card. If so, I will take care of them. yes ! -- thank you. > > Thanks, > Arindam > >> >> 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
