Re: [PATCH v1] mmc: sdhci_am654: Add sdhci_am654_start_signal_voltage_switch

[Adrian Hunter]

On 10/09/24 17:30, Judith Mendez wrote:
> Hi Adrian,
> 
> On 9/9/24 1:26 AM, Adrian Hunter wrote:
>> On 6/09/24 20:50, Judith Mendez wrote:
>>> The sdhci_start_signal_voltage_switch function sets
>>> V1P8_SIGNAL_ENA by default after switching to 1v8 signaling.
>>> V1P8_SIGNAL_ENA determines whether to launch cmd/data on neg
>>> edge or pos edge of clock.
>>>
>>> Due to some eMMC and SD failures seen across am62x platform,
>>> do not set V1P8_SIGNAL_ENA by default, only enable the bit
>>> for devices that require this bit in order to switch to 1v8
>>> voltage for uhs modes.
>>>
>>> Signed-off-by: Judith Mendez <jm@xxxxxx>
>>> ---
>>>   drivers/mmc/host/sdhci_am654.c | 86 ++++++++++++++++++++++++++++++++++
>>>   1 file changed, 86 insertions(+)
>>>
>>> diff --git a/drivers/mmc/host/sdhci_am654.c b/drivers/mmc/host/sdhci_am654.c
>>> index 0aa3c40ea6ed8..fb6232e56606b 100644
>>> --- a/drivers/mmc/host/sdhci_am654.c
>>> +++ b/drivers/mmc/host/sdhci_am654.c
>>> @@ -155,6 +155,7 @@ struct sdhci_am654_data {
>>>       u32 tuning_loop;
>>>     #define SDHCI_AM654_QUIRK_FORCE_CDTEST BIT(0)
>>> +#define SDHCI_AM654_QUIRK_SET_V1P8_ENA BIT(1)
>>
>> It would be better for the quirk to represent the deviation
>> from normal i.e.
>>
>> #define SDHCI_AM654_QUIRK_SUPPRESS_V1P8_ENA BIT(1)
>>
>>>   };
>>>     struct window {
>>> @@ -356,6 +357,79 @@ static void sdhci_j721e_4bit_set_clock(struct sdhci_host *host,
>>>       sdhci_set_clock(host, clock);
>>>   }
>>>   +int sdhci_am654_start_signal_voltage_switch(struct mmc_host *mmc,
>>> +                        struct mmc_ios *ios)
>>
>> Simpler to call sdhci_start_signal_voltage_switch() for the normal
>> case e.g.
> 
> This is simpler, so sure will use thanks.
> 
>>
>> static int sdhci_am654_start_signal_voltage_switch(struct mmc_host *mmc, struct mmc_ios *ios)
>> {
>>     struct sdhci_host *host = mmc_priv(mmc);
>>     struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
>>     struct sdhci_am654_data *sdhci_am654 = sdhci_pltfm_priv(pltfm_host);
>>
>>
>>     if ((sdhci_am654->quirks & SDHCI_AM654_QUIRK_SUPPRESS_V1P8_ENA) &&
>>         ios->signal_voltage == MMC_SIGNAL_VOLTAGE_180) {
>>         ret = mmc_regulator_set_vqmmc(mmc, ios);
>>         if (ret < 0) {
>>             pr_warn("%s: Switching to 1.8V signalling voltage failed\n",
>>                 mmc_hostname(mmc));
>>             return -EIO;
>>         }
>>         return 0;
>>     }
>>
>>     return sdhci_start_signal_voltage_switch(mmc, ios);
>> }
>>
>>> +{
>>> +    struct sdhci_host *host = mmc_priv(mmc);
>>> +    struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
>>> +    struct sdhci_am654_data *sdhci_am654 = sdhci_pltfm_priv(pltfm_host);
>>> +    u16 ctrl;
>>> +    int ret;
>>> +
>>> +    if (host->version < SDHCI_SPEC_300)
>>> +        return 0;
>>> +
>>> +    switch (ios->signal_voltage) {
>>> +    case MMC_SIGNAL_VOLTAGE_330:
>>> +        if (!(host->flags & SDHCI_SIGNALING_330))
>>> +            return -EINVAL;
>>> +
>>> +        ctrl &= ~SDHCI_CTRL_VDD_180;
>>> +        sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
>>> +
>>> +        if (!IS_ERR(mmc->supply.vqmmc)) {
>>> +            ret = mmc_regulator_set_vqmmc(mmc, ios);
>>> +            if (ret < 0) {
>>> +                pr_warn("%s: Switching to 3.3V signalling voltage failed\n",
>>> +                    mmc_hostname(mmc));
>>> +                return -EIO;
>>> +            }
>>> +        }
>>> +
>>> +        usleep_range(5000, 5500);
>>> +
>>> +        ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
>>> +        if (!(ctrl & SDHCI_CTRL_VDD_180))
>>> +            return 0;
>>> +
>>> +        pr_warn("%s: 3.3V regulator output did not become stable\n",
>>> +            mmc_hostname(mmc));
>>> +
>>> +        return -EAGAIN;
>>> +
>>> +    case MMC_SIGNAL_VOLTAGE_180:
>>> +        if (!(host->flags & SDHCI_SIGNALING_180))
>>> +            return -EINVAL;
>>> +
>>> +        if (!IS_ERR(mmc->supply.vqmmc)) {
>>> +            ret = mmc_regulator_set_vqmmc(mmc, ios);
>>> +            if (ret < 0) {
>>> +                pr_warn("%s: Switching to 1.8V signalling voltage failed\n",
>>> +                    mmc_hostname(mmc));
>>> +                return -EIO;
>>> +            }
>>> +        }
>>> +
>>> +        if (sdhci_am654->quirks & SDHCI_AM654_QUIRK_SET_V1P8_ENA) {
>>> +            ctrl |= SDHCI_CTRL_VDD_180;
>>> +            sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
>>> +
>>> +            ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
>>> +            if (ctrl & SDHCI_CTRL_VDD_180)
>>> +                return 0;
>>> +
>>> +            pr_warn("%s: 1.8V regulator output did not become stable\n",
>>> +                mmc_hostname(mmc));
>>> +
>>> +            return -EAGAIN;
>>> +        }
>>> +        return 0;
>>> +
>>> +    default:
>>> +        return 0;
>>> +    }
>>> +}
>>> +
>>>   static u8 sdhci_am654_write_power_on(struct sdhci_host *host, u8 val, int reg)
>>>   {
>>>       writeb(val, host->ioaddr + reg);
>>> @@ -801,6 +875,8 @@ static int sdhci_am654_get_of_property(struct platform_device *pdev,
>>>                       struct sdhci_am654_data *sdhci_am654)
>>>   {
>>>       struct device *dev = &pdev->dev;
>>> +    struct device_node *np = dev->of_node;
>>> +    struct device_node *node;
>>>       int drv_strength;
>>>       int ret;
>>>   @@ -844,6 +920,15 @@ static int sdhci_am654_get_of_property(struct platform_device *pdev,
>>>       if (device_property_read_bool(dev, "ti,fails-without-test-cd"))
>>>           sdhci_am654->quirks |= SDHCI_AM654_QUIRK_FORCE_CDTEST;
>>>   +    node = of_parse_phandle(np, "vmmc-supply", 0);
>>> +
>>> +    if (node) {
>>> +        node = of_parse_phandle(np, "vqmmc-supply", 0);
>>> +
>>> +        if (!node)
>>> +            sdhci_am654->quirks |= SDHCI_AM654_QUIRK_SET_V1P8_ENA;
>>> +    }
>>
>> It would be simpler without 'np' and 'node'.  Not sure
>> what the rule is meant to be, but it could be something like:
>>
>>     if (of_parse_phandle(dev->of_node, "vmmc-supply", 0) &&
>>         of_parse_phandle(dev->of_node, "vqmmc-supply", 0)
>>         sdhci_am654->quirks |= SDHCI_AM654_QUIRK_SUPPRESS_V1P8_ENA;
> 
> My issue with this is that I also need the quirk (SDHCI_AM654_QUIRK_SUPPRESS_V1P8_ENA) for eMMC. DT node for eMMC does
> not include vmmc and vqmmc supplies. That is why I had the quirk logic
> inverted.

Ideally there would be a more direct way to distinguish eMMC, but
otherwise, having both supplies or neither would be:

	if (!!of_parse_phandle(dev->of_node, "vmmc-supply", 0) ==
	    !!of_parse_phandle(dev->of_node, "vqmmc-supply", 0))
		sdhci_am654->quirks |= SDHCI_AM654_QUIRK_SUPPRESS_V1P8_ENA;


> 
> This patch fixes timing issues with both eMMC and SD. (:
> 
> ~ Judith
> 
> 
>>
>>> +
>>>       sdhci_get_of_property(pdev);
>>>         return 0;
>>> @@ -940,6 +1025,7 @@ static int sdhci_am654_probe(struct platform_device *pdev)
>>>           goto err_pltfm_free;
>>>       }
>>>   +    host->mmc_host_ops.start_signal_voltage_switch = sdhci_am654_start_signal_voltage_switch;
>>>       host->mmc_host_ops.execute_tuning = sdhci_am654_execute_tuning;
>>>         pm_runtime_get_noresume(dev);
>>>
>>> base-commit: cf6444ba528f043398b112ac36e041a4d8685cb1
>>
>>
>