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

[Judith Mendez <jm@ti.com>]

Hi Adrian,

On 9/10/24 12:10 PM, Adrian Hunter wrote:
> 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@ti.com>
>>>> ---
>>>>    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;


Not sure I love the double NOT, but ok, I can use this, will fix for v2.

Thanks for your suggestion!

~ Judith

> 
> 
>>
>> 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
>>>
>>>
>>
>