On 16/11/16 06:42, Ritesh Harjani wrote:
> Hi,
>
> On 11/15/2016 10:40 AM, Ritesh Harjani wrote:
>> Hi Stephen/Adrian,
>>
>> On 11/15/2016 1:07 AM, Stephen Boyd wrote:
>>> On 11/14, Ritesh Harjani wrote:
>>>> @@ -577,6 +578,90 @@ static unsigned int
>>>> sdhci_msm_get_min_clock(struct sdhci_host *host)
>>>> return SDHCI_MSM_MIN_CLOCK;
>>>> }
>>>>
>>>> +/**
>>>> + * __sdhci_msm_set_clock - sdhci_msm clock control.
>>>> + *
>>>> + * Description:
>>>> + * Implement MSM version of sdhci_set_clock.
>>>> + * This is required since MSM controller does not
>>>> + * use internal divider and instead directly control
>>>> + * the GCC clock as per HW recommendation.
>>>> + **/
>>>> +void __sdhci_msm_set_clock(struct sdhci_host *host, unsigned int clock)
>>>> +{
>>>> + u16 clk;
>>>> + unsigned long timeout;
>>>> +
>>>> + /*
>>>> + * Keep actual_clock as zero -
>>>> + * - since there is no divider used so no need of having
>>>> actual_clock.
>>>> + * - MSM controller uses SDCLK for data timeout calculation. If
>>>> + * actual_clock is zero, host->clock is taken for calculation.
>>>> + */
>>>> + host->mmc->actual_clock = 0;
>>>> +
>>>> + sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL);
>>>> +
>>>> + if (clock == 0)
>>>> + return;
>>>> +
>>>> + /*
>>>> + * MSM controller do not use clock divider.
>>>> + * Thus read SDHCI_CLOCK_CONTROL and only enable
>>>> + * clock with no divider value programmed.
>>>> + */
>>>> + clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL);
>>>> +
>>>> + clk |= SDHCI_CLOCK_INT_EN;
>>>> + sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
>>>> +
>>>> + /* Wait max 20 ms */
>>>> + timeout = 20;
>>>> + while (!((clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL))
>>>> + & SDHCI_CLOCK_INT_STABLE)) {
>>>> + if (timeout == 0) {
>>>> + pr_err("%s: Internal clock never stabilised\n",
>>>> + mmc_hostname(host->mmc));
>>>> + return;
>>>> + }
>>>> + timeout--;
>>>> + mdelay(1);
>>>> + }
>>>> +
>>>> + clk |= SDHCI_CLOCK_CARD_EN;
>>>> + sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
>>>
>>> This is almost a copy/paste of sdhci_set_clock(). Can we make
>>> sdhci_set_clock() call a __sdhci_set_clock() function that takes
>>> unsigned int clock, and also a flag indicating if we want to set
>>> the internal clock divider or not? Then we can call
>>> __sdhci_set_clock() from sdhci_set_clock() with (clock, true) as
>>> arguments and (clock, false).
> Actually what you may be referring here is some sort of quirks which is not
> entertained any more for sdhci driver.
> sdhci is tending towards becoming a library and hence such changes are
> restricted.
>
> But I think we may do below changes to avoid duplication of code which
> enables the sdhci internal clock and waits for internal clock to be stable.
>
> Adrian, could you please tell if this should be ok?
That seems fine, but the name seems too long - how about changing
sdhci_set_clock_enable to sdhci_enable_clk.
> Then we may be able to call for sdhci_set_clock_enable function from
> sdhci_msm_set_clock.
>
>
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 42ef3eb..28e605c 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -1343,19 +1343,8 @@ u16 sdhci_calc_clk(struct sdhci_host *host, unsigned
> int clock,
> }
> EXPORT_SYMBOL_GPL(sdhci_calc_clk);
>
> -void sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
> +void sdhci_set_clock_enable(struct sdhci_host *host, unsigned short clk)
> {
> - u16 clk;
> - unsigned long timeout;
> -
> - host->mmc->actual_clock = 0;
> -
> - sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL);
> -
> - if (clock == 0)
> - return;
> -
> - clk = sdhci_calc_clk(host, clock, &host->mmc->actual_clock);
>
> clk |= SDHCI_CLOCK_INT_EN;
> sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
> @@ -1377,6 +1366,24 @@ void sdhci_set_clock(struct sdhci_host *host,
> unsigned int clock)
> clk |= SDHCI_CLOCK_CARD_EN;
> sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
> }
> +EXPORT_SYMBOL_GPL(sdhci_set_clock_enable);
> +
> +void sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
> +{
> + u16 clk;
> + unsigned long timeout;
> +
> + host->mmc->actual_clock = 0;
> +
> + sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL);
> +
> + if (clock == 0)
> + return;
> +
> + clk = sdhci_calc_clk(host, clock, &host->mmc->actual_clock);
> +
> + sdhci_set_clock_enable(host, clk);
> +}
> EXPORT_SYMBOL_GPL(sdhci_set_clock);
>
> static void sdhci_set_power_reg(struct sdhci_host *host, unsigned char mode,
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> index 766df17..43382e1 100644
> --- a/drivers/mmc/host/sdhci.h
> +++ b/drivers/mmc/host/sdhci.h
> @@ -681,6 +681,7 @@ static inline bool sdhci_sdio_irq_enabled(struct
> sdhci_host *host)
> u16 sdhci_calc_clk(struct sdhci_host *host, unsigned int clock,
> unsigned int *actual_clock);
> void sdhci_set_clock(struct sdhci_host *host, unsigned int clock);
> +void sdhci_set_clock_enable(struct sdhci_host *host, unsigned short clk);
> void sdhci_set_power(struct sdhci_host *host, unsigned char mode,
> unsigned short vdd);
> void sdhci_set_power_noreg(struct sdhci_host *host, unsigned char mode,
>
>
>
>> Adrian,
>> Could you please comment here ?
>>
>>>
>>>> +}
>>>> +
>>>> +/* sdhci_msm_set_clock - Called with (host->lock) spinlock held. */
>>>> +static void sdhci_msm_set_clock(struct sdhci_host *host, unsigned
>>>> int clock)
>>>> +{
>>>> + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
>>>> + struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host);
>>>> + int rc;
>>>> +
>>>> + if (!clock) {
>>>> + msm_host->clk_rate = clock;
>>>> + goto out;
>>>> + }
>>>> +
>>>> + spin_unlock_irq(&host->lock);
>>>> + if (clock != msm_host->clk_rate) {
>>>
>>> Why do we need to check here? Can't we call clk_set_rate()
>>> Unconditionally?
>> Since it may so happen that above layers may call for ->set_clock
>> function with same requested clock more than once, hence we cache the
>> host->clock here.
>> Also, since requested clock (host->clock) can be say 400Mhz but the
>> actual pltfm supported clock would be say 384MHz.
>>
>>
>>>
>>>> + rc = clk_set_rate(msm_host->clk, clock);
>>>> + if (rc) {
>>>> + pr_err("%s: Failed to set clock at rate %u\n",
>>>> + mmc_hostname(host->mmc), clock);
>>>> + spin_lock_irq(&host->lock);
>>>> + goto out;
>>>
>>> Or replace the above two lines with goto err;
>> Ok, I will have another label out_lock instead of err.
>>>
>>>> + }
>>>> + msm_host->clk_rate = clock;
>>>> + pr_debug("%s: Setting clock at rate %lu\n",
>>>> + mmc_hostname(host->mmc), clk_get_rate(msm_host->clk));
>>>> + }
>>>
>>> And put an err label here.
>> will put the label here as out_lock;
>>>
>>>> + spin_lock_irq(&host->lock);
>>>> +out:
>>>> + __sdhci_msm_set_clock(host, clock);
>>>> +}
>>>> +
>>>> static const struct of_device_id sdhci_msm_dt_match[] = {
>>>> { .compatible = "qcom,sdhci-msm-v4" },
>>>> {},
>>>
>>
>
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