[PATCH] mmc: fsl_esdhc: Fix 'Internal clock never stabilised.' error

[Jaehoon Chung]

Hi,

On 6/12/22 18:12, Pali Rohár wrote:
> PING?

Sorry for too late. 

> 
> On Friday 29 April 2022 20:27:34 Pali Rohár wrote:
>> Only newer eSDHC controllers set PRSSTAT_SDSTB flag. So do not wait until
>> flag PRSSTAT_SDSTB is set on old pre-2.2 controllers. Instead sleep for
>> fixed amount of time like it was before commit 6f883e501b65 ("mmc:
>> fsl_esdhc: Add emmc hs200 support").
>>
>> This change fixes error 'Internal clock never stabilised.' which is printed
>> on P2020 board at every access to SD card.
>>
>> Fixes: 6f883e501b65 ("mmc: fsl_esdhc: Add emmc hs200 support")
>> Signed-off-by: Pali Rohár <pali at kernel.org>

Reviewed-by: Jaehoon Chung <jh80.chung at samsung.com>

Best Regards,
Jaehoon Chung

>> ---
>>  drivers/mmc/fsl_esdhc.c | 17 +++++++++++++++++
>>  1 file changed, 17 insertions(+)
>>
>> diff --git a/drivers/mmc/fsl_esdhc.c b/drivers/mmc/fsl_esdhc.c
>> index fdf2cc290e06..3b3587bd8d72 100644
>> --- a/drivers/mmc/fsl_esdhc.c
>> +++ b/drivers/mmc/fsl_esdhc.c
>> @@ -503,6 +503,7 @@ static void set_sysctl(struct fsl_esdhc_priv *priv, struct mmc *mmc, uint clock)
>>  	u32 time_out;
>>  	u32 value;
>>  	uint clk;
>> +	u32 hostver;
>>  
>>  	if (clock < mmc->cfg->f_min)
>>  		clock = mmc->cfg->f_min;
>> @@ -543,6 +544,14 @@ static void set_sysctl(struct fsl_esdhc_priv *priv, struct mmc *mmc, uint clock)
>>  
>>  	esdhc_clrsetbits32(&regs->sysctl, SYSCTL_CLOCK_MASK, clk);
>>  
>> +	/* Only newer eSDHC controllers set PRSSTAT_SDSTB flag */
>> +	hostver = esdhc_read32(&priv->esdhc_regs->hostver);
>> +	if (HOSTVER_VENDOR(hostver) <= VENDOR_V_22) {
>> +		udelay(10000);
>> +		esdhc_setbits32(&regs->sysctl, SYSCTL_PEREN | SYSCTL_CKEN);
>> +		return;
>> +	}
>> +
>>  	time_out = 20;
>>  	value = PRSSTAT_SDSTB;
>>  	while (!(esdhc_read32(&regs->prsstat) & value)) {
>> @@ -562,6 +571,7 @@ static void esdhc_clock_control(struct fsl_esdhc_priv *priv, bool enable)
>>  	struct fsl_esdhc *regs = priv->esdhc_regs;
>>  	u32 value;
>>  	u32 time_out;
>> +	u32 hostver;
>>  
>>  	value = esdhc_read32(&regs->sysctl);
>>  
>> @@ -572,6 +582,13 @@ static void esdhc_clock_control(struct fsl_esdhc_priv *priv, bool enable)
>>  
>>  	esdhc_write32(&regs->sysctl, value);
>>  
>> +	/* Only newer eSDHC controllers set PRSSTAT_SDSTB flag */
>> +	hostver = esdhc_read32(&priv->esdhc_regs->hostver);
>> +	if (HOSTVER_VENDOR(hostver) <= VENDOR_V_22) {
>> +		udelay(10000);
>> +		return;
>> +	}
>> +
>>  	time_out = 20;
>>  	value = PRSSTAT_SDSTB;
>>  	while (!(esdhc_read32(&regs->prsstat) & value)) {
>> -- 
>> 2.20.1
>>
>