Re: [PATCH v3 3/4] mmc: dw-mmc: check whether card is busy or not, before disabling clock

[Jaehoon Chung <jh80.chung@samsung.com>]

On 11/27/2012 05:02 PM, Seungwon Jeon wrote:
> On Thursday, November 08, 2012, Jaehoon Chung <jh80.chung@samsung.com> wrote:
>> Before disabling clock, need to check whether card is busy on not.
>>
>> Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
>> ---
>>  drivers/mmc/host/dw_mmc.c |   53 +++++++++++++++++++++++++++-----------------
>>  drivers/mmc/host/dw_mmc.h |    1 +
>>  2 files changed, 33 insertions(+), 21 deletions(-)
>>
>> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
>> index 0a80b5c..9704b09 100644
>> --- a/drivers/mmc/host/dw_mmc.c
>> +++ b/drivers/mmc/host/dw_mmc.c
>> @@ -228,6 +228,27 @@ static void dw_mci_set_timeout(struct dw_mci *host)
>>  	mci_writel(host, TMOUT, 0xffffffff);
>>  }
>>
>> +static bool mci_wait_reset(struct device *dev, struct dw_mci *host)
>> +{
>> +	unsigned long timeout = jiffies + msecs_to_jiffies(500);
>> +	unsigned int ctrl;
>> +
>> +	mci_writel(host, CTRL, (SDMMC_CTRL_RESET | SDMMC_CTRL_FIFO_RESET |
>> +				SDMMC_CTRL_DMA_RESET));
>> +
>> +	/* wait till resets clear */
>> +	do {
>> +		ctrl = mci_readl(host, CTRL);
>> +		if (!(ctrl & (SDMMC_CTRL_RESET | SDMMC_CTRL_FIFO_RESET |
>> +			      SDMMC_CTRL_DMA_RESET)))
>> +			return true;
>> +	} while (time_before(jiffies, timeout));
>> +
>> +	dev_err(dev, "Timeout resetting block (ctrl %#x)\n", ctrl);
>> +
>> +	return false;
>> +}
>> +
>>  static u32 dw_mci_prepare_command(struct mmc_host *mmc, struct mmc_command *cmd)
>>  {
>>  	struct mmc_data	*data;
>> @@ -622,6 +643,7 @@ static void dw_mci_setup_bus(struct dw_mci_slot *slot)
>>  	struct dw_mci *host = slot->host;
>>  	u32 div;
>>  	u32 clk_en_a;
>> +	int timeout = 1000;
>>
>>  	if (slot->clock != host->current_speed) {
>>  		div = host->bus_hz / slot->clock;
>> @@ -638,6 +660,16 @@ static void dw_mci_setup_bus(struct dw_mci_slot *slot)
>>  			 "Bus speed (slot %d) = %dHz (slot req %dHz, actual %dHZ"
>>  			 " div = %d)\n", slot->id, host->bus_hz, slot->clock,
>>  			 div ? ((host->bus_hz / div) >> 1) : host->bus_hz, div);
>> +		do {
>> +			if (!(mci_readl(host, STATUS) & SDMMC_DATA_BUSY))
>> +				break;
>> +			if (timeout-- < 0) {
>> +				dev_err(host->dev, "Can't disable clock"
>> +					"because Card is busy!!\n");
>> +				return;
>> +			}
>> +			mci_wait_reset(host->dev, host);
> Should 'mci_wait_reset' be called every loop?
> Only if card status is still busy at the end of while, one time is enough.
> 
>> +		} while (1);
> How about counting jiffies for while-loop with usleep_range?
> do {
> ...
> 	usleep_range(10, 20)
> } while (time_before())
Is there reason that use "usleep_range()"?
> 
> Thanks,
> Seungwon Jeon
>>
>>  		/* disable clock */
>>  		mci_writel(host, CLKENA, 0);
>> @@ -1995,27 +2027,6 @@ no_dma:
>>  	return;
>>  }
>>
>> -static bool mci_wait_reset(struct device *dev, struct dw_mci *host)
>> -{
>> -	unsigned long timeout = jiffies + msecs_to_jiffies(500);
>> -	unsigned int ctrl;
>> -
>> -	mci_writel(host, CTRL, (SDMMC_CTRL_RESET | SDMMC_CTRL_FIFO_RESET |
>> -				SDMMC_CTRL_DMA_RESET));
>> -
>> -	/* wait till resets clear */
>> -	do {
>> -		ctrl = mci_readl(host, CTRL);
>> -		if (!(ctrl & (SDMMC_CTRL_RESET | SDMMC_CTRL_FIFO_RESET |
>> -			      SDMMC_CTRL_DMA_RESET)))
>> -			return true;
>> -	} while (time_before(jiffies, timeout));
>> -
>> -	dev_err(dev, "Timeout resetting block (ctrl %#x)\n", ctrl);
>> -
>> -	return false;
>> -}
>> -
>>  #ifdef CONFIG_OF
>>  static struct dw_mci_of_quirks {
>>  	char *quirk;
>> diff --git a/drivers/mmc/host/dw_mmc.h b/drivers/mmc/host/dw_mmc.h
>> index 53b8fd9..4f27357 100644
>> --- a/drivers/mmc/host/dw_mmc.h
>> +++ b/drivers/mmc/host/dw_mmc.h
>> @@ -127,6 +127,7 @@
>>  #define SDMMC_CMD_INDX(n)		((n) & 0x1F)
>>  /* Status register defines */
>>  #define SDMMC_GET_FCNT(x)		(((x)>>17) & 0x1FFF)
>> +#define SDMMC_DATA_BUSY			BIT(9)
>>  /* Internal DMAC interrupt defines */
>>  #define SDMMC_IDMAC_INT_AI		BIT(9)
>>  #define SDMMC_IDMAC_INT_NI		BIT(8)
>> --
>> 1.7.4.1
>> --
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