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

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2012/11/28 Seungwon Jeon <tgih.jun@xxxxxxxxxxx>:
> On Wednesday, November 28, 2012, Jaehoon Chung wrote:
>> On 11/27/2012 05:02 PM, Seungwon Jeon wrote:
>> > On Thursday, November 08, 2012, Jaehoon Chung <jh80.chung@xxxxxxxxxxx> wrote:
>> >> Before disabling clock, need to check whether card is busy on not.
>> >>
>> >> Signed-off-by: Jaehoon Chung <jh80.chung@xxxxxxxxxxx>
>> >> ---
>> >>  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()"?
> If we should wait busy status with long time,
> it would be better sleep-wait rather than just busy-wait.
Thank you for review.
well..it will use the sleep-wait. why use the 10~20? just example?
Then i will check this and resend the patch.

Best Regards,
Jaehoon Chung
>
> Thanks,
> Seungwon Jeon
>> >
>> > 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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