On 08/27/2012 10:38 AM, Seungwon Jeon wrote:
> On Friday, August 24, 2012, Jaehoon Chung <jh80.ch...@samsung.com> wrote:
>> Hi Seungwon,
>>
>> On 08/24/2012 12:55 PM, Seungwon Jeon wrote:
>>> Hi Jaehoon,
>>>
>>> On Thursday, August 23, 2012, Jaehoon Chung <jh80.ch...@samsung.com> wrote:
>>>> To avoid glitches in the card clock output,
>>>> need to check whether card is busy or not.
>>> Could you describe the problem more?
>> synopsys spec is mentioned. (7.1 Software/Hardware Restrictions)
>> "Before disabling clock, ensure that card is not busy due to any previous
>> data command."
>>
>>> In which situation did you meet this?
>> At specific board, i found the problem that didn't inform ciu.
>> (It didn't produce always.)
>> At that time, i checked the status register whether card is busy or not.
>> (Start bit of CMD register is cleared, but card is busy.)
>> Current code didn't check the card status. Just check whether the start-bit
>> cleared.
>> host regard that command is completed, will send the next command.
>> But next command didn't issue because Card is busy.
>> This patch can prevent this situation.
>>
>> If you have any comment or opinion, please let me know. it's great help to me
> If you know a point in time, we can reproduce it.
Well, i didn't sure that you can reproduce this.
On trats board, this problem is produced when kernel is booting.
Best Regards,
Jaehoon Chung
>
>>
>> Best Regards,
>> Jaehoon Chung
>>>
>>> Thanks,
>>> Seungwon Jeon
>>>>
>>>> Signed-off-by: Jaehoon Chung <jh80.ch...@samsung.com>
>>>> Signed-off-by: Kyungmin Park <kyungmin.p...@samsung.com>
>>>> ---
>>>> drivers/mmc/host/dw_mmc.c | 30 ++++++++++++++++++++++++------
>>>> drivers/mmc/host/dw_mmc.h | 1 +
>>>> 2 files changed, 25 insertions(+), 6 deletions(-)
>>>>
>>>> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
>>>> index 36f98c0..8bef3c2 100644
>>>> --- a/drivers/mmc/host/dw_mmc.c
>>>> +++ b/drivers/mmc/host/dw_mmc.c
>>>> @@ -623,6 +623,27 @@ static void mci_send_cmd(struct dw_mci_slot *slot,
>>>> u32 cmd, u32 arg)
>>>> cmd, arg, cmd_status);
>>>> }
>>>>
>>>> +static void dw_mci_inform_ciu(struct dw_mci_slot *slot)
>>>> +{
>>>> + struct dw_mci *host = slot->host;
>>>> + unsigned long timeout = jiffies + msecs_to_jiffies(500);
>>>> + u32 ctrl, status;
>>>> +
>>>> + do {
>>>> + status = mci_readl(host, STATUS);
>>>> + if (!(status & SDMMC_DATA_BUSY))
>>>> + break;
>>>> + ctrl = mci_readl(host, CTRL);
>>>> + ctrl |= SDMMC_CTRL_RESET;
>>>> + mci_writel(host, CTRL, ctrl);
>>>> + } while (time_before(jiffies, timeout));
>>>> +
>>>> + if (status & SDMMC_DATA_BUSY)
>>>> + dev_err(&slot->mmc->class_dev,"Card is busy..!\n");
>>>> +
>>>> + mci_send_cmd(slot, SDMMC_CMD_UPD_CLK | SDMMC_CMD_PRV_DAT_WAIT, 0);
>>>> +}
>>>> +
>>>> static void dw_mci_setup_bus(struct dw_mci_slot *slot)
>>>> {
>>>> struct dw_mci *host = slot->host;
>>>> @@ -650,15 +671,13 @@ static void dw_mci_setup_bus(struct dw_mci_slot
>>>> *slot)
>>>> mci_writel(host, CLKSRC, 0);
>>>>
>>>> /* inform CIU */
>>>> - mci_send_cmd(slot,
>>>> - SDMMC_CMD_UPD_CLK | SDMMC_CMD_PRV_DAT_WAIT, 0);
>>>> + dw_mci_inform_ciu(slot);
>>>>
>>>> /* set clock to desired speed */
>>>> mci_writel(host, CLKDIV, div);
>>>>
>>>> /* inform CIU */
>>>> - mci_send_cmd(slot,
>>>> - SDMMC_CMD_UPD_CLK | SDMMC_CMD_PRV_DAT_WAIT, 0);
>>>> + dw_mci_inform_ciu(slot);
>>>>
>>>> /* enable clock; only low power if no SDIO */
>>>> clk_en_a = SDMMC_CLKEN_ENABLE << slot->id;
>>>> @@ -667,8 +686,7 @@ static void dw_mci_setup_bus(struct dw_mci_slot *slot)
>>>> mci_writel(host, CLKENA, clk_en_a);
>>>>
>>>> /* inform CIU */
>>>> - mci_send_cmd(slot,
>>>> - SDMMC_CMD_UPD_CLK | SDMMC_CMD_PRV_DAT_WAIT, 0);
>>>> + dw_mci_inform_ciu(slot);
>>>>
>>>> host->current_speed = slot->clock;
>>>> }
>>>> diff --git a/drivers/mmc/host/dw_mmc.h b/drivers/mmc/host/dw_mmc.h
>>>> index 15c27e1..b6a1a78 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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>>
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