Re: [PATCH] mmc: dw_mmc: fix bug that cause 'Timeout sending command'

addy ke
2015-02-09T09:18:13Z

On 2015/2/9 15:04, Jaehoon Chung wrote:
> On 02/09/2015 03:56 PM, Addy wrote:
>>
>>
>> On 2015.02.09 12:51, Ulf Hansson wrote:
>>> On 5 February 2015 at 12:13, Addy Ke <addy.ke@rock-chips.com> wrote:
>>>> Because of some uncertain factors, such as worse card or worse hardware,
>>>> DAT[3:0](the data lines) may be pulled down by card, and mmc controller
>>>> will be in busy state. This should not happend when mmc controller
>>>> send command to update card clocks. If this happends, mci_send_cmd will
>>>> be failed and we will get 'Timeout sending command', and then system will
>>>> be blocked. To avoid this, we need reset mmc controller.
>
> I know that it needs to check whether card is busy or not, before clock-off.
> This patch seems to related with it. right?

Yes, it is.

>
> Best Regards,
> Jaehoon Chung
>
>>>>
>>>> Signed-off-by: Addy Ke <addy.ke@rock-chips.com>
>>>
>>> Hi Addy,
>>>
>>> Should I consider $subject patch as a better option to the one below?
>> No:
>> This patch fix the bug, which can be found by script:
>> cd /sys/bus/platform/drivers/dwmmc_rockchip
>> for i in $(seq 1 10000); do
>> echo "========================" $i
>> echo ff0c0000.dwmmc > unbind
>> sleep .5
>> echo ff0c0000.dwmmc > bind
>> sleep 2
>> done
>>
>>> [PATCH] mmc: dw_mmc: rockchip: Add DW_MCI_QUIRK_RETRY_DELAY
>> This patch is for tuning issue: we should delay until card go to idle state, when the previous command return error.
>>> https://lkml.org/lkml/2015/1/13/562
>>>
>>> Kind regards
>>> Uffe
>>>
>>>
>>>> ---
>>>> drivers/mmc/host/dw_mmc.c | 23 +++++++++++++++++++++++
>>>> 1 file changed, 23 insertions(+)
>>>>
>>>> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
>>>> index 4d2e3c2..b1d6dfb 100644
>>>> --- a/drivers/mmc/host/dw_mmc.c
>>>> +++ b/drivers/mmc/host/dw_mmc.c
>>>> @@ -100,6 +100,7 @@ struct idmac_desc {
>>>> };
>>>> #endif /* CONFIG_MMC_DW_IDMAC */
>>>>
>>>> +static int dw_mci_card_busy(struct mmc_host *mmc);
>>>> static bool dw_mci_reset(struct dw_mci *host);
>>>> static bool dw_mci_ctrl_reset(struct dw_mci *host, u32 reset);
>>>>
>>>> @@ -888,6 +889,26 @@ static void mci_send_cmd(struct dw_mci_slot *slot, u32 cmd, u32 arg)
>>>> cmd, arg, cmd_status);
>>>> }
>>>>
>>>> +static void dw_mci_wait_busy(struct dw_mci_slot *slot)
>>>> +{
>>>> + struct dw_mci *host = slot->host;
>>>> + unsigned long timeout = jiffies + msecs_to_jiffies(500);
>>>> +
>>>> + while (time_before(jiffies, timeout)) {
>>>> + if (!dw_mci_card_busy(slot->mmc))
>>>> + return;
>>>> + }
>>>> + dev_err(host->dev, "Data busy (status %#x)\n",
>>>> + mci_readl(slot->host, STATUS));
>>>> +
>>>> + /*
>>>> + * Data busy, this should not happend when mmc controller send command
>>>> + * to update card clocks in non-volt-switch state. If it happends, we
>>>> + * should reset controller to avoid getting "Timeout sending command".
>>>> + */
>>>> + dw_mci_ctrl_reset(host, SDMMC_CTRL_ALL_RESET_FLAGS);
>>>> +}
>>>> +
>>>> static void dw_mci_setup_bus(struct dw_mci_slot *slot, bool force_clkinit)
>>>> {
>>>> struct dw_mci *host = slot->host;
>>>> @@ -899,6 +920,8 @@ static void dw_mci_setup_bus(struct dw_mci_slot *slot, bool force_clkinit)
>>>> /* We must continue to set bit 28 in CMD until the change is complete */
>>>> if (host->state == STATE_WAITING_CMD11_DONE)
>>>> sdmmc_cmd_bits |= SDMMC_CMD_VOLT_SWITCH;
>>>> + else
>>>> + dw_mci_wait_busy(slot);
>>>>
>>>> if (!clock) {
>>>> mci_writel(host, CLKENA, 0);
>>>> --
>>>> 1.8.3.2
>>>>
>>>>
>>>> --
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>>>
>>>
>>
>>
>>
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