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

Jaehoon Chung
2015-02-09T07:04:53Z

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?

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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