Re: [PATCH v2 1/2] mmc: dw_mmc: fix bug that cause 'Timeout sending command'

[Andrzej Hajda <a.hajda@samsung.com>]

On 02/12/2015 03:28 AM, addy ke wrote:
> Hi Andrzej and Alim
>
> On 2015/2/12 07:20, Alim Akhtar wrote:
>> Hi Andrzej,
>>
>> On Wed, Feb 11, 2015 at 5:28 PM, Andrzej Hajda <a.hajda@samsung.com> wrote:
>>> Hi Alim,
>>>
>>> On 02/11/2015 03:57 AM, Addy wrote:
>>>> On 2015/02/10 23:22, Alim Akhtar wrote:
>>>>> Hi Addy,
>>>>>
>>>>> On Mon, Feb 9, 2015 at 12:55 PM, 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.
>>>>>>
>>>>>> Signed-off-by: Addy Ke <addy.ke@rock-chips.com>
>>>>>> ---
>>>>>>   drivers/mmc/host/dw_mmc.c | 28 ++++++++++++++++++++++++++++
>>>>>>   1 file changed, 28 insertions(+)
>>>>>>
>>>>>> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
>>>>>> index 4d2e3c2..b0b57e3 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 +889,31 @@ 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);
>>>>>> +
>>>>> Why 500 msec?
>>>> This timeout value is the same as  mci_send_cmd:
>>>> static void mci_send_cmd(struct dw_mci_slot *slot, u32 cmd, u32 arg)
>>>> {
>>>>          struct dw_mci *host = slot->host;
>>>>          unsigned long timeout = jiffies + msecs_to_jiffies(500);
>>>>          ....
>>>> }
>>>>
>>>> I have not clear that which is suitable.
>>>> Do you have any suggestion on it?
>>>>>> +       do {
>>>>>> +               if (!dw_mci_card_busy(slot->mmc))
>>>>>> +                       return;
>>>>>> +               cpu_relax();
>>>>>> +       } while (time_before(jiffies, timeout));
>>>>>> +
>>>>>> +       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);
>>>>>> +
>>>>> Why you need to reset all blocks? may be CTRL_RESET is good enough here.
>>>> I have tested on rk3288, if only reset ctroller, data busy bit will not
>>>> be cleaned,and we will still get
>>>>
>>>> "Timeout sending command".
>>>>
>>>>>> +       /* Fail to reset controller or still data busy, WARN_ON! */
>>>>>> +       WARN_ON(dw_mci_card_busy(slot->mmc));
>>>>>> +}
>>>>>> +
>>>>>>   static void dw_mci_setup_bus(struct dw_mci_slot *slot, bool force_clkinit)
>>>>>>   {
>>>>>>          struct dw_mci *host = slot->host;
>>>>>> @@ -899,6 +925,8 @@ 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);
>>>>>>
>>>>> hmm...I would suggest you to call dw_mci_wait_busy() from inside
>>>>> mci_send_cmd(), seems like dw_mmc hangs while sending update clock cmd
>>>>> in multiple cases.see [1]
>>>>>
>>>>> [1]: http://permalink.gmane.org/gmane.linux.kernel.mmc/31140
>>>> I think this patch is more reasonable.
>>>> So I will resend patches based on this patch.
>>>> thank you!
>>> I have tested your patches instead [1] above and they do not solve my issue:
>>> Board: odroid-xu3/exynos5422/dw_mmc_250a.
>>> MMC card: absent, broken-cd quirk
>>> SD card: present
>>>
>> I doubt $SUBJECT patch in current form can resolve you issue. I have
>> already given comments on $subject patch.
>>
>> Can you try out below patch (I have not tested yet) on top of $SUBJECT patch?
>>
>> =======
>> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
>> index b0b57e3..ea87844 100644
>> --- a/drivers/mmc/host/dw_mmc.c
>> +++ b/drivers/mmc/host/dw_mmc.c
>> @@ -101,6 +101,7 @@ struct idmac_desc {
>>  #endif /* CONFIG_MMC_DW_IDMAC */
>>
>>  static int dw_mci_card_busy(struct mmc_host *mmc);
>> +static void dw_mci_wait_busy(struct dw_mci_slot *slot);
>>  static bool dw_mci_reset(struct dw_mci *host);
>>  static bool dw_mci_ctrl_reset(struct dw_mci *host, u32 reset);
>>
>> @@ -874,16 +875,22 @@ static void mci_send_cmd(struct dw_mci_slot
>> *slot, u32 cmd, u32 arg)
>>         struct dw_mci *host = slot->host;
>>         unsigned long timeout = jiffies + msecs_to_jiffies(500);
>>         unsigned int cmd_status = 0;
>> +       int re_try = 3; /* just random for now, 1 re-try should be ok */
>>
>> -       mci_writel(host, CMDARG, arg);
>> -       wmb();
>> -       mci_writel(host, CMD, SDMMC_CMD_START | cmd);
>> +       while(re_try--) {
>> +               mci_writel(host, CMDARG, arg);
>> +               wmb();
>> +               mci_writel(host, CMD, SDMMC_CMD_START | cmd);
>>
>> -       while (time_before(jiffies, timeout)) {
>> -               cmd_status = mci_readl(host, CMD);
>> -               if (!(cmd_status & SDMMC_CMD_START))
>> -                       return;
>> +               while (time_before(jiffies, timeout)) {
>> +                       cmd_status = mci_readl(host, CMD);
>> +                       if (!(cmd_status & SDMMC_CMD_START))
>> +                               return;
>> +               }
>> +
>> +               dw_mci_wait_busy(slot);
>>         }
>> +
>>         dev_err(&slot->mmc->class_dev,
>>                 "Timeout sending command (cmd %#x arg %#x status %#x)\n",
>>                 cmd, arg, cmd_status);
>> @@ -925,8 +932,6 @@ 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);
>>
>> ===== end ======
> The reason why we are fail to send command is that we got data busy in
> none-switch-volt state(host->state != STATE_WAITING_CMD11_DONE).
> So:
> if(host->state != STATE_WAITING_CMD11_DONE), we must wait until data not busy,
> And if (host->state == STATE_WAITING_CMD11_DONE) we should not wait.
>
>>> System hangs during boot after few minutes kernel spits:
>>> [  242.188098] INFO: task kworker/u16:1:50 blocked for more than 120
>>> seconds.
>>> [  242.193524]       Not tainted
>>> 3.19.0-next-20150210-00002-gf96831b-dirty #3834
>>> [  242.200622] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs"
>>> disables this message.
>>> [  242.208422] kworker/u16:1   D c04766ac     0    50      2 0x00000000
>>> [  242.214756] Workqueue: kmmcd mmc_rescan
>>> [  242.218553] [<c04766ac>] (__schedule) from [<c0476a58>]
>>> (schedule+0x34/0x98)
>>> [  242.225591] [<c0476a58>] (schedule) from [<c047a4dc>]
>>> (schedule_timeout+0x110/0x164)
>>> [  242.233302] [<c047a4dc>] (schedule_timeout) from [<c04774f0>]
>>> (wait_for_common+0xb8/0x14c)
>>> [  242.241539] [<c04774f0>] (wait_for_common) from [<c0362138>]
>>> (mmc_wait_for_req+0x68/0x17c)
>>> [  242.249861] [<c0362138>] (mmc_wait_for_req) from [<c03622cc>]
>>> (mmc_wait_for_cmd+0x80/0xa0)
>>> [  242.258002] [<c03622cc>] (mmc_wait_for_cmd) from [<c0367e50>]
>>> (mmc_go_idle+0x78/0xf8)
>>> [  242.265796] [<c0367e50>] (mmc_go_idle) from [<c0363e2c>]
>>> (mmc_rescan+0x280/0x314)
>>> [  242.273253] [<c0363e2c>] (mmc_rescan) from [<c0034764>]
>>> (process_one_work+0x120/0x324)
>>> [  242.281135] [<c0034764>] (process_one_work) from [<c00349cc>]
>>> (worker_thread+0x30/0x42c)
>>> [  242.289194] [<c00349cc>] (worker_thread) from [<c003926c>]
>>> (kthread+0xd8/0xf4)
>>> [  242.296389] [<c003926c>] (kthread) from [<c000e7c0>]
>>> (ret_from_fork+0x14/0x34)
>>>
>>> Just for record, Exynos4412/dw_mmc_240a with the same configuration
>>> (no MMC card, broken-cd) works OK without patches.
> This is because mmc start command,but mmc_request_done() is't called.
> I have ever found this issue.
> I found that host does't get DTO interrupt when mmc send command to read data.
> I have sent a patch for it, see:
> https://patchwork.kernel.org/patch/5426531/
>
> Would you please merge it and test again?

I have merged it and added quirk to exynos, but it does not help. There
is still timeout:

[  242.188178] INFO: task kworker/u16:1:50 blocked for more than 120
seconds.
[  242.193605]       Not tainted
3.19.0-next-20150212-00003-g7850750-dirty #3841
[  242.200703] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs"
disables this message.
[  242.208592] kworker/u16:1   D c04755f4     0    50      2 0x00000000
[  242.214840] Workqueue: kmmcd mmc_rescan
[  242.218635] [<c04755f4>] (__schedule) from [<c04759a0>]
(schedule+0x34/0x98)
[  242.225671] [<c04759a0>] (schedule) from [<c0479424>]
(schedule_timeout+0x110/0x164)
[  242.233383] [<c0479424>] (schedule_timeout) from [<c0476438>]
(wait_for_common+0xb8/0x14c)
[  242.241619] [<c0476438>] (wait_for_common) from [<c0361600>]
(mmc_wait_for_req+0xb0/0x13c)
[  242.249848] [<c0361600>] (mmc_wait_for_req) from [<c036170c>]
(mmc_wait_for_cmd+0x80/0xa0)
[  242.258086] [<c036170c>] (mmc_wait_for_cmd) from [<c03676e0>]
(mmc_go_idle+0x78/0xf8)
[  242.265876] [<c03676e0>] (mmc_go_idle) from [<c0363700>]
(mmc_rescan+0x25c/0x2e4)
[  242.273333] [<c0363700>] (mmc_rescan) from [<c0034764>]
(process_one_work+0x120/0x324)
[  242.281216] [<c0034764>] (process_one_work) from [<c00349cc>]
(worker_thread+0x30/0x42c)
[  242.289275] [<c00349cc>] (worker_thread) from [<c003926c>]
(kthread+0xd8/0xf4)
[  242.296469] [<c003926c>] (kthread) from [<c000e7c0>]
(ret_from_fork+0x14/0x34)


Regards
Andrzej

>>>
>>> Regards
>>> Andrzej
>>>
>>>>>>          if (!clock) {
>>>>>>                  mci_writel(host, CLKENA, 0);
>>>>>> --
>>>>>> 1.8.3.2
>>>>>>
>>>>>>
>>>>>>
>>>>>> _______________________________________________
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>>>>>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>>>>>
>>>>
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>>
>>
>