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

[Alim Akhtar <alim.akhtar@gmail.com>]

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



-- 
Regards,
Alim