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

Alim Akhtar
2015-02-12T14:00:09Z

On Thu, Feb 12, 2015 at 4:40 PM, Andrzej Hajda <a.hajda@samsung.com> wrote:
> 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:
>
I don't think this DTO issue. I think we need a way to reproduce this,
at least on Exyons5422/5800.
what type of sd card is being used? Are you trying UHS-I mode by any chance?

> [ 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
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> 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