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

Alim Akhtar
2015-02-12T13:54:22Z

Hi Andrzej,

On Thu, Feb 12, 2015 at 4:43 PM, Andrzej Hajda <a.hajda@samsung.com> wrote:
> On 02/12/2015 12:20 AM, 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);
>
> It does not help, there is still the same timeout.
>
Did you tried this on top of the original $subject patch?
What does STATUS register tells? Can you post the full log here?

> Regards
> Andrzej
>
>>
>> ===== 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
>>>>>
>>>>
>>>> --
>>>> To unsubscribe from this list: send the line "unsubscribe linux-doc" in
>>>> the body of a message to majordomo@vger.kernel.org
>>>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>>>>
>>
>>
>

--
Regards,
Alim