Message-ID: <b61f6fdb-4f42-e889-ac39-1b32b3d73c38@rock-chips.com>
Date:	Fri, 24 Jun 2016 09:25:01 +0800
From:	Shawn Lin <shawn.lin@...k-chips.com>
To:	Jaehoon Chung <jh80.chung@...sung.com>,
	Seung-Woo Kim <sw0312.kim@...sung.com>, ulf.hansson@...aro.org,
	linux-mmc@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:	shawn.lin@...k-chips.com
Subject: Re: mmc: dw_mmc: warning with CONFIG_DMA_API_DEBUG

Hi Jaehoon,

On 2016/6/23 19:39, Jaehoon Chung wrote:
> Hi Shawn,
>
> On 06/21/2016 04:39 PM, Shawn Lin wrote:
>> 在 2016/6/21 13:32, Jaehoon Chung 写道:
>>> Hi guys,
>>>
>>> On 06/21/2016 11:31 AM, Shawn Lin wrote:
>>>> On 2016/6/21 10:24, Seung-Woo Kim wrote:
>>>>> Hello Shawn,
>>>>>
>>>>>> -----Original Message-----
>>>>>> From: Shawn Lin [mailto:shawn.lin@...k-chips.com]
>>>>>> Sent: Tuesday, June 21, 2016 10:52 AM
>>>>>> To: Seung-Woo Kim; jh80.chung@...sung.com; ulf.hansson@...aro.org; linux-mmc@...r.kernel.org; linux-
>>>>>> kernel@...r.kernel.org
>>>>>> Cc: shawn.lin@...k-chips.com
>>>>>> Subject: Re: mmc: dw_mmc: warning with CONFIG_DMA_API_DEBUG
>>>>>>
>>>>>> On 2016/6/20 16:34, Seung-Woo Kim wrote:
>>>>>>> Hi folks,
>>>>>>>
>>>>>>> During booting test on my Exynos5422 based Odroid-XU3, kernel compiled
>>>>>>> with CONFIG_DMA_API_DEBUG reported following warning:
>>>>>>>
>>>>>>> ------------[ cut here ]------------
>>>>>>> WARNING: CPU: 0 PID: 0 at lib/dma-debug.c:1096 check_unmap+0x7bc/0xb38
>>>>>>> dwmmc_exynos 12200000.mmc: DMA-API: device driver tries to free DMA memory it has not allocated [device
>>>>>> address=0x000000006d9d2200]
>>>>>>
>>>>>> Thanks for this report and fix.
>>>>>>
>>>>>> DTO(the same as IDMAC-RI/TI) interrupts may or may not come together
>>>>>> with DATA_ERR. If DATA_ERR occur without geting DTO, we should issue
>>>>>> CMD12 manually to generate DTO. It's a ugly deisgn for dwmmc but from
>>>>>> the vendor's ask.
>>>>>>
>>>>>> So you should never think we complete the xfer without
>>>>>> checking DATA_ERR. This way you got the warning.
>>>
>>> Well, EVENT_DATA_ERR is already checked in tasklet_func..and cleared that flags.
>>
>> From my view, the reality is that when we got DATA_ERROR interrupts,
>> we set EVENT_DATA_ERR to the pending_events and schedule the tasklet
>> but we may still fallback to the IDMAC interrupt case as the tasklet
>> may come up a little late, namely right after the IDMAC interrupt checking.
>>
>> I'm trying to add some log there, and it well proves my guess.
>
> You're right..This is appeared because of "Data Over".
> If Data Over interrupt is occurred, SW needs to read the remaining Data in FIFO.
> At that time, it was set to DATA_COMPLETE. Because SW might read the remaining data, but already set to ERROR_DATA.
>
> In this case, Your suggestion may prevent to free twice.
>
> There is other case..during tuning sequence.. :(
> I found that it also appeared during the tuning sequence.
> - Really..stupid design..
>
> My suggestions are
> First, apply the below solution.

Which solution? This $SUBJECT or the one I sent?



> And then consider the HS200 tuning block with the below patch.
>
> https://patchwork.kernel.org/patch/8935791/

I saw this patch long ago, but I still have not seen
this issue or got reports for it. From the code itself, it should
be ok to landed as I checked the databook. :)

>
> How about?
> Do you have any other opinion?
>
> Best Regards,
> Jaehoon Chung
>
>>
>>>
>>>>>>
>>>>>> So could you try this one:
>>>>>
>>>>> With your patch, there is no more the DMA API waring in my environment.
>>>>
>>>> Nice to hear that.  Thanks for testing, Seung-Woo.
>>>
>>> Really? It's not solution..When send tuning command, it should be returned CRC error.
>>> Then it called the dw_mci_stop_dma() and also dma_ops->complete().
>>
>> Hrmm.. I can't see the reason it will also call dma_ops->complete.
>> Could you explain a bit more here? :)
>>
>> From V2.70a Table 3-2
>> For MMC CMD19, there may be no CRC status returned by the
>> card but EBE is generated. Hence, EBE is set for CMD19. The application
>> should not treat this as an error.
>>
>>
>>>
>>> When i applied you suggestion, also produced.. :)
>>>
>>> [    2.469916] [<c010d6f0>] (unwind_backtrace) from [<c010a478>] (show_stack+0x10/0x14)
>>> [    2.469934] [<c010a478>] (show_stack) from [<c031b324>] (dump_stack+0x74/0x94)
>>> [    2.469949] [<c031b324>] (dump_stack) from [<c011b5ac>] (__warn+0xd4/0x100)
>>> [    2.469961] [<c011b5ac>] (__warn) from [<c011b678>] (warn_slowpath_fmt+0x38/0x48)
>>> [    2.469975] [<c011b678>] (warn_slowpath_fmt) from [<c033ee20>] (check_unmap+0x828/0x8a8)
>>> [    2.469991] [<c033ee20>] (check_unmap) from [<c033f7c0>] (debug_dma_unmap_sg+0x5c/0x13c)
>>> [    2.470012] [<c033f7c0>] (debug_dma_unmap_sg) from [<c051e6a4>] (dw_mci_dma_cleanup+0x68/0xa4)
>>> [    2.470029] [<c051e6a4>] (dw_mci_dma_cleanup) from [<c0553bf4>] (dw_mci_stop_dma+0x30/0x40)
>>> [    2.470045] [<c0553bf4>] (dw_mci_stop_dma) from [<c0521b30>] (dw_mci_tasklet_func+0x340/0x3b4)
>>> [    2.470063] [<c0521b30>] (dw_mci_tasklet_func) from [<c011fcb0>] (tasklet_action+0x84/0x12c)
>>> [    2.470076] [<c011fcb0>] (tasklet_action) from [<c011f35c>] (__do_softirq+0xec/0x244)
>>> [    2.470089] [<c011f35c>] (__do_softirq) from [<c011f750>] (irq_exit+0xb4/0xf8)
>>> [    2.470109] [<c011f750>] (irq_exit) from [<c015d004>] (__handle_domain_irq+0x70/0xe4)
>>> [    2.470123] [<c015d004>] (__handle_domain_irq) from [<c0101470>] (gic_handle_irq+0x50/0x9c)
>>> [    2.470135] [<c0101470>] (gic_handle_irq) from [<c010af14>] (__irq_svc+0x54/0x90)
>>> [    2.470141] Exception stack(0xee3d3c58 to 0xee3d3ca0)
>>> [    2.470148] 3c40:                                                       c0b1ef0c 0000000a
>>> [    2.470159] 3c60: 00000001 0000005c 0000016d 00000000 c0b4f7a4 00000006 00000000 0000005c
>>> [    2.470170] 3c80: 00000006 c0b671e8 60000013 ee3d3ca8 c0398e08 c015b830 60000013 ffffffff
>>> [    2.470183] [<c010af14>] (__irq_svc) from [<c015b830>] (console_unlock+0x560/0x628)
>>> [    2.470196] [<c015b830>] (console_unlock) from [<c015c1b0>] (vprintk_emit+0x1fc/0x508)
>>> [    2.470211] [<c015c1b0>] (vprintk_emit) from [<c03ed21c>] (dev_vprintk_emit+0xf8/0x198)
>>> [    2.470224] [<c03ed21c>] (dev_vprintk_emit) from [<c03ed2d8>] (dev_printk_emit+0x1c/0x2c)
>>> [    2.470235] [<c03ed2d8>] (dev_printk_emit) from [<c03ed334>] (__dev_printk+0x4c/0x70)
>>> [    2.470246] [<c03ed334>] (__dev_printk) from [<c03ed390>] (_dev_info+0x38/0x48)
>>> [    2.470258] [<c03ed390>] (_dev_info) from [<c045a7a4>] (usb_new_device+0xe8/0x3d0)
>>> [    2.470270] [<c045a7a4>] (usb_new_device) from [<c045bc20>] (hub_event+0x760/0xff4)
>>> [    2.470289] [<c045bc20>] (hub_event) from [<c012ff68>] (process_one_work+0x120/0x328)
>>> [    2.470304] [<c012ff68>] (process_one_work) from [<c01301d4>] (worker_thread+0x2c/0x4ac)
>>> [    2.470321] [<c01301d4>] (worker_thread) from [<c01353a4>] (kthread+0xd8/0xf4)
>>> [    2.470335] [<c01353a4>] (kthread) from [<c0107978
>>>
>>> I'm checking this..
>>>
>>> Best Regards,
>>> Jaehoon Chung
>>>
>>>>
>>>> Hi Jaehoon,
>>>>
>>>> How about this?
>>>>
>>>>>
>>>>> Best Regards,
>>>>> - Seung-Woo Kim
>>>>>
>>>>>>
>>>>>> --- a/drivers/mmc/host/dw_mmc.c
>>>>>> +++ b/drivers/mmc/host/dw_mmc.c
>>>>>> @@ -2474,7 +2474,8 @@ static irqreturn_t dw_mci_interrupt(int irq, void
>>>>>> *dev_id)
>>>>>>                          mci_writel(host, IDSTS64, SDMMC_IDMAC_INT_TI |
>>>>>>
>>>>>> SDMMC_IDMAC_INT_RI);
>>>>>>                          mci_writel(host, IDSTS64, SDMMC_IDMAC_INT_NI);
>>>>>> -                       host->dma_ops->complete((void *)host);
>>>>>> +                       if (!test_bit(EVENT_DATA_ERROR,
>>>>>> &host->pending_events))
>>>>>> +                               host->dma_ops->complete((void *)host);
>>>>>>                  }
>>>>>>          } else {
>>>>>>                  pending = mci_readl(host, IDSTS);
>>>>>> @@ -2482,7 +2483,8 @@ static irqreturn_t dw_mci_interrupt(int irq, void
>>>>>> *dev_id)
>>>>>>                          mci_writel(host, IDSTS, SDMMC_IDMAC_INT_TI |
>>>>>>
>>>>>> SDMMC_IDMAC_INT_RI);
>>>>>>                          mci_writel(host, IDSTS, SDMMC_IDMAC_INT_NI);
>>>>>> -                       host->dma_ops->complete((void *)host);
>>>>>> +                       if (!test_bit(EVENT_DATA_ERROR,
>>>>>> &host->pending_events))
>>>>>> +                               host->dma_ops->complete((void *)host);
>>>>>>                  }
>>>>>>          }
>>>>>>
>>>>>>
>>>>>>> [size=128 bytes]
>>>>>>> Modules linked in:
>>>>>>> CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.7.0-rc4 #26
>>>>>>> Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
>>>>>>> [<c0112b4c>] (unwind_backtrace) from [<c010d888>] (show_stack+0x20/0x24)
>>>>>>> [<c010d888>] (show_stack) from [<c03fab0c>] (dump_stack+0x80/0x94)
>>>>>>> [<c03fab0c>] (dump_stack) from [<c0123548>] (__warn+0xf8/0x110)
>>>>>>> [<c0123548>] (__warn) from [<c01235a8>] (warn_slowpath_fmt+0x48/0x50)
>>>>>>> [<c01235a8>] (warn_slowpath_fmt) from [<c042ac90>] (check_unmap+0x7bc/0xb38)
>>>>>>> [<c042ac90>] (check_unmap) from [<c042b25c>] (debug_dma_unmap_sg+0x118/0x148)
>>>>>>> [<c042b25c>] (debug_dma_unmap_sg) from [<c077512c>] (dw_mci_dma_cleanup+0x7c/0xb8)
>>>>>>> [<c077512c>] (dw_mci_dma_cleanup) from [<c0773f24>] (dw_mci_stop_dma+0x40/0x50)
>>>>>>> [<c0773f24>] (dw_mci_stop_dma) from [<c0777d04>] (dw_mci_tasklet_func+0x130/0x3b4)
>>>>>>> [<c0777d04>] (dw_mci_tasklet_func) from [<c0129760>] (tasklet_action+0xb4/0x150)
>>>>>>> [<c0129760>] (tasklet_action) from [<c0101674>] (__do_softirq+0xe4/0x3cc)
>>>>>>> [<c0101674>] (__do_softirq) from [<c0129030>] (irq_exit+0xd0/0x10c)
>>>>>>> [<c0129030>] (irq_exit) from [<c01778a0>] (__handle_domain_irq+0x90/0xfc)
>>>>>>> [<c01778a0>] (__handle_domain_irq) from [<c0101548>] (gic_handle_irq+0x64/0xa8)
>>>>>>> [<c0101548>] (gic_handle_irq) from [<c010e3d4>] (__irq_svc+0x54/0x90)
>>>>>>> Exception stack(0xc1101ef8 to 0xc1101f40)
>>>>>>> 1ee0:                                                       00000001 00000000
>>>>>>> 1f00: 00000000 c011b600 c1100000 c110753c 00000000 c11c3984 c11074d4 c1107548
>>>>>>> 1f20: 00000000 c1101f54 c1101f58 c1101f48 c010a1fc c010a200 60000013 ffffffff
>>>>>>> [<c010e3d4>] (__irq_svc) from [<c010a200>] (arch_cpu_idle+0x48/0x4c)
>>>>>>> [<c010a200>] (arch_cpu_idle) from [<c01669d8>] (default_idle_call+0x30/0x3c)
>>>>>>> [<c01669d8>] (default_idle_call) from [<c0166d3c>] (cpu_startup_entry+0x358/0x3b4)
>>>>>>> [<c0166d3c>] (cpu_startup_entry) from [<c0aa6ab8>] (rest_init+0x94/0x98)
>>>>>>> [<c0aa6ab8>] (rest_init) from [<c1000d58>] (start_kernel+0x3a4/0x3b0)
>>>>>>> [<c1000d58>] (start_kernel) from [<4000807c>] (0x4000807c)
>>>>>>> ---[ end trace 256f83eed365daf0 ]---
>>>>>>>
>>>>>>> The warning occurs because after complete callback function,
>>>>>>> dw_mci_dmac_complete_dma() is called, then dw_mci_stop_dma() is called
>>>>>>> again. So it causes dma_unmap_sg() is called twice for same sg. It
>>>>>>> occurs during clock setting at booting time.
>>>>>>>
>>>>>>> Simply, clearing host->using_dma flag on dw_mci_dmac_complete_dma() and
>>>>>>> dw_mci_stop_dma() like following fixes the issue, but I am not sure
>>>>>>> this approach is proper.
>>>>>>> ---
>>>>>>> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
>>>>>>> index 2cc6123..a71c94b 100644
>>>>>>> --- a/drivers/mmc/host/dw_mmc.c
>>>>>>> +++ b/drivers/mmc/host/dw_mmc.c
>>>>>>> @@ -388,6 +388,7 @@ static void dw_mci_stop_dma(struct dw_mci *host)
>>>>>>>      if (host->using_dma) {
>>>>>>>          host->dma_ops->stop(host);
>>>>>>>          host->dma_ops->cleanup(host);
>>>>>>> +        host->using_dma = 0;
>>>>>>>      }
>>>>>>>
>>>>>>>      /* Data transfer was stopped by the interrupt handler */
>>>>>>> @@ -455,6 +456,7 @@ static void dw_mci_dmac_complete_dma(void *arg)
>>>>>>>                      DMA_FROM_DEVICE);
>>>>>>>
>>>>>>>      host->dma_ops->cleanup(host);
>>>>>>> +    host->using_dma = 0;
>>>>>>>
>>>>>>>      /*
>>>>>>>       * If the card was removed, data will be NULL. No point in trying to
>>>>>>> @@ -943,8 +945,6 @@ static int dw_mci_submit_data_dma(struct dw_mci *host, struct mmc_data *data)
>>>>>>>      int sg_len;
>>>>>>>      u32 temp;
>>>>>>>
>>>>>>> -    host->using_dma = 0;
>>>>>>> -
>>>>>>>      /* If we don't have a channel, we can't do DMA */
>>>>>>>      if (!host->use_dma)
>>>>>>>          return -ENODEV;
>>>>>>> ---
>>>>>>>
>>>>>>> Best Regards,
>>>>>>> - Seung-Woo Kim
>>>>>>>
>>>>>>> --
>>>>>>> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
>>>>>>> the body of a message to majordomo@...r.kernel.org
>>>>>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> Best Regards
>>>>>> Shawn Lin
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>
>>>
>>>
>>>
>>
>>
>
>
>
>


-- 
Best Regards
Shawn Lin

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