Re: mmc: dw_mmc: warning with CONFIG_DMA_API_DEBUG

[Jaehoon Chung <jh80.chung@samsung.com>]

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@rock-chips.com]
>>> Sent: Tuesday, June 21, 2016 10:52 AM
>>> To: Seung-Woo Kim; jh80.chung@samsung.com; ulf.hansson@linaro.org; linux-mmc@vger.kernel.org; linux-
>>> kernel@vger.kernel.org
>>> Cc: shawn.lin@rock-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.

>>>
>>> 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().

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
>>>>
>>>> -- 
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>>>> the body of a message to majordomo@vger.kernel.org
>>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>>>
>>>
>>>
>>> -- 
>>> Best Regards
>>> Shawn Lin
>>>
>>
>>
>>
>>
>>
> 
>