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Message-ID: <c4589cb4-b3b6-6f97-d994-cb311591e5b2@rock-chips.com>
Date: Tue, 21 Jun 2016 10:31:07 +0800
From: Shawn Lin <shawn.lin@...k-chips.com>
To: Seung-Woo Kim <sw0312.kim@...sung.com>, 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 2016/6/21 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.
>>
>> 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.
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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