diff mbox

Self-detected stall on CPU when using SD card

Message ID 0f262b04fab61ec75b7e368a8f4968aa@agner.ch
State New
Headers show

Commit Message

Stefan Agner June 26, 2018, 2:45 p.m. UTC
On 26.06.2018 12:53, Stefan Agner wrote:
> Hi,
> 
> On our Colibri iMX6 (arch/arm/boot/dts/imx6qdl-colibri.dtsi) we
> experience the following stack trace when a SD card is plugged in:
> 

[...]

> [<c08396f4>] (esdhc_pltfm_set_clock) from [<c083622c>]
> (sdhci_set_ios+0xd8/0x584)
>  r10:ffffe000 r9:c1105900 r8:00004097 r7:d818f2e8 r6:d818f480
> r5:d818f2e8
>  r4:d818f000
> [<c0836154>] (sdhci_set_ios) from [<c0836070>]
> (sdhci_runtime_resume_host+0xa0/0x184)
>  r9:c1105900 r8:00004097 r7:d818f2e8 r6:d818f648 r5:d818f000 r4:d818f480

[...]

> 
> It used to work in v4.9, so I started a git bisect. It pointed me to
> this commit:
> 
> Commit d1e4f74f911d ("mmc: sdhci: Do not use spin lock in set_ios
> paths").
> 
> Reverting the commit on-top of v4.18-rc1 seems to fix the issue too.
> 
> Any idea?

I figured out that the same platform had a GPIO Key which triggered all
the time. This seems to exacerbate the MMC issue such that it triggers
on very boot, about rootfs mount time.

This change seems to fix the issue as well, not sure though whether this
is a proper fix:

        if (clock == 0) {
@@ -724,6 +725,7 @@ static inline void esdhc_pltfm_set_clock(struct
sdhci_host *host,
                        pre_div = 2;
        }
 
+       spin_lock_irqsave(&host->lock, flags);
        temp = sdhci_readl(host, ESDHC_SYSTEM_CONTROL);
        temp &= ~(ESDHC_CLOCK_IPGEN | ESDHC_CLOCK_HCKEN |
ESDHC_CLOCK_PEREN
                | ESDHC_CLOCK_MASK);
@@ -754,6 +756,7 @@ static inline void esdhc_pltfm_set_clock(struct
sdhci_host *host,
                writel(val | ESDHC_VENDOR_SPEC_FRC_SDCLK_ON,
                host->ioaddr + ESDHC_VENDOR_SPEC);
        }
+       spin_unlock_irqrestore(&host->lock, flags);
 
        mdelay(1);
 }

--
Stefan
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Comments

Stefan Agner July 3, 2018, 1:13 p.m. UTC | #1
Dong Aisheng,

Maybe you can shed some light on the issue below?


On 26.06.2018 16:45, Stefan Agner wrote:
> On 26.06.2018 12:53, Stefan Agner wrote:
>> Hi,
>>
>> On our Colibri iMX6 (arch/arm/boot/dts/imx6qdl-colibri.dtsi) we
>> experience the following stack trace when a SD card is plugged in:
>>
> 
> [...]
> 
>> [<c08396f4>] (esdhc_pltfm_set_clock) from [<c083622c>]
>> (sdhci_set_ios+0xd8/0x584)
>>  r10:ffffe000 r9:c1105900 r8:00004097 r7:d818f2e8 r6:d818f480
>> r5:d818f2e8
>>  r4:d818f000
>> [<c0836154>] (sdhci_set_ios) from [<c0836070>]
>> (sdhci_runtime_resume_host+0xa0/0x184)
>>  r9:c1105900 r8:00004097 r7:d818f2e8 r6:d818f648 r5:d818f000 r4:d818f480
> 
> [...]
> 
>>
>> It used to work in v4.9, so I started a git bisect. It pointed me to
>> this commit:
>>
>> Commit d1e4f74f911d ("mmc: sdhci: Do not use spin lock in set_ios
>> paths").
>>
>> Reverting the commit on-top of v4.18-rc1 seems to fix the issue too.
>>
>> Any idea?
> 
> I figured out that the same platform had a GPIO Key which triggered all
> the time. This seems to exacerbate the MMC issue such that it triggers
> on very boot, about rootfs mount time.
> 
> This change seems to fix the issue as well, not sure though whether this
> is a proper fix:
> 
> --- a/drivers/mmc/host/sdhci-esdhc-imx.c
> +++ b/drivers/mmc/host/sdhci-esdhc-imx.c
> @@ -697,6 +697,7 @@ static inline void esdhc_pltfm_set_clock(struct
> sdhci_host *host,
>         int ddr_pre_div = imx_data->is_ddr ? 2 : 1;
>         int pre_div = 1;
>         int div = 1;
> +       unsigned long flags;
>         u32 temp, val;
>  
>         if (clock == 0) {
> @@ -724,6 +725,7 @@ static inline void esdhc_pltfm_set_clock(struct
> sdhci_host *host,
>                         pre_div = 2;
>         }
>  
> +       spin_lock_irqsave(&host->lock, flags);
>         temp = sdhci_readl(host, ESDHC_SYSTEM_CONTROL);
>         temp &= ~(ESDHC_CLOCK_IPGEN | ESDHC_CLOCK_HCKEN |
> ESDHC_CLOCK_PEREN
>                 | ESDHC_CLOCK_MASK);
> @@ -754,6 +756,7 @@ static inline void esdhc_pltfm_set_clock(struct
> sdhci_host *host,
>                 writel(val | ESDHC_VENDOR_SPEC_FRC_SDCLK_ON,
>                 host->ioaddr + ESDHC_VENDOR_SPEC);
>         }
> +       spin_unlock_irqrestore(&host->lock, flags);

The bits ESDHC_CLOCK_IPGEN, ESDHC_CLOCK_HCKEN, ESDHC_CLOCK_PEREN which
are cleared and written in that section are actually mentioned as
"Reserved. Always write as 1." in the reference manual...

--
Stefan

>  
>         mdelay(1);
>  }
> 
> --
> Stefan
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Aisheng Dong July 5, 2018, 3:13 a.m. UTC | #2
> -----Original Message-----
> From: Stefan Agner [mailto:stefan@agner.ch]
> Sent: Tuesday, July 3, 2018 9:13 PM
> To: adrian.hunter@intel.com; A.s. Dong <aisheng.dong@nxp.com>; Fabio
> Estevam <fabio.estevam@nxp.com>
> Cc: linux-mmc@vger.kernel.org; linux-arm-kernel@lists.infradead.org; linux-
> mmc-owner@vger.kernel.org
> Subject: Re: Self-detected stall on CPU when using SD card
> 
> Dong Aisheng,
> 
> Maybe you can shed some light on the issue below?
> 

I tried on MX6Q SDB board but did not reproduce it with a SD card
plugged into Slot2 with 4.18-rc1.
Any difference we need to care?

> 
> On 26.06.2018 16:45, Stefan Agner wrote:
> > On 26.06.2018 12:53, Stefan Agner wrote:
> >> Hi,
> >>
> >> On our Colibri iMX6 (arch/arm/boot/dts/imx6qdl-colibri.dtsi) we
> >> experience the following stack trace when a SD card is plugged in:
> >>
> >
> > [...]
> >
> >> [<c08396f4>] (esdhc_pltfm_set_clock) from [<c083622c>]
> >> (sdhci_set_ios+0xd8/0x584)
> >>  r10:ffffe000 r9:c1105900 r8:00004097 r7:d818f2e8 r6:d818f480
> >> r5:d818f2e8
> >>  r4:d818f000
> >> [<c0836154>] (sdhci_set_ios) from [<c0836070>]
> >> (sdhci_runtime_resume_host+0xa0/0x184)
> >>  r9:c1105900 r8:00004097 r7:d818f2e8 r6:d818f648 r5:d818f000
> >> r4:d818f480
> >
> > [...]
> >
> >>
> >> It used to work in v4.9, so I started a git bisect. It pointed me to
> >> this commit:
> >>
> >> Commit d1e4f74f911d ("mmc: sdhci: Do not use spin lock in set_ios
> >> paths").
> >>
> >> Reverting the commit on-top of v4.18-rc1 seems to fix the issue too.
> >>
> >> Any idea?
> >
> > I figured out that the same platform had a GPIO Key which triggered
> > all the time. This seems to exacerbate the MMC issue such that it
> > triggers on very boot, about rootfs mount time.
> >

That's a bit strange.... Why that GPIO key triggers all the time?

> > This change seems to fix the issue as well, not sure though whether
> > this is a proper fix:
> >
> > --- a/drivers/mmc/host/sdhci-esdhc-imx.c
> > +++ b/drivers/mmc/host/sdhci-esdhc-imx.c
> > @@ -697,6 +697,7 @@ static inline void esdhc_pltfm_set_clock(struct
> > sdhci_host *host,
> >         int ddr_pre_div = imx_data->is_ddr ? 2 : 1;
> >         int pre_div = 1;
> >         int div = 1;
> > +       unsigned long flags;
> >         u32 temp, val;
> >
> >         if (clock == 0) {
> > @@ -724,6 +725,7 @@ static inline void esdhc_pltfm_set_clock(struct
> > sdhci_host *host,
> >                         pre_div = 2;
> >         }
> >
> > +       spin_lock_irqsave(&host->lock, flags);
> >         temp = sdhci_readl(host, ESDHC_SYSTEM_CONTROL);
> >         temp &= ~(ESDHC_CLOCK_IPGEN | ESDHC_CLOCK_HCKEN |
> > ESDHC_CLOCK_PEREN
> >                 | ESDHC_CLOCK_MASK);
> > @@ -754,6 +756,7 @@ static inline void esdhc_pltfm_set_clock(struct
> > sdhci_host *host,
> >                 writel(val | ESDHC_VENDOR_SPEC_FRC_SDCLK_ON,
> >                 host->ioaddr + ESDHC_VENDOR_SPEC);
> >         }
> > +       spin_unlock_irqrestore(&host->lock, flags);
> 
> The bits ESDHC_CLOCK_IPGEN, ESDHC_CLOCK_HCKEN,
> ESDHC_CLOCK_PEREN which are cleared and written in that section are
> actually mentioned as "Reserved. Always write as 1." in the reference
> manual...
> 

That's for legacy platforms like MX5. No side affect on MX6&7 as we know.
So keep it now. Is the issue related to that?

Regards
Dong Aisheng

> --
> Stefan
> 
> >
> >         mdelay(1);
> >  }
> >
> > --
> > Stefan
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diff mbox

Patch

--- a/drivers/mmc/host/sdhci-esdhc-imx.c
+++ b/drivers/mmc/host/sdhci-esdhc-imx.c
@@ -697,6 +697,7 @@  static inline void esdhc_pltfm_set_clock(struct
sdhci_host *host,
        int ddr_pre_div = imx_data->is_ddr ? 2 : 1;
        int pre_div = 1;
        int div = 1;
+       unsigned long flags;
        u32 temp, val;