mmc: sdhci-of-at91: Internal clock never stabilised

[Ludovic Desroches]

On Mon, Jan 09, 2017 at 12:44:42PM +0200, Alex Gershgorin wrote:
> Hi Ludovic,
> As we read the chip ID from CHIPID_CIDR register we get 0x8a5c08c0 (we
> use ATSAMA5D27A-CU).
> 

It seems the device you have is a rev A device, this issue should be fixed in
the revision B.

I say should, because the bug was identified and I provided a workaround with
the use of our own set_clock function has been done. Unfortunately, even
if it happens less frequently, it seems the bug is still here.

The hardware part has been reworked on the revision B. I don't recall facing
this issue again but I can't guarantee that it won't happen anymore
since the root cause was not properly identified on rev A.

Regards

Ludovic

> 
> Thanks,
> Alex
> 
> On Mon, Jan 9, 2017 at 9:19 AM, Ludovic Desroches
> <ludovic.desroches at atmel.com> wrote:
> > Hi Alex,
> >
> > Which revision of SoC are you using?
> >
> > Regards
> >
> > Ludovic
> >
> > On Sun, Jan 08, 2017 at 01:53:44PM +0100, Alexandre Belloni wrote:
> >> Hi,
> >>
> >> I think Cyrille worked on that a few month ago, maybe he has a comment.
> >>
> >> On 08/01/2017 at 14:07:53 +0200, Alex Gershgorin wrote :
> >> > Hi All,
> >> > We have two different HW platforms based on SAMA5D2 SoC (SAMA5D2 Xplained
> >> > Board and our own HW).
> >> > On both of them we are facing stabilization of the internal
> >> > clock problem, it does not happen all the time but quite often.
> >> > Please see below my Kernel boot messages:
> >> >
> >> > sdhci: Copyright(c) Pierre Ossman
> >> > sdhci-pltfm: SDHCI platform and OF driver helper
> >> > sdhci-at91 a0000000.sdio-host: update clk mul to 39 as gck rate is
> >> > 480000000 Hz
> >> > mmc0: Internal clock never stabilised.
> >> > mmc0: Internal clock never stabilised.
> >> > mmc0: SDHCI controller on a0000000.sdio-host [a0000000.sdio-host] using ADMA
> >> >
> >> > snip
> >> >
> >> > snip
> >> >
> >> > Waiting for root device /dev/mmcblk0p2...
> >> > mmc0: Internal clock never stabilised.
> >> > mmc0: Timeout waiting for hardware cmd interrupt.
> >> > sdhci: =========== REGISTER DUMP (mmc0)===========
> >> > sdhci: Sys addr: 0x00000000 | Version:  0x00001502
> >> > sdhci: Blk size: 0x00000000 | Blk cnt:  0x00000000
> >> > sdhci: Argument: 0x00000000 | Trn mode: 0x00000000
> >> > sdhci: Present: 0x01ff0001 | Host ctl: 0x00000001
> >> > sdhci: Power: 0x0000000f | Blk gap:  0x00000000
> >> > sdhci: Wake-up: 0x00000000 | Clock:    0x0000ffe1
> >> > sdhci: Timeout: 0x00000000 | Int stat: 0x00000000
> >> > sdhci: Int enab: 0x00ff0003 | Sig enab: 0x00ff0003
> >> > sdhci: AC12 err: 0x00000000 | Slot int: 0x00000000
> >> > sdhci: Caps: 0x27ec0c8c | Caps_1: 0x00270f77
> >> > sdhci: Cmd: 0x00000000 | Max curr: 0x00000000
> >> > sdhci: Host ctl2: 0x00000000
> >> > sdhci: ADMA Err: 0x00000000 | ADMA Ptr: 0x00000000
> >> > sdhci: ===========================================
> >> >
> >> > Any direction to solve this problem?
> >> >
> >> > Thanks,
> >> > Alex Gershgorin
> >>
> >> --
> >> Alexandre Belloni, Free Electrons
> >> Embedded Linux and Kernel engineering
> >> http://free-electrons.com
> >>
> >> _______________________________________________
> >> linux-arm-kernel mailing list
> >> linux-arm-kernel at lists.infradead.org
> >> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> 
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