RE: [PATCH] mmc: sdhci-esdhc-imx: correct the fix of ERR004536

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> -----Original Message-----
> From: Ulf Hansson [mailto:ulf.hansson@xxxxxxxxxx]
> Sent: 2019年2月28日 16:25
> To: BOUGH CHEN <haibo.chen@xxxxxxx>
> Cc: adrian.hunter@xxxxxxxxx; Aisheng Dong <aisheng.dong@xxxxxxx>;
> shawnguo@xxxxxxxxxx; s.hauer@xxxxxxxxxxxxxx; kernel@xxxxxxxxxxxxxx;
> festevam@xxxxxxxxx; dl-linux-imx <linux-imx@xxxxxxx>;
> linux-mmc@xxxxxxxxxxxxxxx; stable@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH] mmc: sdhci-esdhc-imx: correct the fix of ERR004536
> 
> On Thu, 28 Feb 2019 at 09:01, BOUGH CHEN <haibo.chen@xxxxxxx> wrote:
> >
> > Commit 18094430d6b5 ("mmc: sdhci-esdhc-imx: add ADMA Length
> Mismatch
> > errata fix") involve the fix of ERR004536, but the fix is incorrect.
> > Double confirm with IC, need to clear the bit 7 of register 0x6c
> > rather than set this bit 7.
> > Here is the definition of bit 7 of 0x6c:
> >     0: enable the new IC fix for ERR004536
> >     1: do not use the IC fix, keep the same as before
> >
> > Due to the reset value of this bit 7 is 0, ROM code and bootloader do
> > not touch this bit 7, so here directly remove the operation of this
> > bit 7, make sure the fix of ERR004536 can work.
> 
> Well, rather than relying on the bootloader, let the kernel do the right thing.
> That is, write a zero to the register bit rather than a one.
> 
> Is the code doing that?
> 

Yes, write a zero to the register bit is correct.
Why I just remove the code rather than directly write 0 to this bit is because the register 0x6c should be invisible to software, and is not defined in reference manual. It is a register only open for IC to test.
If you prefer to write a zero to the register bit, I can do that.

Best Regards
Haibo Chen 

> Kind regards
> Uffe
> 
> >
> > Find this issue on i.MX845s-evk board when enable CMDQ, and let system
> > in heavy loading.
> >
> > root@imx8mmevk:~# dd if=/dev/mmcblk2 of=/dev/null bs=1M &
> > root@imx8mmevk:~# memtester 1000M > /dev/zero &
> root@imx8mmevk:~# [
> > 139.897220] mmc2: cqhci: timeout for tag 16 [  139.901417] mmc2:
> > cqhci: ============ CQHCI REGISTER DUMP ===========
> > [  139.907862] mmc2: cqhci: Caps:      0x0000310a | Version:
> 0x00000510
> > [  139.914311] mmc2: cqhci: Config:    0x00001001 | Control:
> 0x00000000
> > [  139.920753] mmc2: cqhci: Int stat:  0x00000000 | Int enab: 0x00000006
> > [  139.927193] mmc2: cqhci: Int sig:   0x00000006 | Int Coal: 0x00000000
> > [  139.933634] mmc2: cqhci: TDL base:  0x7809c000 | TDL up32:
> 0x00000000
> > [  139.940073] mmc2: cqhci: Doorbell:  0x00030000 | TCN:
> 0x00000000
> > [  139.946518] mmc2: cqhci: Dev queue: 0x00010000 | Dev Pend:
> 0x00010000
> > [  139.952967] mmc2: cqhci: Task clr:  0x00000000 | SSC1:
> 0x00011000
> > [  139.959411] mmc2: cqhci: SSC2:      0x00000001 | DCMD rsp:
> 0x00000000
> > [  139.965857] mmc2: cqhci: RED mask:  0xfdf9a080 | TERRI:
> 0x00000000
> > [  139.972308] mmc2: cqhci: Resp idx:  0x0000002e | Resp arg:
> > 0x00000900 [  139.978761] mmc2: sdhci: ============ SDHCI REGISTER
> > DUMP =========== [  139.985214] mmc2: sdhci: Sys addr:  0xb2c19000 |
> > Version:  0x00000002 [  139.991669] mmc2: sdhci: Blk size:  0x00000200
> > | Blk cnt:  0x00000400 [  139.998127] mmc2: sdhci: Argument:
> 0x40110400 | Trn mode: 0x00000033
> > [  140.004618] mmc2: sdhci: Present:   0x01088a8f | Host ctl: 0x00000030
> > [  140.011113] mmc2: sdhci: Power:     0x00000002 | Blk gap:
> 0x00000080
> > [  140.017583] mmc2: sdhci: Wake-up:   0x00000008 | Clock:
> 0x0000000f
> > [  140.024039] mmc2: sdhci: Timeout:   0x0000008f | Int stat: 0x00000000
> > [  140.030497] mmc2: sdhci: Int enab:  0x107f4000 | Sig enab:
> > 0x107f4000 [  140.036972] mmc2: sdhci: AC12 err:  0x00000000 | Slot int:
> 0x00000502
> > [  140.043426] mmc2: sdhci: Caps:      0x07eb0000 | Caps_1:
> 0x8000b407
> > [  140.049867] mmc2: sdhci: Cmd:       0x00002c1a | Max curr: 0x00ffffff
> > [  140.056314] mmc2: sdhci: Resp[0]:   0x00000900 | Resp[1]:  0xffffffff
> > [  140.062755] mmc2: sdhci: Resp[2]:   0x328f5903 | Resp[3]:
> 0x00d00f00
> > [  140.069195] mmc2: sdhci: Host ctl2: 0x00000008 [  140.073640] mmc2:
> > sdhci: ADMA Err:  0x00000007 | ADMA Ptr: 0x7809c108 [  140.080079]
> > mmc2: sdhci: ============================================
> > [  140.086662] mmc2: running CQE recovery
> >
> > Fixes commit 18094430d6b5 ("mmc: sdhci-esdhc-imx: add ADMA Length
> > Mismatch errata fix")
> > Signed-off-by: Haibo Chen <haibo.chen@xxxxxxx>
> > Cc: stable@xxxxxxxxxxxxxxx
> > ---
> >  drivers/mmc/host/sdhci-esdhc-imx.c | 6 ------
> >  1 file changed, 6 deletions(-)
> >
> > diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c
> > b/drivers/mmc/host/sdhci-esdhc-imx.c
> > index 32ca3703b432..5ee7613c818f 100644
> > --- a/drivers/mmc/host/sdhci-esdhc-imx.c
> > +++ b/drivers/mmc/host/sdhci-esdhc-imx.c
> > @@ -1171,12 +1171,6 @@ static void sdhci_esdhc_imx_hwinit(struct
> sdhci_host *host)
> >                 writel(readl(host->ioaddr + SDHCI_HOST_CONTROL)
> >                         | ESDHC_BURST_LEN_EN_INCR,
> >                         host->ioaddr + SDHCI_HOST_CONTROL);
> > -               /*
> > -               * erratum ESDHC_FLAG_ERR004536 fix for MX6Q TO1.2
> and MX6DL
> > -               * TO1.1, it's harmless for MX6SL
> > -               */
> > -               writel(readl(host->ioaddr + 0x6c) | BIT(7),
> > -                       host->ioaddr + 0x6c);
> >
> >                 /* disable DLL_CTRL delay line settings */
> >                 writel(0x0, host->ioaddr + ESDHC_DLL_CTRL);
> > --
> > 2.17.1
> >




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