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Subject: Re: [PATCH 1/1] mmc: sdhci-pci: fix eMMC controller issue on Intel
 Baytrail SoCs
To:     Kurt Kanzenbach <kurt@linutronix.de>
Cc:     ulf.hansson@linaro.org, linux-mmc@vger.kernel.org,
        linux-kernel@vger.kernel.org, tglx@linutronix.de
References: <20180619063119.3955-1-kurt@linutronix.de>
 <20180619063119.3955-2-kurt@linutronix.de>
From:   Adrian Hunter <adrian.hunter@intel.com>
Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki,
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Message-ID: <293c2771-ea9b-4f0c-bd31-f8844de12dc4@intel.com>
Date:   Tue, 19 Jun 2018 10:03:01 +0300
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On 19/06/18 09:31, Kurt Kanzenbach wrote:
> Sometimes the eMMC controller doesn't respond anymore on Intel Baytrail
> SoCs. The resulting error looks like:
> 
> |mmc1: Reset 0x1 never completed.
> |sdhci: =========== REGISTER DUMP (mmc1)===========
> |sdhci: Sys addr: 0xffffffff | Version:  0x0000ffff
> |sdhci: Blk size: 0x0000ffff | Blk cnt:  0x0000ffff
> |sdhci: Argument: 0xffffffff | Trn mode: 0x0000ffff
> |sdhci: Present:  0xffffffff | Host ctl: 0x000000ff
> |sdhci: Power:    0x000000ff | Blk gap:  0x000000ff
> |sdhci: Wake-up:  0x000000ff | Clock:    0x0000ffff
> |sdhci: Timeout:  0x000000ff | Int stat: 0xffffffff
> |sdhci: Int enab: 0xffffffff | Sig enab: 0xffffffff
> |sdhci: AC12 err: 0x0000ffff | Slot int: 0x0000ffff
> |sdhci: Caps:     0xffffffff | Caps_1:   0xffffffff
> |sdhci: Cmd:      0x0000ffff | Max curr: 0xffffffff
> |sdhci: Host ctl2: 0x0000ffff
> |sdhci: ADMA Err: 0xffffffff | ADMA Ptr: 0xffffffff
> 
> The behavior was observed on an Intel Atom E3825 performing lots of reboots. The

So you are saying this only happens at boot time?  And only when re-booting?
Can you send all the kernel messages?  Can you send an acpidump?

> issue seems to occur if runtime power management is used. Found by utilizing
> ftrace.
> 
> The erratum VLI10 for the Intel E3825 states, that the eMMC controller
> incorrectly announces that it supports suspend/resume. However, that shouldn't
> be used, as the controller may incorrectly transfer data between memory and the
> SD device.

That erratum is not related to this problem.  The suspend/resume that is
documented is an internal SDHCI feature, not the kernel's suspend/resume.
The SDHCI Suspend/Resume Mechanism is not supported in the driver, so it is
not being used anyway.

> 
> Therefore, disallowing runtime pm resolves the issue. Tested on the E3825.
> 
> Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
> ---
>  drivers/mmc/host/sdhci-pci-core.c | 17 ++++++++++++++++-
>  1 file changed, 16 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mmc/host/sdhci-pci-core.c b/drivers/mmc/host/sdhci-pci-core.c
> index 77dd3521daae..df89381944cd 100644
> --- a/drivers/mmc/host/sdhci-pci-core.c
> +++ b/drivers/mmc/host/sdhci-pci-core.c
> @@ -870,6 +870,21 @@ static const struct sdhci_pci_fixes sdhci_intel_byt_emmc = {
>  	.priv_size	= sizeof(struct intel_host),
>  };
>  
> +/*
> + * See Erratum VLI10 from Errata List for Intel Atom E3825, Link:
> + * https://www.intel.ca/content/dam/www/public/us/en/documents/specification-updates/atom-e3800-family-spec-update.pdf
> + */
> +static const struct sdhci_pci_fixes sdhci_intel_byt_emmc_no_runtime_pm = {
> +	.allow_runtime_pm = false,
> +	.probe_slot	= byt_emmc_probe_slot,
> +	.quirks		= SDHCI_QUIRK_NO_ENDATTR_IN_NOPDESC,
> +	.quirks2	= SDHCI_QUIRK2_PRESET_VALUE_BROKEN |
> +			  SDHCI_QUIRK2_CAPS_BIT63_FOR_HS400 |
> +			  SDHCI_QUIRK2_STOP_WITH_TC,
> +	.ops		= &sdhci_intel_byt_ops,
> +	.priv_size	= sizeof(struct intel_host),
> +};
> +
>  static const struct sdhci_pci_fixes sdhci_intel_glk_emmc = {
>  	.allow_runtime_pm	= true,
>  	.probe_slot		= glk_emmc_probe_slot,
> @@ -1470,7 +1485,7 @@ static const struct pci_device_id pci_ids[] = {
>  	SDHCI_PCI_SUBDEVICE(INTEL, BYT_SDIO, NI, 7884, ni_byt_sdio),
>  	SDHCI_PCI_DEVICE(INTEL, BYT_SDIO,  intel_byt_sdio),
>  	SDHCI_PCI_DEVICE(INTEL, BYT_SD,    intel_byt_sd),
> -	SDHCI_PCI_DEVICE(INTEL, BYT_EMMC2, intel_byt_emmc),
> +	SDHCI_PCI_DEVICE(INTEL, BYT_EMMC2, intel_byt_emmc_no_runtime_pm),
>  	SDHCI_PCI_DEVICE(INTEL, BSW_EMMC,  intel_byt_emmc),
>  	SDHCI_PCI_DEVICE(INTEL, BSW_SDIO,  intel_byt_sdio),
>  	SDHCI_PCI_DEVICE(INTEL, BSW_SD,    intel_byt_sd),
>