[PATCH 4/4] mmc: sdhci-st: Handle interconnect clock

[Ulf Hansson]

On 8 September 2016 at 13:58, Lee Jones <lee.jones at linaro.org> wrote:
> Sorry Adrian, left you of the list.  Rectifying.
>
> FYI, this patch is due for the v4.8 -rcs:
>
>   http://www.spinics.net/lists/kernel/msg2338219.html
>
>> Some ST platforms contain interconnect (ICN) clocks which must be handed
>> correctly in order to obtain full functionality of a given IP.  In this
>> case, if the ICN clocks are not handled properly by the ST SDHCI driver
>> MMC will break and the following output can be observed:
>>
>>     [   13.916949] mmc0: Timeout waiting for hardware interrupt.
>>     [   13.922349] sdhci: =========== REGISTER DUMP (mmc0)===========
>>     [   13.928175] sdhci: Sys addr: 0x00000000 | Version:  0x00001002
>>     [   13.933999] sdhci: Blk size: 0x00007040 | Blk cnt:  0x00000001
>>     [   13.939825] sdhci: Argument: 0x00fffff0 | Trn mode: 0x00000013
>>     [   13.945650] sdhci: Present:  0x1fff0206 | Host ctl: 0x00000011
>>     [   13.951475] sdhci: Power:    0x0000000f | Blk gap:  0x00000080
>>     [   13.957300] sdhci: Wake-up:  0x00000000 | Clock:    0x00003f07
>>     [   13.963126] sdhci: Timeout:  0x00000004 | Int stat: 0x00000000
>>     [   13.968952] sdhci: Int enab: 0x02ff008b | Sig enab: 0x02ff008b
>>     [   13.974777] sdhci: AC12 err: 0x00000000 | Slot int: 0x00000000
>>     [   13.980602] sdhci: Caps:     0x21ed3281 | Caps_1:   0x00000000
>>     [   13.986428] sdhci: Cmd:      0x0000063a | Max curr: 0x00000000
>>     [   13.992252] sdhci: Host ctl2: 0x00000000
>>     [   13.996166] sdhci: ADMA Err: 0x00000000 | ADMA Ptr: 0x7c048200
>>     [   14.001990] sdhci: ===========================================
>>     [   14.009802] mmc0: Got data interrupt 0x02000000 even though no data operation was in progress.
>>
>> A decent point was raised about minimising the use of a local variable that
>> we 'could' do without.  I've chosen consistency over the possibility of
>> reducing the local variable count by 1.  Thinking that it's more important
>> for the code to be grouped and authoured in a similar manner/style for
>> greater maintainability/readability.
>>
>> Cc: stable at vger.kernel.org
>> Tested-by: Peter Griffin <peter.griffin at linaro.org>
>> Signed-off-by: Lee Jones <lee.jones at linaro.org>

Thanks, applied for fixes!

Adrian, please tell if you have any objections else I intend to send
this for the rcs later this week.

Kind regards
Uffe

>> ---
>>  drivers/mmc/host/sdhci-st.c | 15 ++++++++++++++-
>>  1 file changed, 14 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/mmc/host/sdhci-st.c b/drivers/mmc/host/sdhci-st.c
>> index c95ba83..ed92ce7 100644
>> --- a/drivers/mmc/host/sdhci-st.c
>> +++ b/drivers/mmc/host/sdhci-st.c
>> @@ -28,6 +28,7 @@
>>
>>  struct st_mmc_platform_data {
>>       struct  reset_control *rstc;
>> +     struct  clk *icnclk;
>>       void __iomem *top_ioaddr;
>>  };
>>
>> @@ -353,7 +354,7 @@ static int sdhci_st_probe(struct platform_device *pdev)
>>       struct sdhci_host *host;
>>       struct st_mmc_platform_data *pdata;
>>       struct sdhci_pltfm_host *pltfm_host;
>> -     struct clk *clk;
>> +     struct clk *clk, *icnclk;
>>       int ret = 0;
>>       u16 host_version;
>>       struct resource *res;
>> @@ -365,6 +366,11 @@ static int sdhci_st_probe(struct platform_device *pdev)
>>               return PTR_ERR(clk);
>>       }
>>
>> +     /* ICN clock isn't compulsory, but use it if it's provided. */
>> +     icnclk = devm_clk_get(&pdev->dev, "icn");
>> +     if (IS_ERR(icnclk))
>> +             icnclk = NULL;
>> +
>>       rstc = devm_reset_control_get(&pdev->dev, NULL);
>>       if (IS_ERR(rstc))
>>               rstc = NULL;
>> @@ -389,6 +395,7 @@ static int sdhci_st_probe(struct platform_device *pdev)
>>       }
>>
>>       clk_prepare_enable(clk);
>> +     clk_prepare_enable(icnclk);
>>
>>       /* Configure the FlashSS Top registers for setting eMMC TX/RX delay */
>>       res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
>> @@ -400,6 +407,7 @@ static int sdhci_st_probe(struct platform_device *pdev)
>>       }
>>
>>       pltfm_host->clk = clk;
>> +     pdata->icnclk = icnclk;
>>
>>       /* Configure the Arasan HC inside the flashSS */
>>       st_mmcss_cconfig(np, host);
>> @@ -422,6 +430,7 @@ static int sdhci_st_probe(struct platform_device *pdev)
>>       return 0;
>>
>>  err_out:
>> +     clk_disable_unprepare(icnclk);
>>       clk_disable_unprepare(clk);
>>  err_of:
>>       sdhci_pltfm_free(pdev);
>> @@ -442,6 +451,8 @@ static int sdhci_st_remove(struct platform_device *pdev)
>>
>>       ret = sdhci_pltfm_unregister(pdev);
>>
>> +     clk_disable_unprepare(pdata->icnclk);
>> +
>>       if (rstc)
>>               reset_control_assert(rstc);
>>
>> @@ -462,6 +473,7 @@ static int sdhci_st_suspend(struct device *dev)
>>       if (pdata->rstc)
>>               reset_control_assert(pdata->rstc);
>>
>> +     clk_disable_unprepare(pdata->icnclk);
>>       clk_disable_unprepare(pltfm_host->clk);
>>  out:
>>       return ret;
>> @@ -475,6 +487,7 @@ static int sdhci_st_resume(struct device *dev)
>>       struct device_node *np = dev->of_node;
>>
>>       clk_prepare_enable(pltfm_host->clk);
>> +     clk_prepare_enable(pdata->icnclk);
>>
>>       if (pdata->rstc)
>>               reset_control_deassert(pdata->rstc);
>
> --
> Lee Jones
> Linaro STMicroelectronics Landing Team Lead
> Linaro.org │ Open source software for ARM SoCs
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