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Message-ID: <CAPDyKFpVKYzJEAWkHsp2ZZdS=tQmVjFRymkXFHxyGqmgteNbUw@mail.gmail.com>
Date: Mon, 12 Sep 2016 14:35:23 +0200
From: Ulf Hansson <ulf.hansson@...aro.org>
To: Lee Jones <lee.jones@...aro.org>
Cc: Patrice CHOTARD <patrice.chotard@...com>,
Peter Griffin <peter.griffin@...aro.org>,
Rob Herring <robh@...nel.org>,
Adrian Hunter <adrian.hunter@...el.com>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
kernel@...inux.com, "# 4.0+" <stable@...r.kernel.org>,
linux-mmc <linux-mmc@...r.kernel.org>
Subject: Re: [PATCH 4/4] mmc: sdhci-st: Handle interconnect clock
On 8 September 2016 at 13:58, Lee Jones <lee.jones@...aro.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@...r.kernel.org
>> Tested-by: Peter Griffin <peter.griffin@...aro.org>
>> Signed-off-by: Lee Jones <lee.jones@...aro.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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