From mboxrd@z Thu Jan  1 00:00:00 1970
From: Georgi Djakov <georgi.djakov@linaro.org>
Subject: Re: [PATCH v2] mmc: sdhci-msm: Add sdhci_reset() implementation
Date: Wed, 18 Jan 2017 14:28:13 +0200
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To: Ritesh Harjani <riteshh@codeaurora.org>
Cc: adrian.hunter@intel.com, ulf.hansson@linaro.org, linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org
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On 01/18/2017 01:47 PM, Ritesh Harjani wrote:
> Hi Georgi,
>
> I checked this patch again on internal msm8996 target which has more
> than 1 core. And I can still see below issue with this patch. Please
> check the dmesg log snip. (I enabled card runtime suspend/resume to
> reproduce this more frequently).
>
> In that case we still need to work over this issue.

Hi Ritesh,

Thanks for checking this. I will submit a new version.

BR,
Georgi

>
>
> <dmesg snip>
> # [    5.854979] mmc0: mmc_runtime_suspend
> [    5.854982] mmc1: mmc_runtime_suspend
> [    5.957925] mmc1: Reset 0x1 never completed.
> [    6.071244] mmc0: Reset 0x1 never completed.
>
>
> Regards
> Ritesh
>
>
> On 1/18/2017 2:46 PM, Ritesh Harjani wrote:
>> Hi Georgi,
>>
>> Sorry for delaying this.
>> I did check with HW folks here, but it seems like we still don't have
>> confirmation. In case if I get any new updates later, we can revisit it.
>>
>> Also I see that we have the same implementation in current driver for
>> changing IO voltage. In that case I think this patch should be fine to
>> avoid the error message on reboot.
>>
>>
>> On 12/3/2016 2:24 PM, Ritesh Harjani wrote:
>>>
>>>
>>> On 12/1/2016 11:38 PM, Georgi Djakov wrote:
>>>> On 11/29/2016 05:40 AM, Ritesh Harjani wrote:
>>>>> Hi Georgi,
>>>>>
>>>>> On 11/28/2016 11:09 PM, Georgi Djakov wrote:
>>>>>> On apq8016, apq8084 and apq8074 platforms, writing to the software
>>>>>> reset register triggers the "power irq". We need to ack and handle
>>>>>> the irq, otherwise the following message appears:
>>>>>>
>>>>>> mmc0: Reset 0x1 never completed.
>>>>>> sdhci: =========== REGISTER DUMP (mmc0)===========
>>>>>> sdhci: Sys addr: 0x00000000 | Version:  0x00002e02
>>>>>> sdhci: Blk size: 0x00004000 | Blk cnt:  0x00000000
>>>>>> sdhci: Argument: 0x00000000 | Trn mode: 0x00000000
>>>>>> sdhci: Present:  0x01f80000 | Host ctl: 0x00000000
>>>>>> sdhci: Power:    0x00000000 | Blk gap:  0x00000000
>>>>>> sdhci: Wake-up:  0x00000000 | Clock:    0x00000003
>>>>>> sdhci: Timeout:  0x00000000 | Int stat: 0x00000000
>>>>>> sdhci: Int enab: 0x00000000 | Sig enab: 0x00000000
>>>>>> sdhci: AC12 err: 0x00000000 | Slot int: 0x00000000
>>>>>> sdhci: Caps:     0x322dc8b2 | Caps_1:   0x00008007
>>>>>> sdhci: Cmd:      0x00000000 | Max curr: 0x00000000
>>>>>> sdhci: Host ctl2: 0x00000000
>>>>>> sdhci: ADMA Err: 0x00000000 | ADMA Ptr: 0x0000000000000000
>>>>>> sdhci: ===========================================
>>>>>>
>>>>>> Fix it by implementing the custom sdhci_reset() function,
>>>>>> which performs the software reset and then handles the irq.
>>>>>>
>>>>>> Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
>>>>>> ---
>> Reviewed-by: Ritesh Harjani <riteshh@codeaurora.org>
>>
>>
>>>>>>
>>>>>> Changes since v1: (https://lkml.org/lkml/2016/11/22/411)
>>>>>>  * Perform the software reset by just writing to the
>>>>>> SDHCI_SOFTWARE_RESET
>>>>>>    register and then check for the irq.
>>>>> I am still not sure about this change. Below change will trigger the
>>>>> IRQ, once this call is completed (say on a single core system) -since
>>>>> this is called while holding spin_lock_irqsave.
>>>>>
>>>>> But you will be end up calling sdhci_msm_voltage_switch twice,
>>>>> which to me does not seems correct.
>>>>> 1. 1st time you are directly calling it in sdhci_msm_reset.
>>>>> 2. 2nd time will be called from within pwr_irq to handle the same
>>>>> case.
>>>>
>>>> Yes, that would be the behavior. This function actually is not doing
>>>> anything much than to check irq status and ack it. Testing the patch
>>> Ok.
>>>
>>>> on a few different platforms does not show any side effects, however i
>>>> could not be 100% sure as i have limited information about the
>>>> hardware.
>>> what about the case when say the IRQ is delayed because of some other
>>> overheads in the system. Will this approach still works?
>>> I understand this would require some HW knowledge to understand the
>>> functioning/importance of this pwr_irq. I will try and get in touch with
>>> HW folk here.
>>>
>>> Regards
>>> Ritesh
>>>
>>>
>>>>
>>>> Thanks,
>>>> Georgi
>>>>
>>>>>
>>>>> Please let me know your thoughts on this ?
>>>>>
>>>>> Regards
>>>>> Ritesh
>>>>>
>>>>>>
>>>>>>  drivers/mmc/host/sdhci-msm.c | 29 ++++++++++++++++++++++++++++-
>>>>>>  1 file changed, 28 insertions(+), 1 deletion(-)
>>>>>>
>>>>>> diff --git a/drivers/mmc/host/sdhci-msm.c
>>>>>> b/drivers/mmc/host/sdhci-msm.c
>>>>>> index 32879b845b75..157ae07f9309 100644
>>>>>> --- a/drivers/mmc/host/sdhci-msm.c
>>>>>> +++ b/drivers/mmc/host/sdhci-msm.c
>>>>>> @@ -1019,6 +1019,33 @@ static void sdhci_msm_set_clock(struct
>>>>>> sdhci_host *host, unsigned int clock)
>>>>>>      __sdhci_msm_set_clock(host, clock);
>>>>>>  }
>>>>>>
>>>>>> +void sdhci_msm_reset(struct sdhci_host *host, u8 mask)
>>>>>> +{
>>>>>> +    unsigned long timeout = 100;
>>>>>> +
>>>>>> +    sdhci_writeb(host, mask, SDHCI_SOFTWARE_RESET);
>>>>>> +
>>>>>> +    if (mask & SDHCI_RESET_ALL) {
>>>>>> +        host->clock = 0;
>>>>>> +
>>>>>> +        /*
>>>>>> +         * SDHCI_RESET_ALL triggers the PWR IRQ and we need
>>>>>> +         * to handle it here.
>>>>>> +         */
>>>>>> +        sdhci_msm_voltage_switch(host);
>>>>>> +    }
>>>>>> +
>>>>>> +    while (sdhci_readb(host, SDHCI_SOFTWARE_RESET) & mask) {
>>>>>> +        if (timeout == 0) {
>>>>>> +            pr_err("%s: Reset 0x%x never completed.\n",
>>>>>> +                   mmc_hostname(host->mmc), (int)mask);
>>>>>> +            return;
>>>>>> +        }
>>>>>> +        timeout--;
>>>>>> +        mdelay(1);
>>>>>> +    }
>>>>>> +}
>>>>>> +
>>>>>>  static const struct of_device_id sdhci_msm_dt_match[] = {
>>>>>>      { .compatible = "qcom,sdhci-msm-v4" },
>>>>>>      {},
>>>>>> @@ -1028,7 +1055,7 @@ MODULE_DEVICE_TABLE(of, sdhci_msm_dt_match);
>>>>>>
>>>>>>  static const struct sdhci_ops sdhci_msm_ops = {
>>>>>>      .platform_execute_tuning = sdhci_msm_execute_tuning,
>>>>>> -    .reset = sdhci_reset,
>>>>>> +    .reset = sdhci_msm_reset,
>>>>>>      .set_clock = sdhci_msm_set_clock,
>>>>>>      .get_min_clock = sdhci_msm_get_min_clock,
>>>>>>      .get_max_clock = sdhci_msm_get_max_clock,
>>>>>> --
>>>>>> To unsubscribe from this list: send the line "unsubscribe
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>>>>>> the body of a message to majordomo@vger.kernel.org
>>>>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>>>>>
>>>>>
>>>> --
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>>>
>>
>