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Re: [PATCH v2] mmc: sdhci-msm: Add sdhci_reset() implementation

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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.


<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
>>>>> linux-mmc" in
>>>>> the body of a message to majordomo@vger.kernel.org
>>>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>>>>
>>>>
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
>>> 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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Re: [PATCH v2] mmc: sdhci-msm: Add sdhci_reset() implementation Ritesh Harjani <riteshh@codeaurora.org> - 2017-01-18 10:30 +0100
  Re: [PATCH v2] mmc: sdhci-msm: Add sdhci_reset() implementation Ritesh Harjani <riteshh@codeaurora.org> - 2017-01-18 13:00 +0100
    Re: [PATCH v2] mmc: sdhci-msm: Add sdhci_reset() implementation Georgi Djakov <georgi.djakov@linaro.org> - 2017-01-18 13:30 +0100

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