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Date: Wed, 18 Jan 2017 17:17:13 +0530
From: Ritesh Harjani <riteshh@...eaurora.org>
To: Georgi Djakov <georgi.djakov@...aro.org>
Cc: adrian.hunter@...el.com, ulf.hansson@...aro.org,
linux-mmc@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-arm-msm@...r.kernel.org
Subject: Re: [PATCH v2] mmc: sdhci-msm: Add sdhci_reset() implementation
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@...aro.org>
>>>>> ---
> Reviewed-by: Ritesh Harjani <riteshh@...eaurora.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@...r.kernel.org
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>>>>>
>>>>
>>> --
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>>
>
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