linux-kernel - Re: [PATCH v4 2/2] mmc: sdhci-omap: Don't finish

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Date:   Fri, 29 Mar 2019 13:12:38 +0530
From:   Faiz Abbas <faiz_abbas@...com>
To:     Adrian Hunter <adrian.hunter@...el.com>,
        <linux-kernel@...r.kernel.org>, <linux-mmc@...r.kernel.org>,
        <linux-omap@...r.kernel.org>
CC:     <ulf.hansson@...aro.org>, <kishon@...com>
Subject: Re: [PATCH v4 2/2] mmc: sdhci-omap: Don't finish_mrq() on a command
 error during tuning

Hi Adrian,

On 28/03/19 1:43 PM, Adrian Hunter wrote:
> On 27/03/19 1:47 PM, Faiz Abbas wrote:
>> Hi Adrian,
>>
>> On 27/03/19 4:45 PM, Adrian Hunter wrote:
>>> On 26/03/19 1:00 PM, Faiz Abbas wrote:
>>>> commit 5b0d62108b46 ("mmc: sdhci-omap: Add platform specific reset
>>>> callback") skips data resets during tuning operation. Because of this,
>>>> a data error or data finish interrupt might still arrive after a command
>>>> error has been handled and the mrq ended. This ends up with a "mmc0: Got
>>>> data interrupt 0x00000002 even though no data operation was in progress"
>>>> error message.
>>>>
>>>> Fix this by adding a platform specific callback for sdhci_irq. Mark the
>>>> mrq as a failure but wait for a data interrupt instead of calling
>>>> finish_mrq().
>>>>
>>>> Signed-off-by: Faiz Abbas <faiz_abbas@...com>
>>>> ---
>>>>  drivers/mmc/host/sdhci-omap.c | 37 +++++++++++++++++++++++++++++++++++
>>>>  1 file changed, 37 insertions(+)
>>>>
>>>> diff --git a/drivers/mmc/host/sdhci-omap.c b/drivers/mmc/host/sdhci-omap.c
>>>> index 5bbed477c9b1..9da2ff9ede8b 100644
>>>> --- a/drivers/mmc/host/sdhci-omap.c
>>>> +++ b/drivers/mmc/host/sdhci-omap.c
>>>> @@ -797,6 +797,42 @@ void sdhci_omap_reset(struct sdhci_host *host, u8 mask)
>>>>  	sdhci_reset(host, mask);
>>>>  }
>>>>  
>>>> +#define CMD_ERR_MASK (SDHCI_INT_CRC | SDHCI_INT_END_BIT | SDHCI_INT_INDEX |\
>>>> +		      SDHCI_INT_TIMEOUT)
>>>> +#define CMD_MASK (CMD_ERR_MASK | SDHCI_INT_RESPONSE)
>>>> +
>>>> +static irqreturn_t sdhci_omap_irq(struct sdhci_host *host, u32 intmask)
>>>> +{
>>>> +	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
>>>> +	struct sdhci_omap_host *omap_host = sdhci_pltfm_priv(pltfm_host);
>>>> +
>>>> +	if (omap_host->is_tuning && (intmask & CMD_ERR_MASK)) {
>>>> +
>>>> +		/*
>>>> +		 * Since we are not resetting data lines during tuning
>>>> +		 * operation, data error or data complete interrupts
>>>> +		 * might still arrive. Mark this request as a failure
>>>> +		 * but still wait for the data interrupt
>>>> +		 */
>>>> +		if (intmask & SDHCI_INT_TIMEOUT)
>>>> +			host->cmd->error = -ETIMEDOUT;
>>>> +		else
>>>> +			host->cmd->error = -EILSEQ;
>>>> +
>>>> +		sdhci_finish_command(host);
>>>
>>> Would it be possible to set SDHCI_INT_RESPONSE instead of calling
>>> sdhci_finish_command() directly?
>>>
>>
>> It should be possible. But what we are trying to do won't be very clear
>> from the code. Ideally an interrupt handler should not set any interrupt
>> bits, just handle and clear them. Also, setting the RESPONSE bit even
>> when there has been no response seems wrong and makes the code more
>> convoluted.
> 
> Well, I am not in favour of exporting sdhci_finish_command().
> So I had a look and it is not obvious why you need to call it.
> What about something this:
> 
> 	if (omap_host->is_tuning && host->cmd && !host->data_early &&
> 	    (intmask & CMD_ERR_MASK)) {
> 
> 		if (intmask & SDHCI_INT_TIMEOUT)
> 			host->cmd->error = -ETIMEDOUT;
> 		else
> 			host->cmd->error = -EILSEQ;
> 
> 		host->cmd = NULL;
> 
> 		sdhci_writel(host, intmask & CMD_MASK, SDHCI_INT_STATUS);
> 		intmask &= ~CMD_MASK;
> 	}
> 

Yeah. I guess host->cmd = NULL was the only thing that was being done
sdhci_finish_command(). This works with 100 time boot tests for me. Will
post next version.

Thanks,
Faiz