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

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Message-ID: <ee4c90b8-aed8-ba3b-3aea-9e4257771cfe@intel.com>
Date:   Thu, 28 Mar 2019 10:13:58 +0200
From:   Adrian Hunter <adrian.hunter@...el.com>
To:     Faiz Abbas <faiz_abbas@...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

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;
	}