Subject: [PATCH 17/23] mmc: sdhci: add standard hw auto retuning support

From: [email-masked] (Adrian Hunter)
Date: Tue, 10 May 2016 11:35:29 +0300

On 15/04/16 20:29, Dong Aisheng wrote:
> If HW supports SDHCI_TUNING_MODE_3 which is auto retuning, we won't

Since this is about tuning mode 3, could you put that in the subject e.g.
"Add support for auto re-tuning (tuning mode 3)"

> retune during runtime suspend and resume, instead we use Re-tuning
> Request signaled via SDHCI_INT_RETUNE interrupt to do retuning and
> hw auto retuning during data transfer to guarantee the signal sample
> window correction.
> 
> This can avoid a mass of repeatly retuning during small file system

repeatly -> repeatedly

> data access and improve the performance.
> 
> Signed-off-by: Dong Aisheng <[email-masked]>
> ---
>  drivers/mmc/host/sdhci.c | 18 ++++++++++++++----
>  drivers/mmc/host/sdhci.h |  3 +++
>  2 files changed, 17 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 2eb0e34..0027b87 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -252,6 +252,9 @@ static void sdhci_init(struct sdhci_host *host, int soft)
>  		    SDHCI_INT_TIMEOUT | SDHCI_INT_DATA_END |
>  		    SDHCI_INT_RESPONSE;
>  
> +	if (host->tuning_mode == SDHCI_TUNING_MODE_3)

Tuning mode 2 uses this as well.  Might as well add it here.

> +		host->ier |= SDHCI_INT_RETUNE;
> +
>  	sdhci_writel(host, host->ier, SDHCI_INT_ENABLE);
>  	sdhci_writel(host, host->ier, SDHCI_SIGNAL_ENABLE);
>  
> @@ -2477,6 +2480,9 @@ static irqreturn_t sdhci_irq(int irq, void *dev_id)
>  			pr_err("%s: Card is consuming too much power!\n",
>  				mmc_hostname(host->mmc));
>  
> +		if (intmask & SDHCI_INT_RETUNE)
> +			mmc_retune_needed(host->mmc);
> +

Also need to add SDHCI_INT_RETUNE to the bits cleared further on, otherwise
it will show up in the "Unexpected interrupt" message

>  		if (intmask & SDHCI_INT_CARD_INT) {
>  			sdhci_enable_sdio_irq_nolock(host, false);
>  			host->thread_isr |= SDHCI_INT_CARD_INT;
> @@ -2575,8 +2581,10 @@ int sdhci_suspend_host(struct sdhci_host *host)
>  {
>  	sdhci_disable_card_detection(host);
>  
> -	mmc_retune_timer_stop(host->mmc);
> -	mmc_retune_needed(host->mmc);
> +	if (host->tuning_mode == SDHCI_TUNING_MODE_1) {
> +		mmc_retune_timer_stop(host->mmc);
> +		mmc_retune_needed(host->mmc);
> +	}

Probably wouldn't hurt to stop the timer always whether it's going or not.
And tuning mode 2 is not auto re-tuning, so I would still expect to need
re-tuning after power loss i.e.

	mmc_retune_timer_stop(host->mmc);
	if (host->tuning_mode != SDHCI_TUNING_MODE_3)
		mmc_retune_needed(host->mmc);

>  
>  	if (!device_may_wakeup(mmc_dev(host->mmc))) {
>  		host->ier = 0;
> @@ -2651,8 +2659,10 @@ int sdhci_runtime_suspend_host(struct sdhci_host *host)
>  {
>  	unsigned long flags;
>  
> -	mmc_retune_timer_stop(host->mmc);
> -	mmc_retune_needed(host->mmc);
> +	if (host->tuning_mode == SDHCI_TUNING_MODE_1) {
> +		mmc_retune_timer_stop(host->mmc);
> +		mmc_retune_needed(host->mmc);
> +	}

Ditto

>  
>  	spin_lock_irqsave(&host->lock, flags);
>  	host->ier &= SDHCI_INT_CARD_INT;
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> index afa4de8..2c2404f 100644
> --- a/drivers/mmc/host/sdhci.h
> +++ b/drivers/mmc/host/sdhci.h
> @@ -128,6 +128,7 @@
>  #define  SDHCI_INT_CARD_INSERT	0x00000040
>  #define  SDHCI_INT_CARD_REMOVE	0x00000080
>  #define  SDHCI_INT_CARD_INT	0x00000100
> +#define  SDHCI_INT_RETUNE	0x00001000
>  #define  SDHCI_INT_ERROR	0x00008000
>  #define  SDHCI_INT_TIMEOUT	0x00010000
>  #define  SDHCI_INT_CRC		0x00020000
> @@ -514,6 +515,8 @@ struct sdhci_host {
>  	unsigned int		tuning_count;	/* Timer count for re-tuning */
>  	unsigned int		tuning_mode;	/* Re-tuning mode supported by host */
>  #define SDHCI_TUNING_MODE_1	0
> +#define SDHCI_TUNING_MODE_2	1
> +#define SDHCI_TUNING_MODE_3	2
>  
>  	unsigned long private[0] ____cacheline_aligned;
>  };
>