linux-kernel - Re: [PATCH v4 4/5] mmc: core: Add sdio_retune_hold_now() and sdio_retune

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Message-ID: <d46161e8-cf2b-0aa0-1445-2d92580bf1a6@intel.com>
Date:   Mon, 17 Jun 2019 11:34:12 +0300
From:   Adrian Hunter <adrian.hunter@...el.com>
To:     Douglas Anderson <dianders@...omium.org>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Kalle Valo <kvalo@...eaurora.org>,
        Arend van Spriel <arend.vanspriel@...adcom.com>
Cc:     brcm80211-dev-list.pdl@...adcom.com,
        linux-rockchip@...ts.infradead.org,
        Double Lo <double.lo@...ress.com>, briannorris@...omium.org,
        linux-wireless@...r.kernel.org,
        Naveen Gupta <naveen.gupta@...ress.com>,
        Madhan Mohan R <madhanmohan.r@...ress.com>, mka@...omium.org,
        Wright Feng <wright.feng@...ress.com>,
        Chi-Hsien Lin <chi-hsien.lin@...ress.com>,
        netdev@...r.kernel.org, brcm80211-dev-list@...ress.com,
        linux-mmc@...r.kernel.org, linux-kernel@...r.kernel.org,
        Thomas Gleixner <tglx@...utronix.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Avri Altman <avri.altman@....com>
Subject: Re: [PATCH v4 4/5] mmc: core: Add sdio_retune_hold_now() and
 sdio_retune_release()

On 14/06/19 2:41 AM, Douglas Anderson wrote:
> We want SDIO drivers to be able to temporarily stop retuning when the
> driver knows that the SDIO card is not in a state where retuning will
> work (maybe because the card is asleep).  We'll move the relevant
> functions to a place where drivers can call them.
> 
> Signed-off-by: Douglas Anderson <dianders@...omium.org>

Acked-by: Adrian Hunter <adrian.hunter@...el.com>

> ---
> 
> Changes in v4:
> - Moved retune hold/release to SDIO API (Adrian).
> 
> Changes in v3:
> - ("mmc: core: Export mmc_retune_hold_now() mmc_retune_release()") new for v3.
> 
> Changes in v2: None
> 
>  drivers/mmc/core/sdio_io.c    | 40 +++++++++++++++++++++++++++++++++++
>  include/linux/mmc/sdio_func.h |  3 +++
>  2 files changed, 43 insertions(+)
> 
> diff --git a/drivers/mmc/core/sdio_io.c b/drivers/mmc/core/sdio_io.c
> index f822a9630b0e..1b6fe737bd72 100644
> --- a/drivers/mmc/core/sdio_io.c
> +++ b/drivers/mmc/core/sdio_io.c
> @@ -15,6 +15,7 @@
>  #include "sdio_ops.h"
>  #include "core.h"
>  #include "card.h"
> +#include "host.h"
>  
>  /**
>   *	sdio_claim_host - exclusively claim a bus for a certain SDIO function
> @@ -770,3 +771,42 @@ void sdio_retune_crc_enable(struct sdio_func *func)
>  	func->card->host->retune_crc_disable = false;
>  }
>  EXPORT_SYMBOL_GPL(sdio_retune_crc_enable);
> +
> +/**
> + *	sdio_retune_hold_now - start deferring retuning requests till release
> + *	@func: SDIO function attached to host
> + *
> + *	This function can be called if it's currently a bad time to do
> + *	a retune of the SDIO card.  Retune requests made during this time
> + *	will be held and we'll actually do the retune sometime after the
> + *	release.
> + *
> + *	This function could be useful if an SDIO card is in a power state
> + *	where it can respond to a small subset of commands that doesn't
> + *	include the retuning command.  Care should be taken when using
> + *	this function since (presumably) the retuning request we might be
> + *	deferring was made for a good reason.
> + *
> + *	This function should be called while the host is claimed.
> + */
> +void sdio_retune_hold_now(struct sdio_func *func)
> +{
> +	mmc_retune_hold_now(func->card->host);
> +}
> +EXPORT_SYMBOL_GPL(sdio_retune_hold_now);
> +
> +/**
> + *	sdio_retune_release - signal that it's OK to retune now
> + *	@func: SDIO function attached to host
> + *
> + *	This is the complement to sdio_retune_hold_now().  Calling this
> + *	function won't make a retune happen right away but will allow
> + *	them to be scheduled normally.
> + *
> + *	This function should be called while the host is claimed.
> + */
> +void sdio_retune_release(struct sdio_func *func)
> +{
> +	mmc_retune_release(func->card->host);
> +}
> +EXPORT_SYMBOL_GPL(sdio_retune_release);
> diff --git a/include/linux/mmc/sdio_func.h b/include/linux/mmc/sdio_func.h
> index 4820e6d09dac..5a177f7a83c3 100644
> --- a/include/linux/mmc/sdio_func.h
> +++ b/include/linux/mmc/sdio_func.h
> @@ -170,4 +170,7 @@ extern int sdio_set_host_pm_flags(struct sdio_func *func, mmc_pm_flag_t flags);
>  extern void sdio_retune_crc_disable(struct sdio_func *func);
>  extern void sdio_retune_crc_enable(struct sdio_func *func);
>  
> +extern void sdio_retune_hold_now(struct sdio_func *func);
> +extern void sdio_retune_release(struct sdio_func *func);
> +
>  #endif /* LINUX_MMC_SDIO_FUNC_H */
>