linux-kernel - Re: [PATCH V7 7/9] mmc: sdhci: SDMA may use Auto-CMD23 in v4 mode

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Message-ID: <a38f8d87-a373-5de4-c3b5-bba68f8ffeec@intel.com>
Date:   Wed, 29 Aug 2018 13:59:45 +0300
From:   Adrian Hunter <adrian.hunter@...el.com>
To:     Chunyan Zhang <zhang.chunyan@...aro.org>,
        Ulf Hansson <ulf.hansson@...aro.org>
Cc:     linux-mmc@...r.kernel.org, linux-kernel@...r.kernel.org,
        Orson Zhai <orsonzhai@...il.com>,
        Baolin Wang <baolin.wang@...aro.org>,
        Billows Wu <billows.wu@...soc.com>,
        Jason Wu <jason.wu@...soc.com>,
        Chunyan Zhang <chunyan.zhang@...soc.com>,
        Chunyan Zhang <zhang.lyra@...il.com>
Subject: Re: [PATCH V7 7/9] mmc: sdhci: SDMA may use Auto-CMD23 in v4 mode

On 29/08/18 10:03, Chunyan Zhang wrote:
> When Host Version 4 Enable is set to 1, SDMA uses ADMA System Address
> register (05Fh-058h) instead of using register (000h-004h) to indicate
> its system address of data location. The register (000h-004h) is
> re-assigned to 32-bit Block Count and Auto CMD23 argument, so then SDMA
> may use Auto CMD23.
> 
> Signed-off-by: Chunyan Zhang <zhang.chunyan@...aro.org>
> ---
>  drivers/mmc/host/sdhci.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 62d843ac90..ac92e0f 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -3834,10 +3834,14 @@ int sdhci_setup_host(struct sdhci_host *host)
>  	if (host->quirks & SDHCI_QUIRK_MULTIBLOCK_READ_ACMD12)
>  		host->flags |= SDHCI_AUTO_CMD12;
>  
> -	/* Auto-CMD23 stuff only works in ADMA or PIO. */
> +	/*
> +	 * For v3 mode, Auto-CMD23 stuff only works in ADMA or PIO;

; -> .

> +	 * For v4 mode, SDMA may use Auto-CMD23 as well.
> +	 */
>  	if ((host->version >= SDHCI_SPEC_300) &&
>  	    ((host->flags & SDHCI_USE_ADMA) ||
> -	     !(host->flags & SDHCI_USE_SDMA)) &&
> +	     (!host->v4_mode && !(host->flags & SDHCI_USE_SDMA)) ||
> +	     (host->v4_mode && (host->flags & SDHCI_USE_SDMA))) &&
>  	     !(host->quirks2 & SDHCI_QUIRK2_ACMD23_BROKEN)) {

This is over complicated.  We can use auto-CMD23 if not using SDMA or if in
v4_mode i.e.

	if (host->version >= SDHCI_SPEC_300 &&
	    (!(host->flags & SDHCI_USE_SDMA) || host->v4_mode) &&
	    !(host->quirks2 & SDHCI_QUIRK2_ACMD23_BROKEN)) {

>  		host->flags |= SDHCI_AUTO_CMD23;
>  		DBG("Auto-CMD23 available\n");
>