linux-kernel - Re: [PATCH V4 4/7] mmc: sdhci: add 32-bit block count support for v4 mode

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Date:   Mon, 30 Jul 2018 16:05:47 +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@...eadtrum.com>,
        Jason Wu <jason.wu@...soc.com>, zhang.lyra@...il.com
Subject: Re: [PATCH V4 4/7] mmc: sdhci: add 32-bit block count support for v4
 mode

On 24/07/18 05:51, Chunyan Zhang wrote:
> Host Controller Version 4.10 re-defines SDMA System Address register
> as 32-bit Block Count for v4 mode, and SDMA uses ADMA System
> Address register (05Fh-058h) instead if v4 mode is enabled. Also
> when using 32-bit block count, 16-bit block count register need
> to be set to zero.
> 
> Signed-off-by: Chunyan Zhang <zhang.chunyan@...aro.org>
> ---
>  drivers/mmc/host/sdhci.c | 14 +++++++++++++-
>  drivers/mmc/host/sdhci.h |  1 +
>  2 files changed, 14 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 920d8ec..c272a2b 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -1070,7 +1070,19 @@ static void sdhci_prepare_data(struct sdhci_host *host, struct mmc_command *cmd)
>  	/* Set the DMA boundary value and block size */
>  	sdhci_writew(host, SDHCI_MAKE_BLKSZ(host->sdma_boundary, data->blksz),
>  		     SDHCI_BLOCK_SIZE);
> -	sdhci_writew(host, data->blocks, SDHCI_BLOCK_COUNT);
> +
> +	/*
> +	 * For Version 4.10 onwards, if v4 mode is enabled, 16-bit Block Count
> +	 * register need to be set to zero, 32-bit Block Count register would
> +	 * be selected.
> +	 */
> +	if (host->version >= SDHCI_SPEC_410 && host->v4_mode) {
> +		if (sdhci_readw(host, SDHCI_BLOCK_COUNT))
> +			sdhci_writew(host, 0, SDHCI_BLOCK_COUNT);
> +		sdhci_writew(host, data->blocks, SDHCI_32BIT_BLK_CNT);

So this is also SDHCI_ARGUMENT2 which is why there is a conflict with
auto-CMD23.  We need to write SDHCI_32BIT_BLK_CNT only once, but also cater
for eMMC which uses the CMD23 argument for more than just block count.

> +	} else {
> +		sdhci_writew(host, data->blocks, SDHCI_BLOCK_COUNT);
> +	}
>  }
>  
>  static inline bool sdhci_auto_cmd12(struct sdhci_host *host,
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> index 23318ff..81aae07 100644
> --- a/drivers/mmc/host/sdhci.h
> +++ b/drivers/mmc/host/sdhci.h
> @@ -28,6 +28,7 @@
>  
>  #define SDHCI_DMA_ADDRESS	0x00
>  #define SDHCI_ARGUMENT2		SDHCI_DMA_ADDRESS
> +#define SDHCI_32BIT_BLK_CNT	SDHCI_DMA_ADDRESS
>  
>  #define SDHCI_BLOCK_SIZE	0x04
>  #define  SDHCI_MAKE_BLKSZ(dma, blksz) (((dma & 0x7) << 12) | (blksz & 0xFFF))
>