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Subject: Re: [PATCH V3 4/7] mmc: sdhci: add 32-bit block count support for v4
 mode
To:     Chunyan Zhang <zhang.chunyan@linaro.org>,
        Ulf Hansson <ulf.hansson@linaro.org>
Cc:     linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org,
        Orson Zhai <orsonzhai@gmail.com>,
        Baolin Wang <baolin.wang@linaro.org>,
        Billows Wu <billows.wu@spreadtrum.com>, zhang.lyra@gmail.com
References: <1531106398-14062-1-git-send-email-zhang.chunyan@linaro.org>
 <1531106398-14062-5-git-send-email-zhang.chunyan@linaro.org>
From:   Adrian Hunter <adrian.hunter@intel.com>
Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki,
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Message-ID: <892181d5-61f2-55da-2a79-1d2cbfc00f8f@intel.com>
Date:   Tue, 17 Jul 2018 11:29:20 +0300
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On 09/07/18 06:19, Chunyan Zhang wrote:
> When Host Version 4 is enabled, SDMA System Address register is
> re-defined as 32-bit Block Count, and SDMA uses ADMA System
> Address register (05Fh-058h) instead.
> 
> Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org>
> ---
>  drivers/mmc/host/sdhci.c | 4 +++-
>  drivers/mmc/host/sdhci.h | 1 +
>  2 files changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 7871ae2..f64e766 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -889,6 +889,7 @@ static void sdhci_set_timeout(struct sdhci_host *host, struct mmc_command *cmd)
>  static void sdhci_prepare_data(struct sdhci_host *host, struct mmc_command *cmd)
>  {
>  	u8 ctrl;
> +	u32 reg;
>  	struct mmc_data *data = cmd->data;
>  
>  	host->data_timeout = 0;
> @@ -1021,7 +1022,8 @@ 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);
> +	reg = host->v4_mode ? SDHCI_32BIT_BLK_CNT : SDHCI_BLOCK_COUNT;
> +	sdhci_writew(host, data->blocks, reg);

The specification says to set 16-bit block count register to zero when using
32-bit block count.  It also says it is valid for V4.1 onwards and also for
V4 with SDMA and auto-CMD23.

So maybe we should continue to use the 16-bit block count register with V4.0

>  }
>  
>  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 24fa58a..889e48b 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))
>