Re: [PATCH v2] mmc: arm_pl180_mmci: Enable HWFC for specific versions of MCI

[Jaehoon Chung <jh80.chung@samsung.com>]

On 10/19/21 11:49 PM, Usama Arif wrote:
> There are 4 registers (PERIPHID{0-3}) that contain the ID of MCI.
> For MMCs' with peripheral id 0x02041180 and 0x03041180, H/W flow control
> needs to be enabled for multi block writes (MMC CMD 18).
> 
> Signed-off-by: Usama Arif <usama.arif@arm.com>

Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>

Best Regards,
Jaehoon Chung

> ---
>  drivers/mmc/arm_pl180_mmci.c | 14 ++++++++++++++
>  drivers/mmc/arm_pl180_mmci.h |  1 +
>  2 files changed, 15 insertions(+)
> 
> diff --git a/drivers/mmc/arm_pl180_mmci.c b/drivers/mmc/arm_pl180_mmci.c
> index f99b5f997e..9c5d48e90c 100644
> --- a/drivers/mmc/arm_pl180_mmci.c
> +++ b/drivers/mmc/arm_pl180_mmci.c
> @@ -282,6 +282,14 @@ static int host_request(struct mmc *dev,
>  	return result;
>  }
>  
> +static int check_peripheral_id(struct pl180_mmc_host *host, u32 periph_id)
> +{
> +	return readl(&host->base->periph_id0) == (periph_id & 0xFF) &&
> +		readl(&host->base->periph_id1) == ((periph_id >> 8) & 0xFF)  &&
> +		readl(&host->base->periph_id2) == ((periph_id >> 16) & 0xFF) &&
> +		readl(&host->base->periph_id3) == ((periph_id >> 24) & 0xFF);
> +}
> +
>  static int  host_set_ios(struct mmc *dev)
>  {
>  	struct pl180_mmc_host *host = dev->priv;
> @@ -337,6 +345,12 @@ static int  host_set_ios(struct mmc *dev)
>  		sdi_clkcr &= ~(SDI_CLKCR_WIDBUS_MASK);
>  		sdi_clkcr |= buswidth;
>  	}
> +	/* For MMCs' with peripheral id 0x02041180 and 0x03041180, H/W flow control
> +	 * needs to be enabled for multi block writes (MMC CMD 18).
> +	 */
> +	if (check_peripheral_id(host, 0x02041180) ||
> +		check_peripheral_id(host, 0x03041180))
> +		sdi_clkcr |= SDI_CLKCR_HWFCEN;
>  
>  	writel(sdi_clkcr, &host->base->clock);
>  	udelay(CLK_CHANGE_DELAY);
> diff --git a/drivers/mmc/arm_pl180_mmci.h b/drivers/mmc/arm_pl180_mmci.h
> index 15c29beadb..fca15910a8 100644
> --- a/drivers/mmc/arm_pl180_mmci.h
> +++ b/drivers/mmc/arm_pl180_mmci.h
> @@ -43,6 +43,7 @@
>  #define SDI_CLKCR_CLKEN		0x00000100
>  #define SDI_CLKCR_PWRSAV	0x00000200
>  #define SDI_CLKCR_BYPASS	0x00000400
> +#define SDI_CLKCR_HWFCEN	0x00001000
>  #define SDI_CLKCR_WIDBUS_MASK	0x00001800
>  #define SDI_CLKCR_WIDBUS_1	0x00000000
>  #define SDI_CLKCR_WIDBUS_4	0x00000800
>