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Date:   Thu, 16 Jul 2020 18:13:58 +0200
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     Ulf Hansson <ulf.hansson@linaro.org>
Cc:     linux-mmc@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
        Arnd Bergmann <arnd@arndb.de>,
        Rui Feng <rui_feng@realsil.com.cn>,
        linux-nvme@lists.infradead.org, linux-pci@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Adrian Hunter <adrian.hunter@intel.com>
Subject: Re: [PATCH] mmc: core: Initial support for SD express card/host
Message-ID: <20200716161358.GA3135454@kroah.com>
References: <20200716141534.30241-1-ulf.hansson@linaro.org>
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On Thu, Jul 16, 2020 at 04:15:34PM +0200, Ulf Hansson wrote:
> +int mmc_send_if_cond_pcie(struct mmc_host *host, u32 ocr)
> +{
> +	u32 resp = 0;
> +	u8 pcie_bits = 0;
> +	int ret;
> +
> +	if (host->caps2 & MMC_CAP2_SD_EXP) {
> +		/* Probe card for SD express support via PCIe. */
> +		pcie_bits = 0x10;
> +		if (host->caps2 & MMC_CAP2_SD_EXP_1_2V)
> +			/* Probe also for 1.2V support. */
> +			pcie_bits = 0x30;
> +	}
> +
> +	ret = __mmc_send_if_cond(host, ocr, pcie_bits, &resp);
> +	if (ret)
> +		return 0;
> +
> +	/* Continue with the SD express init, if the card supports it. */
> +	resp &= 0x3000;
> +	if (pcie_bits && resp) {
> +		if (resp == 0x3000)

0x3000 should be some defined value, right?  Otherwise it just looks
like magic bits :)

> --- a/include/linux/mmc/host.h
> +++ b/include/linux/mmc/host.h
> @@ -60,6 +60,8 @@ struct mmc_ios {
>  #define MMC_TIMING_MMC_DDR52	8
>  #define MMC_TIMING_MMC_HS200	9
>  #define MMC_TIMING_MMC_HS400	10
> +#define MMC_TIMING_SD_EXP	11
> +#define MMC_TIMING_SD_EXP_1_2V	12
>  
>  	unsigned char	signal_voltage;		/* signalling voltage (1.8V or 3.3V) */
>  
> @@ -172,6 +174,9 @@ struct mmc_host_ops {
>  	 */
>  	int	(*multi_io_quirk)(struct mmc_card *card,
>  				  unsigned int direction, int blk_size);
> +
> +	/* Initialize an SD express card, mandatory for MMC_CAP2_SD_EXP. */
> +	int	(*init_sd_express)(struct mmc_host *host, struct mmc_ios *ios);
>  };
>  
>  struct mmc_cqe_ops {
> @@ -357,6 +362,8 @@ struct mmc_host {
>  #define MMC_CAP2_HS200_1_2V_SDR	(1 << 6)        /* can support */
>  #define MMC_CAP2_HS200		(MMC_CAP2_HS200_1_8V_SDR | \
>  				 MMC_CAP2_HS200_1_2V_SDR)
> +#define MMC_CAP2_SD_EXP		(1 << 7)	/* SD express via PCIe */

BIT(7)?

> +#define MMC_CAP2_SD_EXP_1_2V	(1 << 8)	/* SD express 1.2V */

BIT(8)?

thanks,

greg k-h