Re: [PATCH v2 2/3] mci: imx-esdhc-pbl: support eMMC boot partitions on i.MX8MP

[Sascha Hauer <sha@pengutronix.de>]

On Mon, Aug 30, 2021 at 01:51:55PM +0200, Ahmad Fatoum wrote:
> The i.MX header for SD/MMC starts at an offset to allow for a partition
> table at offset 0. i.MX8MN/P bootrom did away with the offset for eMMC
> boot partitions, which usually lack on-disk partition tables, but kept a
> 32-byte offset for SD and eMMC user partitions.
> 
> The i.MX8MN/P also introduced a ROM API that allows chainloading from
> boot medium by calling back into ROM. This likely handles that
> difference for us, but as we don't support it yet and we already have
> the PBL eSDHC driver, teach it to detect whether boot is from eMMC boot
> partition or not and use the appropriate offset.
> 
> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> ---
> v1 -> v2:
>   - new patch. Without, barebox can be written, but not booted.
>     Tested on i.MX8MN.
> ---
>  drivers/mci/imx-esdhc-pbl.c | 39 ++++++++++++++++++++++++++++++++++++-
>  1 file changed, 38 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mci/imx-esdhc-pbl.c b/drivers/mci/imx-esdhc-pbl.c
> index e649eb8bbafb..66df4f6dfc74 100644
> --- a/drivers/mci/imx-esdhc-pbl.c
> +++ b/drivers/mci/imx-esdhc-pbl.c
> @@ -25,6 +25,40 @@
>  
>  #define esdhc_send_cmd	__esdhc_send_cmd
>  
> +static u8 ext_csd[512] __aligned(64);
> +
> +static int esdhc_send_ext_csd(struct fsl_esdhc_host *host)
> +{
> +	struct mci_cmd cmd;
> +	struct mci_data data;
> +
> +	cmd.cmdidx = MMC_CMD_SEND_EXT_CSD;
> +	cmd.cmdarg = 0;
> +	cmd.resp_type = MMC_RSP_R1;
> +
> +	data.dest = ext_csd;
> +	data.blocks = 1;
> +	data.blocksize = sizeof(ext_csd);
> +	data.flags = MMC_DATA_READ;
> +
> +	return esdhc_send_cmd(host, &cmd, &data);
> +}

Is this operation valid for SD cards as well? If not we would first have
to know if we have a SD or eMMC card.

Sascha

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