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

[Ahmad Fatoum]

Hello Sascha,

On 04.10.21 12:56, Sascha Hauer wrote:
> 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 at 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.

This has been tested on both SD and eMMC cards.
In SD case, esdhc_send_cmd will fail and esdhc_bootpart_active will
return false. In MMC case, it will succeed and result will be
evaluated.

> 
> Sascha
> 


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