Re: [PATCH] mmc: sdhci-esdhc-imx: Enable boot partition access from DT

Jean-Michel Hautbois
2014-09-04T09:37:20Z

Hi Ulf,

> I am not sure adding a DT binding for non access to rpmb would be
> needed. At least until we heard of a similar case as Adrian describes
> but for rpmb.
>
> BTW, I just posted a patch which disabled partition scan of the boot
> area, what to you think about that?
> http://marc.info/?l=linux-mmc&m=140973496402028&w=2
>
> Finally I am also wondering whether we could and thus should, handle
> these situations entirely without using a host cap. In principle what
> we need is a more sophisticated error handling when the switch errors
> occurs, while trying to switch to the boot area/rpmb partitions. Could
> you maybe investigate that option, before we decide to add a new DT
> binding?

According to me and what Hsin-Hsiang Tseng wrote, it seems that we
should be able to have access to boot partitions if we want to give a
possibility of writing u-boot in one (or both) of them. This is the
way the i.MX6 will boot on a eMMC if I read the reference manual
correctly, but I didn't tested it yet.
But there is no need to scan those partitions at boot, as there will
probably never be a partition table inside, as you said.
All we need is providing access to mmc[n]blkpboot0 and mmc[n]blkpboot1
and a way to tell which one is used as default boot partition.

This is my point of view, but I didn't read JESD84-A441 so I don't
know if this is the good way.

Regards,
JM