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

Jean-Michel Hautbois
2014-09-04T10:33:36Z

2014-09-04 11:37 GMT+02:00 Jean-Michel Hautbois
<jean-michel.hautbois@vodalys.com>:
> 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

BTW, here is an interesting commit from Freescale tree :
http://git.freescale.com/git/cgit.cgi/imx/linux-2.6-imx.git/commit/?h=imx_3.10.17_1.0.0_ga&id=28774b788ae0de5d88045dd60cac3656c305821d

JM