fsl-esdhc on P2020 weird endianess behavior

tiejun.chen tiejun.chen at windriver.com
Mon Jan 24 14:26:16 EST 2011

Elie De Brauwer wrote:
> Hello list,
> I have a P2020 processor on a custom board which uses the embedded
> fsl-esdhc controller. Hardware-wise this is functional and in u-boot
> everything seems to behave (mmc part 0 gives the correct partition table
> and ext2ls/fatls are capable of reading the contents of the sd card).
> However as soon as I start Linux (2.6.36), I get all sorts of unwanted
> behavior. Linux is unable to detect the partition layout (but if I do a

Can you re-partition that under Linux? i.e, you can use fdisk to do this. Then
I'm a bit curious what it'll be happened.

> hexdump of the MBR, I see the endianness is swapped (last 4 bytes are aa
> 55 00 00). Also when I try to obtain the card registers they show the
> same behavior:
> # cat ./devices/soc.0/ff72e000.sdhci/mmc_host/mmc0/mmc0:0001/scr
> 0000b50200000000
> While for comparison the same value on my (x86) laptop gives:
> edb at lapedb:/sys/devices/pci0000:00/0000:00:1e.0/0000:15:00.2/mmc_host/mmc0/mmc0:0001$
> cat scr
> 02b5000000000000
> In my config I have the following set:
> # CONFIG_MMC_SDHCI_PCI is not set

At least looks the config is fine.


> any pointers are welcome.
> gr
> E.

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