On 01/24/11 10:28, tiejun.chen wrote:
Elie De Brauwer wrote:
On 01/24/11 09:15, tiejun.chen wrote:
Elie De Brauwer wrote:
On 01/24/11 04:26, tiejun.chen wrote:
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.
This was already partitioned under (x86) Linux, and when I plug it into
I means you should partition the disk on the PPC Linux, not x86. As
you know x86
work with LE for Linux, but PPC with BE. So I think you should
partition that on
the same type machine. Can you try it?
my laptop it sees the MBR (but also on target, in U-boot, the mmc part 0
command shows the correct partition table). And this does not explain
I didn't check this implemented codes within u-boot. Maybe u-boot can do
something to swap MMC ending problem. You can try to get the
conclusion. Firstly
you can re-partition that on PPC Linux then check if u-boot can
identify it
properly. I guess u-boot still can read that successfully.
Unfortunately two wrongs don't make a right here. When I fdisk it on
target, then on target the partition gets detected, in u-boot it fails
(Unknown partition table). To be honest this was already the behavior
which I expected because the endianness swap was also seen for the card
registers. So I think something more fundamental is wrong (which in turn
smells like the "BIG_ENDIAN_32BIT_BYTE_SWAPPER" but this is used in a
very convincing way by the fsl-esdh driver...
As you said looks you can disable 'MMC_SDHCI_BIG_ENDIAN_32BIT_BYTE_SWAPPER' from
the Kconfig to rebuild Linux since its unnecessary for your target.
Well no, since this gets selected by the fsl-esdhc driver
config MMC_SDHCI_OF_ESDHC
bool "SDHCI OF support for the Freescale eSDHC controller"
depends on MMC_SDHCI_OF
select MMC_SDHCI_BIG_ENDIAN_32BIT_BYTE_SWAPPER
help
This selects the Freescale eSDHC controller support.
If unsure, say N.
And if you look in the sdhc-of.esdhc.c
(http://lxr.linux.no/#linux+v2.6.37/drivers/mmc/host/sdhci-of-esdhc.c#L75 )
you can see that this driver is very stubborn in using the sdhci_be32bs*
variants, so it just won't compile without the BYTE_SWAPPER set. But the
entire sdhci_esdhc struct looks odd (for example they do byteswapping
for the read_b but nog for the write_b, and it gets only done for the
{read|write}_l. I'll try using the 'regular' callbacks here instead of
the byteswapped versions.
Tiejun
why the card registers (such as the scr pasted below) also seem to have
their endianess swapped, which will result in other side-effects, such
as improper reading of card capabilities.
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@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=y
CONFIG_MMC_SDHCI_IO_ACCESSORS=y
CONFIG_MMC_SDHCI_BIG_ENDIAN_32BIT_BYTE_SWAPPER=y
# CONFIG_MMC_SDHCI_PCI is not set
CONFIG_MMC_SDHCI_OF=y
CONFIG_MMC_SDHCI_OF_ESDHC=y
At least looks the config is fine.
Tiejun
--
Elie De Brauwer
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