Pierre Savary wrote:
I use a MMCplus 4GB on my design (with at91sam9260). It's wired with 4 bits.
The MCI controller on the AT91SAM926x family does not support MMCplus. There is no way to support a 4 bit bus, since the MCI controller supports only 1 bit to an MMC chip. The MCI will support a 4 bit SD chip, but I don't think it can be tricked into working with a 4 bit MMC chip (at least not via software alone).
The only reasonable solution is switching to a processor that has MMCplus support. Maybe Atmel has been working on one?
Currently U-boot (1.1.5) can't detect correctly the MMC and so I can't read my Linux kernel Image on the ext3 part of this MMC. If I use MMC 1GB, it works.
Did you add MMCplus commands to the MCI U-Boot driver? You can do this to the extent that these changes do not require the MCI controller to be MMCplus compliant. (The MCI U-Boot driver I'm aware of contains no MMCplus support.)
I suggest that you use the u-boot sources available via git. You will get very little support (if any) from the U-Boot ML for two reasons:
1) U-Boot 1.1.5 is extremely old and no one on the list is interested in supporting it.
2) The version of U-Boot 1.1.5 you are using almost certainly has an Atmel patch applied to it that was never accepted into the "official" U-Boot tree.
However, ...
It appears that someone is working on the AT91SAM9260 within the official U-Boot (git) tree, since the ./include/configs/at91sam9260ek.h file is there. Other file structures like ./cpu/arm926ejs/* seem to be missing some drivers and other support files. I know that the AT91SAM926x specific U-Boot files were never an official part of U-Boot, but that appears to be changing. It is my understanding that the AT91SAM926x support is being completely reworked and integrated with the AT91CAP9 code that has been present in git for over a month already. The AT91CAP9 and AT91SAM926x are very similar and should share a lot of code.
Even if the AT91SAM9260 is not quite ready, the AT91CAP9 code should provide the basis of a current U-Boot for the AT91SAM926x family.
Somebody have already use it? Or somebody have already implemented the ext_csd and high capacity with MMC on another platform?
I know that the MCI controller can be used to access 1GB MMCplus chips, but I'm not sure it can be used to access MMCplus chips larger than that. There may be a special MMCplus command that will allow larger chips to be accessed. Try looking for it in your MMCplus chip's manual.
Sincerely,
Ken Fuchs
-----Original Message----- From: u-boot-users-bounces@lists.sourceforge.net [mailto:u-boot-users-bounces@lists.sourceforge.net] On Behalf Of Pierre Savary Sent: Tuesday, April 08, 2008 09:32 To: u-boot-users@lists.sourceforge.net Cc: 'Pierre Ossman' Subject: [U-Boot-Users] drivers MMCplus for at91sam9x
Hi, I use a MMCplus 4GB on my design (with at91sam9260). It's wired with 4 bits. Currently U-boot (1.1.5) can't detect correctly the MMC and so I can't read my Linux kernel Image on the ext3 part of this MMC. If I use MMC 1GB, it works. Somebody have already use it? Or somebody have already implemented the ext_csd and high capacity with MMC on another platform? I need help. Thanks in advance to help me.
Regards,
Pierre
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