I have Intel Atom based development board which has eMMC chip.
I can successfully boot Fedora 11 on this board from SATA drive.
However Fedora doesn't see this eMMC chip as external storage.
The "fdisk -lu" command doesn't show presence of any mmc device.

Can anyone advise how to start to troubleshoot this problem?

Thanks

Have you tried with a supported version of Fedora? Fedora 11 is no longer supported, and support for 12 will soon terminate.

The point is, older kernel releases may not include support for newer devices.

(Note that this is just a guess, since I have nothing with a eMMC chip in it, but using an unsupported distribution is, generally speaking, not a good thing.)

For some reasons I am limited to Fedora 11 for now. May be I should update MMC driver?

Here is part of boot log that might help to understand the problem:

Mar 10 12:46:03 localhost kernel: Registered led device: mmc0::
Mar 10 12:46:03 localhost kernel: mmc0: SDHCI controller on PCI [0000:02:04.0] using DMA
Mar 10 12:46:03 localhost kernel: sdhci-pci 0000:02:04.1: SDHCI controller found [8086:880a] (rev 1)
Mar 10 12:46:03 localhost kernel: sdhci-pci 0000:02:04.1: Invalid iomem size. You may experience problems.
Mar 10 12:46:03 localhost kernel: Registered led device: mmc1::
Mar 10 12:46:03 localhost kernel: mmc1: SDHCI controller on PCI [0000:02:04.1] using DMA
Mar 10 12:46:03 localhost kernel: mmc0: unrecognised EXT_CSD structure version 3
Mar 10 12:46:03 localhost kernel: mmc0: error -22 whilst initialising MMC card

What do the last two error messages mean?

Well, it looks to me like the first of those last two messages is telling you that the driver is using a structure that is either not defined in kernel you're using or is not the same size as that structure. The last line just tells you that the device was not initialized, and will not be available.

Note also the fourth line: "Invalid iomem size. You may experience problems." which tells you that the driver is not working correctly for the second mmc device. (The last digit of the pci address string shows that you have two mmc devices.)

I don't understand why you are "limited to Fedora 11." Since the Fedora update and support policies have been published for some time, nobody with any sense would develop any applications that depend on specific versions of Fedora. Upgrading should be trivial. In fact, the only Linux programs that, typically, need to be recompiled for a new distribution are programs, like device drivers, that are specific for a kernel release.

Keeping that in mind, I suspect that the eMMC driver you're using may be compiled for a newer version of the kernel than the version your Fedora 11 uses. Since the kernel's memory usage is incongruent with the driver's usage, you need to find a driver designed for use with your kernel. Perhaps it would be as simple as recompiling the driver using your kernel's headers.