Re: RAMDISK on EP88xc

Mikhail Zaturenskiy wrote:

On Thu, Jul 2, 2009 at 2:10 AM, Frank
Svendsbøe[off-list ref] wrote:

quoted

On Wed, Jul 1, 2009 at 10:14 PM, Mikhail
Zaturenskiy[off-list ref] wrote:
Hmm... according to "Kernel command line: console=ttyCPM0,9600n8
loglevel=7" you haven't
specified where root is. Add root=/dev/ram to the kernel command line,
and specify where the
init process is located (for instance init=/sbin/init).

I haven't tried Denks ramdisk image. You can create one for yourself
using dd, gzip and U-Boots
mkimage tool. If the ramdisk image is larger than 4MB, you must either
change the default
CONFIG_BLK_DEV_RAM_SIZE=4096, or set ramdisk size in the kernel command line.

Btw, I use an older kernel than you use, but I have these defined:
CONFIG_BLK_DEV=y
CONFIG_BLK_DEV_LOOP=y
CONFIG_BLK_DEV_RAM=y
CONFIG_BLK_DEV_RAM_COUNT=16
CONFIG_BLK_DEV_RAM_SIZE=4096

Maybe they're obsolete now, but you can try to add them to your defconfig file.

Good luck ;-)

Thanks Frank, this seems to be leading me down the right path. I tried
some of those defines out yesterday and they got the kernel to at
least attempt to load the ramdisk, so I'm getting somewhere. Also
added root=/dev/ram (also tried /dev/ram0) and init=/sbin/init but for
now things are failing before processing those args.

I haven't tried CONFIG_BLK_DEV or CONFIG_BLK_DEV_LOOP and am still
playing around with the values for CONFIG_BLK_DEV_RAM_COUNT and
CONFIG_BLK_DEV_RAM_SIZE. Strangely, the DEV_RAM defines are completely
missing from my config so I have to put them in manually... (as
opposed to via menuconfig). I'll post back when it's working or when
I've tried all of this and still am getting some error.

If you don't have CONFIG_BLK_DEV defined, you can't have CONFIG_BLK_DEV_RAM_COUNT
or CONFIG_BLK_DEV_RAM_SIZE.  Use 'menuconfig' to help straighten this out.

Meanwhile a side question - why does BLK_DEV_RAM_COUNT default to 16?

This is just the number of unique RAM disk devices supported.

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Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
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