Dear Bill, I'm CCing Fabio ... he might have some idea for you.
> Marek, > > Yes, I checked the kernel and it is enabled for ramdisk support in > Linux, gzip compression, and loop back block driver. I did find some > other posts where some folks added the address of the ram drive. So I > changed the kernel arguments from: > > setenv bootargs console=ttyAM0,115200n8 debug root=/dev/ram rw ip=dhcp > fec_mac= TO: > > setenv bootargs console=ttyAM0,115200n8 debug root=/dev/ram rw > initrd=0x43000000,40K ip=dhcp fec_mac= > > > And now the kernel output generates a additional error line from RAMDISK: > > ... > ... > ... > RAMDISK: Couldn't find valid RAM disk image starting at 0. <<<<<<<< This > line now appears on the console > List of all partitions: > b300 3872256 mmcblk0 driver: mmcblk > b301 1024 mmcblk0p1 > 0800 503808 sda driver: sd > 0801 503792 sda1 > No filesystem could mount root, tried: ext3 ext2 vfat msdos iso9660 > Kernel panic - not syncing: VFS: Unable to mount root fs on > unknown-block(1,0) > ... > ... > ... > > > Is it something with the RAM disk format or the uboot tool mkimage > parameters? > > Thanks, > Bill > > On 9/12/2012 6:44 PM, Marek Vasut wrote: > > Dear Bill, > > > >> I'm using U-boot version: U-Boot 2012.07 > >> > >> Through googling, I've come across several variations of using a > >> ramdisk. So I selected some things that looked good. So basically, I > >> > >> am building a rootfs as a ramdisk by: > >> dd if=/dev/zero of=./myinitrd.img bs=1M count=35 > >> mke2fs -m 1 ./myinitrd.img > >> mkdir ./myinitrd > >> mount -t ext2 ./myinitrd.img ./myinitrd -o loop > >> cp -r rootfs/* ./myinitrd/. > >> umount ./myinitrd/ > >> gzip ./myinitrd.img > >> rm -rf myinitrd > >> > >> Then I use the u-boot tool to prepare it for use with u-boot by: > >> u-boot-imx/tools/mkimage -n 'MyRamDisk' -A arm -O linux -T > >> > >> ramdisk -C none -d ./myinitrd.img.gz rootfs-initrd > >> > >> I place both both my uImage and rootfs-initrd on a USB stick and insert > >> > >> it into the imx28evk and enter u-boot command line. I then do: > >> usb start > >> fatload usb 0 0x42000000 uimage > >> fatload usb 0 0x43000000 rootfs-initrd > >> setenv bootargs console=ttyAM0,115200n8 debug root=/dev/ram rw > >> > >> ip=dhcp fec_mac= > >> > >> bootm 0x42000000 0x43000000 > >> > >> u-boot then starts booting with: > >> > >> ## Booting kernel from Legacy Image at 42000000 ... > >> > >> Image Name: Linux-2.6.35.3-571-gcca29a0-g45b > >> Created: 2012-09-08 22:31:46 UTC > >> Image Type: ARM Linux Kernel Image (uncompressed) > >> Data Size: 2582304 Bytes = 2.5 MiB > >> Load Address: 40008000 > >> Entry Point: 40008000 > >> Verifying Checksum ... OK > >> > >> ## Loading init Ramdisk from Legacy Image at 43000000 ... > >> > >> Image Name: MyRamDisk > >> Created: 2012-09-12 20:51:35 UTC > >> Image Type: ARM Linux RAMDisk Image (uncompressed) > >> Data Size: 37774 Bytes = 36.9 KiB > >> Load Address: 00000000 > >> Entry Point: 00000000 > >> Verifying Checksum ... OK > >> Loading Kernel Image ... OK > >> > >> OK > >> > >> Starting kernel ... > >> > >> Uncompressing Linux... done, booting the kernel. > >> Linux version 2.6.35.3-571-gcca29a0-g45b53d0-dirty (blsousan@ubuntu) > >> (gcc version 4.4.4 (4.4.4_09.06.2010) ) #13 PREEMPT Sat Sep 8 14:06:34 > >> PDT 2012 > >> CPU: ARM926EJ-S [41069265] revision 5 (ARMv5TEJ), cr=00053177 > >> CPU: VIVT data cache, VIVT instruction cache > >> Machine: Freescale MX28EVK board > >> .... > >> .... > >> .... > >> > >> The kernel starts to boot, I get all the kernel output, and at the end > >> it does not find the rootfs. I get: > >> > >> ... > >> ... > >> ... > >> > >> List of all partitions: > >> b300 3872256 mmcblk0 driver: mmcblk > >> > >> b301 1024 mmcblk0p1 > >> > >> 0800 503808 sda driver: sd > >> > >> 0801 503792 sda1 > >> > >> No filesystem could mount root, tried: ext3 ext2 vfat msdos iso9660 > >> Kernel panic - not syncing: VFS: Unable to mount root fs on > >> unknown-block(1,0) > >> Backtrace: > >> > >> > >> I not sure how the kernel knows where the ramdisk lives in memory ( > >> 0x43000000) where the the uboot put it ? > >> > >> > >> Thanks, > >> Bill > >> > >> On 9/12/2012 5:29 PM, Marek Vasut wrote: > >>> Dear Bill, > >>> > >>>> Has anyone used U-boot on the imx28evk with initrd to setup a small > >>>> rootfs in RAM? I need the ability to do have a small temp rootfs to > >>>> assist in mounting a full rootfs from a USB for field upgrade > >>>> purposes. > >>> > >>> Yes, it's a linux thingie though. What's the problem? What version of > >>> uboot do you use? > > > > Some ancient kernel you have ... did you enable ramdisk support in Linux? > > And gzip compression for it ? And loop back block driver ? > > > >>>> Thanks, > >>>> Bill > >>> > >>> Best regards, > >>> Marek Vasut > > > > Best regards, > > Marek Vasut _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
