Hi All, hope you are having a nice day! I'm not sure this this a proper place to ask this question. I tried to ask it on a specialized maillist (OSELAS.PHytec) with no luck - nobody answered. Mainly I'm interested in how to use XIP in practice rather than reading that somebody/somwhere/somewhen succeded in what I'm trying to do. I use Phycore i.MX31 and my task is to reduce the time required for booting Linux system. As one of the steps I'm trying to boot a xipImage (an uncompressed Linux kernel image for running directly from NOR memory). What I've reached is: uboot> boot ## Booting image at a0040000 ... Image Name: xip-0xA0040040 Image Type: ARM Linux Kernel Image (uncompressed) Data Size: 3418416 Bytes = 3.3 MB Load Address: a0040000 Entry Point: a0040040 Verifying Checksum ... OK XIP Kernel Image ... OK Starting kernel ... (it hangs up at this position) The kernel version is 2.6.19.2. The version of u-boot is 1.2.0 I think I'm doing something wrong. Therefore I'm gonna write in detail every my step I've done to boot the kernel hoping that someone can correct me. Default eeprom variables are: bootargs=console=ttymxc0,115200 mtdparts=mtdparts=phys_mapped_flash.0:128k(uboot)ro,128k(env),1792k(kernel),-(root) root=/dev /mtdblock3 rootfstype=jffs2 prg_kernel=tftpboot 0x80000000 $(uimage); erase 0xa0040000 +0x1C0000; cp.b 0x80000000 0xa0040000 $(filesize) The memory region starting at 0xA000_0000 is NOR. I've built the xipImage with the following command: make O=/usr/local/src/kernel/ xipImage ARCH=arm CROSS_COMPILE=arm-none-linux-gnueabi- and got: Kernel: arch/arm/boot/xipImage is ready (physical address: 0xa0040040) (note: it's 0xA004_0040. Id est the same area a compressed kernel resided in + 0x40. Why 0x40? See further). An experiment showed u-boot can't deal with raw images like xipImage. It needs to be wrapped by a u-boot header. This is where mkimage comes into action. An experiment showed that mkimage can't deal with raw xipImage either. Thus I looked at its sources to understand why. It checks the header of xipImage to see if there is enough space for the u-boot header. The sign of "free space" is sizeof(image_header_t) of 0xFF. Trying to make use of just generated xipImage leads to appearing the following message: printf(stderr, "%s: Bad file: \"%s\" has invalid buffer for XIP\n", cmdname, datafile); Thus I did the following: $ for i in `seq 1 64`; do echo -n -e "\377" >>xipheader;done to create a 64 byte length file named xipheader consisting of 0xFF. 64(0x40) is the size of image_header_t (in u-boot 1.2.0) $ cat xipheader xipImage-0xa0040040 >xip-0xA0040040 to combine the space reserved for u-boot header with xImage $ /usr/local/bin/mkimage -x -A arm -O linux -T kernel -C none -a 0xA0040000 -n "xip-0xA0040040" -d xip-0xA0040040 xip-0xA0040040.img Image Name: xip-0xA0040040 Created: Thu Apr 10 14:52:15 2008 Image Type: ARM Linux Kernel Image (uncompressed) Data Size: 3418416 Bytes = 3338.30 kB = 3.26 MB Load Address: 0xA0040000 Entry Point: 0xA0040040 Then I uploaded the newly created file xip-0xA0040040.img to the target host: uboot> tftpboot 0x80000000 xip-0xA0040040.img uboot> erase 0xa0040000 +0x342970 0x342970 is a size of xip-0xA0040040.img uboot> cp.b 0x80000000 0xa0040000 $(filesize) I know I've overwritten a part of the root file system (as an uncompressed kernel is larger than the previous compressed one) but it doesn't matter now as I can flash rootfs to a higher address once I managed to boot xipImage. Then I changed bootargs to console=ttymxc0,115200 mtdparts=mtdparts=phys_mapped_flash.0:128k(uboot)ro,128k(env),3340k(kernel),-(root) root=/dev /mtdblock3 rootfstype=jffs2 3340k is the size of xipImage (I rounded 3338.30k). and tried to boot the kernel. The result is in the beginning of the letter. What am doing wrong? I am not sure about Entry Point. Should it really be 0xA0040040? Sincerely Yours, Eugene Now it is safe to turn off your computer -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
