EMAC- Preface Most of the black magic outlined in the file is no longer required thanks to the Cold-Boot distribution available here. Cold-Boot does not require a pre-loader, or flashing itself from a RAM copy on any such weirdness. Nevertheless, this document is included for historical reasons, and because it does give some useful documentation on using U-Boot. -NZG U-Boot for Motorola Coldfire M5272C3 and M5282EVB ================================================= Introduction ------------ U-Boot is a bootloader originaly invented for PowerPC based microcontrollers but has been also ported to ARM and MIPS platforms. This document describes howto get u-boot up and running for Motorola Coldfire. U-Boot offers the following key features: o Command line interface o Environment variables o Flash write access o TFTP download via Ethernet to RAM o Download over the serial line o Bootp/DHCP protocol for auto-configuration o Scripting facilities o Booting compressed kernels o Booting kernel from a JFFS2 partition Status ------ In the current incarnation of the Coldfire version of the U-Boot loader, there is only support for the Motorola M5272C3 and M5282EVB evaluation boards. It works out quite good for me, but YMMV. GDB-BDM Installation -------------------- In order to be able to deploy U-Boot on your board, you first need to get the BDM interface cable working with gdb. Download gdb and the bdm patch and place them into a convenient loacation: export ARCHIVE=/tmp/downloads install -d $ARCHIVE wget -c ftp://ftp.gnu.org/gnu/gdb/gdb-5.2.1.tar.gz wget -c ftp://www.cybertec.com.au/pub/bdm/src/gdb-5.2.1.patch wget -c ftp://www.cybertec.com.au/pub/bdm/src/gdb-bdm-20020210.tar.gz cp gdb-5.2.1.tar.gz $ARCHIVE cp gdb-5.2.1.patch $ARCHIVE cp gdb-bdm-20020210.tar.gz $ARCHIVE Unpack and patch gdb: cd /usr/local/src/ tar -xzf $ARCHIVE/gdb-5.2.1.tar.gz cd gdb-5.2.1/ patch -p1 < $ARCHIVE/gdb-5.2.1.patch Install the kernel driver for the BDM interface cd /usr/local/src/ tar -xzf $ARCHIVE/gdb-bdm-20020210.tar.gz cd gdb-bdm-20020210/driver/linux/ make install -d /lib/modules/`uname -r`/misc/ cp linux-bdm.o /lib/modules/`uname -r`/misc/bdm.o depmod -a Create the device BDM node and add an appropriate entry to the module configuration files: mknod /dev/bdmcf0 c 34 4 chmod a+rw /dev/bdmcf0 echo "alias char-major-34 bdm" >> /etc/modules.conf Please note that if you are using an M5282EVB, then you need to modify the gdb-bdm-20020210/driver/bdm.c in line 1230: 0xc04, /* BDM_REG_RAMBAR */ Change this line to: 0xc05, /* BDM_REG_RAMBAR */ Background: RAMBAR is used for the internal flash of the MCF5282 and a new register was invented for the periperials associated with a different register number. Finally compile and install the bdm enhanced gdb: cd /usr/local/src/gdb-bdm-20020210 ../gdb-5.2.1/configure --target=m68k-bdm-elf make strip -g gdb/gdb cp gdb/gdb /usr/local/bin/m68k-bdm-elf-gdb Compilation and Installation ---------------------------- Compilatino and Installation are very similar for M5272C3 and M5282EVB, but to make things easier to understand, there are seperate chapters for each of the boards. Compilation and Installation for Motorola M5272C3 ------------------------------------------------ It is assumed that you have an uClinux m68k-elf toolchain in order to be able to cross compile the bootloader. 1) Download U-Boot and the patch for Coldfire: export ARCHIVE=/tmp/downloads install -d $ARCHIVE wget -c http://twtelecom.dl.sourceforge.net/sourceforge/u-boot/u-boot-0.4.0.tar.bz2 wget -c http://www.uclinux.org/~bkuhn/Platforms/Coldfire/tarifa/20030707/patch-u-boot-0.4.0-mcf-20030707.bz2 cp u-boot-0.4.0.tar.bz2 $ARCHIVE cp patch-u-boot-0.4.0-mcf-20030707.bz2 $ARCHIVE 2) Unpack the sources and apply the patch tar -xjf $ARCHIVE/u-boot-0.4.0.tar.bz2 cd u-boot-0.4.0/ bunzip2 -cd $ARCHIVE/patch-u-boot-0.4.0-mcf-20030707.bz2 | patch -p1 3) Configure for Motorola Coldfire MCF5272C3 evaluation board make M5272C3_config 4) Compile U-Boot make 5) Compile the pre-loader and generate a flashable image cd pre/coldfire/M5272C3/loader make cp loader.bin /tftpboot 6) Compile a board initialization file for the BDM interface cd ../../../../utils/coldfire/M5272C3/bdm/boardinit make 7) Load U-Boot to target RAM through the BDM cable cd .. sh load The following output should appear on the shell: GNU gdb 5.2.1 Copyright 2002 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "--host=i686-pc-linux-gnu --target=m68k-bdm-elf"... Coldfire debug module version is 0 (5206(e)) Program received signal SIGTRAP, Trace/breakpoint trap. 0x200004a4 in ?? () 1: x/i $pc 0x200004a4: halt and after a few seconds, U-Boot should come up on the seriel console (19200,8,N,1): U-Boot 0.4.0 (Jul 3 2003 - 19:55:38) CPU: MOTOROLA Coldfire MCF5272 Board: MOTOROLA MCF5272C3 Evaluation Board DRAM: 4 MB FLASH: 2 MB *** Warning - bad CRC, using default environment MCF5272C3> 8. Just to be sure, delete the whole flash: protect off ffe00000 ffffffff erase ffe00000 ffffffff If unsure what should actually happen, here is a sample console output: MCF5272C3> protect off ffe00000 ffffffff Un-Protected 11 sectors MCF5272C3> erase ffe00000 ffffffff Erase Flash from 0xffe00000 to 0xffffffff Erasing sector 0 ... ok. Erasing sector 1 ... ok. Erasing sector 2 ... ok. ... Erasing sector 10 ... ok. Erased 11 sectors MCF5272C3> When the flash has been erased, re-invoke U-Boot through the BDM cable: goto the shell where you have have "sh load", press "CTRL+C", type 'q' and 'Enter'. Re-start U-Boot bye typing "sh load" again. 9. Configure U-Boot and install the bootloader Type the following commands on the seriel console: setenv ethaddr 00:cf:52:72:c3:01 setenv ipaddr 192.168.1.60 setenv serverip 192.168.1.1 tftp 20000 /tftpboot/loader.bin protect off ffe00000 ffe3ffff erase ffe00000 ffe3ffff cp.b 20000 ffe00000 10000 saveenv If unsure what should actually happen, here is a sample console output: MCF5272C3> setenv ethaddr 00:cf:52:72:c3:01 MCF5272C3> setenv ipaddr 192.168.1.60 MCF5272C3> setenv serverip 192.168.1.1 MCF5272C3> tftp 20000 /tftpboot/loader.bin TFTP from server 192.168.1.1; our IP address is 192.168.1.60 Filename '/tftpboot/loader.bin'. Load address: 0x20000 Loading: ############# done Bytes transferred = 65536 (10000 hex) MCF5272C3> protect off ffe00000 ffffffff Un-Protected 11 sectors MCF5272C3> cp.b 20000 ffe00000 10000 Copy to Flash... done MCF5272C3> saveenv Saving Environment to Flash... Un-Protected 1 sectors Erasing Flash... Erasing sector 1 ... ok. Erased 1 sectors Writing to Flash... done Protected 1 sectors MCF5272C3> Congratulations, you are done! Here are some additional environment variables that allows you to boot Linux via NFSroot: setenv bootcmd tftp 20000 /tftpboot/image.bin \; go 20000 setenv bootargs root=/dev/nfs rw ip=192.168.1.60:192.168.1.1::::eth0:off setenv bootdelay 2 setenv ptable env,2,4:kernel,c0,40:filesystem,100,100 saveenv Compilation and Insatllation for Motorola M5272EVB -------------------------------------------------- It is assumed that you have an uClinux m68k-elf toolchain in order to be able to cross compile the bootloader. 1) Download U-Boot and the patch for Coldfire: export ARCHIVE=/tmp/downloads install -d $ARCHIVE wget -c http://twtelecom.dl.sourceforge.net/sourceforge/u-boot/u-boot-0.4.0.tar.bz2 wget -c http://www.uclinux.org/~bkuhn/Platforms/Coldfire/tarifa/20030707/patch-u-boot-0.4.0-mcf-20030707.bz2 cp u-boot-0.4.0.tar.bz2 $ARCHIVE cp patch-u-boot-0.4.0-mcf-20030707.bz2 $ARCHIVE 2) Unpack the sources and apply the patch tar -xjf $ARCHIVE/u-boot-0.4.0.tar.bz2 bunzip2 -cd $ARCHIVE/patch-u-boot-0.4.0-mcf-20030707.bz2 | patch -p1 3) Configure for Motorola Coldfire M5272EVB evaluation board make M5282EVB_config 4) Compile U-Boot make 5) Compile the pre-loader and generate a flashable image cd pre/coldfire/M5282EVB/loader make cp loader.bin /tftpboot 6) Compile a board initialization file for the BDM interface cd ../../../../utils/coldfire/M5282EVB/bdm/boardinit make 7) Load U-Boot to target RAM through the BDM cable cd .. sh load The following output should appear on the shell: GNU gdb 5.2.1 Copyright 2002 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "--host=i686-pc-linux-gnu --target=m68k-bdm-elf"... Coldfire debug module version is 0 (5206(e)) Program received signal SIGTRAP, Trace/breakpoint trap. 0x200004a4 in ?? () 1: x/i $pc 0x200004a4: halt and after a few seconds, U-Boot should come up on the seriel console (19200,8,N,1): U-Boot 0.4.0 (Jul 7 2003 - 02:20:28) CPU: MOTOROLA Coldfire MCF5282 Board: MOTOROLA M5272EVB Evaluation Board DRAM: 16 MB FLASH: 2 MB *** Warning - bad CRC, using default environment M5282EVB> 8. Just to be sure, delete the whole flash: protect off ffe00000 ffffffff erase ffe00000 ffffffff If unsure what should actually happen, here is a sample console output: M5282EVB> protect off ffe00000 ffffffff Un-Protected 35 sectors M5282EVB> erase ffe00000 ffffffff Erase Flash from 0xffe00000 to 0xffffffff Erasing sector 0 ... ok. Erasing sector 1 ... ok. Erasing sector 2 ... ok. ... Erasing sector 34 ... ok Erased 35 sectors M5282EVB> When the flash has been erased, re-invoke U-Boot through the BDM cable: goto the shell where you have have "sh load", press "CTRL+C", type 'q' and 'Enter'. Re-start U-Boot bye typing "sh load" again. 9. Configure U-Boot and install the bootloader Type the following commands on the seriel console: setenv ethaddr 00:cf:52:82:eb:01 setenv ipaddr 192.168.1.60 setenv serverip 192.168.1.1 tftp 10000 /tftpboot/loader.bin protect off ffe00000 ffe0ffff erase ffe00000 ffe0ffff cp.b 10000 ffe00000 10000 saveenv If unsure what should actually happen, here is a sample console output: M5282EVB> setenv ethaddr 00:cf:52:82:eb:01 M5282EVB> setenv ipaddr 192.168.1.60 M5282EVB> setenv serverip 192.168.1.1 M5282EVB> tftp 10000 /tftpboot/loader.bin TFTP from server 192.168.1.1; our IP address is 192.168.1.60 Filename '/tftpboot/loader.bin'. Load address: 0x10000 Loading: ############# done Bytes transferred = 65536 (10000 hex) M5282EVB> protect off ffe00000 ffe0ffff Un-Protected 4 sectors M5282EVB> erase ffe00000 ffe0ffff Erase Flash from 0xffe00000 to 0xffe0ffff Erasing sector 0 ... ok. Erasing sector 1 ... ok. Erasing sector 2 ... ok. Erasing sector 3 ... ok. Erased 4 sectors M5282EVB> cp.b 10000 ffe00000 10000 Copy to Flash... done M5282EVB> saveenv Saving Environment to Flash... Un-Protected 1 sectors Erasing Flash... Erasing sector 1 ... ok. Erased 1 sectors Writing to Flash... done Protected 1 sectors M5282EVB> TFTP downloading and starting a linux kernel image -------------------------------------------------- First, copy an appropriate kernel+romfs image to /tftpboot on your development host. Then download and start the image. Note that the default download loaction is 0x20000 to be compliant with the start address of the current uClinux kernel that is optimized for the dBUG bootloader. Use the "loadaddr" environment variable to override this setting. The filename is determined by the "bootfile" environment variable. Both, location and filename can also be given on the command line MCF5272C3> tftp 20000 image.bin Or just type "tftp" if "bootfile" is set properly. The response from the bootloader should look like this: TFTP from server 192.168.1.1; our IP address is 192.168.1.9 Filename 'image.bin'. Load address: 0x20000 Loading: ################################################################# ################################################################# ################################################################# ################################################# done Bytes transferred = 1247760 (130a10 hex) Now start the image: MCF5272C3> go 20000 Flashing a kernel image ----------------------- First, you have to generate a "pkg"-file that U-Boot can understand. This pkg file consists of the (compressed) image and a prepended header containing information such as load and start addresses. The tool to generate such a file is "mkimage" and can be found in u-boot/0.4.0/tools after compilation of the ppcboot image. Copy mkimge to i.e. /usr/local/bin or to somewhere else in your executable search path, and then perform the following commands: cd /tftpboot gzip image.bin mkimage -O linux -T kernel -C gzip -a 0x20000 -e 0x20000 \ -d image.bin.gz image.pkg gunzip image.bin.gz The output of mkimage should look like this: Image Name: Created: Sat May 25 15:52:13 2002 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 547665 Bytes = 534.83 kB = 0.52 MB Load Address: 0x00020000 Entry Point: 0x00020000 Don't be bothered that "Image Type" tells "PowerPC Linux Kernel Image" :-) Now download the package and flash it: MCF5272C3> tftp 20000 image.pkg [ ARP broadcast 1 TFTP from server 192.168.1.1; our IP address is 192.168.1.9 Filename 'image.pkg'. Load address: 0x20000 Loading: ############################################################## ########################################## done Bytes transferred = 547729 (85b91 hex) ] MCF5272C3> erase ffe40000 ffefffff [ Erase Flash from 0xffe40000 to 0xffefffff Erasing sector 4 ... ok. Erasing sector 5 ... ok. Erasing sector 6 ... ok. Erased 3 sectors ] MCF5272C3> cp.b 20000 ffe40000 $(filesize) [ Copy to Flash... done ] You may now try out the "iminfo" command to get some information about the flashed package: MCF5272C3> iminfo ffe40000 The output should look like this: ## Checking Image at ffe40000 ... Image Name: Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 547665 Bytes = 534 kB = 0 MB Load Address: 00020000 Entry Point: 00020000 Verifying Checksum ... OK Start the image with the "bootm" command: MCF5272C3> bootm ffe40000 In order to make the image auto-bootable, you will have to set two more environment variables: MCF5272C3> setenv bootcmd bootm ffe40000 MCF5272C3> setenv bootdelay 3 MCF5272C3> saveenv WARNING: if "bootdelay" is not set or set to "0", then the system will start immediatly after reset and the user won't have a chance to interrupt the boot process. To recover from that situation, you will have to compile ppcboot with CFG_ENV_ADDR set to i.e. 0xffe40000 (refer to include/config_M5272C3.h), so that ppcboot won't find the valid environment variables suitable for autoboot. After downloading the bootloader, using the BDM interface cable, erase the flash block containing the environment variables: MCF5272C3> protect off ffe04000 ffe05fff MCF5272C3> erase ffe04000 ffe05fff After reset, the bootloader should be again accessable by the user User Address Range ------------------ The user may access the SDRAM ranging from 0x400 to 0x37ffff for his/her own application. The area below 0x400 (1 KiB) is reserved for exception vectors and the last 512 KiB are reserved for U-Boot. Once a kernel image has been started, the it certainly may feel free to use the whole 4 MiB. You espcialy don't have to modify any dBUG compliant images to limit them to 3.5 MiB. The last 512 KiB are only reserved for U-Boot during it's operation, i.e. it's not allowed to do something like this: tftp 380000 image.bin This, for instance, would corrupt the ethernet send/receive buffers. tftp 0 kernel.bin May work, but if an exception happens during download, then the system may not recover from it. The Flash may be accessed from 0xffe40000 to 0xffffffff. However, the bootloader only needs 64 KiB, but the address range from 0xffe10000 to 0xffe3ffff cannot be accessed without affecting the bootloader stored in flash (see section "Memory Layout (Flash)" below for more details). In order to save 196 KiB of flash memory, you may attach the pkg file to the ppcboot binary and store the whole thing at once, i.e.: cd /tftpboot cat loader.bin image.pkg > flash.img On the target, type: MCF5272C3> protect off ffe00000 ffe3ffff MCF5272C3> tftp 20000 flash.img MCF5272C3> erase ffe00000 ffefffff MCF5272C3> cp.b 20000 ffe00000 $(filesize) MCF5272C3> setenv bootcmd bootm ffe10000 MCF5272C3> setenv bootdelay 3 MCF5272C3> saveenv WARNING: This method affects the bootloader stored in flash. If you have a power outage (or other problems) during flashing, then you may need a BDM interface cable to recover the system (Type "bdm/load" in the ppcboot toplevel directory after compiling the sources to download the U-Boot loader). Memory Layout ------------- There are Two memory layouts: one for the first stage bootlader (COLILO) and one for the second stage bootloader (U-Boot). COLILO operation mode Exception Vectors 0x00000000 - 0x000003ff Data, BSS and Heap 0x00000400 - 0x000fffff Unused 0x00100000 - 0x0037ffff U-Boot 0x00380000 - 0x003fffff Stack (Built-in SRAM) 0x20000000 - 0x20003fff Code 0xffe00000 - 0xffe04000 Reserved 0xffe10000 - 0xffffffff U-Boot operation mode Exception Vectors 0x00000000 - 0x000003ff User RAM 0x00000400 - 0x0037ffff Ethernet Buffers 0x00380000 - 0x00384000 Stack 0x00384000 - 0x003bffff Code, Data, BSS 0x003e0000 - 0x003fffff COLILO 0xffe00000 - 0xffe04000 Environment variables 0xffe04000 - 0xffe05fff U-Boot 0xffe06000 - 0xffe0ffff Reserved 0xffe10000 - 0xffe3ffff User Flash 0xffe40000 - 0xffffffff Unforntuatly, the AM29PL160CB provided on the MCF5272C3 evaluation board has a very bad flash block arrangement with respect to U-Boot and Linux: although U-Boot fits into 64 KiB, you will always need 256 KiB, because U-Boot overlaps flash blocks 2 and 3 (flash blocks 0 to 3 sizes: 16/8/8/224 KiB). One trick certainly would be to prepend a U-Boot image to the kernel that is stored starting at flash block 3 (see section "User Address Ranges" above for more details). Recovering dBUG --------------- If you don't like U-Boot, you may recover dBUG with the following command sequence on U-Boot: MCF5272C3> protect off ffe00000 ffe3ffff MCF5272C3> erase ffe00000 ffe3ffff MCF5272C3> tftp 20000 dBUG.bin MCF5272C3> cp.b 20000 ffe00000 $(filesize) An appropriate dBUG binary suitable for the MCF5272C3 Evaluation Board may be found at: http://home.t-online.de/home/Bernhard_Kuhn/uclinux/Platforms/Coldfire/tarifa/20011119/images/boot_cramfs/dBUG/ (No) Warranty ------------- I certainly cannot provide any warranties. Although this document was put together with best intensions, i cannot be held responsible for any demage (physicaly or mentaly) that may result by following the instructions given above. Thanks ------ Many thanks to Wolfgang Denk for providing and maintaining U-Boot. Bernhard Kuhn, Senior Software Engineerer, Metrowerks. Mon Jul 7 03:22:07 CEST 2003