| How to use ARC U-BOOT |
| |
| Configuring u-boot |
| ================== |
| |
| See the file include/configs/arcangel_arc700_ram.h |
| |
| Right near the top of the file you'll see an include of config_cmd_default |
| this causes the build to include all the u-boot default commands. |
| The following lines either add to or subtract from that configuration. |
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| |
| |
| Building u-boot |
| ================ |
| |
| For a RAM based build : |
| |
| $ make arcangel_arc700_ram_config |
| $ make |
| |
| The resulting u-boot ELF file can be loaded with a suitable debugger / loader |
| |
| To make a flash based image you'll need to edit the linker script and locate the image |
| correctly for your memory layout. |
| |
| Look in board/arcangel/u-boot.lds for a working example. |
| |
| |
| |
| Booting large files. |
| ==================== |
| |
| u-boot by default starts at TEXT_BASE specified in board/arcangel/config.mk |
| which which is mapped to 0x80000000 + TEXT_BASE in the memory (in untranslated |
| space). u-boot uses memory region from TEXT_BASE - CONFIG_SYS_MALLOC_LEN to |
| TEXT_BASE for malloc. |
| |
| When an image is loaded (either via network or IDE), the address where the image |
| is loaded is specified in the boot command and its elf header specifies the |
| address where the image has to be copied to. You should make sure that their is |
| no overlap of u-boot image with the memory where image it is loaded to and with |
| the memory where it is copied to. |
| |
| By default TEXT_BASE is 0x3000000 and CONFIG_SYS_MALLOC_LEN is 0x8000. If |
| 0x4000000 is specified as load address and the image is copied to 0x80000000, |
| then you will clobber the loader code if the image size is bigger than |
| 47.96875MB, which is TEXT_BASE - CONFIG_SYS_MALLOC_LEN. |
| |
| You have to modify TEXT_BASE in board/arcangel/config.mk to avoid the overlaps |
| or to change uboot starting address. |
| |
| Network booting |
| =============== |
| |
| For TFTP boot the following has been tested. |
| |
| ArcAngel4 # tftpboot 0x4000000 vmlinux |
| Using ARC EMAC device |
| TFTP from server 172.16.18.73; our IP address is 172.16.18.98 |
| Filename 'vmlinux'. |
| Load address: 0x4000000 |
| Loading: ################################################################# |
| ################################################################# |
| ################################################################# |
| ##################### |
| done |
| Bytes transferred = 3170437 (306085 hex) |
| ArcAngel4 # |
| ArcAngel4 # bootelf |
| Loading .vector @ 0x80000000 (504 bytes) |
| Loading .init @ 0x80002000 (73728 bytes) |
| Loading .text @ 0x80014000 (2016384 bytes) |
| Loading __ksymtab @ 0x80201000 (14408 bytes) |
| Loading __ksymtab_gpl @ 0x80204848 (2808 bytes) |
| Loading __ksymtab_strings @ 0x80205340 (38956 bytes) |
| Loading __param @ 0x8020eb6c (400 bytes) |
| Loading .data @ 0x80210000 (76728 bytes) |
| Clearing .bss @ 0x80224000 (97576 bytes) |
| copying linux command line into BSS: arcclk=65 |
| Loading .init.ramfs @ 0x8023c000 (133 bytes) |
| ## Starting application at 0x80002000 ... |
| EMAC : RESET |
| LXT970A : RESET |
| Linux version 2.6.19-04142008 (simonrs@jasper) (gcc version 4.2.1 (ARC_2.0)) #3 PREEMPT Mon Jun 9 12:17:34 PDT 2008 |
| Parsing ATAG parameters |
| |
| etc. |
| |
| NFS Booting has also been tested. |
| |
| # ArcAngel4 # nfs 0x4000000 172.16.18.73:/shared/simons_aa4/simon/vmlinux |
| |
| ARC Angel 4 IDE Booting. |
| ======================== |
| |
| Although highly dependent on ARC Angel 4 hardware the u-boot port also supports |
| booting from an IDE disk. This will likely form the basis of your own loader should |
| you wish to support booting from an IDE type disk (flash card etc) |
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