| To make relocation on arm working, the following changes are done: |
| |
| Add new compilerflag: |
| |
| -fPIC |
| |
| -> compiler generates position independent code |
| |
| changes in board code: |
| |
| - dram_init: |
| - bd pointer is now at this point not accessible, so only |
| detect the real dramsize, and store it in gd->ram_size. |
| best detected with get_ram_size(); |
| ToDo: move there also the dram initialization on boards where |
| it is possible. |
| - setup the bd_t dram bank info in the new function |
| dram_init_banksize(). |
| |
| - board.c code is adapted from ppc code |
| |
| - undef CONFIG_RELOC_FIXUP_WORKS |
| |
| -> cmdtabl, and subcommand table must be handled from "hand" |
| collected in section "__datarellocal_start". |
| |
| - How To fixup the sections: |
| |
| __datarel_start, __datarelrolocal_start, __datarellocal_start and |
| __datarelro_start |
| |
| automatically? Then it should be possible to define again |
| CONFIG_RELOC_FIXUP_WORKS |
| |
| - irq stack setup is now not longer on a fix position, instead it is |
| calculated in board_init_f, and stored in gd->irq_sp |
| |
| ------------------------------------------------------------------------------------- |
| |
| To compile a board without relocation, define CONFIG_SYS_ARM_WITHOUT_RELOC |
| This possibility will removed!! So please fix your board to compile without |
| CONFIG_SYS_ARM_WITHOUT_RELOC defined!!! |
| |
| ------------------------------------------------------------------------------------- |
| |
| For boards which boot from nand_spl, it is possible to save a copy |
| if TEXT_BASE == relocation address! This prevents that uboot code |
| is copied again in relocate_code(). |
| |
| example for the tx25 board: |
| |
| a) cpu starts |
| b) it copies the first page in nand to internal ram |
| (nand_spl_code) |
| c) end executes this code |
| d) this initialize CPU, RAM, ... and copy itself to RAM |
| (this bin must fit in one page, so board_init_f() |
| don;t fit in it ... ) |
| e) there it copy u-boot to CONFIG_SYS_NAND_U_BOOT_DST and |
| starts this image @ CONFIG_SYS_NAND_U_BOOT_START |
| f) u-boot code steps through board_init_f() and calculates |
| the relocation address and copy itself to it |
| |
| If TEXT_BASE == relocation address, the copying of u-boot |
| in f) could be saved. |
| |
| ------------------------------------------------------------------------------------- |
| |
| ToDo: |
| |
| - fill in bd_t infos (check) |
| - adapt all boards |
| |
| - maybe adapt TEXT_BASE (this must be checked from board maintainers) |
| This *must* be done for boards, which boot from NOR flash |
| |
| on other boards if TEXT_BASE = relocation baseaddr, this saves |
| one copying from u-boot code. |
| |
| - new function dram_init_banksize() is actual board specific. Maybe |
| we make a weak default function in arch/arm/lib/board.c ? |
| |
| ------------------------------------------------------------------------------------- |
| |
| Relocation with NAND_SPL (example for the tx25): |
| |
| - cpu copies the first page from NAND to 0xbb000000 (IMX_NFC_BASE) |
| and start with code execution on this address. |
| |
| - The First page contains u-boot code from u-boot:nand_spl/nand_boot_fsl_nfc.c |
| which inits the dram, cpu registers, reloacte itself to TEXT_BASE and loads |
| the "real" u-boot to CONFIG_SYS_NAND_U_BOOT_DST and starts execution |
| @CONFIG_SYS_NAND_U_BOOT_START |
| |
| - This u-boot does no ram int, nor cpu register setup. Just looks |
| where it have to relocate and relocate itself to this address. |
| If relocate address = TEXT_BASE(not the same, as the TEXT_BASE |
| from the nand_spl code), no need to copy, just go on with bss clear |
| and jump to board_init_r. |
| |
| ------------------------------------------------------------------------------------- |
| |
| Relocation: |
| How to translate flash addresses in GOT to ram addresses. |
| This is automagically done from code, but this example |
| shows, how this magic code works ;-) |
| (example on the qong board) |
| |
| Find a variable: |
| |
| a) search it in System.map |
| (for example flash_info) |
| |
| a005b4c0 B BootpID |
| a005b4c4 B BootpTry |
| a005b4c8 b slave |
| a005b4cc B flash_info |
| ^^^^^^^^ |
| a005c908 b saved_sector.4002 |
| a005c910 b cfi_mtd_info |
| a005c9c0 b cfi_mtd_names |
| a005c9d0 B mtd_table |
| |
| --------------------------------------- |
| |
| b) create hexdump from u-boot code: |
| |
| hexdump -C u-boot > gnlmpfhex |
| |
| --------------------------------------- |
| |
| c) search the variables address in the hexdump |
| |
| |
| * |
| 0005fc80 00 00 00 00 00 00 00 00 2c 06 01 a0 18 cd 05 a0 |........,.......| |
| 0005fc90 9c d4 05 a0 bc b4 05 a0 1c 7f 05 a0 f0 05 01 a0 |................| |
| 0005fca0 08 5a 04 a0 1c ab 05 a0 ec a4 05 a0 98 c3 01 a0 |.Z..............| |
| 0005fcb0 a0 d6 05 a0 04 71 05 a0 c0 f9 00 a0 3c cd 05 a0 |.....q......<...| |
| 0005fcc0 cc b4 05 a0 f0 fa 00 a0 f0 d6 05 a0 10 86 05 a0 |................| |
| ^^^^^^^^^^^ |
| 0005fcd0 a4 16 06 a0 dc 64 05 a0 18 86 05 a0 52 48 05 a0 |.....d......RH..| |
| 0005fce0 c0 86 05 a0 24 6e 02 a0 b4 6c 05 a0 b0 94 01 a0 |....$n...l......| |
| 0005fcf0 1c 86 05 a0 50 85 05 a0 d4 0c 06 a0 bc 0b 06 a0 |....P...........| |
| |
| |
| -> 0005fcc0 |
| |
| ---------------------------------------- |
| |
| d) know we calculate this address in RAM |
| |
| |
| 8ff08000 (new address of code in RAM *1) |
| |
| + 0005fcc0 |
| |
| - 00008000 (offset of text *2) |
| |
| ---------- |
| |
| 8ff5fcc0 -> Addr GOT in RAM |
| |
| *1: |
| activate debug and look for the line: |
| Now running in RAM - U-Boot at: 8ff08000 |
| ^^^^^^^^ |
| new address of u-boot code in RAM |
| |
| *2: |
| Section Headers: |
| [Nr] Name Type Addr Off Size ES Flg Lk Inf Al |
| [ 0] NULL 00000000 000000 000000 00 0 0 0 |
| [ 1] .text PROGBITS a0000000 008000 04599c 00 AX 0 0 32 |
| ^^^^^^ |
| Offset of text |
| |
| ---------------------------------------- |
| |
| e) now we look in 8ff5fcc0 (RAM) |
| |
| |
| QongEVB>md 0x8ff5fcc0 |
| 8ff5fcc0 : a005b4cc a000faf0 a005d6f0 a0058610 ................ |
| ^^^^^^^^ |
| Bingo, here we have the old flash address (when relocation |
| is working, here is the fixed ram address. see @ f, how |
| it gets calculated) |
| |
| |
| ---------------------------------------- |
| |
| f) now translate it in the new RAM address |
| |
| a005b4cc |
| |
| - a0000000 TextBase |
| |
| + 8ff08000 new address of u-boot in ram |
| ---------- |
| 8ff634cc |
| |
| QongEVB>mm 0x8ff5fcc0 0x8ff634cc 1 |
| QongEVB>md 0x8ff5fcc0 |
| 8ff5fcc0 : 8ff634cc a000faf0 a005d6f0 a0058610 .4.............. |
| 8ff5fcd0 : a00616a4 a00564dc a0058618 a0054852 .....d......RH.. |
| |
| As this must be done for all address in the GOT, the u-boot |
| code did this automagically ... :-) |
| |
| ---------------------------------------------- |
| |
| g) check if the new address is really in the bss section: |
| |
| bss start: |
| 8ff6054c (8ff08000 + 0005854C monitorlen) |
| |
| bss end: |
| 8ff698ac (8ff08000 + 618AC) |
| |
| 8ff634cc is in bss :-) |
| |
| ---------------------------------------------- |
| |
| h) u-boot prints: |
| |
| important addresses: |
| |
| U-Boot code: A0000000 -> A005854C BSS: -> A00618AC TextBase 0xa0000000 |
| Now running in RAM - U-Boot at: 8ff08000 relocBase 0x8ff08000 |
| |
| |
| --------- |
| |
| U-Boot 2010.06-rc2-00002-gf8fbb25-dirty (Jun 18 2010 - 17:07:19) |
| |
| U-Boot code: A0000000 -> A005854C BSS: -> A00618AC |
| CPU: Freescale i.MX31 at 398 MHz |
| Board: DAVE/DENX Qong |
| mon: FFFFFFFF gd->monLen: 000618AC |
| Top of RAM usable for U-Boot at: 90000000 |
| LCD panel info: 640 x 480, 16 bit/pix |
| Reserving 600k for LCD Framebuffer at: 8ff6a000 |
| Reserving 390k for U-Boot at: 8ff08000 |
| Reserving 1280k for malloc() at: 8fdc8000 |
| Reserving 28 Bytes for Board Info at: 8fdc7fe4 |
| Reserving 48 Bytes for Global Data at: 8fdc7fb4 |
| New Stack Pointer is: 8fdc7fb0 |
| RAM Configuration: |
| Bank #0: 80000000 256 MiB |
| mon: 0005854C gd->monLen: 000618AC |
| Now running in RAM - U-Boot at: 8ff08000 |
| |
| ------------------------------------------------------------------------------------- |
| |
| Debugging u-boot in RAM: |
| (example on the qong board) |
| |
| a) add in config.mk: |
| |
| PLATFORM_CPPFLAGS += -DDEBUG |
| |
| ----------------- |
| |
| b) start debugger |
| |
| arm-linux-gdb u-boot |
| |
| [hs@pollux u-boot]$ arm-linux-gdb u-boot |
| GNU gdb Red Hat Linux (6.7-2rh) |
| Copyright (C) 2007 Free Software Foundation, Inc. |
| License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> |
| This is free software: you are free to change and redistribute it. |
| There is NO WARRANTY, to the extent permitted by law. Type "show copying" |
| and "show warranty" for details. |
| This GDB was configured as "--host=i686-pc-linux-gnu --target=arm-linux". |
| The target architecture is set automatically (currently arm) |
| .. |
| (gdb) |
| |
| ----------------- |
| |
| c) connect to target |
| |
| target remote bdi10:2001 |
| |
| (gdb) target remote bdi10:2001 |
| Remote debugging using bdi10:2001 |
| 0x8ff17f10 in ?? () |
| (gdb) |
| |
| ----------------- |
| |
| d) discard symbol-file |
| |
| (gdb) symbol-file |
| Discard symbol table from `/home/hs/celf/u-boot/u-boot'? (y or n) y |
| No symbol file now. |
| (gdb) |
| |
| ----------------- |
| |
| e) load new symbol table: |
| |
| (gdb) add-symbol-file u-boot 0x8ff08000 |
| add symbol table from file "u-boot" at |
| .text_addr = 0x8ff08000 |
| (y or n) y |
| Reading symbols from /home/hs/celf/u-boot/u-boot...done. |
| (gdb) c |
| Continuing. |
| ^C |
| Program received signal SIGSTOP, Stopped (signal). |
| 0x8ff17f18 in serial_getc () at serial_mxc.c:192 |
| 192 while (__REG(UART_PHYS + UTS) & UTS_RXEMPTY); |
| (gdb) |
| |
| add-symbol-file u-boot 0x8ff08000 |
| ^^^^^^^^^^ |
| get this address from u-boot debug printfs |
| |
| U-Boot 2010.06-rc2-00009-gf77b8b8-dirty (Jun 22 2010 - 09:43:46) |
| |
| U-Boot code: A0000000 -> A0058BAC BSS: -> A0061F10 |
| CPU: Freescale i.MX31 at 398 MHz |
| Board: DAVE/DENX Qong |
| mon: FFFFFFFF gd->monLen: 00061F10 |
| Top of RAM usable for U-Boot at: 90000000 |
| LCD panel info: 640 x 480, 16 bit/pix |
| Reserving 600k for LCD Framebuffer at: 8ff6a000 |
| Reserving 391k for U-Boot at: 8ff08000 |
| ^^^^^^^^ |
| Reserving 1280k for malloc() at: 8fdc8000 |
| Reserving 24 Bytes for Board Info at: 8fdc7fe8 |
| Reserving 52 Bytes for Global Data at: 8fdc7fb4 |
| New Stack Pointer is: 8fdc7fb0 |
| RAM Configuration: |
| Bank #0: 80000000 256 MiB |
| relocation Offset is: eff08000 |
| mon: 00058BAC gd->monLen: 00061F10 |
| Now running in RAM - U-Boot at: 8ff08000 |
| ^^^^^^^^ |
| |
| Now you can use gdb as usual :-) |