u-boot/doc/README.arm-relocation

3 At arch level: add linker flag -pie
10 	(program-base-relative) and 2 (symbol-relative)
16 	code to access these tables
25 	detect the real dramsize, and store it in gd->ram_size. Bst detected
35 	Board.c code is adapted from ppc code
41 -----------------------------------------------------------------------------
44 if CONFIG_SYS_TEXT_BASE == relocation address! This prevents that uboot code
50 b) it copies the first page in nand to internal ram
51    (spl code)
52 c) end executes this code
53 d) this initialize CPU, RAM, ... and copy itself to RAM
56 e) there it copy u-boot to CONFIG_SYS_NAND_U_BOOT_DST and
58 f) u-boot code steps through board_init_f() and calculates
61 If CONFIG_SYS_TEXT_BASE == relocation address, the copying of u-boot
64 -----------------------------------------------------------------------------
68 - fill in bd_t infos (check)
69 - adapt all boards
71 - maybe adapt CONFIG_SYS_TEXT_BASE (this must be checked from board maintainers)
75   one copying from u-boot code.
77 - new function dram_init_banksize() is actual board specific. Maybe
80 -----------------------------------------------------------------------------
84 - cpu copies the first page from NAND to 0xbb000000 (IMX_NFC_BASE)
85   and start with code execution on this address.
87 - The First page contains u-boot code from drivers/mtd/nand/raw/mxc_nand_spl.c
89   the "real" u-boot to CONFIG_SYS_NAND_U_BOOT_DST and starts execution
92 - This u-boot does no RAM init, nor CPU register setup. Just look
95   CONFIG_SPL_TEXT_BASE from the spl code), then there is no need
98 -----------------------------------------------------------------------------
104 -------------------------------------------------------------------------------------
106 Debugging u-boot in RAM:
109 -----------------
113 arm-linux-gdb u-boot
115 [hs@pollux u-boot]$ arm-linux-gdb u-boot
116 GNU gdb Red Hat Linux (6.7-2rh)
122 This GDB was configured as "--host=i686-pc-linux-gnu --target=arm-linux".
127 -----------------
138 -----------------
140 c) discard symbol-file
142 (gdb) symbol-file
143 Discard symbol table from `/home/hs/celf/u-boot/u-boot'? (y or n) y
147 -----------------
151 (gdb) add-symbol-file u-boot 0x8ff08000
152 add symbol table from file "u-boot" at
155 Reading symbols from /home/hs/celf/u-boot/u-boot...done.
164 add-symbol-file u-boot 0x8ff08000
166 		       get this address from u-boot bdinfo command
167 		       or get it from gd->relocaddr in gdb
173 -> start    = XXXXXXXXXX
174 -> size     = XXXXXXXXXX
186 or interrupt execution by any means and re-load the symbols at the location
187 specified by gd->relocaddr -- this is only valid after board_init_f.
189 (gdb) set $s = gd->relocaddr
190 (gdb) symbol-file
191 (gdb) add-symbol-file u-boot $s
193 Now you can use gdb as usual :-)