2 * armboot - Startup Code for ARM920 CPU-core
4 * Copyright (c) 2001 Marius Gröger <mag@sysgo.de>
5 * Copyright (c) 2002 Alex Züpke <azu@sysgo.de>
6 * Copyright (c) 2002 Gary Jennejohn <garyj@denx.de>
8 * See file CREDITS for list of people who contributed to this
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License as
13 * published by the Free Software Foundation; either version 2 of
14 * the License, or (at your option) any later version.
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
27 #include <asm-offsets.h>
32 *************************************************************************
34 * Jump vector table as in table 3.1 in [1]
36 *************************************************************************
42 ldr pc, _undefined_instruction
43 ldr pc, _software_interrupt
44 ldr pc, _prefetch_abort
50 _undefined_instruction: .word undefined_instruction
51 _software_interrupt: .word software_interrupt
52 _prefetch_abort: .word prefetch_abort
53 _data_abort: .word data_abort
54 _not_used: .word not_used
58 .balignl 16,0xdeadbeef
62 *************************************************************************
64 * Startup Code (reset vector)
66 * do important init only if we don't start from memory!
67 * relocate armboot to ram
69 * jump to second stage
71 *************************************************************************
76 .word CONFIG_SYS_TEXT_BASE
79 * These are defined in the board-specific linker script.
80 * Subtracting _start from them lets the linker put their
81 * relative position in the executable instead of leaving
86 .word __bss_start - _start
93 /* IRQ stack memory (calculated at run-time) */
94 .globl IRQ_STACK_START
98 /* IRQ stack memory (calculated at run-time) */
99 .globl FIQ_STACK_START
104 /* IRQ stack memory (calculated at run-time) + 8 bytes */
105 .globl IRQ_STACK_START_IN
110 * the actual reset code
115 * set the cpu to SVC32 mode
122 #define pWDTCTL 0x80001400 /* Watchdog Timer control register */
123 #define pINTENC 0x8000050C /* Interupt-Controller enable clear register */
124 #define pCLKSET 0x80000420 /* clock divisor register */
126 /* disable watchdog, set watchdog control register to
127 * all zeros (default reset)
134 * mask all IRQs by setting all bits in the INTENC register (default)
140 /* FCLK:HCLK:PCLK = 1:2:2 */
141 /* default FCLK is 200 MHz, using 14.7456 MHz fin */
144 @ ldr r1, =0x0005ee39 @ 1: 2: 4
148 * we do sys-critical inits only at reboot,
149 * not when booting from ram!
151 #ifndef CONFIG_SKIP_LOWLEVEL_INIT
155 /* Set stackpointer in internal RAM to call board_init_f */
157 ldr sp, =(CONFIG_SYS_INIT_SP_ADDR)
158 bic sp, sp, #7 /* 8-byte alignment for ABI compliance */
162 /*------------------------------------------------------------------------------*/
165 * void relocate_code (addr_sp, gd, addr_moni)
167 * This "function" does not return, instead it continues in RAM
168 * after relocating the monitor code.
173 mov r4, r0 /* save addr_sp */
174 mov r5, r1 /* save addr of gd */
175 mov r6, r2 /* save addr of destination */
177 /* Set up the stack */
183 beq clear_bss /* skip relocation */
184 mov r1, r6 /* r1 <- scratch for copy_loop */
186 ldr r3, _bss_start_ofs
187 add r2, r0, r3 /* r2 <- source end address */
190 ldmia r0!, {r9-r10} /* copy from source address [r0] */
191 stmia r1!, {r9-r10} /* copy to target address [r1] */
192 cmp r0, r2 /* until source end address [r2] */
195 #ifndef CONFIG_PRELOADER
197 * fix .rel.dyn relocations
199 ldr r0, _TEXT_BASE /* r0 <- Text base */
200 sub r9, r6, r0 /* r9 <- relocation offset */
201 ldr r10, _dynsym_start_ofs /* r10 <- sym table ofs */
202 add r10, r10, r0 /* r10 <- sym table in FLASH */
203 ldr r2, _rel_dyn_start_ofs /* r2 <- rel dyn start ofs */
204 add r2, r2, r0 /* r2 <- rel dyn start in FLASH */
205 ldr r3, _rel_dyn_end_ofs /* r3 <- rel dyn end ofs */
206 add r3, r3, r0 /* r3 <- rel dyn end in FLASH */
208 ldr r0, [r2] /* r0 <- location to fix up, IN FLASH! */
209 add r0, r0, r9 /* r0 <- location to fix up in RAM */
212 cmp r7, #23 /* relative fixup? */
214 cmp r7, #2 /* absolute fixup? */
216 /* ignore unknown type of fixup */
219 /* absolute fix: set location to (offset) symbol value */
220 mov r1, r1, LSR #4 /* r1 <- symbol index in .dynsym */
221 add r1, r10, r1 /* r1 <- address of symbol in table */
222 ldr r1, [r1, #4] /* r1 <- symbol value */
223 add r1, r1, r9 /* r1 <- relocated sym addr */
226 /* relative fix: increase location by offset */
231 add r2, r2, #8 /* each rel.dyn entry is 8 bytes */
237 #ifndef CONFIG_PRELOADER
238 ldr r0, _bss_start_ofs
240 ldr r3, _TEXT_BASE /* Text base */
241 mov r4, r6 /* reloc addr */
244 mov r2, #0x00000000 /* clear */
246 clbss_l:str r2, [r0] /* clear loop... */
253 * We are done. Do not return, instead branch to second part of board
254 * initialization, now running from RAM.
256 ldr r0, _board_init_r_ofs
260 /* setup parameters for board_init_r */
261 mov r0, r5 /* gd_t */
262 mov r1, r6 /* dest_addr */
267 .word board_init_r - _start
270 .word __rel_dyn_start - _start
272 .word __rel_dyn_end - _start
274 .word __dynsym_start - _start
277 *************************************************************************
279 * CPU_init_critical registers
281 * setup important registers
282 * setup memory timing
284 *************************************************************************
290 * flush v4 I/D caches
293 mcr p15, 0, r0, c7, c7, 0 /* flush v3/v4 cache */
294 mcr p15, 0, r0, c8, c7, 0 /* flush v4 TLB */
297 * disable MMU stuff and caches
299 mrc p15, 0, r0, c1, c0, 0
300 bic r0, r0, #0x00002300 @ clear bits 13, 9:8 (--V- --RS)
301 bic r0, r0, #0x00000087 @ clear bits 7, 2:0 (B--- -CAM)
302 orr r0, r0, #0x00000002 @ set bit 2 (A) Align
303 orr r0, r0, #0x00001000 @ set bit 12 (I) I-Cache
304 orr r0, r0, #0x40000000 @ set bit 30 (nF) notFastBus
305 mcr p15, 0, r0, c1, c0, 0
309 * before relocating, we have to setup RAM timing
310 * because memory timing is board-dependend, you will
311 * find a lowlevel_init.S in your board directory.
321 *************************************************************************
325 *************************************************************************
331 #define S_FRAME_SIZE 72
353 #define MODE_SVC 0x13
357 * use bad_save_user_regs for abort/prefetch/undef/swi ...
358 * use irq_save_user_regs / irq_restore_user_regs for IRQ/FIQ handling
361 .macro bad_save_user_regs
362 sub sp, sp, #S_FRAME_SIZE
363 stmia sp, {r0 - r12} @ Calling r0-r12
364 ldr r2, IRQ_STACK_START_IN
365 ldmia r2, {r2 - r3} @ get pc, cpsr
366 add r0, sp, #S_FRAME_SIZE @ restore sp_SVC
370 stmia r5, {r0 - r3} @ save sp_SVC, lr_SVC, pc, cpsr
374 .macro irq_save_user_regs
375 sub sp, sp, #S_FRAME_SIZE
376 stmia sp, {r0 - r12} @ Calling r0-r12
378 stmdb r8, {sp, lr}^ @ Calling SP, LR
379 str lr, [r8, #0] @ Save calling PC
381 str r6, [r8, #4] @ Save CPSR
382 str r0, [r8, #8] @ Save OLD_R0
386 .macro irq_restore_user_regs
387 ldmia sp, {r0 - lr}^ @ Calling r0 - lr
389 ldr lr, [sp, #S_PC] @ Get PC
390 add sp, sp, #S_FRAME_SIZE
391 subs pc, lr, #4 @ return & move spsr_svc into cpsr
395 ldr r13, IRQ_STACK_START_IN @ setup our mode stack
397 str lr, [r13] @ save caller lr / spsr
401 mov r13, #MODE_SVC @ prepare SVC-Mode
408 .macro get_irq_stack @ setup IRQ stack
409 ldr sp, IRQ_STACK_START
412 .macro get_fiq_stack @ setup FIQ stack
413 ldr sp, FIQ_STACK_START
420 undefined_instruction:
423 bl do_undefined_instruction
429 bl do_software_interrupt
449 #ifdef CONFIG_USE_IRQ
456 irq_restore_user_regs
461 /* someone ought to write a more effiction fiq_save_user_regs */
464 irq_restore_user_regs
485 bl disable_interrupts
487 /* Disable watchdog */
496 /* Enable the watchdog */