start.S 9.06 KB
Newer Older
1 2 3 4 5 6 7 8 9
/*
 *  armboot - Startup Code for ARM926EJS CPU-core
 *
 *  Copyright (c) 2003  Texas Instruments
 *
 *  ----- Adapted for OMAP1610 OMAP730 from ARM925t code ------
 *
 *  Copyright (c) 2001	Marius Grger <mag@sysgo.de>
 *  Copyright (c) 2002	Alex Zpke <azu@sysgo.de>
10
 *  Copyright (c) 2002	Gary Jennejohn <garyj@denx.de>
11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135
 *  Copyright (c) 2003	Richard Woodruff <r-woodruff2@ti.com>
 *  Copyright (c) 2003	Kshitij <kshitij@ti.com>
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 */


#include <config.h>
#include <version.h>

/*
 *************************************************************************
 *
 * Jump vector table as in table 3.1 in [1]
 *
 *************************************************************************
 */


.globl _start
_start:
	b	reset
	ldr	pc, _undefined_instruction
	ldr	pc, _software_interrupt
	ldr	pc, _prefetch_abort
	ldr	pc, _data_abort
	ldr	pc, _not_used
	ldr	pc, _irq
	ldr	pc, _fiq

_undefined_instruction:
	.word undefined_instruction
_software_interrupt:
	.word software_interrupt
_prefetch_abort:
	.word prefetch_abort
_data_abort:
	.word data_abort
_not_used:
	.word not_used
_irq:
	.word irq
_fiq:
	.word fiq

	.balignl 16,0xdeadbeef


/*
 *************************************************************************
 *
 * Startup Code (reset vector)
 *
 * do important init only if we don't start from memory!
 * setup Memory and board specific bits prior to relocation.
 * relocate armboot to ram
 * setup stack
 *
 *************************************************************************
 */

_TEXT_BASE:
	.word	TEXT_BASE

.globl _armboot_start
_armboot_start:
	.word _start

/*
 * These are defined in the board-specific linker script.
 */
.globl _bss_start
_bss_start:
	.word __bss_start

.globl _bss_end
_bss_end:
	.word _end

#ifdef CONFIG_USE_IRQ
/* IRQ stack memory (calculated at run-time) */
.globl IRQ_STACK_START
IRQ_STACK_START:
	.word	0x0badc0de

/* IRQ stack memory (calculated at run-time) */
.globl FIQ_STACK_START
FIQ_STACK_START:
	.word 0x0badc0de
#endif


/*
 * the actual reset code
 */

reset:
	/*
	 * set the cpu to SVC32 mode
	 */
	mrs	r0,cpsr
	bic	r0,r0,#0x1f
	orr	r0,r0,#0xd3
	msr	cpsr,r0

	/*
	 * we do sys-critical inits only at reboot,
	 * not when booting from ram!
	 */
136
#ifndef CONFIG_SKIP_LOWLEVEL_INIT
137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159
	bl	cpu_init_crit
#endif

relocate:				/* relocate U-Boot to RAM	    */
	adr	r0, _start		/* r0 <- current position of code   */
	ldr	r1, _TEXT_BASE		/* test if we run from flash or RAM */
	cmp     r0, r1                  /* don't reloc during debug         */
	beq     stack_setup

	ldr	r2, _armboot_start
	ldr	r3, _bss_start
	sub	r2, r3, r2		/* r2 <- size of armboot            */
	add	r2, r0, r2		/* r2 <- source end address         */

copy_loop:
	ldmia	r0!, {r3-r10}		/* copy from source address [r0]    */
	stmia	r1!, {r3-r10}		/* copy to   target address [r1]    */
	cmp	r0, r2			/* until source end addreee [r2]    */
	ble	copy_loop

	/* Set up the stack						    */
stack_setup:
	ldr	r0, _TEXT_BASE		/* upper 128 KiB: relocated uboot   */
160 161
	sub	r0, r0, #CONFIG_SYS_MALLOC_LEN	/* malloc area                      */
	sub	r0, r0, #CONFIG_SYS_GBL_DATA_SIZE /* bdinfo                        */
162 163 164 165 166 167 168 169
#ifdef CONFIG_USE_IRQ
	sub	r0, r0, #(CONFIG_STACKSIZE_IRQ+CONFIG_STACKSIZE_FIQ)
#endif
	sub	sp, r0, #12		/* leave 3 words for abort-stack    */

clear_bss:
	ldr	r0, _bss_start		/* find start of bss segment        */
	ldr	r1, _bss_end		/* stop here                        */
Wolfgang Denk's avatar
Wolfgang Denk committed
170
	mov	r2, #0x00000000		/* clear                            */
171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194

clbss_l:str	r2, [r0]		/* clear loop...                    */
	add	r0, r0, #4
	cmp	r0, r1
	bne	clbss_l

	ldr	pc, _start_armboot

_start_armboot:
	.word start_armboot


/*
 *************************************************************************
 *
 * CPU_init_critical registers
 *
 * setup important registers
 * setup memory timing
 *
 *************************************************************************
 */


195
#ifndef CONFIG_SKIP_LOWLEVEL_INIT
196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217
cpu_init_crit:
	/*
	 * flush v4 I/D caches
	 */
	mov	r0, #0
	mcr	p15, 0, r0, c7, c5, 0	/* flush v4 I-cache */
	mcr	p15, 0, r0, c7, c6, 0	/* flush v4 D-cache */

	/*
	 * disable MMU stuff and caches
	 */
	mrc	p15, 0, r0, c1, c0, 0
	bic	r0, r0, #0x00002300	/* clear bits 13, 9:8 (--V- --RS) */
	bic	r0, r0, #0x00000087	/* clear bits 7, 2:0 (B--- -CAM) */
	orr	r0, r0, #0x00000002	/* set bit 2 (A) Align */
	orr	r0, r0, #0x00001000	/* set bit 12 (I) I-Cache */
	mcr	p15, 0, r0, c1, c0, 0

	/*
	 * Go setup Memory and board specific bits prior to relocation.
	 */
	mov	ip, lr		/* perserve link reg across call */
218
	bl	lowlevel_init	/* go setup memory */
219 220
	mov	lr, ip		/* restore link */
	mov	pc, lr		/* back to my caller */
221
#endif
222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268
/*
 *************************************************************************
 *
 * Interrupt handling
 *
 *************************************************************************
 */

@
@ IRQ stack frame.
@
#define S_FRAME_SIZE	72

#define S_OLD_R0	68
#define S_PSR		64
#define S_PC		60
#define S_LR		56
#define S_SP		52

#define S_IP		48
#define S_FP		44
#define S_R10		40
#define S_R9		36
#define S_R8		32
#define S_R7		28
#define S_R6		24
#define S_R5		20
#define S_R4		16
#define S_R3		12
#define S_R2		8
#define S_R1		4
#define S_R0		0

#define MODE_SVC 0x13
#define I_BIT	 0x80

/*
 * use bad_save_user_regs for abort/prefetch/undef/swi ...
 * use irq_save_user_regs / irq_restore_user_regs for IRQ/FIQ handling
 */

	.macro	bad_save_user_regs
	@ carve out a frame on current user stack
	sub	sp, sp, #S_FRAME_SIZE
	stmia	sp, {r0 - r12}	@ Save user registers (now in svc mode) r0-r12

	ldr	r2, _armboot_start
269 270
	sub	r2, r2, #(CONFIG_STACKSIZE+CONFIG_SYS_MALLOC_LEN)
	sub	r2, r2, #(CONFIG_SYS_GBL_DATA_SIZE+8)  @ set base 2 words into abort stack
271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302
	@ get values for "aborted" pc and cpsr (into parm regs)
	ldmia	r2, {r2 - r3}
	add	r0, sp, #S_FRAME_SIZE		@ grab pointer to old stack
	add	r5, sp, #S_SP
	mov	r1, lr
	stmia	r5, {r0 - r3}	@ save sp_SVC, lr_SVC, pc, cpsr
	mov	r0, sp		@ save current stack into r0 (param register)
	.endm

	.macro	irq_save_user_regs
	sub	sp, sp, #S_FRAME_SIZE
	stmia	sp, {r0 - r12}			@ Calling r0-r12
	@ !!!! R8 NEEDS to be saved !!!! a reserved stack spot would be good.
	add	r8, sp, #S_PC
	stmdb	r8, {sp, lr}^		@ Calling SP, LR
	str	lr, [r8, #0]		@ Save calling PC
	mrs	r6, spsr
	str	r6, [r8, #4]		@ Save CPSR
	str	r0, [r8, #8]		@ Save OLD_R0
	mov	r0, sp
	.endm

	.macro	irq_restore_user_regs
	ldmia	sp, {r0 - lr}^			@ Calling r0 - lr
	mov	r0, r0
	ldr	lr, [sp, #S_PC]			@ Get PC
	add	sp, sp, #S_FRAME_SIZE
	subs	pc, lr, #4		@ return & move spsr_svc into cpsr
	.endm

	.macro get_bad_stack
	ldr	r13, _armboot_start		@ setup our mode stack
303 304
	sub	r13, r13, #(CONFIG_STACKSIZE+CONFIG_SYS_MALLOC_LEN)
	sub	r13, r13, #(CONFIG_SYS_GBL_DATA_SIZE+8) @ reserved a couple spots in abort stack
305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362

	str	lr, [r13]	@ save caller lr in position 0 of saved stack
	mrs	lr, spsr	@ get the spsr
	str	lr, [r13, #4]	@ save spsr in position 1 of saved stack
	mov	r13, #MODE_SVC	@ prepare SVC-Mode
	@ msr	spsr_c, r13
	msr	spsr, r13	@ switch modes, make sure moves will execute
	mov	lr, pc		@ capture return pc
	movs	pc, lr		@ jump to next instruction & switch modes.
	.endm

	.macro get_irq_stack			@ setup IRQ stack
	ldr	sp, IRQ_STACK_START
	.endm

	.macro get_fiq_stack			@ setup FIQ stack
	ldr	sp, FIQ_STACK_START
	.endm

/*
 * exception handlers
 */
	.align  5
undefined_instruction:
	get_bad_stack
	bad_save_user_regs
	bl	do_undefined_instruction

	.align	5
software_interrupt:
	get_bad_stack
	bad_save_user_regs
	bl	do_software_interrupt

	.align	5
prefetch_abort:
	get_bad_stack
	bad_save_user_regs
	bl	do_prefetch_abort

	.align	5
data_abort:
	get_bad_stack
	bad_save_user_regs
	bl	do_data_abort

	.align	5
not_used:
	get_bad_stack
	bad_save_user_regs
	bl	do_not_used

#ifdef CONFIG_USE_IRQ

	.align	5
irq:
	get_irq_stack
	irq_save_user_regs
Wolfgang Denk's avatar
Wolfgang Denk committed
363
	bl	do_irq
364 365 366 367 368 369 370
	irq_restore_user_regs

	.align	5
fiq:
	get_fiq_stack
	/* someone ought to write a more effiction fiq_save_user_regs */
	irq_save_user_regs
Wolfgang Denk's avatar
Wolfgang Denk committed
371
	bl	do_fiq
372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411
	irq_restore_user_regs

#else

	.align	5
irq:
	get_bad_stack
	bad_save_user_regs
	bl	do_irq

	.align	5
fiq:
	get_bad_stack
	bad_save_user_regs
	bl	do_fiq

#endif

# ifdef CONFIG_INTEGRATOR

	/* Satisfied by general board level routine */

#else

	.align	5
.globl reset_cpu
reset_cpu:

	ldr	r1, rstctl1	/* get clkm1 reset ctl */
	mov	r3, #0x0
	strh	r3, [r1]	/* clear it */
	mov	r3, #0x8
	strh	r3, [r1]	/* force dsp+arm reset */
_loop_forever:
	b	_loop_forever

rstctl1:
	.word	0xfffece10

#endif	/* #ifdef CONFIG_INTEGRATOR */