diff options
Diffstat (limited to 'arch/arm/plat-s3c24xx/sleep.S')
| -rw-r--r-- | arch/arm/plat-s3c24xx/sleep.S | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/arch/arm/plat-s3c24xx/sleep.S b/arch/arm/plat-s3c24xx/sleep.S new file mode 100644 index 000000000000..2018c2e1dcc5 --- /dev/null +++ b/arch/arm/plat-s3c24xx/sleep.S @@ -0,0 +1,159 @@ +/* linux/arch/arm/mach-s3c2410/sleep.S + * + * Copyright (c) 2004 Simtec Electronics + * Ben Dooks <ben@simtec.co.uk> + * + * S3C2410 Power Manager (Suspend-To-RAM) support + * + * Based on PXA/SA1100 sleep code by: + * Nicolas Pitre, (c) 2002 Monta Vista Software Inc + * Cliff Brake, (c) 2001 + * + * 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 <linux/linkage.h> +#include <asm/assembler.h> +#include <asm/hardware.h> +#include <asm/arch/map.h> + +#include <asm/arch/regs-gpio.h> +#include <asm/arch/regs-clock.h> +#include <asm/arch/regs-mem.h> +#include <asm/arch/regs-serial.h> + +/* CONFIG_DEBUG_RESUME is dangerous if your bootloader does not + * reset the UART configuration, only enable if you really need this! +*/ +//#define CONFIG_DEBUG_RESUME + + .text + + /* s3c2410_cpu_save + * + * save enough of the CPU state to allow us to re-start + * pm.c code. as we store items like the sp/lr, we will + * end up returning from this function when the cpu resumes + * so the return value is set to mark this. + * + * This arangement means we avoid having to flush the cache + * from this code. + * + * entry: + * r0 = pointer to save block + * + * exit: + * r0 = 0 => we stored everything + * 1 => resumed from sleep + */ + +ENTRY(s3c2410_cpu_save) + stmfd sp!, { r4 - r12, lr } + + @@ store co-processor registers + + mrc p15, 0, r4, c15, c1, 0 @ CP access register + mrc p15, 0, r5, c13, c0, 0 @ PID + mrc p15, 0, r6, c3, c0, 0 @ Domain ID + mrc p15, 0, r7, c2, c0, 0 @ translation table base address + mrc p15, 0, r8, c1, c0, 0 @ control register + + stmia r0, { r4 - r13 } + + mov r0, #0 + ldmfd sp, { r4 - r12, pc } + + @@ return to the caller, after having the MMU + @@ turned on, this restores the last bits from the + @@ stack +resume_with_mmu: + mov r0, #1 + ldmfd sp!, { r4 - r12, pc } + + .ltorg + + @@ the next bits sit in the .data segment, even though they + @@ happen to be code... the s3c2410_sleep_save_phys needs to be + @@ accessed by the resume code before it can restore the MMU. + @@ This means that the variable has to be close enough for the + @@ code to read it... since the .text segment needs to be RO, + @@ the data segment can be the only place to put this code. + + .data + + .global s3c2410_sleep_save_phys +s3c2410_sleep_save_phys: + .word 0 + + /* s3c2410_cpu_resume + * + * resume code entry for bootloader to call + * + * we must put this code here in the data segment as we have no + * other way of restoring the stack pointer after sleep, and we + * must not write to the code segment (code is read-only) + */ + +ENTRY(s3c2410_cpu_resume) + mov r0, #PSR_I_BIT | PSR_F_BIT | SVC_MODE + msr cpsr_c, r0 + + @@ load UART to allow us to print the two characters for + @@ resume debug + + mov r2, #S3C24XX_PA_UART & 0xff000000 + orr r2, r2, #S3C24XX_PA_UART & 0xff000 + +#if 0 + /* SMDK2440 LED set */ + mov r14, #S3C24XX_PA_GPIO + ldr r12, [ r14, #0x54 ] + bic r12, r12, #3<<4 + orr r12, r12, #1<<7 + str r12, [ r14, #0x54 ] +#endif + +#ifdef CONFIG_DEBUG_RESUME + mov r3, #'L' + strb r3, [ r2, #S3C2410_UTXH ] +1001: + ldrb r14, [ r3, #S3C2410_UTRSTAT ] + tst r14, #S3C2410_UTRSTAT_TXE + beq 1001b +#endif /* CONFIG_DEBUG_RESUME */ + + mov r1, #0 + mcr p15, 0, r1, c8, c7, 0 @@ invalidate I & D TLBs + mcr p15, 0, r1, c7, c7, 0 @@ invalidate I & D caches + + ldr r0, s3c2410_sleep_save_phys @ address of restore block + ldmia r0, { r4 - r13 } + + mcr p15, 0, r4, c15, c1, 0 @ CP access register + mcr p15, 0, r5, c13, c0, 0 @ PID + mcr p15, 0, r6, c3, c0, 0 @ Domain ID + mcr p15, 0, r7, c2, c0, 0 @ translation table base + +#ifdef CONFIG_DEBUG_RESUME + mov r3, #'R' + strb r3, [ r2, #S3C2410_UTXH ] +#endif + + ldr r2, =resume_with_mmu + mcr p15, 0, r8, c1, c0, 0 @ turn on MMU, etc + nop @ second-to-last before mmu + mov pc, r2 @ go back to virtual address + + .ltorg |