arch/arm/mach-s3c24xx/sleep.S

   1 /* linux/arch/arm/plat-s3c24xx/sleep.S
   2  *
   3  * Copyright (c) 2004 Simtec Electronics
   4  *      Ben Dooks <ben@simtec.co.uk>
   5  *
   6  * S3C2410 Power Manager (Suspend-To-RAM) support
   7  *
   8  * Based on PXA/SA1100 sleep code by:
   9  *      Nicolas Pitre, (c) 2002 Monta Vista Software Inc
  10  *      Cliff Brake, (c) 2001
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2 of the License, or
  15  * (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  25 */
  26
  27 #include <linux/linkage.h>
  28 #include <linux/serial_s3c.h>
  29 #include <asm/assembler.h>
  30 #include <mach/hardware.h>
  31 #include <mach/map.h>
  32
  33 #include <mach/regs-gpio.h>
  34 #include <mach/regs-clock.h>
  35
  36 /* CONFIG_DEBUG_RESUME is dangerous if your bootloader does not
  37  * reset the UART configuration, only enable if you really need this!
  38 */
  39 //#define CONFIG_DEBUG_RESUME
  40
  41         .text
  42
  43         /* sleep magic, to allow the bootloader to check for an valid
  44          * image to resume to. Must be the first word before the
  45          * s3c_cpu_resume entry.
  46         */
  47
  48         .word   0x2bedf00d
  49
  50         /* s3c_cpu_resume
  51          *
  52          * resume code entry for bootloader to call
  53         */
  54
  55 ENTRY(s3c_cpu_resume)
  56         mov     r0, #PSR_I_BIT | PSR_F_BIT | SVC_MODE
  57         msr     cpsr_c, r0
  58
  59         @@ load UART to allow us to print the two characters for
  60         @@ resume debug
  61
  62         mov     r2, #S3C24XX_PA_UART & 0xff000000
  63         orr     r2, r2, #S3C24XX_PA_UART & 0xff000
  64
  65 #if 0
  66         /* SMDK2440 LED set */
  67         mov     r14, #S3C24XX_PA_GPIO
  68         ldr     r12, [ r14, #0x54 ]
  69         bic     r12, r12, #3<<4
  70         orr     r12, r12, #1<<7
  71         str     r12, [ r14, #0x54 ]
  72 #endif
  73
  74 #ifdef CONFIG_DEBUG_RESUME
  75         mov     r3, #'L'
  76         strb    r3, [ r2, #S3C2410_UTXH ]
  77 1001:
  78         ldrb    r14, [ r3, #S3C2410_UTRSTAT ]
  79         tst     r14, #S3C2410_UTRSTAT_TXE
  80         beq     1001b
  81 #endif /* CONFIG_DEBUG_RESUME */
  82
  83         b       cpu_resume