arch/sh/kernel/cpu/shmobile/pm.c

   1 /*
   2  * arch/sh/kernel/cpu/sh4a/pm-sh_mobile.c
   3  *
   4  * Power management support code for SuperH Mobile
   5  *
   6  *  Copyright (C) 2009 Magnus Damm
   7  *
   8  * This file is subject to the terms and conditions of the GNU General Public
   9  * License.  See the file "COPYING" in the main directory of this archive
  10  * for more details.
  11  */
  12 #include <linux/init.h>
  13 #include <linux/kernel.h>
  14 #include <linux/io.h>
  15 #include <linux/suspend.h>
  16 #include <asm/suspend.h>
  17 #include <asm/uaccess.h>
  18
  19 /*
  20  * Sleep modes available on SuperH Mobile:
  21  *
  22  * Sleep mode is just plain "sleep" instruction
  23  * Sleep Self-Refresh mode is above plus RAM put in Self-Refresh
  24  * Standby Self-Refresh mode is above plus stopped clocks
  25  */
  26 #define SUSP_MODE_SLEEP         (SUSP_SH_SLEEP)
  27 #define SUSP_MODE_SLEEP_SF      (SUSP_SH_SLEEP | SUSP_SH_SF)
  28 #define SUSP_MODE_STANDBY_SF    (SUSP_SH_STANDBY | SUSP_SH_SF)
  29
  30 /*
  31  * The following modes are not there yet:
  32  *
  33  * R-standby mode is unsupported, but will be added in the future
  34  * U-standby mode is low priority since it needs bootloader hacks
  35  *
  36  * All modes should be tied in with cpuidle. But before that can
  37  * happen we need to keep track of enabled hardware blocks so we
  38  * can avoid entering sleep modes that stop clocks to hardware
  39  * blocks that are in use even though the cpu core is idle.
  40  */
  41
  42 extern const unsigned char sh_mobile_standby[];
  43 extern const unsigned int sh_mobile_standby_size;
  44
  45 static void sh_mobile_call_standby(unsigned long mode)
  46 {
  47         extern void *vbr_base;
  48         void *onchip_mem = (void *)0xe5200000; /* ILRAM */
  49         void (*standby_onchip_mem)(unsigned long) = onchip_mem;
  50
  51         /* Note: Wake up from sleep may generate exceptions!
  52          * Setup VBR to point to on-chip ram if self-refresh is
  53          * going to be used.
  54          */
  55         if (mode & SUSP_SH_SF)
  56                 asm volatile("ldc %0, vbr" : : "r" (onchip_mem) : "memory");
  57
  58         /* Copy the assembly snippet to the otherwise ununsed ILRAM */
  59         memcpy(onchip_mem, sh_mobile_standby, sh_mobile_standby_size);
  60         wmb();
  61         ctrl_barrier();
  62
  63         /* Let assembly snippet in on-chip memory handle the rest */
  64         standby_onchip_mem(mode);
  65
  66         /* Put VBR back in System RAM again */
  67         if (mode & SUSP_SH_SF)
  68                 asm volatile("ldc %0, vbr" : : "r" (&vbr_base) : "memory");
  69 }
  70
  71 static int sh_pm_enter(suspend_state_t state)
  72 {
  73         local_irq_disable();
  74         set_bl_bit();
  75         sh_mobile_call_standby(SUSP_MODE_STANDBY_SF);
  76         local_irq_disable();
  77         clear_bl_bit();
  78         return 0;
  79 }
  80
  81 static struct platform_suspend_ops sh_pm_ops = {
  82         .enter          = sh_pm_enter,
  83         .valid          = suspend_valid_only_mem,
  84 };
  85
  86 static int __init sh_pm_init(void)
  87 {
  88         suspend_set_ops(&sh_pm_ops);
  89         return 0;
  90 }
  91
  92 late_initcall(sh_pm_init);