arch/mips/vr41xx/common/pmu.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  pmu.c, Power Management Unit routines for NEC VR4100 series.
   4  *
   5  *  Copyright (C) 2003-2007  Yoichi Yuasa <yuasa@linux-mips.org>
   6  */
   7 #include <linux/cpu.h>
   8 #include <linux/errno.h>
   9 #include <linux/init.h>
  10 #include <linux/ioport.h>
  11 #include <linux/kernel.h>
  12 #include <linux/pm.h>
  13 #include <linux/sched.h>
  14 #include <linux/types.h>
  15
  16 #include <asm/cacheflush.h>
  17 #include <asm/cpu.h>
  18 #include <asm/idle.h>
  19 #include <asm/io.h>
  20 #include <asm/processor.h>
  21 #include <asm/reboot.h>
  22
  23 #define PMU_TYPE1_BASE  0x0b0000a0UL
  24 #define PMU_TYPE1_SIZE  0x0eUL
  25
  26 #define PMU_TYPE2_BASE  0x0f0000c0UL
  27 #define PMU_TYPE2_SIZE  0x10UL
  28
  29 #define PMUCNT2REG      0x06
  30  #define SOFTRST        0x0010
  31
  32 static void __iomem *pmu_base;
  33
  34 #define pmu_read(offset)                readw(pmu_base + (offset))
  35 #define pmu_write(offset, value)        writew((value), pmu_base + (offset))
  36
  37 static void __cpuidle vr41xx_cpu_wait(void)
  38 {
  39         local_irq_disable();
  40         if (!need_resched())
  41                 /*
  42                  * "standby" sets IE bit of the CP0_STATUS to 1.
  43                  */
  44                 __asm__("standby;\n");
  45         else
  46                 local_irq_enable();
  47 }
  48
  49 static inline void software_reset(void)
  50 {
  51         uint16_t pmucnt2;
  52
  53         switch (current_cpu_type()) {
  54         case CPU_VR4122:
  55         case CPU_VR4131:
  56         case CPU_VR4133:
  57                 pmucnt2 = pmu_read(PMUCNT2REG);
  58                 pmucnt2 |= SOFTRST;
  59                 pmu_write(PMUCNT2REG, pmucnt2);
  60                 break;
  61         default:
  62                 set_c0_status(ST0_BEV | ST0_ERL);
  63                 change_c0_config(CONF_CM_CMASK, CONF_CM_UNCACHED);
  64                 __flush_cache_all();
  65                 write_c0_wired(0);
  66                 __asm__("jr     %0"::"r"(0xbfc00000));
  67                 break;
  68         }
  69 }
  70
  71 static void vr41xx_restart(char *command)
  72 {
  73         local_irq_disable();
  74         software_reset();
  75         while (1) ;
  76 }
  77
  78 static void vr41xx_halt(void)
  79 {
  80         local_irq_disable();
  81         printk(KERN_NOTICE "\nYou can turn off the power supply\n");
  82         __asm__("hibernate;\n");
  83 }
  84
  85 static int __init vr41xx_pmu_init(void)
  86 {
  87         unsigned long start, size;
  88
  89         switch (current_cpu_type()) {
  90         case CPU_VR4111:
  91         case CPU_VR4121:
  92                 start = PMU_TYPE1_BASE;
  93                 size = PMU_TYPE1_SIZE;
  94                 break;
  95         case CPU_VR4122:
  96         case CPU_VR4131:
  97         case CPU_VR4133:
  98                 start = PMU_TYPE2_BASE;
  99                 size = PMU_TYPE2_SIZE;
 100                 break;
 101         default:
 102                 printk("Unexpected CPU of NEC VR4100 series\n");
 103                 return -ENODEV;
 104         }
 105
 106         if (request_mem_region(start, size, "PMU") == NULL)
 107                 return -EBUSY;
 108
 109         pmu_base = ioremap(start, size);
 110         if (pmu_base == NULL) {
 111                 release_mem_region(start, size);
 112                 return -EBUSY;
 113         }
 114
 115         cpu_wait = vr41xx_cpu_wait;
 116         _machine_restart = vr41xx_restart;
 117         _machine_halt = vr41xx_halt;
 118         pm_power_off = vr41xx_halt;
 119
 120         return 0;
 121 }
 122
 123 core_initcall(vr41xx_pmu_init);