arch/arm/mach-shmobile/pm-rcar.c

   1 /*
   2  * R-Car SYSC Power management support
   3  *
   4  * Copyright (C) 2014  Magnus Damm
   5  *
   6  * This file is subject to the terms and conditions of the GNU General Public
   7  * License.  See the file "COPYING" in the main directory of this archive
   8  * for more details.
   9  */
  10
  11 #include <linux/delay.h>
  12 #include <linux/err.h>
  13 #include <linux/mm.h>
  14 #include <linux/spinlock.h>
  15 #include <asm/io.h>
  16 #include "pm-rcar.h"
  17
  18 /* SYSC */
  19 #define SYSCSR 0x00
  20 #define SYSCISR 0x04
  21 #define SYSCISCR 0x08
  22
  23 #define PWRSR_OFFS 0x00
  24 #define PWROFFCR_OFFS 0x04
  25 #define PWRONCR_OFFS 0x0c
  26 #define PWRER_OFFS 0x14
  27
  28 #define SYSCSR_RETRIES 100
  29 #define SYSCSR_DELAY_US 1
  30
  31 #define SYSCISR_RETRIES 1000
  32 #define SYSCISR_DELAY_US 1
  33
  34 static void __iomem *rcar_sysc_base;
  35 static DEFINE_SPINLOCK(rcar_sysc_lock); /* SMP CPUs + I/O devices */
  36
  37 static int rcar_sysc_pwr_on_off(struct rcar_sysc_ch *sysc_ch,
  38                                 int sr_bit, int reg_offs)
  39 {
  40         int k;
  41
  42         for (k = 0; k < SYSCSR_RETRIES; k++) {
  43                 if (ioread32(rcar_sysc_base + SYSCSR) & (1 << sr_bit))
  44                         break;
  45                 udelay(SYSCSR_DELAY_US);
  46         }
  47
  48         if (k == SYSCSR_RETRIES)
  49                 return -EAGAIN;
  50
  51         iowrite32(1 << sysc_ch->chan_bit,
  52                   rcar_sysc_base + sysc_ch->chan_offs + reg_offs);
  53
  54         return 0;
  55 }
  56
  57 static int rcar_sysc_pwr_off(struct rcar_sysc_ch *sysc_ch)
  58 {
  59         return rcar_sysc_pwr_on_off(sysc_ch, 0, PWROFFCR_OFFS);
  60 }
  61
  62 static int rcar_sysc_pwr_on(struct rcar_sysc_ch *sysc_ch)
  63 {
  64         return rcar_sysc_pwr_on_off(sysc_ch, 1, PWRONCR_OFFS);
  65 }
  66
  67 static int rcar_sysc_update(struct rcar_sysc_ch *sysc_ch,
  68                             int (*on_off_fn)(struct rcar_sysc_ch *))
  69 {
  70         unsigned int isr_mask = 1 << sysc_ch->isr_bit;
  71         unsigned int chan_mask = 1 << sysc_ch->chan_bit;
  72         unsigned int status;
  73         unsigned long flags;
  74         int ret = 0;
  75         int k;
  76
  77         spin_lock_irqsave(&rcar_sysc_lock, flags);
  78
  79         iowrite32(isr_mask, rcar_sysc_base + SYSCISCR);
  80
  81         do {
  82                 ret = on_off_fn(sysc_ch);
  83                 if (ret)
  84                         goto out;
  85
  86                 status = ioread32(rcar_sysc_base +
  87                                   sysc_ch->chan_offs + PWRER_OFFS);
  88         } while (status & chan_mask);
  89
  90         for (k = 0; k < SYSCISR_RETRIES; k++) {
  91                 if (ioread32(rcar_sysc_base + SYSCISR) & isr_mask)
  92                         break;
  93                 udelay(SYSCISR_DELAY_US);
  94         }
  95
  96         if (k == SYSCISR_RETRIES)
  97                 ret = -EIO;
  98
  99         iowrite32(isr_mask, rcar_sysc_base + SYSCISCR);
 100
 101  out:
 102         spin_unlock_irqrestore(&rcar_sysc_lock, flags);
 103
 104         pr_debug("sysc power domain %d: %08x -> %d\n",
 105                  sysc_ch->isr_bit, ioread32(rcar_sysc_base + SYSCISR), ret);
 106         return ret;
 107 }
 108
 109 int rcar_sysc_power_down(struct rcar_sysc_ch *sysc_ch)
 110 {
 111         return rcar_sysc_update(sysc_ch, rcar_sysc_pwr_off);
 112 }
 113
 114 int rcar_sysc_power_up(struct rcar_sysc_ch *sysc_ch)
 115 {
 116         return rcar_sysc_update(sysc_ch, rcar_sysc_pwr_on);
 117 }
 118
 119 bool rcar_sysc_power_is_off(struct rcar_sysc_ch *sysc_ch)
 120 {
 121         unsigned int st;
 122
 123         st = ioread32(rcar_sysc_base + sysc_ch->chan_offs + PWRSR_OFFS);
 124         if (st & (1 << sysc_ch->chan_bit))
 125                 return true;
 126
 127         return false;
 128 }
 129
 130 void __iomem *rcar_sysc_init(phys_addr_t base)
 131 {
 132         rcar_sysc_base = ioremap_nocache(base, PAGE_SIZE);
 133         if (!rcar_sysc_base)
 134                 panic("unable to ioremap R-Car SYSC hardware block\n");
 135
 136         return rcar_sysc_base;
 137 }