arch/sparc/kernel/pmc.c

   1 /* pmc - Driver implementation for power management functions
   2  * of Power Management Controller (PMC) on SPARCstation-Voyager.
   3  *
   4  * Copyright (c) 2002 Eric Brower (ebrower@usa.net)
   5  */
   6
   7 #include <linux/kernel.h>
   8 #include <linux/fs.h>
   9 #include <linux/errno.h>
  10 #include <linux/init.h>
  11 #include <linux/miscdevice.h>
  12 #include <linux/pm.h>
  13
  14 #include <asm/io.h>
  15 #include <asm/sbus.h>
  16 #include <asm/oplib.h>
  17 #include <asm/uaccess.h>
  18 #include <asm/auxio.h>
  19
  20 /* Debug
  21  *
  22  * #define PMC_DEBUG_LED
  23  * #define PMC_NO_IDLE
  24  */
  25
  26 #define PMC_MINOR       MISC_DYNAMIC_MINOR
  27 #define PMC_OBPNAME     "SUNW,pmc"
  28 #define PMC_DEVNAME "pmc"
  29
  30 #define PMC_IDLE_REG    0x00
  31 #define PMC_IDLE_ON             0x01
  32
  33 volatile static u8 __iomem *regs;
  34 static int pmc_regsize;
  35
  36 #define pmc_readb(offs)                 (sbus_readb(regs+offs))
  37 #define pmc_writeb(val, offs)   (sbus_writeb(val, regs+offs))
  38
  39 /*
  40  * CPU idle callback function
  41  * See .../arch/sparc/kernel/process.c
  42  */
  43 void pmc_swift_idle(void)
  44 {
  45 #ifdef PMC_DEBUG_LED
  46         set_auxio(0x00, AUXIO_LED);
  47 #endif
  48
  49         pmc_writeb(pmc_readb(PMC_IDLE_REG) | PMC_IDLE_ON, PMC_IDLE_REG);
  50
  51 #ifdef PMC_DEBUG_LED
  52         set_auxio(AUXIO_LED, 0x00);
  53 #endif
  54 }
  55
  56 static inline void pmc_free(void)
  57 {
  58         sbus_iounmap(regs, pmc_regsize);
  59 }
  60
  61 static int __init pmc_probe(void)
  62 {
  63         struct sbus_bus *sbus = NULL;
  64         struct sbus_dev *sdev = NULL;
  65         for_each_sbus(sbus) {
  66                 for_each_sbusdev(sdev, sbus) {
  67                         if (!strcmp(sdev->prom_name, PMC_OBPNAME)) {
  68                                 goto sbus_done;
  69                         }
  70                 }
  71         }
  72
  73 sbus_done:
  74         if (!sdev) {
  75                 return -ENODEV;
  76         }
  77
  78         pmc_regsize = sdev->reg_addrs[0].reg_size;
  79         regs = sbus_ioremap(&sdev->resource[0], 0,
  80                                    pmc_regsize, PMC_OBPNAME);
  81         if (!regs) {
  82                 printk(KERN_ERR "%s: unable to map registers\n", PMC_DEVNAME);
  83                 return -ENODEV;
  84         }
  85
  86 #ifndef PMC_NO_IDLE
  87         /* Assign power management IDLE handler */
  88         pm_idle = pmc_swift_idle;
  89 #endif
  90
  91         printk(KERN_INFO "%s: power management initialized\n", PMC_DEVNAME);
  92         return 0;
  93 }
  94
  95 /* This driver is not critical to the boot process
  96  * and is easiest to ioremap when SBus is already
  97  * initialized, so we install ourselves thusly:
  98  */
  99 __initcall(pmc_probe);