arch/sparc/kernel/apc.c

   1 /* apc - Driver implementation for power management functions
   2  * of Aurora Personality Chip (APC) on SPARCstation-4/5 and
   3  * derivatives.
   4  *
   5  * Copyright (c) 2002 Eric Brower (ebrower@usa.net)
   6  */
   7
   8 #include <linux/kernel.h>
   9 #include <linux/fs.h>
  10 #include <linux/errno.h>
  11 #include <linux/init.h>
  12 #include <linux/miscdevice.h>
  13 #include <linux/smp_lock.h>
  14 #include <linux/pm.h>
  15
  16 #include <asm/io.h>
  17 #include <asm/sbus.h>
  18 #include <asm/oplib.h>
  19 #include <asm/uaccess.h>
  20 #include <asm/auxio.h>
  21 #include <asm/apc.h>
  22
  23 /* Debugging
  24  *
  25  * #define APC_DEBUG_LED
  26  */
  27
  28 #define APC_MINOR       MISC_DYNAMIC_MINOR
  29 #define APC_OBPNAME     "power-management"
  30 #define APC_DEVNAME "apc"
  31
  32 volatile static u8 __iomem *regs;
  33 static int apc_regsize;
  34 static int apc_no_idle __initdata = 0;
  35
  36 #define apc_readb(offs)                 (sbus_readb(regs+offs))
  37 #define apc_writeb(val, offs)   (sbus_writeb(val, regs+offs))
  38
  39 /* Specify "apc=noidle" on the kernel command line to
  40  * disable APC CPU standby support.  Certain prototype
  41  * systems (SPARCstation-Fox) do not play well with APC
  42  * CPU idle, so disable this if your system has APC and
  43  * crashes randomly.
  44  */
  45 static int __init apc_setup(char *str)
  46 {
  47         if(!strncmp(str, "noidle", strlen("noidle"))) {
  48                 apc_no_idle = 1;
  49                 return 1;
  50         }
  51         return 0;
  52 }
  53 __setup("apc=", apc_setup);
  54
  55 /*
  56  * CPU idle callback function
  57  * See .../arch/sparc/kernel/process.c
  58  */
  59 static void apc_swift_idle(void)
  60 {
  61 #ifdef APC_DEBUG_LED
  62         set_auxio(0x00, AUXIO_LED);
  63 #endif
  64
  65         apc_writeb(apc_readb(APC_IDLE_REG) | APC_IDLE_ON, APC_IDLE_REG);
  66
  67 #ifdef APC_DEBUG_LED
  68         set_auxio(AUXIO_LED, 0x00);
  69 #endif
  70 }
  71
  72 static inline void apc_free(void)
  73 {
  74         sbus_iounmap(regs, apc_regsize);
  75 }
  76
  77 static int apc_open(struct inode *inode, struct file *f)
  78 {
  79         cycle_kernel_lock();
  80         return 0;
  81 }
  82
  83 static int apc_release(struct inode *inode, struct file *f)
  84 {
  85         return 0;
  86 }
  87
  88 static int apc_ioctl(struct inode *inode, struct file *f,
  89                      unsigned int cmd, unsigned long __arg)
  90 {
  91         __u8 inarg, __user *arg;
  92
  93         arg = (__u8 __user *) __arg;
  94         switch (cmd) {
  95         case APCIOCGFANCTL:
  96                 if (put_user(apc_readb(APC_FANCTL_REG) & APC_REGMASK, arg))
  97                                 return -EFAULT;
  98                 break;
  99
 100         case APCIOCGCPWR:
 101                 if (put_user(apc_readb(APC_CPOWER_REG) & APC_REGMASK, arg))
 102                         return -EFAULT;
 103                 break;
 104
 105         case APCIOCGBPORT:
 106                 if (put_user(apc_readb(APC_BPORT_REG) & APC_BPMASK, arg))
 107                         return -EFAULT;
 108                 break;
 109
 110         case APCIOCSFANCTL:
 111                 if (get_user(inarg, arg))
 112                         return -EFAULT;
 113                 apc_writeb(inarg & APC_REGMASK, APC_FANCTL_REG);
 114                 break;
 115         case APCIOCSCPWR:
 116                 if (get_user(inarg, arg))
 117                         return -EFAULT;
 118                 apc_writeb(inarg & APC_REGMASK, APC_CPOWER_REG);
 119                 break;
 120         case APCIOCSBPORT:
 121                 if (get_user(inarg, arg))
 122                         return -EFAULT;
 123                 apc_writeb(inarg & APC_BPMASK, APC_BPORT_REG);
 124                 break;
 125         default:
 126                 return -EINVAL;
 127         };
 128
 129         return 0;
 130 }
 131
 132 static const struct file_operations apc_fops = {
 133         .ioctl =        apc_ioctl,
 134         .open =         apc_open,
 135         .release =      apc_release,
 136 };
 137
 138 static struct miscdevice apc_miscdev = { APC_MINOR, APC_DEVNAME, &apc_fops };
 139
 140 static int __init apc_probe(void)
 141 {
 142         struct sbus_bus *sbus = NULL;
 143         struct sbus_dev *sdev = NULL;
 144         int iTmp = 0;
 145
 146         for_each_sbus(sbus) {
 147                 for_each_sbusdev(sdev, sbus) {
 148                         if (!strcmp(sdev->prom_name, APC_OBPNAME)) {
 149                                 goto sbus_done;
 150                         }
 151                 }
 152         }
 153
 154 sbus_done:
 155         if (!sdev) {
 156                 return -ENODEV;
 157         }
 158
 159         apc_regsize = sdev->reg_addrs[0].reg_size;
 160         regs = sbus_ioremap(&sdev->resource[0], 0,
 161                                    apc_regsize, APC_OBPNAME);
 162         if(!regs) {
 163                 printk(KERN_ERR "%s: unable to map registers\n", APC_DEVNAME);
 164                 return -ENODEV;
 165         }
 166
 167         iTmp = misc_register(&apc_miscdev);
 168         if (iTmp != 0) {
 169                 printk(KERN_ERR "%s: unable to register device\n", APC_DEVNAME);
 170                 apc_free();
 171                 return -ENODEV;
 172         }
 173
 174         /* Assign power management IDLE handler */
 175         if(!apc_no_idle)
 176                 pm_idle = apc_swift_idle;
 177
 178         printk(KERN_INFO "%s: power management initialized%s\n",
 179                 APC_DEVNAME, apc_no_idle ? " (CPU idle disabled)" : "");
 180         return 0;
 181 }
 182
 183 /* This driver is not critical to the boot process
 184  * and is easiest to ioremap when SBus is already
 185  * initialized, so we install ourselves thusly:
 186  */
 187 __initcall(apc_probe);
 188