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/pm.h>
  14 #include <linux/of.h>
  15 #include <linux/of_device.h>
  16 #include <linux/module.h>
  17
  18 #include <asm/io.h>
  19 #include <asm/oplib.h>
  20 #include <asm/uaccess.h>
  21 #include <asm/auxio.h>
  22 #include <asm/apc.h>
  23
  24 /* Debugging
  25  *
  26  * #define APC_DEBUG_LED
  27  */
  28
  29 #define APC_MINOR       MISC_DYNAMIC_MINOR
  30 #define APC_OBPNAME     "power-management"
  31 #define APC_DEVNAME "apc"
  32
  33 static u8 __iomem *regs;
  34 static int apc_no_idle __devinitdata = 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(struct platform_device *op)
  73 {
  74         of_iounmap(&op->resource[0], regs, resource_size(&op->resource[0]));
  75 }
  76
  77 static int apc_open(struct inode *inode, struct file *f)
  78 {
  79         return 0;
  80 }
  81
  82 static int apc_release(struct inode *inode, struct file *f)
  83 {
  84         return 0;
  85 }
  86
  87 static long apc_ioctl(struct file *f, unsigned int cmd, unsigned long __arg)
  88 {
  89         __u8 inarg, __user *arg = (__u8 __user *) __arg;
  90
  91         switch (cmd) {
  92         case APCIOCGFANCTL:
  93                 if (put_user(apc_readb(APC_FANCTL_REG) & APC_REGMASK, arg))
  94                         return -EFAULT;
  95                 break;
  96
  97         case APCIOCGCPWR:
  98                 if (put_user(apc_readb(APC_CPOWER_REG) & APC_REGMASK, arg))
  99                         return -EFAULT;
 100                 break;
 101
 102         case APCIOCGBPORT:
 103                 if (put_user(apc_readb(APC_BPORT_REG) & APC_BPMASK, arg))
 104                         return -EFAULT;
 105                 break;
 106
 107         case APCIOCSFANCTL:
 108                 if (get_user(inarg, arg))
 109                         return -EFAULT;
 110                 apc_writeb(inarg & APC_REGMASK, APC_FANCTL_REG);
 111                 break;
 112
 113         case APCIOCSCPWR:
 114                 if (get_user(inarg, arg))
 115                         return -EFAULT;
 116                 apc_writeb(inarg & APC_REGMASK, APC_CPOWER_REG);
 117                 break;
 118
 119         case APCIOCSBPORT:
 120                 if (get_user(inarg, arg))
 121                         return -EFAULT;
 122                 apc_writeb(inarg & APC_BPMASK, APC_BPORT_REG);
 123                 break;
 124
 125         default:
 126                 return -EINVAL;
 127         }
 128
 129         return 0;
 130 }
 131
 132 static const struct file_operations apc_fops = {
 133         .unlocked_ioctl =       apc_ioctl,
 134         .open =                 apc_open,
 135         .release =              apc_release,
 136         .llseek =               noop_llseek,
 137 };
 138
 139 static struct miscdevice apc_miscdev = { APC_MINOR, APC_DEVNAME, &apc_fops };
 140
 141 static int __devinit apc_probe(struct platform_device *op)
 142 {
 143         int err;
 144
 145         regs = of_ioremap(&op->resource[0], 0,
 146                           resource_size(&op->resource[0]), APC_OBPNAME);
 147         if (!regs) {
 148                 printk(KERN_ERR "%s: unable to map registers\n", APC_DEVNAME);
 149                 return -ENODEV;
 150         }
 151
 152         err = misc_register(&apc_miscdev);
 153         if (err) {
 154                 printk(KERN_ERR "%s: unable to register device\n", APC_DEVNAME);
 155                 apc_free(op);
 156                 return -ENODEV;
 157         }
 158
 159         /* Assign power management IDLE handler */
 160         if (!apc_no_idle)
 161                 pm_idle = apc_swift_idle;
 162
 163         printk(KERN_INFO "%s: power management initialized%s\n",
 164                APC_DEVNAME, apc_no_idle ? " (CPU idle disabled)" : "");
 165
 166         return 0;
 167 }
 168
 169 static struct of_device_id apc_match[] = {
 170         {
 171                 .name = APC_OBPNAME,
 172         },
 173         {},
 174 };
 175 MODULE_DEVICE_TABLE(of, apc_match);
 176
 177 static struct platform_driver apc_driver = {
 178         .driver = {
 179                 .name = "apc",
 180                 .owner = THIS_MODULE,
 181                 .of_match_table = apc_match,
 182         },
 183         .probe          = apc_probe,
 184 };
 185
 186 static int __init apc_init(void)
 187 {
 188         return platform_driver_register(&apc_driver);
 189 }
 190
 191 /* This driver is not critical to the boot process
 192  * and is easiest to ioremap when SBus is already
 193  * initialized, so we install ourselves thusly:
 194  */
 195 __initcall(apc_init);