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
  17 #include <asm/io.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 static u8 __iomem *regs;
  33 static int apc_no_idle __devinitdata = 0;
  34
  35 #define apc_readb(offs)         (sbus_readb(regs+offs))
  36 #define apc_writeb(val, offs)   (sbus_writeb(val, regs+offs))
  37
  38 /* Specify "apc=noidle" on the kernel command line to
  39  * disable APC CPU standby support.  Certain prototype
  40  * systems (SPARCstation-Fox) do not play well with APC
  41  * CPU idle, so disable this if your system has APC and
  42  * crashes randomly.
  43  */
  44 static int __init apc_setup(char *str)
  45 {
  46         if(!strncmp(str, "noidle", strlen("noidle"))) {
  47                 apc_no_idle = 1;
  48                 return 1;
  49         }
  50         return 0;
  51 }
  52 __setup("apc=", apc_setup);
  53
  54 /*
  55  * CPU idle callback function
  56  * See .../arch/sparc/kernel/process.c
  57  */
  58 static void apc_swift_idle(void)
  59 {
  60 #ifdef APC_DEBUG_LED
  61         set_auxio(0x00, AUXIO_LED);
  62 #endif
  63
  64         apc_writeb(apc_readb(APC_IDLE_REG) | APC_IDLE_ON, APC_IDLE_REG);
  65
  66 #ifdef APC_DEBUG_LED
  67         set_auxio(AUXIO_LED, 0x00);
  68 #endif
  69 }
  70
  71 static inline void apc_free(struct platform_device *op)
  72 {
  73         of_iounmap(&op->resource[0], regs, resource_size(&op->resource[0]));
  74 }
  75
  76 static int apc_open(struct inode *inode, struct file *f)
  77 {
  78         return 0;
  79 }
  80
  81 static int apc_release(struct inode *inode, struct file *f)
  82 {
  83         return 0;
  84 }
  85
  86 static long apc_ioctl(struct file *f, unsigned int cmd, unsigned long __arg)
  87 {
  88         __u8 inarg, __user *arg = (__u8 __user *) __arg;
  89
  90         switch (cmd) {
  91         case APCIOCGFANCTL:
  92                 if (put_user(apc_readb(APC_FANCTL_REG) & APC_REGMASK, arg))
  93                         return -EFAULT;
  94                 break;
  95
  96         case APCIOCGCPWR:
  97                 if (put_user(apc_readb(APC_CPOWER_REG) & APC_REGMASK, arg))
  98                         return -EFAULT;
  99                 break;
 100
 101         case APCIOCGBPORT:
 102                 if (put_user(apc_readb(APC_BPORT_REG) & APC_BPMASK, arg))
 103                         return -EFAULT;
 104                 break;
 105
 106         case APCIOCSFANCTL:
 107                 if (get_user(inarg, arg))
 108                         return -EFAULT;
 109                 apc_writeb(inarg & APC_REGMASK, APC_FANCTL_REG);
 110                 break;
 111
 112         case APCIOCSCPWR:
 113                 if (get_user(inarg, arg))
 114                         return -EFAULT;
 115                 apc_writeb(inarg & APC_REGMASK, APC_CPOWER_REG);
 116                 break;
 117
 118         case APCIOCSBPORT:
 119                 if (get_user(inarg, arg))
 120                         return -EFAULT;
 121                 apc_writeb(inarg & APC_BPMASK, APC_BPORT_REG);
 122                 break;
 123
 124         default:
 125                 return -EINVAL;
 126         };
 127
 128         return 0;
 129 }
 130
 131 static const struct file_operations apc_fops = {
 132         .unlocked_ioctl =       apc_ioctl,
 133         .open =                 apc_open,
 134         .release =              apc_release,
 135         .llseek =               noop_llseek,
 136 };
 137
 138 static struct miscdevice apc_miscdev = { APC_MINOR, APC_DEVNAME, &apc_fops };
 139
 140 static int __devinit apc_probe(struct platform_device *op)
 141 {
 142         int err;
 143
 144         regs = of_ioremap(&op->resource[0], 0,
 145                           resource_size(&op->resource[0]), APC_OBPNAME);
 146         if (!regs) {
 147                 printk(KERN_ERR "%s: unable to map registers\n", APC_DEVNAME);
 148                 return -ENODEV;
 149         }
 150
 151         err = misc_register(&apc_miscdev);
 152         if (err) {
 153                 printk(KERN_ERR "%s: unable to register device\n", APC_DEVNAME);
 154                 apc_free(op);
 155                 return -ENODEV;
 156         }
 157
 158         /* Assign power management IDLE handler */
 159         if (!apc_no_idle)
 160                 pm_idle = apc_swift_idle;
 161
 162         printk(KERN_INFO "%s: power management initialized%s\n",
 163                APC_DEVNAME, apc_no_idle ? " (CPU idle disabled)" : "");
 164
 165         return 0;
 166 }
 167
 168 static struct of_device_id __initdata apc_match[] = {
 169         {
 170                 .name = APC_OBPNAME,
 171         },
 172         {},
 173 };
 174 MODULE_DEVICE_TABLE(of, apc_match);
 175
 176 static struct platform_driver apc_driver = {
 177         .driver = {
 178                 .name = "apc",
 179                 .owner = THIS_MODULE,
 180                 .of_match_table = apc_match,
 181         },
 182         .probe          = apc_probe,
 183 };
 184
 185 static int __init apc_init(void)
 186 {
 187         return platform_driver_register(&apc_driver);
 188 }
 189
 190 /* This driver is not critical to the boot process
 191  * and is easiest to ioremap when SBus is already
 192  * initialized, so we install ourselves thusly:
 193  */
 194 __initcall(apc_init);