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 #include <asm/processor.h>
  24
  25 /* Debugging
  26  *
  27  * #define APC_DEBUG_LED
  28  */
  29
  30 #define APC_MINOR       MISC_DYNAMIC_MINOR
  31 #define APC_OBPNAME     "power-management"
  32 #define APC_DEVNAME "apc"
  33
  34 static u8 __iomem *regs;
  35 static int apc_no_idle = 0;
  36
  37 #define apc_readb(offs)         (sbus_readb(regs+offs))
  38 #define apc_writeb(val, offs)   (sbus_writeb(val, regs+offs))
  39
  40 /* Specify "apc=noidle" on the kernel command line to
  41  * disable APC CPU standby support.  Certain prototype
  42  * systems (SPARCstation-Fox) do not play well with APC
  43  * CPU idle, so disable this if your system has APC and
  44  * crashes randomly.
  45  */
  46 static int __init apc_setup(char *str)
  47 {
  48         if(!strncmp(str, "noidle", strlen("noidle"))) {
  49                 apc_no_idle = 1;
  50                 return 1;
  51         }
  52         return 0;
  53 }
  54 __setup("apc=", apc_setup);
  55
  56 /*
  57  * CPU idle callback function
  58  * See .../arch/sparc/kernel/process.c
  59  */
  60 static void apc_swift_idle(void)
  61 {
  62 #ifdef APC_DEBUG_LED
  63         set_auxio(0x00, AUXIO_LED);
  64 #endif
  65
  66         apc_writeb(apc_readb(APC_IDLE_REG) | APC_IDLE_ON, APC_IDLE_REG);
  67
  68 #ifdef APC_DEBUG_LED
  69         set_auxio(AUXIO_LED, 0x00);
  70 #endif
  71 }
  72
  73 static inline void apc_free(struct platform_device *op)
  74 {
  75         of_iounmap(&op->resource[0], regs, resource_size(&op->resource[0]));
  76 }
  77
  78 static int apc_open(struct inode *inode, struct file *f)
  79 {
  80         return 0;
  81 }
  82
  83 static int apc_release(struct inode *inode, struct file *f)
  84 {
  85         return 0;
  86 }
  87
  88 static long apc_ioctl(struct file *f, unsigned int cmd, unsigned long __arg)
  89 {
  90         __u8 inarg, __user *arg = (__u8 __user *) __arg;
  91
  92         switch (cmd) {
  93         case APCIOCGFANCTL:
  94                 if (put_user(apc_readb(APC_FANCTL_REG) & APC_REGMASK, arg))
  95                         return -EFAULT;
  96                 break;
  97
  98         case APCIOCGCPWR:
  99                 if (put_user(apc_readb(APC_CPOWER_REG) & APC_REGMASK, arg))
 100                         return -EFAULT;
 101                 break;
 102
 103         case APCIOCGBPORT:
 104                 if (put_user(apc_readb(APC_BPORT_REG) & APC_BPMASK, arg))
 105                         return -EFAULT;
 106                 break;
 107
 108         case APCIOCSFANCTL:
 109                 if (get_user(inarg, arg))
 110                         return -EFAULT;
 111                 apc_writeb(inarg & APC_REGMASK, APC_FANCTL_REG);
 112                 break;
 113
 114         case APCIOCSCPWR:
 115                 if (get_user(inarg, arg))
 116                         return -EFAULT;
 117                 apc_writeb(inarg & APC_REGMASK, APC_CPOWER_REG);
 118                 break;
 119
 120         case APCIOCSBPORT:
 121                 if (get_user(inarg, arg))
 122                         return -EFAULT;
 123                 apc_writeb(inarg & APC_BPMASK, APC_BPORT_REG);
 124                 break;
 125
 126         default:
 127                 return -EINVAL;
 128         }
 129
 130         return 0;
 131 }
 132
 133 static const struct file_operations apc_fops = {
 134         .unlocked_ioctl =       apc_ioctl,
 135         .open =                 apc_open,
 136         .release =              apc_release,
 137         .llseek =               noop_llseek,
 138 };
 139
 140 static struct miscdevice apc_miscdev = { APC_MINOR, APC_DEVNAME, &apc_fops };
 141
 142 static int apc_probe(struct platform_device *op)
 143 {
 144         int err;
 145
 146         regs = of_ioremap(&op->resource[0], 0,
 147                           resource_size(&op->resource[0]), APC_OBPNAME);
 148         if (!regs) {
 149                 printk(KERN_ERR "%s: unable to map registers\n", APC_DEVNAME);
 150                 return -ENODEV;
 151         }
 152
 153         err = misc_register(&apc_miscdev);
 154         if (err) {
 155                 printk(KERN_ERR "%s: unable to register device\n", APC_DEVNAME);
 156                 apc_free(op);
 157                 return -ENODEV;
 158         }
 159
 160         /* Assign power management IDLE handler */
 161         if (!apc_no_idle)
 162                 sparc_idle = apc_swift_idle;
 163
 164         printk(KERN_INFO "%s: power management initialized%s\n",
 165                APC_DEVNAME, apc_no_idle ? " (CPU idle disabled)" : "");
 166
 167         return 0;
 168 }
 169
 170 static struct of_device_id apc_match[] = {
 171         {
 172                 .name = APC_OBPNAME,
 173         },
 174         {},
 175 };
 176 MODULE_DEVICE_TABLE(of, apc_match);
 177
 178 static struct platform_driver apc_driver = {
 179         .driver = {
 180                 .name = "apc",
 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);