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Linux/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                 .owner = THIS_MODULE,
182                 .of_match_table = apc_match,
183         },
184         .probe          = apc_probe,
185 };
186 
187 static int __init apc_init(void)
188 {
189         return platform_driver_register(&apc_driver);
190 }
191 
192 /* This driver is not critical to the boot process
193  * and is easiest to ioremap when SBus is already
194  * initialized, so we install ourselves thusly:
195  */
196 __initcall(apc_init);
197 

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