LXR linux/arch/sparc/kernel/apc.c

   1// SPDX-License-Identifier: GPL-2.0
   2/* apc - Driver implementation for power management functions
   3 * of Aurora Personality Chip (APC) on SPARCstation-4/5 and
   4 * derivatives.
   5 *
   6 * Copyright (c) 2002 Eric Brower (ebrower@usa.net)
   7 */
   8
   9#include <linux/kernel.h>
  10#include <linux/fs.h>
  11#include <linux/errno.h>
  12#include <linux/init.h>
  13#include <linux/miscdevice.h>
  14#include <linux/pm.h>
  15#include <linux/of.h>
  16#include <linux/of_device.h>
  17#include <linux/module.h>
  18
  19#include <asm/io.h>
  20#include <asm/oplib.h>
  21#include <linux/uaccess.h>
  22#include <asm/auxio.h>
  23#include <asm/apc.h>
  24#include <asm/processor.h>
  25
  26/* Debugging
  27 * 
  28 * #define APC_DEBUG_LED
  29 */
  30
  31#define APC_MINOR       MISC_DYNAMIC_MINOR
  32#define APC_OBPNAME     "power-management"
  33#define APC_DEVNAME "apc"
  34
  35static u8 __iomem *regs;
  36static int apc_no_idle = 0;
  37
  38#define apc_readb(offs)         (sbus_readb(regs+offs))
  39#define apc_writeb(val, offs)   (sbus_writeb(val, regs+offs))
  40
  41/* Specify "apc=noidle" on the kernel command line to 
  42 * disable APC CPU standby support.  Certain prototype
  43 * systems (SPARCstation-Fox) do not play well with APC
  44 * CPU idle, so disable this if your system has APC and 
  45 * crashes randomly.
  46 */
  47static int __init apc_setup(char *str) 
  48{
  49        if(!strncmp(str, "noidle", strlen("noidle"))) {
  50                apc_no_idle = 1;
  51                return 1;
  52        }
  53        return 0;
  54}
  55__setup("apc=", apc_setup);
  56
  57/* 
  58 * CPU idle callback function
  59 * See .../arch/sparc/kernel/process.c
  60 */
  61static void apc_swift_idle(void)
  62{
  63#ifdef APC_DEBUG_LED
  64        set_auxio(0x00, AUXIO_LED); 
  65#endif
  66
  67        apc_writeb(apc_readb(APC_IDLE_REG) | APC_IDLE_ON, APC_IDLE_REG);
  68
  69#ifdef APC_DEBUG_LED
  70        set_auxio(AUXIO_LED, 0x00); 
  71#endif
  72} 
  73
  74static inline void apc_free(struct platform_device *op)
  75{
  76        of_iounmap(&op->resource[0], regs, resource_size(&op->resource[0]));
  77}
  78
  79static int apc_open(struct inode *inode, struct file *f)
  80{
  81        return 0;
  82}
  83
  84static int apc_release(struct inode *inode, struct file *f)
  85{
  86        return 0;
  87}
  88
  89static long apc_ioctl(struct file *f, unsigned int cmd, unsigned long __arg)
  90{
  91        __u8 inarg, __user *arg = (__u8 __user *) __arg;
  92
  93        switch (cmd) {
  94        case APCIOCGFANCTL:
  95                if (put_user(apc_readb(APC_FANCTL_REG) & APC_REGMASK, arg))
  96                        return -EFAULT;
  97                break;
  98
  99        case APCIOCGCPWR:
 100                if (put_user(apc_readb(APC_CPOWER_REG) & APC_REGMASK, arg))
 101                        return -EFAULT;
 102                break;
 103
 104        case APCIOCGBPORT:
 105                if (put_user(apc_readb(APC_BPORT_REG) & APC_BPMASK, arg))
 106                        return -EFAULT;
 107                break;
 108
 109        case APCIOCSFANCTL:
 110                if (get_user(inarg, arg))
 111                        return -EFAULT;
 112                apc_writeb(inarg & APC_REGMASK, APC_FANCTL_REG);
 113                break;
 114
 115        case APCIOCSCPWR:
 116                if (get_user(inarg, arg))
 117                        return -EFAULT;
 118                apc_writeb(inarg & APC_REGMASK, APC_CPOWER_REG);
 119                break;
 120
 121        case APCIOCSBPORT:
 122                if (get_user(inarg, arg))
 123                        return -EFAULT;
 124                apc_writeb(inarg & APC_BPMASK, APC_BPORT_REG);
 125                break;
 126
 127        default:
 128                return -EINVAL;
 129        }
 130
 131        return 0;
 132}
 133
 134static const struct file_operations apc_fops = {
 135        .unlocked_ioctl =       apc_ioctl,
 136        .open =                 apc_open,
 137        .release =              apc_release,
 138        .llseek =               noop_llseek,
 139};
 140
 141static struct miscdevice apc_miscdev = { APC_MINOR, APC_DEVNAME, &apc_fops };
 142
 143static int apc_probe(struct platform_device *op)
 144{
 145        int err;
 146
 147        regs = of_ioremap(&op->resource[0], 0,
 148                          resource_size(&op->resource[0]), APC_OBPNAME);
 149        if (!regs) {
 150                printk(KERN_ERR "%s: unable to map registers\n", APC_DEVNAME);
 151                return -ENODEV;
 152        }
 153
 154        err = misc_register(&apc_miscdev);
 155        if (err) {
 156                printk(KERN_ERR "%s: unable to register device\n", APC_DEVNAME);
 157                apc_free(op);
 158                return -ENODEV;
 159        }
 160
 161        /* Assign power management IDLE handler */
 162        if (!apc_no_idle)
 163                sparc_idle = apc_swift_idle;
 164
 165        printk(KERN_INFO "%s: power management initialized%s\n", 
 166               APC_DEVNAME, apc_no_idle ? " (CPU idle disabled)" : "");
 167
 168        return 0;
 169}
 170
 171static const struct of_device_id apc_match[] = {
 172        {
 173                .name = APC_OBPNAME,
 174        },
 175        {},
 176};
 177MODULE_DEVICE_TABLE(of, apc_match);
 178
 179static struct platform_driver apc_driver = {
 180        .driver = {
 181                .name = "apc",
 182                .of_match_table = apc_match,
 183        },
 184        .probe          = apc_probe,
 185};
 186
 187static 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