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 35 static u8 __iomem *regs; 36 static 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 */ 47 static 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 */ 61 static 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 74 static inline void apc_free(struct platform_device *op) 75 { 76 of_iounmap(&op->resource[0], regs, resource_size(&op->resource[0])); 77 } 78 79 static int apc_open(struct inode *inode, struct file *f) 80 { 81 return 0; 82 } 83 84 static int apc_release(struct inode *inode, struct file *f) 85 { 86 return 0; 87 } 88 89 static 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 } 133 134 static const struct file_operations apc_fops = { 135 .unlocked_ioctl = apc_ioctl, 136 .open = apc_open, 137 .release = apc_release, 138 .llseek = noop_llseek, 139 }; 140 141 static struct miscdevice apc_miscdev = { APC_MINOR, APC_DEVNAME, &apc_fops }; 142 143 static 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 } 170 171 static const struct of_device_id apc_match[] = { 172 { 173 .name = APC_OBPNAME, 174 }, 175 {}, 176 }; 177 MODULE_DEVICE_TABLE(of, apc_match); 178 179 static struct platform_driver apc_driver = { 180 .driver = { 181 .name = "apc", 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