xref: /openbmc/linux/arch/sparc/kernel/apc.c (revision 263291fa)
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/platform_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  */
apc_setup(char * str)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  */
apc_swift_idle(void)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 
apc_free(struct platform_device * op)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 
apc_open(struct inode * inode,struct file * f)79 static int apc_open(struct inode *inode, struct file *f)
80 {
81 	return 0;
82 }
83 
apc_release(struct inode * inode,struct file * f)84 static int apc_release(struct inode *inode, struct file *f)
85 {
86 	return 0;
87 }
88 
apc_ioctl(struct file * f,unsigned int cmd,unsigned long __arg)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 
apc_probe(struct platform_device * op)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 
apc_init(void)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