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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 ([email protected])
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_OBPNAME "power-management"
32#define APC_DEVNAME "apc"
33
34static u8 __iomem *regs;
35static 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 */
46static 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 */
60static 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
73static inline void apc_free(struct platform_device *op)
74{
75 of_iounmap(&op->resource[0], regs, resource_size(&op->resource[0]));
76}
77
78static int apc_open(struct inode *inode, struct file *f)
79{
80 return 0;
81}
82
83static int apc_release(struct inode *inode, struct file *f)
84{
85 return 0;
86}
87
88static 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
133static 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
140static struct miscdevice apc_miscdev = { MISC_DYNAMIC_MINOR, APC_DEVNAME, &apc_fops };
141
142static 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
170static const struct of_device_id apc_match[] = {
171 {
172 .name = APC_OBPNAME,
173 },
174 {},
175};
176MODULE_DEVICE_TABLE(of, apc_match);
177
178static struct platform_driver apc_driver = {
179 .driver = {
180 .name = "apc",
181 .of_match_table = apc_match,
182 },
183 .probe = apc_probe,
184};
185
186static 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);