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
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