xref: /openbmc/linux/arch/sparc/kernel/pmc.c (revision 1da177e4)
1 /* pmc - Driver implementation for power management functions
2  * of Power Management Controller (PMC) on SPARCstation-Voyager.
3  *
4  * Copyright (c) 2002 Eric Brower (ebrower@usa.net)
5  */
6 
7 #include <linux/kernel.h>
8 #include <linux/fs.h>
9 #include <linux/errno.h>
10 #include <linux/init.h>
11 #include <linux/miscdevice.h>
12 #include <linux/pm.h>
13 
14 #include <asm/io.h>
15 #include <asm/sbus.h>
16 #include <asm/oplib.h>
17 #include <asm/uaccess.h>
18 #include <asm/auxio.h>
19 
20 /* Debug
21  *
22  * #define PMC_DEBUG_LED
23  * #define PMC_NO_IDLE
24  */
25 
26 #define PMC_MINOR	MISC_DYNAMIC_MINOR
27 #define PMC_OBPNAME	"SUNW,pmc"
28 #define PMC_DEVNAME "pmc"
29 
30 #define PMC_IDLE_REG	0x00
31 #define PMC_IDLE_ON		0x01
32 
33 volatile static u8 __iomem *regs;
34 static int pmc_regsize;
35 
36 #define pmc_readb(offs)			(sbus_readb(regs+offs))
37 #define pmc_writeb(val, offs) 	(sbus_writeb(val, regs+offs))
38 
39 /*
40  * CPU idle callback function
41  * See .../arch/sparc/kernel/process.c
42  */
43 void pmc_swift_idle(void)
44 {
45 #ifdef PMC_DEBUG_LED
46 	set_auxio(0x00, AUXIO_LED);
47 #endif
48 
49 	pmc_writeb(pmc_readb(PMC_IDLE_REG) | PMC_IDLE_ON, PMC_IDLE_REG);
50 
51 #ifdef PMC_DEBUG_LED
52 	set_auxio(AUXIO_LED, 0x00);
53 #endif
54 }
55 
56 static inline void pmc_free(void)
57 {
58 	sbus_iounmap(regs, pmc_regsize);
59 }
60 
61 static int __init pmc_probe(void)
62 {
63 	struct sbus_bus *sbus = NULL;
64 	struct sbus_dev *sdev = NULL;
65 	for_each_sbus(sbus) {
66 		for_each_sbusdev(sdev, sbus) {
67 			if (!strcmp(sdev->prom_name, PMC_OBPNAME)) {
68 				goto sbus_done;
69 			}
70 		}
71 	}
72 
73 sbus_done:
74 	if (!sdev) {
75 		return -ENODEV;
76 	}
77 
78 	pmc_regsize = sdev->reg_addrs[0].reg_size;
79 	regs = sbus_ioremap(&sdev->resource[0], 0,
80 				   pmc_regsize, PMC_OBPNAME);
81 	if (!regs) {
82 		printk(KERN_ERR "%s: unable to map registers\n", PMC_DEVNAME);
83 		return -ENODEV;
84 	}
85 
86 #ifndef PMC_NO_IDLE
87 	/* Assign power management IDLE handler */
88 	pm_idle = pmc_swift_idle;
89 #endif
90 
91 	printk(KERN_INFO "%s: power management initialized\n", PMC_DEVNAME);
92 	return 0;
93 }
94 
95 /* This driver is not critical to the boot process
96  * and is easiest to ioremap when SBus is already
97  * initialized, so we install ourselves thusly:
98  */
99 __initcall(pmc_probe);
100