1/*
2 *	Real Time Clock interface for Linux on the BVME6000
3 *
4 * Based on the PC driver by Paul Gortmaker.
5 */
6
7#define RTC_VERSION		"1.00"
8
9#include <linux/types.h>
10#include <linux/errno.h>
11#include <linux/miscdevice.h>
12#include <linux/ioport.h>
13#include <linux/capability.h>
14#include <linux/fcntl.h>
15#include <linux/init.h>
16#include <linux/poll.h>
17#include <linux/module.h>
18#include <linux/mc146818rtc.h>	/* For struct rtc_time and ioctls, etc */
19#include <linux/bcd.h>
20#include <asm/bvme6000hw.h>
21
22#include <asm/io.h>
23#include <asm/uaccess.h>
24#include <asm/setup.h>
25
26/*
27 *	We sponge a minor off of the misc major. No need slurping
28 *	up another valuable major dev number for this. If you add
29 *	an ioctl, make sure you don't conflict with SPARC's RTC
30 *	ioctls.
31 */
32
33static unsigned char days_in_mo[] =
34{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
35
36static atomic_t rtc_status = ATOMIC_INIT(1);
37
38static long rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
39{
40	volatile RtcPtr_t rtc = (RtcPtr_t)BVME_RTC_BASE;
41	unsigned char msr;
42	unsigned long flags;
43	struct rtc_time wtime;
44	void __user *argp = (void __user *)arg;
45
46	switch (cmd) {
47	case RTC_RD_TIME:	/* Read the time/date from RTC	*/
48	{
49		local_irq_save(flags);
50		/* Ensure clock and real-time-mode-register are accessible */
51		msr = rtc->msr & 0xc0;
52		rtc->msr = 0x40;
53		memset(&wtime, 0, sizeof(struct rtc_time));
54		do {
55			wtime.tm_sec =  bcd2bin(rtc->bcd_sec);
56			wtime.tm_min =  bcd2bin(rtc->bcd_min);
57			wtime.tm_hour = bcd2bin(rtc->bcd_hr);
58			wtime.tm_mday =  bcd2bin(rtc->bcd_dom);
59			wtime.tm_mon =  bcd2bin(rtc->bcd_mth)-1;
60			wtime.tm_year = bcd2bin(rtc->bcd_year);
61			if (wtime.tm_year < 70)
62				wtime.tm_year += 100;
63			wtime.tm_wday = bcd2bin(rtc->bcd_dow)-1;
64		} while (wtime.tm_sec != bcd2bin(rtc->bcd_sec));
65		rtc->msr = msr;
66		local_irq_restore(flags);
67		return copy_to_user(argp, &wtime, sizeof wtime) ?
68								-EFAULT : 0;
69	}
70	case RTC_SET_TIME:	/* Set the RTC */
71	{
72		struct rtc_time rtc_tm;
73		unsigned char mon, day, hrs, min, sec, leap_yr;
74		unsigned int yrs;
75
76		if (!capable(CAP_SYS_ADMIN))
77			return -EACCES;
78
79		if (copy_from_user(&rtc_tm, argp, sizeof(struct rtc_time)))
80			return -EFAULT;
81
82		yrs = rtc_tm.tm_year;
83		if (yrs < 1900)
84			yrs += 1900;
85		mon = rtc_tm.tm_mon + 1;   /* tm_mon starts at zero */
86		day = rtc_tm.tm_mday;
87		hrs = rtc_tm.tm_hour;
88		min = rtc_tm.tm_min;
89		sec = rtc_tm.tm_sec;
90
91		leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
92
93		if ((mon > 12) || (mon < 1) || (day == 0))
94			return -EINVAL;
95
96		if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
97			return -EINVAL;
98
99		if ((hrs >= 24) || (min >= 60) || (sec >= 60))
100			return -EINVAL;
101
102		if (yrs >= 2070)
103			return -EINVAL;
104
105		local_irq_save(flags);
106		/* Ensure clock and real-time-mode-register are accessible */
107		msr = rtc->msr & 0xc0;
108		rtc->msr = 0x40;
109
110		rtc->t0cr_rtmr = yrs%4;
111		rtc->bcd_tenms = 0;
112		rtc->bcd_sec   = bin2bcd(sec);
113		rtc->bcd_min   = bin2bcd(min);
114		rtc->bcd_hr    = bin2bcd(hrs);
115		rtc->bcd_dom   = bin2bcd(day);
116		rtc->bcd_mth   = bin2bcd(mon);
117		rtc->bcd_year  = bin2bcd(yrs%100);
118		if (rtc_tm.tm_wday >= 0)
119			rtc->bcd_dow = bin2bcd(rtc_tm.tm_wday+1);
120		rtc->t0cr_rtmr = yrs%4 | 0x08;
121
122		rtc->msr = msr;
123		local_irq_restore(flags);
124		return 0;
125	}
126	default:
127		return -EINVAL;
128	}
129}
130
131/*
132 * We enforce only one user at a time here with the open/close.
133 */
134static int rtc_open(struct inode *inode, struct file *file)
135{
136	if (!atomic_dec_and_test(&rtc_status)) {
137		atomic_inc(&rtc_status);
138		return -EBUSY;
139	}
140	return 0;
141}
142
143static int rtc_release(struct inode *inode, struct file *file)
144{
145	atomic_inc(&rtc_status);
146	return 0;
147}
148
149/*
150 *	The various file operations we support.
151 */
152
153static const struct file_operations rtc_fops = {
154	.unlocked_ioctl	= rtc_ioctl,
155	.open		= rtc_open,
156	.release	= rtc_release,
157	.llseek		= noop_llseek,
158};
159
160static struct miscdevice rtc_dev = {
161	.minor =	RTC_MINOR,
162	.name =		"rtc",
163	.fops =		&rtc_fops
164};
165
166static int __init rtc_DP8570A_init(void)
167{
168	if (!MACH_IS_BVME6000)
169		return -ENODEV;
170
171	printk(KERN_INFO "DP8570A Real Time Clock Driver v%s\n", RTC_VERSION);
172	return misc_register(&rtc_dev);
173}
174module_init(rtc_DP8570A_init);
175