1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * Real Time Clock interface for Linux on the BVME6000 |
4 | * |
5 | * Based on the PC driver by Paul Gortmaker. |
6 | */ |
7 | |
8 | #define RTC_VERSION "1.00" |
9 | |
10 | #include <linux/types.h> |
11 | #include <linux/errno.h> |
12 | #include <linux/miscdevice.h> |
13 | #include <linux/ioport.h> |
14 | #include <linux/capability.h> |
15 | #include <linux/fcntl.h> |
16 | #include <linux/init.h> |
17 | #include <linux/poll.h> |
18 | #include <linux/module.h> |
19 | #include <linux/rtc.h> /* For struct rtc_time and ioctls, etc */ |
20 | #include <linux/bcd.h> |
21 | #include <asm/bvme6000hw.h> |
22 | |
23 | #include <asm/io.h> |
24 | #include <linux/uaccess.h> |
25 | #include <asm/setup.h> |
26 | |
27 | /* |
28 | * We sponge a minor off of the misc major. No need slurping |
29 | * up another valuable major dev number for this. If you add |
30 | * an ioctl, make sure you don't conflict with SPARC's RTC |
31 | * ioctls. |
32 | */ |
33 | |
34 | static unsigned char days_in_mo[] = |
35 | {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; |
36 | |
37 | static atomic_t rtc_status = ATOMIC_INIT(1); |
38 | |
39 | static long rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
40 | { |
41 | volatile RtcPtr_t rtc = (RtcPtr_t)BVME_RTC_BASE; |
42 | unsigned char msr; |
43 | unsigned long flags; |
44 | struct rtc_time wtime; |
45 | void __user *argp = (void __user *)arg; |
46 | |
47 | switch (cmd) { |
48 | case RTC_RD_TIME: /* Read the time/date from RTC */ |
49 | { |
50 | local_irq_save(flags); |
51 | /* Ensure clock and real-time-mode-register are accessible */ |
52 | msr = rtc->msr & 0xc0; |
53 | rtc->msr = 0x40; |
54 | memset(&wtime, 0, sizeof(struct rtc_time)); |
55 | do { |
56 | wtime.tm_sec = bcd2bin(rtc->bcd_sec); |
57 | wtime.tm_min = bcd2bin(rtc->bcd_min); |
58 | wtime.tm_hour = bcd2bin(rtc->bcd_hr); |
59 | wtime.tm_mday = bcd2bin(rtc->bcd_dom); |
60 | wtime.tm_mon = bcd2bin(rtc->bcd_mth)-1; |
61 | wtime.tm_year = bcd2bin(rtc->bcd_year); |
62 | if (wtime.tm_year < 70) |
63 | wtime.tm_year += 100; |
64 | wtime.tm_wday = bcd2bin(rtc->bcd_dow)-1; |
65 | } while (wtime.tm_sec != bcd2bin(rtc->bcd_sec)); |
66 | rtc->msr = msr; |
67 | local_irq_restore(flags); |
68 | return copy_to_user(to: argp, from: &wtime, n: sizeof wtime) ? |
69 | -EFAULT : 0; |
70 | } |
71 | case RTC_SET_TIME: /* Set the RTC */ |
72 | { |
73 | struct rtc_time rtc_tm; |
74 | unsigned char mon, day, hrs, min, sec, leap_yr; |
75 | unsigned int yrs; |
76 | |
77 | if (!capable(CAP_SYS_ADMIN)) |
78 | return -EACCES; |
79 | |
80 | if (copy_from_user(to: &rtc_tm, from: argp, n: sizeof(struct rtc_time))) |
81 | return -EFAULT; |
82 | |
83 | yrs = rtc_tm.tm_year; |
84 | if (yrs < 1900) |
85 | yrs += 1900; |
86 | mon = rtc_tm.tm_mon + 1; /* tm_mon starts at zero */ |
87 | day = rtc_tm.tm_mday; |
88 | hrs = rtc_tm.tm_hour; |
89 | min = rtc_tm.tm_min; |
90 | sec = rtc_tm.tm_sec; |
91 | |
92 | leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400)); |
93 | |
94 | if ((mon > 12) || (mon < 1) || (day == 0)) |
95 | return -EINVAL; |
96 | |
97 | if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr))) |
98 | return -EINVAL; |
99 | |
100 | if ((hrs >= 24) || (min >= 60) || (sec >= 60)) |
101 | return -EINVAL; |
102 | |
103 | if (yrs >= 2070) |
104 | return -EINVAL; |
105 | |
106 | local_irq_save(flags); |
107 | /* Ensure clock and real-time-mode-register are accessible */ |
108 | msr = rtc->msr & 0xc0; |
109 | rtc->msr = 0x40; |
110 | |
111 | rtc->t0cr_rtmr = yrs%4; |
112 | rtc->bcd_tenms = 0; |
113 | rtc->bcd_sec = bin2bcd(sec); |
114 | rtc->bcd_min = bin2bcd(min); |
115 | rtc->bcd_hr = bin2bcd(hrs); |
116 | rtc->bcd_dom = bin2bcd(day); |
117 | rtc->bcd_mth = bin2bcd(mon); |
118 | rtc->bcd_year = bin2bcd(yrs%100); |
119 | if (rtc_tm.tm_wday >= 0) |
120 | rtc->bcd_dow = bin2bcd(rtc_tm.tm_wday+1); |
121 | rtc->t0cr_rtmr = yrs%4 | 0x08; |
122 | |
123 | rtc->msr = msr; |
124 | local_irq_restore(flags); |
125 | return 0; |
126 | } |
127 | default: |
128 | return -EINVAL; |
129 | } |
130 | } |
131 | |
132 | /* |
133 | * We enforce only one user at a time here with the open/close. |
134 | */ |
135 | static int rtc_open(struct inode *inode, struct file *file) |
136 | { |
137 | if (!atomic_dec_and_test(v: &rtc_status)) { |
138 | atomic_inc(v: &rtc_status); |
139 | return -EBUSY; |
140 | } |
141 | return 0; |
142 | } |
143 | |
144 | static int rtc_release(struct inode *inode, struct file *file) |
145 | { |
146 | atomic_inc(v: &rtc_status); |
147 | return 0; |
148 | } |
149 | |
150 | /* |
151 | * The various file operations we support. |
152 | */ |
153 | |
154 | static const struct file_operations rtc_fops = { |
155 | .unlocked_ioctl = rtc_ioctl, |
156 | .open = rtc_open, |
157 | .release = rtc_release, |
158 | .llseek = noop_llseek, |
159 | }; |
160 | |
161 | static struct miscdevice rtc_dev = { |
162 | .minor = RTC_MINOR, |
163 | .name = "rtc" , |
164 | .fops = &rtc_fops |
165 | }; |
166 | |
167 | static int __init rtc_DP8570A_init(void) |
168 | { |
169 | if (!MACH_IS_BVME6000) |
170 | return -ENODEV; |
171 | |
172 | pr_info("DP8570A Real Time Clock Driver v%s\n" , RTC_VERSION); |
173 | return misc_register(misc: &rtc_dev); |
174 | } |
175 | module_init(rtc_DP8570A_init); |
176 | |