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-rw-r--r--drivers/char/ds1286.c578
1 files changed, 578 insertions, 0 deletions
diff --git a/drivers/char/ds1286.c b/drivers/char/ds1286.c
new file mode 100644
index 000000000000..d755cac14bc1
--- /dev/null
+++ b/drivers/char/ds1286.c
@@ -0,0 +1,578 @@
+/*
+ * DS1286 Real Time Clock interface for Linux
+ *
+ * Copyright (C) 1998, 1999, 2000 Ralf Baechle
+ *
+ * Based on code written by Paul Gortmaker.
+ *
+ * This driver allows use of the real time clock (built into nearly all
+ * computers) from user space. It exports the /dev/rtc interface supporting
+ * various ioctl() and also the /proc/rtc pseudo-file for status
+ * information.
+ *
+ * The ioctls can be used to set the interrupt behaviour and generation rate
+ * from the RTC via IRQ 8. Then the /dev/rtc interface can be used to make
+ * use of these timer interrupts, be they interval or alarm based.
+ *
+ * The /dev/rtc interface will block on reads until an interrupt has been
+ * received. If a RTC interrupt has already happened, it will output an
+ * unsigned long and then block. The output value contains the interrupt
+ * status in the low byte and the number of interrupts since the last read
+ * in the remaining high bytes. The /dev/rtc interface can also be used with
+ * the select(2) call.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ */
+#include <linux/ds1286.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/miscdevice.h>
+#include <linux/slab.h>
+#include <linux/ioport.h>
+#include <linux/fcntl.h>
+#include <linux/init.h>
+#include <linux/poll.h>
+#include <linux/rtc.h>
+#include <linux/spinlock.h>
+#include <linux/bcd.h>
+#include <linux/proc_fs.h>
+
+#include <asm/uaccess.h>
+#include <asm/system.h>
+
+#define DS1286_VERSION "1.0"
+
+/*
+ * We sponge a minor off of the misc major. No need slurping
+ * up another valuable major dev number for this. If you add
+ * an ioctl, make sure you don't conflict with SPARC's RTC
+ * ioctls.
+ */
+
+static DECLARE_WAIT_QUEUE_HEAD(ds1286_wait);
+
+static ssize_t ds1286_read(struct file *file, char *buf,
+ size_t count, loff_t *ppos);
+
+static int ds1286_ioctl(struct inode *inode, struct file *file,
+ unsigned int cmd, unsigned long arg);
+
+static unsigned int ds1286_poll(struct file *file, poll_table *wait);
+
+static void ds1286_get_alm_time (struct rtc_time *alm_tm);
+static void ds1286_get_time(struct rtc_time *rtc_tm);
+static int ds1286_set_time(struct rtc_time *rtc_tm);
+
+static inline unsigned char ds1286_is_updating(void);
+
+static DEFINE_SPINLOCK(ds1286_lock);
+
+static int ds1286_read_proc(char *page, char **start, off_t off,
+ int count, int *eof, void *data);
+
+/*
+ * Bits in rtc_status. (7 bits of room for future expansion)
+ */
+
+#define RTC_IS_OPEN 0x01 /* means /dev/rtc is in use */
+#define RTC_TIMER_ON 0x02 /* missed irq timer active */
+
+static unsigned char ds1286_status; /* bitmapped status byte. */
+
+static unsigned char days_in_mo[] = {
+ 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
+};
+
+/*
+ * Now all the various file operations that we export.
+ */
+
+static ssize_t ds1286_read(struct file *file, char *buf,
+ size_t count, loff_t *ppos)
+{
+ return -EIO;
+}
+
+static int ds1286_ioctl(struct inode *inode, struct file *file,
+ unsigned int cmd, unsigned long arg)
+{
+ struct rtc_time wtime;
+
+ switch (cmd) {
+ case RTC_AIE_OFF: /* Mask alarm int. enab. bit */
+ {
+ unsigned int flags;
+ unsigned char val;
+
+ if (!capable(CAP_SYS_TIME))
+ return -EACCES;
+
+ spin_lock_irqsave(&ds1286_lock, flags);
+ val = rtc_read(RTC_CMD);
+ val |= RTC_TDM;
+ rtc_write(val, RTC_CMD);
+ spin_unlock_irqrestore(&ds1286_lock, flags);
+
+ return 0;
+ }
+ case RTC_AIE_ON: /* Allow alarm interrupts. */
+ {
+ unsigned int flags;
+ unsigned char val;
+
+ if (!capable(CAP_SYS_TIME))
+ return -EACCES;
+
+ spin_lock_irqsave(&ds1286_lock, flags);
+ val = rtc_read(RTC_CMD);
+ val &= ~RTC_TDM;
+ rtc_write(val, RTC_CMD);
+ spin_unlock_irqrestore(&ds1286_lock, flags);
+
+ return 0;
+ }
+ case RTC_WIE_OFF: /* Mask watchdog int. enab. bit */
+ {
+ unsigned int flags;
+ unsigned char val;
+
+ if (!capable(CAP_SYS_TIME))
+ return -EACCES;
+
+ spin_lock_irqsave(&ds1286_lock, flags);
+ val = rtc_read(RTC_CMD);
+ val |= RTC_WAM;
+ rtc_write(val, RTC_CMD);
+ spin_unlock_irqrestore(&ds1286_lock, flags);
+
+ return 0;
+ }
+ case RTC_WIE_ON: /* Allow watchdog interrupts. */
+ {
+ unsigned int flags;
+ unsigned char val;
+
+ if (!capable(CAP_SYS_TIME))
+ return -EACCES;
+
+ spin_lock_irqsave(&ds1286_lock, flags);
+ val = rtc_read(RTC_CMD);
+ val &= ~RTC_WAM;
+ rtc_write(val, RTC_CMD);
+ spin_unlock_irqrestore(&ds1286_lock, flags);
+
+ return 0;
+ }
+ case RTC_ALM_READ: /* Read the present alarm time */
+ {
+ /*
+ * This returns a struct rtc_time. Reading >= 0xc0
+ * means "don't care" or "match all". Only the tm_hour,
+ * tm_min, and tm_sec values are filled in.
+ */
+
+ memset(&wtime, 0, sizeof(wtime));
+ ds1286_get_alm_time(&wtime);
+ break;
+ }
+ case RTC_ALM_SET: /* Store a time into the alarm */
+ {
+ /*
+ * This expects a struct rtc_time. Writing 0xff means
+ * "don't care" or "match all". Only the tm_hour,
+ * tm_min and tm_sec are used.
+ */
+ unsigned char hrs, min, sec;
+ struct rtc_time alm_tm;
+
+ if (!capable(CAP_SYS_TIME))
+ return -EACCES;
+
+ if (copy_from_user(&alm_tm, (struct rtc_time*)arg,
+ sizeof(struct rtc_time)))
+ return -EFAULT;
+
+ hrs = alm_tm.tm_hour;
+ min = alm_tm.tm_min;
+
+ if (hrs >= 24)
+ hrs = 0xff;
+
+ if (min >= 60)
+ min = 0xff;
+
+ BIN_TO_BCD(sec);
+ BIN_TO_BCD(min);
+ BIN_TO_BCD(hrs);
+
+ spin_lock(&ds1286_lock);
+ rtc_write(hrs, RTC_HOURS_ALARM);
+ rtc_write(min, RTC_MINUTES_ALARM);
+ spin_unlock(&ds1286_lock);
+
+ return 0;
+ }
+ case RTC_RD_TIME: /* Read the time/date from RTC */
+ {
+ memset(&wtime, 0, sizeof(wtime));
+ ds1286_get_time(&wtime);
+ break;
+ }
+ case RTC_SET_TIME: /* Set the RTC */
+ {
+ struct rtc_time rtc_tm;
+
+ if (!capable(CAP_SYS_TIME))
+ return -EACCES;
+
+ if (copy_from_user(&rtc_tm, (struct rtc_time*)arg,
+ sizeof(struct rtc_time)))
+ return -EFAULT;
+
+ return ds1286_set_time(&rtc_tm);
+ }
+ default:
+ return -EINVAL;
+ }
+ return copy_to_user((void *)arg, &wtime, sizeof wtime) ? -EFAULT : 0;
+}
+
+/*
+ * We enforce only one user at a time here with the open/close.
+ * Also clear the previous interrupt data on an open, and clean
+ * up things on a close.
+ */
+
+static int ds1286_open(struct inode *inode, struct file *file)
+{
+ spin_lock_irq(&ds1286_lock);
+
+ if (ds1286_status & RTC_IS_OPEN)
+ goto out_busy;
+
+ ds1286_status |= RTC_IS_OPEN;
+
+ spin_unlock_irq(&ds1286_lock);
+ return 0;
+
+out_busy:
+ spin_lock_irq(&ds1286_lock);
+ return -EBUSY;
+}
+
+static int ds1286_release(struct inode *inode, struct file *file)
+{
+ ds1286_status &= ~RTC_IS_OPEN;
+
+ return 0;
+}
+
+static unsigned int ds1286_poll(struct file *file, poll_table *wait)
+{
+ poll_wait(file, &ds1286_wait, wait);
+
+ return 0;
+}
+
+/*
+ * The various file operations we support.
+ */
+
+static struct file_operations ds1286_fops = {
+ .llseek = no_llseek,
+ .read = ds1286_read,
+ .poll = ds1286_poll,
+ .ioctl = ds1286_ioctl,
+ .open = ds1286_open,
+ .release = ds1286_release,
+};
+
+static struct miscdevice ds1286_dev=
+{
+ .minor = RTC_MINOR,
+ .name = "rtc",
+ .fops = &ds1286_fops,
+};
+
+static int __init ds1286_init(void)
+{
+ int err;
+
+ printk(KERN_INFO "DS1286 Real Time Clock Driver v%s\n", DS1286_VERSION);
+
+ err = misc_register(&ds1286_dev);
+ if (err)
+ goto out;
+
+ if (!create_proc_read_entry("driver/rtc", 0, 0, ds1286_read_proc, NULL)) {
+ err = -ENOMEM;
+
+ goto out_deregister;
+ }
+
+ return 0;
+
+out_deregister:
+ misc_deregister(&ds1286_dev);
+
+out:
+ return err;
+}
+
+static void __exit ds1286_exit(void)
+{
+ remove_proc_entry("driver/rtc", NULL);
+ misc_deregister(&ds1286_dev);
+}
+
+static char *days[] = {
+ "***", "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
+};
+
+/*
+ * Info exported via "/proc/rtc".
+ */
+static int ds1286_proc_output(char *buf)
+{
+ char *p, *s;
+ struct rtc_time tm;
+ unsigned char hundredth, month, cmd, amode;
+
+ p = buf;
+
+ ds1286_get_time(&tm);
+ hundredth = rtc_read(RTC_HUNDREDTH_SECOND);
+ BCD_TO_BIN(hundredth);
+
+ p += sprintf(p,
+ "rtc_time\t: %02d:%02d:%02d.%02d\n"
+ "rtc_date\t: %04d-%02d-%02d\n",
+ tm.tm_hour, tm.tm_min, tm.tm_sec, hundredth,
+ tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
+
+ /*
+ * We implicitly assume 24hr mode here. Alarm values >= 0xc0 will
+ * match any value for that particular field. Values that are
+ * greater than a valid time, but less than 0xc0 shouldn't appear.
+ */
+ ds1286_get_alm_time(&tm);
+ p += sprintf(p, "alarm\t\t: %s ", days[tm.tm_wday]);
+ if (tm.tm_hour <= 24)
+ p += sprintf(p, "%02d:", tm.tm_hour);
+ else
+ p += sprintf(p, "**:");
+
+ if (tm.tm_min <= 59)
+ p += sprintf(p, "%02d\n", tm.tm_min);
+ else
+ p += sprintf(p, "**\n");
+
+ month = rtc_read(RTC_MONTH);
+ p += sprintf(p,
+ "oscillator\t: %s\n"
+ "square_wave\t: %s\n",
+ (month & RTC_EOSC) ? "disabled" : "enabled",
+ (month & RTC_ESQW) ? "disabled" : "enabled");
+
+ amode = ((rtc_read(RTC_MINUTES_ALARM) & 0x80) >> 5) |
+ ((rtc_read(RTC_HOURS_ALARM) & 0x80) >> 6) |
+ ((rtc_read(RTC_DAY_ALARM) & 0x80) >> 7);
+ if (amode == 7) s = "each minute";
+ else if (amode == 3) s = "minutes match";
+ else if (amode == 1) s = "hours and minutes match";
+ else if (amode == 0) s = "days, hours and minutes match";
+ else s = "invalid";
+ p += sprintf(p, "alarm_mode\t: %s\n", s);
+
+ cmd = rtc_read(RTC_CMD);
+ p += sprintf(p,
+ "alarm_enable\t: %s\n"
+ "wdog_alarm\t: %s\n"
+ "alarm_mask\t: %s\n"
+ "wdog_alarm_mask\t: %s\n"
+ "interrupt_mode\t: %s\n"
+ "INTB_mode\t: %s_active\n"
+ "interrupt_pins\t: %s\n",
+ (cmd & RTC_TDF) ? "yes" : "no",
+ (cmd & RTC_WAF) ? "yes" : "no",
+ (cmd & RTC_TDM) ? "disabled" : "enabled",
+ (cmd & RTC_WAM) ? "disabled" : "enabled",
+ (cmd & RTC_PU_LVL) ? "pulse" : "level",
+ (cmd & RTC_IBH_LO) ? "low" : "high",
+ (cmd & RTC_IPSW) ? "unswapped" : "swapped");
+
+ return p - buf;
+}
+
+static int ds1286_read_proc(char *page, char **start, off_t off,
+ int count, int *eof, void *data)
+{
+ int len = ds1286_proc_output (page);
+ if (len <= off+count) *eof = 1;
+ *start = page + off;
+ len -= off;
+ if (len>count)
+ len = count;
+ if (len<0)
+ len = 0;
+
+ return len;
+}
+
+/*
+ * Returns true if a clock update is in progress
+ */
+static inline unsigned char ds1286_is_updating(void)
+{
+ return rtc_read(RTC_CMD) & RTC_TE;
+}
+
+
+static void ds1286_get_time(struct rtc_time *rtc_tm)
+{
+ unsigned char save_control;
+ unsigned int flags;
+ unsigned long uip_watchdog = jiffies;
+
+ /*
+ * read RTC once any update in progress is done. The update
+ * can take just over 2ms. We wait 10 to 20ms. There is no need to
+ * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP.
+ * If you need to know *exactly* when a second has started, enable
+ * periodic update complete interrupts, (via ioctl) and then
+ * immediately read /dev/rtc which will block until you get the IRQ.
+ * Once the read clears, read the RTC time (again via ioctl). Easy.
+ */
+
+ if (ds1286_is_updating() != 0)
+ while (jiffies - uip_watchdog < 2*HZ/100)
+ barrier();
+
+ /*
+ * Only the values that we read from the RTC are set. We leave
+ * tm_wday, tm_yday and tm_isdst untouched. Even though the
+ * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
+ * by the RTC when initially set to a non-zero value.
+ */
+ spin_lock_irqsave(&ds1286_lock, flags);
+ save_control = rtc_read(RTC_CMD);
+ rtc_write((save_control|RTC_TE), RTC_CMD);
+
+ rtc_tm->tm_sec = rtc_read(RTC_SECONDS);
+ rtc_tm->tm_min = rtc_read(RTC_MINUTES);
+ rtc_tm->tm_hour = rtc_read(RTC_HOURS) & 0x3f;
+ rtc_tm->tm_mday = rtc_read(RTC_DATE);
+ rtc_tm->tm_mon = rtc_read(RTC_MONTH) & 0x1f;
+ rtc_tm->tm_year = rtc_read(RTC_YEAR);
+
+ rtc_write(save_control, RTC_CMD);
+ spin_unlock_irqrestore(&ds1286_lock, flags);
+
+ BCD_TO_BIN(rtc_tm->tm_sec);
+ BCD_TO_BIN(rtc_tm->tm_min);
+ BCD_TO_BIN(rtc_tm->tm_hour);
+ BCD_TO_BIN(rtc_tm->tm_mday);
+ BCD_TO_BIN(rtc_tm->tm_mon);
+ BCD_TO_BIN(rtc_tm->tm_year);
+
+ /*
+ * Account for differences between how the RTC uses the values
+ * and how they are defined in a struct rtc_time;
+ */
+ if (rtc_tm->tm_year < 45)
+ rtc_tm->tm_year += 30;
+ if ((rtc_tm->tm_year += 40) < 70)
+ rtc_tm->tm_year += 100;
+
+ rtc_tm->tm_mon--;
+}
+
+static int ds1286_set_time(struct rtc_time *rtc_tm)
+{
+ unsigned char mon, day, hrs, min, sec, leap_yr;
+ unsigned char save_control;
+ unsigned int yrs, flags;
+
+
+ yrs = rtc_tm->tm_year + 1900;
+ mon = rtc_tm->tm_mon + 1; /* tm_mon starts at zero */
+ day = rtc_tm->tm_mday;
+ hrs = rtc_tm->tm_hour;
+ min = rtc_tm->tm_min;
+ sec = rtc_tm->tm_sec;
+
+ if (yrs < 1970)
+ return -EINVAL;
+
+ leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
+
+ if ((mon > 12) || (day == 0))
+ return -EINVAL;
+
+ if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
+ return -EINVAL;
+
+ if ((hrs >= 24) || (min >= 60) || (sec >= 60))
+ return -EINVAL;
+
+ if ((yrs -= 1940) > 255) /* They are unsigned */
+ return -EINVAL;
+
+ if (yrs >= 100)
+ yrs -= 100;
+
+ BIN_TO_BCD(sec);
+ BIN_TO_BCD(min);
+ BIN_TO_BCD(hrs);
+ BIN_TO_BCD(day);
+ BIN_TO_BCD(mon);
+ BIN_TO_BCD(yrs);
+
+ spin_lock_irqsave(&ds1286_lock, flags);
+ save_control = rtc_read(RTC_CMD);
+ rtc_write((save_control|RTC_TE), RTC_CMD);
+
+ rtc_write(yrs, RTC_YEAR);
+ rtc_write(mon, RTC_MONTH);
+ rtc_write(day, RTC_DATE);
+ rtc_write(hrs, RTC_HOURS);
+ rtc_write(min, RTC_MINUTES);
+ rtc_write(sec, RTC_SECONDS);
+ rtc_write(0, RTC_HUNDREDTH_SECOND);
+
+ rtc_write(save_control, RTC_CMD);
+ spin_unlock_irqrestore(&ds1286_lock, flags);
+
+ return 0;
+}
+
+static void ds1286_get_alm_time(struct rtc_time *alm_tm)
+{
+ unsigned char cmd;
+ unsigned int flags;
+
+ /*
+ * Only the values that we read from the RTC are set. That
+ * means only tm_wday, tm_hour, tm_min.
+ */
+ spin_lock_irqsave(&ds1286_lock, flags);
+ alm_tm->tm_min = rtc_read(RTC_MINUTES_ALARM) & 0x7f;
+ alm_tm->tm_hour = rtc_read(RTC_HOURS_ALARM) & 0x1f;
+ alm_tm->tm_wday = rtc_read(RTC_DAY_ALARM) & 0x07;
+ cmd = rtc_read(RTC_CMD);
+ spin_unlock_irqrestore(&ds1286_lock, flags);
+
+ BCD_TO_BIN(alm_tm->tm_min);
+ BCD_TO_BIN(alm_tm->tm_hour);
+ alm_tm->tm_sec = 0;
+}
+
+module_init(ds1286_init);
+module_exit(ds1286_exit);
+
+MODULE_AUTHOR("Ralf Baechle");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(RTC_MINOR);
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.