diff options
Diffstat (limited to 'kernel/drivers/char/genrtc.c')
-rw-r--r-- | kernel/drivers/char/genrtc.c | 539 |
1 files changed, 539 insertions, 0 deletions
diff --git a/kernel/drivers/char/genrtc.c b/kernel/drivers/char/genrtc.c new file mode 100644 index 000000000..4f943759d --- /dev/null +++ b/kernel/drivers/char/genrtc.c @@ -0,0 +1,539 @@ +/* + * Real Time Clock interface for + * - q40 and other m68k machines, + * - HP PARISC machines + * - PowerPC machines + * emulate some RTC irq capabilities in software + * + * Copyright (C) 1999 Richard Zidlicky + * + * based on Paul Gortmaker's rtc.c device and + * Sam Creasey Generic rtc driver + * + * 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/driver/rtc + * pseudo-file for status information. + * + * The ioctls can be used to set the interrupt behaviour where + * supported. + * + * 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. + * + + * 1.01 fix for 2.3.X rz@linux-m68k.org + * 1.02 merged with code from genrtc.c rz@linux-m68k.org + * 1.03 make it more portable zippel@linux-m68k.org + * 1.04 removed useless timer code rz@linux-m68k.org + * 1.05 portable RTC_UIE emulation rz@linux-m68k.org + * 1.06 set_rtc_time can return an error trini@kernel.crashing.org + * 1.07 ported to HP PARISC (hppa) Helge Deller <deller@gmx.de> + */ + +#define RTC_VERSION "1.07" + +#include <linux/module.h> +#include <linux/sched.h> +#include <linux/errno.h> +#include <linux/miscdevice.h> +#include <linux/fcntl.h> + +#include <linux/rtc.h> +#include <linux/init.h> +#include <linux/poll.h> +#include <linux/proc_fs.h> +#include <linux/seq_file.h> +#include <linux/mutex.h> +#include <linux/workqueue.h> + +#include <asm/uaccess.h> +#include <asm/rtc.h> + +/* + * 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 DEFINE_MUTEX(gen_rtc_mutex); +static DECLARE_WAIT_QUEUE_HEAD(gen_rtc_wait); + +/* + * Bits in gen_rtc_status. + */ + +#define RTC_IS_OPEN 0x01 /* means /dev/rtc is in use */ + +static unsigned char gen_rtc_status; /* bitmapped status byte. */ +static unsigned long gen_rtc_irq_data; /* our output to the world */ + +/* months start at 0 now */ +static unsigned char days_in_mo[] = +{31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; + +static int irq_active; + +#ifdef CONFIG_GEN_RTC_X +static struct work_struct genrtc_task; +static struct timer_list timer_task; + +static unsigned int oldsecs; +static int lostint; +static unsigned long tt_exp; + +static void gen_rtc_timer(unsigned long data); + +static volatile int stask_active; /* schedule_work */ +static volatile int ttask_active; /* timer_task */ +static int stop_rtc_timers; /* don't requeue tasks */ +static DEFINE_SPINLOCK(gen_rtc_lock); + +static void gen_rtc_interrupt(unsigned long arg); + +/* + * Routine to poll RTC seconds field for change as often as possible, + * after first RTC_UIE use timer to reduce polling + */ +static void genrtc_troutine(struct work_struct *work) +{ + unsigned int tmp = get_rtc_ss(); + + if (stop_rtc_timers) { + stask_active = 0; + return; + } + + if (oldsecs != tmp){ + oldsecs = tmp; + + timer_task.function = gen_rtc_timer; + timer_task.expires = jiffies + HZ - (HZ/10); + tt_exp=timer_task.expires; + ttask_active=1; + stask_active=0; + add_timer(&timer_task); + + gen_rtc_interrupt(0); + } else if (schedule_work(&genrtc_task) == 0) + stask_active = 0; +} + +static void gen_rtc_timer(unsigned long data) +{ + lostint = get_rtc_ss() - oldsecs ; + if (lostint<0) + lostint = 60 - lostint; + if (time_after(jiffies, tt_exp)) + printk(KERN_INFO "genrtc: timer task delayed by %ld jiffies\n", + jiffies-tt_exp); + ttask_active=0; + stask_active=1; + if ((schedule_work(&genrtc_task) == 0)) + stask_active = 0; +} + +/* + * call gen_rtc_interrupt function to signal an RTC_UIE, + * arg is unused. + * Could be invoked either from a real interrupt handler or + * from some routine that periodically (eg 100HZ) monitors + * whether RTC_SECS changed + */ +static void gen_rtc_interrupt(unsigned long arg) +{ + /* We store the status in the low byte and the number of + * interrupts received since the last read in the remainder + * of rtc_irq_data. */ + + gen_rtc_irq_data += 0x100; + gen_rtc_irq_data &= ~0xff; + gen_rtc_irq_data |= RTC_UIE; + + if (lostint){ + printk("genrtc: system delaying clock ticks?\n"); + /* increment count so that userspace knows something is wrong */ + gen_rtc_irq_data += ((lostint-1)<<8); + lostint = 0; + } + + wake_up_interruptible(&gen_rtc_wait); +} + +/* + * Now all the various file operations that we export. + */ +static ssize_t gen_rtc_read(struct file *file, char __user *buf, + size_t count, loff_t *ppos) +{ + unsigned long data; + ssize_t retval; + + if (count != sizeof (unsigned int) && count != sizeof (unsigned long)) + return -EINVAL; + + if (file->f_flags & O_NONBLOCK && !gen_rtc_irq_data) + return -EAGAIN; + + retval = wait_event_interruptible(gen_rtc_wait, + (data = xchg(&gen_rtc_irq_data, 0))); + if (retval) + goto out; + + /* first test allows optimizer to nuke this case for 32-bit machines */ + if (sizeof (int) != sizeof (long) && count == sizeof (unsigned int)) { + unsigned int uidata = data; + retval = put_user(uidata, (unsigned int __user *)buf) ?: + sizeof(unsigned int); + } + else { + retval = put_user(data, (unsigned long __user *)buf) ?: + sizeof(unsigned long); + } +out: + return retval; +} + +static unsigned int gen_rtc_poll(struct file *file, + struct poll_table_struct *wait) +{ + poll_wait(file, &gen_rtc_wait, wait); + if (gen_rtc_irq_data != 0) + return POLLIN | POLLRDNORM; + return 0; +} + +#endif + +/* + * Used to disable/enable interrupts, only RTC_UIE supported + * We also clear out any old irq data after an ioctl() that + * meddles with the interrupt enable/disable bits. + */ + +static inline void gen_clear_rtc_irq_bit(unsigned char bit) +{ +#ifdef CONFIG_GEN_RTC_X + stop_rtc_timers = 1; + if (ttask_active){ + del_timer_sync(&timer_task); + ttask_active = 0; + } + while (stask_active) + schedule(); + + spin_lock(&gen_rtc_lock); + irq_active = 0; + spin_unlock(&gen_rtc_lock); +#endif +} + +static inline int gen_set_rtc_irq_bit(unsigned char bit) +{ +#ifdef CONFIG_GEN_RTC_X + spin_lock(&gen_rtc_lock); + if ( !irq_active ) { + irq_active = 1; + stop_rtc_timers = 0; + lostint = 0; + INIT_WORK(&genrtc_task, genrtc_troutine); + oldsecs = get_rtc_ss(); + init_timer(&timer_task); + + stask_active = 1; + if (schedule_work(&genrtc_task) == 0){ + stask_active = 0; + } + } + spin_unlock(&gen_rtc_lock); + gen_rtc_irq_data = 0; + return 0; +#else + return -EINVAL; +#endif +} + +static int gen_rtc_ioctl(struct file *file, + unsigned int cmd, unsigned long arg) +{ + struct rtc_time wtime; + struct rtc_pll_info pll; + void __user *argp = (void __user *)arg; + + switch (cmd) { + + case RTC_PLL_GET: + if (get_rtc_pll(&pll)) + return -EINVAL; + else + return copy_to_user(argp, &pll, sizeof pll) ? -EFAULT : 0; + + case RTC_PLL_SET: + if (!capable(CAP_SYS_TIME)) + return -EACCES; + if (copy_from_user(&pll, argp, sizeof(pll))) + return -EFAULT; + return set_rtc_pll(&pll); + + case RTC_UIE_OFF: /* disable ints from RTC updates. */ + gen_clear_rtc_irq_bit(RTC_UIE); + return 0; + + case RTC_UIE_ON: /* enable ints for RTC updates. */ + return gen_set_rtc_irq_bit(RTC_UIE); + + case RTC_RD_TIME: /* Read the time/date from RTC */ + /* this doesn't get week-day, who cares */ + memset(&wtime, 0, sizeof(wtime)); + get_rtc_time(&wtime); + + return copy_to_user(argp, &wtime, sizeof(wtime)) ? -EFAULT : 0; + + case RTC_SET_TIME: /* Set the RTC */ + { + int year; + unsigned char leap_yr; + + if (!capable(CAP_SYS_TIME)) + return -EACCES; + + if (copy_from_user(&wtime, argp, sizeof(wtime))) + return -EFAULT; + + year = wtime.tm_year + 1900; + leap_yr = ((!(year % 4) && (year % 100)) || + !(year % 400)); + + if ((wtime.tm_mon < 0 || wtime.tm_mon > 11) || (wtime.tm_mday < 1)) + return -EINVAL; + + if (wtime.tm_mday < 0 || wtime.tm_mday > + (days_in_mo[wtime.tm_mon] + ((wtime.tm_mon == 1) && leap_yr))) + return -EINVAL; + + if (wtime.tm_hour < 0 || wtime.tm_hour >= 24 || + wtime.tm_min < 0 || wtime.tm_min >= 60 || + wtime.tm_sec < 0 || wtime.tm_sec >= 60) + return -EINVAL; + + return set_rtc_time(&wtime); + } + } + + return -EINVAL; +} + +static long gen_rtc_unlocked_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + int ret; + + mutex_lock(&gen_rtc_mutex); + ret = gen_rtc_ioctl(file, cmd, arg); + mutex_unlock(&gen_rtc_mutex); + + return ret; +} + +/* + * 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 gen_rtc_open(struct inode *inode, struct file *file) +{ + mutex_lock(&gen_rtc_mutex); + if (gen_rtc_status & RTC_IS_OPEN) { + mutex_unlock(&gen_rtc_mutex); + return -EBUSY; + } + + gen_rtc_status |= RTC_IS_OPEN; + gen_rtc_irq_data = 0; + irq_active = 0; + mutex_unlock(&gen_rtc_mutex); + + return 0; +} + +static int gen_rtc_release(struct inode *inode, struct file *file) +{ + /* + * Turn off all interrupts once the device is no longer + * in use and clear the data. + */ + + gen_clear_rtc_irq_bit(RTC_PIE|RTC_AIE|RTC_UIE); + + gen_rtc_status &= ~RTC_IS_OPEN; + return 0; +} + + +#ifdef CONFIG_PROC_FS + +/* + * Info exported via "/proc/driver/rtc". + */ + +static int gen_rtc_proc_show(struct seq_file *m, void *v) +{ + struct rtc_time tm; + unsigned int flags; + struct rtc_pll_info pll; + + flags = get_rtc_time(&tm); + + seq_printf(m, + "rtc_time\t: %02d:%02d:%02d\n" + "rtc_date\t: %04d-%02d-%02d\n" + "rtc_epoch\t: %04u\n", + tm.tm_hour, tm.tm_min, tm.tm_sec, + tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, 1900); + + tm.tm_hour = tm.tm_min = tm.tm_sec = 0; + + seq_puts(m, "alarm\t\t: "); + if (tm.tm_hour <= 24) + seq_printf(m, "%02d:", tm.tm_hour); + else + seq_puts(m, "**:"); + + if (tm.tm_min <= 59) + seq_printf(m, "%02d:", tm.tm_min); + else + seq_puts(m, "**:"); + + if (tm.tm_sec <= 59) + seq_printf(m, "%02d\n", tm.tm_sec); + else + seq_puts(m, "**\n"); + + seq_printf(m, + "DST_enable\t: %s\n" + "BCD\t\t: %s\n" + "24hr\t\t: %s\n" + "square_wave\t: %s\n" + "alarm_IRQ\t: %s\n" + "update_IRQ\t: %s\n" + "periodic_IRQ\t: %s\n" + "periodic_freq\t: %ld\n" + "batt_status\t: %s\n", + (flags & RTC_DST_EN) ? "yes" : "no", + (flags & RTC_DM_BINARY) ? "no" : "yes", + (flags & RTC_24H) ? "yes" : "no", + (flags & RTC_SQWE) ? "yes" : "no", + (flags & RTC_AIE) ? "yes" : "no", + irq_active ? "yes" : "no", + (flags & RTC_PIE) ? "yes" : "no", + 0L /* freq */, + (flags & RTC_BATT_BAD) ? "bad" : "okay"); + if (!get_rtc_pll(&pll)) + seq_printf(m, + "PLL adjustment\t: %d\n" + "PLL max +ve adjustment\t: %d\n" + "PLL max -ve adjustment\t: %d\n" + "PLL +ve adjustment factor\t: %d\n" + "PLL -ve adjustment factor\t: %d\n" + "PLL frequency\t: %ld\n", + pll.pll_value, + pll.pll_max, + pll.pll_min, + pll.pll_posmult, + pll.pll_negmult, + pll.pll_clock); + return 0; +} + +static int gen_rtc_proc_open(struct inode *inode, struct file *file) +{ + return single_open(file, gen_rtc_proc_show, NULL); +} + +static const struct file_operations gen_rtc_proc_fops = { + .open = gen_rtc_proc_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + +static int __init gen_rtc_proc_init(void) +{ + struct proc_dir_entry *r; + + r = proc_create("driver/rtc", 0, NULL, &gen_rtc_proc_fops); + if (!r) + return -ENOMEM; + return 0; +} +#else +static inline int gen_rtc_proc_init(void) { return 0; } +#endif /* CONFIG_PROC_FS */ + + +/* + * The various file operations we support. + */ + +static const struct file_operations gen_rtc_fops = { + .owner = THIS_MODULE, +#ifdef CONFIG_GEN_RTC_X + .read = gen_rtc_read, + .poll = gen_rtc_poll, +#endif + .unlocked_ioctl = gen_rtc_unlocked_ioctl, + .open = gen_rtc_open, + .release = gen_rtc_release, + .llseek = noop_llseek, +}; + +static struct miscdevice rtc_gen_dev = +{ + .minor = RTC_MINOR, + .name = "rtc", + .fops = &gen_rtc_fops, +}; + +static int __init rtc_generic_init(void) +{ + int retval; + + printk(KERN_INFO "Generic RTC Driver v%s\n", RTC_VERSION); + + retval = misc_register(&rtc_gen_dev); + if (retval < 0) + return retval; + + retval = gen_rtc_proc_init(); + if (retval) { + misc_deregister(&rtc_gen_dev); + return retval; + } + + return 0; +} + +static void __exit rtc_generic_exit(void) +{ + remove_proc_entry ("driver/rtc", NULL); + misc_deregister(&rtc_gen_dev); +} + + +module_init(rtc_generic_init); +module_exit(rtc_generic_exit); + +MODULE_AUTHOR("Richard Zidlicky"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS_MISCDEV(RTC_MINOR); |