Messages in this thread Patch in this message | | | Date | Fri, 21 Mar 2003 19:24:58 GMT | From | Alan Cox <> | Subject | PATCH: real time clock support for PC9800 systems |
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diff -u --new-file --recursive --exclude-from /usr/src/exclude linux-2.5.65/drivers/char/upd4990a.c linux-2.5.65-ac2/drivers/char/upd4990a.c --- linux-2.5.65/drivers/char/upd4990a.c 1970-01-01 01:00:00.000000000 +0100 +++ linux-2.5.65-ac2/drivers/char/upd4990a.c 2003-03-14 01:23:19.000000000 +0000 @@ -0,0 +1,423 @@ +/* + * NEC PC-9800 Real Time Clock interface for Linux + * + * Copyright (C) 1997-2001 Linux/98 project, + * Kyoto University Microcomputer Club. + * + * Based on: + * drivers/char/rtc.c by Paul Gortmaker + * + * Changes: + * 2001-02-09 Call check_region on rtc_init and do not request I/O 0033h. + * Call del_timer and release_region on rtc_exit. -- tak + * 2001-07-14 Rewrite <linux/upd4990a.h> and split to <linux/upd4990a.h> + * and <asm-i386/upd4990a.h>. + * Introduce a lot of spin_lock/unlock (&rtc_lock). + */ + +#define RTC98_VERSION "1.2" + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/types.h> +#include <linux/miscdevice.h> +#include <linux/ioport.h> +#include <linux/fcntl.h> +#include <linux/rtc.h> +#include <linux/bcd.h> +#include <linux/upd4990a.h> +#include <linux/init.h> +#include <linux/poll.h> +#include <linux/proc_fs.h> +#include <linux/spinlock.h> + +#include <asm/io.h> +#include <asm/uaccess.h> +#include <asm/system.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 struct fasync_struct *rtc_async_queue; + +static DECLARE_WAIT_QUEUE_HEAD(rtc_wait); + +static struct timer_list rtc_uie_timer; +static u8 old_refclk; + +static int rtc_ioctl(struct inode *inode, struct file *file, + unsigned int cmd, unsigned long arg); + +static int rtc_read_proc(char *page, char **start, off_t off, + int count, int *eof, void *data); + +/* + * Bits in rtc_status. (5 bits of room for future expansion) + */ + +#define RTC_IS_OPEN 0x01 /* means /dev/rtc is in use */ +#define RTC_TIMER_ON 0x02 /* not used */ +#define RTC_UIE_TIMER_ON 0x04 /* UIE emulation timer is active */ + +/* + * rtc_status is never changed by rtc_interrupt, and ioctl/open/close is + * protected by the big kernel lock. However, ioctl can still disable the timer + * in rtc_status and then with del_timer after the interrupt has read + * rtc_status but before mod_timer is called, which would then reenable the + * timer (but you would need to have an awful timing before you'd trip on it) + */ +static unsigned char rtc_status; /* bitmapped status byte. */ +static unsigned long rtc_irq_data; /* our output to the world */ + +static const unsigned char days_in_mo[] = +{31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; + +extern spinlock_t rtc_lock; /* defined in arch/i386/kernel/time.c */ + +static void rtc_uie_intr(unsigned long data) +{ + u8 refclk, tmp; + + /* Kernel timer does del_timer internally before calling + each timer entry, so this is unnecessary. + del_timer(&rtc_uie_timer); */ + spin_lock(&rtc_lock); + + /* Detect rising edge of 1Hz reference clock. */ + refclk = UPD4990A_READ_DATA(); + tmp = old_refclk & refclk; + old_refclk = ~refclk; + if (!(tmp & 1)) + rtc_irq_data += 0x100; + + spin_unlock(&rtc_lock); + + if (!(tmp & 1)) { + /* Now do the rest of the actions */ + wake_up_interruptible(&rtc_wait); + kill_fasync(&rtc_async_queue, SIGIO, POLL_IN); + } + + rtc_uie_timer.expires = jiffies + 1; + add_timer(&rtc_uie_timer); +} + +/* + * Now all the various file operations that we export. + */ + +static ssize_t rtc_read(struct file *file, char *buf, + size_t count, loff_t *ppos) +{ + DECLARE_WAITQUEUE(wait, current); + unsigned long data; + ssize_t retval = 0; + + if (count < sizeof(unsigned long)) + return -EINVAL; + + add_wait_queue(&rtc_wait, &wait); + + set_current_state(TASK_INTERRUPTIBLE); + + do { + /* First make it right. Then make it fast. Putting this whole + * block within the parentheses of a while would be too + * confusing. And no, xchg() is not the answer. */ + spin_lock_irq(&rtc_lock); + data = rtc_irq_data; + rtc_irq_data = 0; + spin_unlock_irq(&rtc_lock); + + if (data != 0) + break; + if (file->f_flags & O_NONBLOCK) { + retval = -EAGAIN; + goto out; + } + if (signal_pending(current)) { + retval = -ERESTARTSYS; + goto out; + } + schedule(); + } while (1); + + retval = put_user(data, (unsigned long *)buf); + if (!retval) + retval = sizeof(unsigned long); + out: + set_current_state(TASK_RUNNING); + remove_wait_queue(&rtc_wait, &wait); + + return retval; +} + +static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd, + unsigned long arg) +{ + struct rtc_time wtime; + struct upd4990a_raw_data raw; + + switch (cmd) { + case RTC_UIE_OFF: /* Mask ints from RTC updates. */ + spin_lock_irq(&rtc_lock); + if (rtc_status & RTC_UIE_TIMER_ON) { + rtc_status &= ~RTC_UIE_TIMER_ON; + del_timer(&rtc_uie_timer); + } + spin_unlock_irq(&rtc_lock); + return 0; + + case RTC_UIE_ON: /* Allow ints for RTC updates. */ + spin_lock_irq(&rtc_lock); + rtc_irq_data = 0; + if (!(rtc_status & RTC_UIE_TIMER_ON)) { + rtc_status |= RTC_UIE_TIMER_ON; + rtc_uie_timer.expires = jiffies + 1; + add_timer(&rtc_uie_timer); + } + /* Just in case... */ + upd4990a_serial_command(UPD4990A_REGISTER_HOLD); + old_refclk = ~UPD4990A_READ_DATA(); + spin_unlock_irq(&rtc_lock); + return 0; + + case RTC_RD_TIME: /* Read the time/date from RTC */ + spin_lock_irq(&rtc_lock); + upd4990a_get_time(&raw, 0); + spin_unlock_irq(&rtc_lock); + + wtime.tm_sec = BCD2BIN(raw.sec); + wtime.tm_min = BCD2BIN(raw.min); + wtime.tm_hour = BCD2BIN(raw.hour); + wtime.tm_mday = BCD2BIN(raw.mday); + wtime.tm_mon = raw.mon - 1; /* convert to 0-base */ + wtime.tm_wday = raw.wday; + + /* + * Account for differences between how the RTC uses the values + * and how they are defined in a struct rtc_time; + */ + if ((wtime.tm_year = BCD2BIN(raw.year)) < 95) + wtime.tm_year += 100; + + wtime.tm_isdst = 0; + break; + + case RTC_SET_TIME: /* Set the RTC */ + { + int leap_yr; + + if (!capable(CAP_SYS_TIME)) + return -EACCES; + + if (copy_from_user(&wtime, (struct rtc_time *) arg, + sizeof (struct rtc_time))) + return -EFAULT; + + /* Valid year is 1995 - 2094, inclusive. */ + if (wtime.tm_year < 95 || wtime.tm_year > 194) + return -EINVAL; + + if (wtime.tm_mon > 11 || wtime.tm_mday == 0) + return -EINVAL; + + /* For acceptable year domain (1995 - 2094), + this IS sufficient. */ + leap_yr = !(wtime.tm_year % 4); + + if (wtime.tm_mday > (days_in_mo[wtime.tm_mon] + + (wtime.tm_mon == 2 && leap_yr))) + return -EINVAL; + + if (wtime.tm_hour >= 24 + || wtime.tm_min >= 60 || wtime.tm_sec >= 60) + return -EINVAL; + + if (wtime.tm_wday > 6) + return -EINVAL; + + raw.sec = BIN2BCD(wtime.tm_sec); + raw.min = BIN2BCD(wtime.tm_min); + raw.hour = BIN2BCD(wtime.tm_hour); + raw.mday = BIN2BCD(wtime.tm_mday); + raw.mon = wtime.tm_mon + 1; + raw.wday = wtime.tm_wday; + raw.year = BIN2BCD(wtime.tm_year % 100); + + spin_lock_irq(&rtc_lock); + upd4990a_set_time(&raw, 0); + spin_unlock_irq(&rtc_lock); + + return 0; + } + 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 rtc_open(struct inode *inode, struct file *file) +{ + spin_lock_irq(&rtc_lock); + + if(rtc_status & RTC_IS_OPEN) + goto out_busy; + + rtc_status |= RTC_IS_OPEN; + + rtc_irq_data = 0; + spin_unlock_irq(&rtc_lock); + return 0; + + out_busy: + spin_unlock_irq(&rtc_lock); + return -EBUSY; +} + +static int rtc_fasync(int fd, struct file *filp, int on) +{ + return fasync_helper(fd, filp, on, &rtc_async_queue); +} + +static int rtc_release(struct inode *inode, struct file *file) +{ + del_timer(&rtc_uie_timer); + + if (file->f_flags & FASYNC) + rtc_fasync(-1, file, 0); + + rtc_irq_data = 0; + + /* No need for locking -- nobody else can do anything until this rmw is + * committed, and no timer is running. */ + rtc_status &= ~(RTC_IS_OPEN | RTC_UIE_TIMER_ON); + return 0; +} + +static unsigned int rtc_poll(struct file *file, poll_table *wait) +{ + unsigned long l; + + poll_wait(file, &rtc_wait, wait); + + spin_lock_irq(&rtc_lock); + l = rtc_irq_data; + spin_unlock_irq(&rtc_lock); + + if (l != 0) + return POLLIN | POLLRDNORM; + return 0; +} + +/* + * The various file operations we support. + */ + +static struct file_operations rtc_fops = { + .owner = THIS_MODULE, + .read = rtc_read, + .poll = rtc_poll, + .ioctl = rtc_ioctl, + .open = rtc_open, + .release = rtc_release, + .fasync = rtc_fasync, +}; + +static struct miscdevice rtc_dev= +{ + .minor = RTC_MINOR, + .name = "rtc", + .fops = &rtc_fops, +}; + +static int __init rtc_init(void) +{ + if (!request_region(UPD4990A_IO, 1, "rtc")) { + printk(KERN_ERR "upd4990a: could not acquire I/O port %#x\n", + UPD4990A_IO); + return -EBUSY; + } + +#if 0 + printk(KERN_INFO "\xB6\xDA\xDD\xC0\xDE \xC4\xDE\xB9\xB2 Driver\n"); /* Calender Clock Driver */ +#else + printk(KERN_INFO + "Real Time Clock driver for NEC PC-9800 v" RTC98_VERSION "\n"); +#endif + misc_register(&rtc_dev); + create_proc_read_entry("driver/rtc", 0, NULL, rtc_read_proc, NULL); + + init_timer(&rtc_uie_timer); + rtc_uie_timer.function = rtc_uie_intr; + + return 0; +} + +module_init (rtc_init); + +static void __exit rtc_exit(void) +{ + del_timer(&rtc_uie_timer); + release_region(UPD4990A_IO, 1); + remove_proc_entry("driver/rtc", NULL); + misc_deregister(&rtc_dev); +} + +module_exit (rtc_exit); + +/* + * Info exported via "/proc/driver/rtc". + */ + +static inline int rtc_get_status(char *buf) +{ + char *p; + unsigned int year; + struct upd4990a_raw_data data; + + p = buf; + + upd4990a_get_time(&data, 0); + + /* + * There is no way to tell if the luser has the RTC set for local + * time or for Universal Standard Time (GMT). Probably local though. + */ + if ((year = BCD2BIN(data.year) + 1900) < 1995) + year += 100; + p += sprintf(p, + "rtc_time\t: %02d:%02d:%02d\n" + "rtc_date\t: %04d-%02d-%02d\n", + BCD2BIN(data.hour), BCD2BIN(data.min), + BCD2BIN(data.sec), + year, data.mon, BCD2BIN(data.mday)); + + return p - buf; +} + +static int rtc_read_proc(char *page, char **start, off_t off, + int count, int *eof, void *data) +{ + int len = rtc_get_status(page); + + if (len <= off + count) + *eof = 1; + *start = page + off; + len -= off; + if (len > count) + len = count; + if (len < 0) + len = 0; + return len; +} - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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