[PATCH][RESEND x 3] A generic RTC driver [1/3]

Tom Rini (trini@kernel.crashing.org)
Mon, 12 Aug 2002 08:16:35 -0700


This is the current version of the genrtc driver from the m68k
community. This is slightly different than the version I have sent
previously in that it has been switched to C99-style initializers,
which was done in the current m68k CVS tree by Geert Uytterhoeven, and
the needed changes to select/compile it in general. I had previously
asked the m68k community if anyone objected to this being submitted by me,
and I got Richard Zidlicky's (who's at the top of the file) approval, as
well as Geert Uytterhoeven's approval.

-- 
Tom Rini (TR1265)
http://gate.crashing.org/~trini/

===== drivers/char/Config.help 1.8 vs edited ===== --- 1.8/drivers/char/Config.help Sun Jul 28 10:18:15 2002 +++ edited/drivers/char/Config.help Fri Aug 2 08:48:00 2002 @@ -969,6 +969,31 @@ The module is called rtc.o. If you want to compile it as a module, say M here and read <file:Documentation/modules.txt>. +Generic Real Time Clock Support +CONFIG_GEN_RTC + If you say Y here and create a character special file /dev/rtc with + major number 10 and minor number 135 using mknod ("man mknod"), you + will get access to the real time clock (or hardware clock) built + into your computer. + + It reports status information via the file /proc/driver/rtc and its + behaviour is set by various ioctls on /dev/rtc. If you enable the + "extended RTC operation" below it will also provide an emulation + for RTC_UIE which is required by some programs and may improve + precision in some cases. + + This driver is also available as a module ( = code which can be + inserted in and removed from the running kernel whenever you want). + The module is called genrtc.o. If you want to compile it as a module, + say M here and read <file:Documentation/modules.txt>. To load the + module automaticaly add 'alias char-major-10-135 genrtc' to your + /etc/modules.conf + +Extended RTC operation +CONFIG_GEN_RTC_X + Provides an emulation for RTC_UIE which is required by some programs + and may improve precision of the generic RTC support in some cases. + CONFIG_H8 The Hitachi H8/337 is a microcontroller used to deal with the power and thermal environment. If you say Y here, you will be able to ===== drivers/char/Config.in 1.31 vs edited ===== --- 1.31/drivers/char/Config.in Sun Jul 28 10:18:14 2002 +++ edited/drivers/char/Config.in Fri Aug 2 08:48:01 2002 @@ -151,6 +151,12 @@ fi tristate '/dev/nvram support' CONFIG_NVRAM tristate 'Enhanced Real Time Clock Support' CONFIG_RTC +if [ "$CONFIG_RTC" != "y" ]; then + tristate 'Generic /dev/rtc emulation' CONFIG_GEN_RTC + if [ "$CONFIG_GEN_RTC" != "n" ]; then + bool ' Extended RTC operation' CONFIG_GEN_RTC_X + fi +fi if [ "$CONFIG_IA64" = "y" ]; then bool 'EFI Real Time Clock Services' CONFIG_EFI_RTC fi ===== drivers/char/Makefile 1.30 vs edited ===== --- 1.30/drivers/char/Makefile Thu Aug 1 16:52:01 2002 +++ edited/drivers/char/Makefile Fri Aug 2 08:48:01 2002 @@ -161,6 +161,7 @@ obj-$(CONFIG_SONYPI) += sonypi.o obj-$(CONFIG_ATARIMOUSE) += atarimouse.o obj-$(CONFIG_RTC) += rtc.o +obj-$(CONFIG_GEN_RTC) += genrtc.o obj-$(CONFIG_EFI_RTC) += efirtc.o ifeq ($(CONFIG_PPC),) obj-$(CONFIG_NVRAM) += nvram.o ===== include/linux/rtc.h 1.3 vs edited ===== --- 1.3/include/linux/rtc.h Sun Feb 24 12:02:47 2002 +++ edited/include/linux/rtc.h Fri Aug 2 08:48:01 2002 @@ -39,10 +39,32 @@ struct rtc_time time; /* time the alarm is set to */ }; +/* + * Data structure to control PLL correction some better RTC feature + * pll_value is used to get or set current value of correction, + * the rest of the struct is used to query HW capabilities. + * This is modeled after the RTC used in Q40/Q60 computers but + * should be sufficiently flexible for other devices + * + * +ve pll_value means clock will run faster by + * pll_value*pll_posmult/pll_clock + * -ve pll_value means clock will run slower by + * pll_value*pll_negmult/pll_clock + */ + +struct rtc_pll_info { + int pll_ctrl; /* placeholder for fancier control */ + int pll_value; /* get/set correction value */ + int pll_max; /* max +ve (faster) adjustment value */ + int pll_min; /* max -ve (slower) adjustment value */ + int pll_posmult; /* factor for +ve corection */ + int pll_negmult; /* factor for -ve corection */ + long pll_clock; /* base PLL frequency */ +}; /* * ioctl calls that are permitted to the /dev/rtc interface, if - * CONFIG_RTC/CONFIG_EFI_RTC was enabled. + * any of the RTC drivers are enabled. */ #define RTC_AIE_ON _IO('p', 0x01) /* Alarm int. enable on */ @@ -65,6 +87,8 @@ #define RTC_WKALM_SET _IOW('p', 0x0f, struct rtc_wkalrm)/* Set wakeup alarm*/ #define RTC_WKALM_RD _IOR('p', 0x10, struct rtc_wkalrm)/* Get wakeup alarm*/ +#define RTC_PLL_GET _IOR('p', 0x11, struct rtc_pll_info) /* Get PLL correction */ +#define RTC_PLL_SET _IOW('p', 0x12, struct rtc_pll_info) /* Set PLL correction */ #ifdef __KERNEL__ --- a/drivers/char/genrtc.c 1969-12-31 17:00:00.000000000 -0700 +++ b/drivers/char/genrtc.c 2002-08-02 08:24:32.000000000 -0700 @@ -0,0 +1,511 @@ +/* + * Real Time Clock interface for q40 and other m68k 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/dev/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 + */ + +#define RTC_VERSION "1.05" + +#include <linux/module.h> +#include <linux/config.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/tqueue.h> + +#include <asm/uaccess.h> +#include <asm/system.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 DECLARE_WAIT_QUEUE_HEAD(gen_rtc_wait); + +static int gen_rtc_ioctl(struct inode *inode, struct file *file, + unsigned int cmd, unsigned long arg); + +/* + * Bits in gen_rtc_status. + */ + +#define RTC_IS_OPEN 0x01 /* means /dev/rtc is in use */ + +unsigned char gen_rtc_status; /* bitmapped status byte. */ +unsigned long gen_rtc_irq_data; /* our output to the world */ + +/* months start at 0 now */ +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 +struct tq_struct genrtc_task; +static struct timer_list timer_task; + +static unsigned int oldsecs; +static int lostint; +static int tt_exp; + +void gen_rtc_timer(unsigned long data); + +static volatile int stask_active; /* schedule_task */ +static volatile int ttask_active; /* timer_task */ +static int stop_rtc_timers; /* don't requeue tasks */ +static spinlock_t gen_rtc_lock = SPIN_LOCK_UNLOCKED; + +/* + * Routine to poll RTC seconds field for change as often as posible, + * after first RTC_UIE use timer to reduce polling + */ +void genrtc_troutine(void *data) +{ + 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_task(&genrtc_task) == 0) + stask_active = 0; +} + +void gen_rtc_timer(unsigned long data) +{ + lostint = get_rtc_ss() - oldsecs ; + if (lostint<0) + lostint = 60 - lostint; + if (jiffies-tt_exp>1) + printk("genrtc: timer task delayed by %ld jiffies\n", + jiffies-tt_exp); + ttask_active=0; + stask_active=1; + if ((schedule_task(&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 + */ +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 *buf, + size_t count, loff_t *ppos) +{ + DECLARE_WAITQUEUE(wait, current); + unsigned long data; + ssize_t retval; + + if (count < sizeof(unsigned long)) + return -EINVAL; + + if (file->f_flags & O_NONBLOCK && !gen_rtc_irq_data) + return -EAGAIN; + + add_wait_queue(&gen_rtc_wait, &wait); + retval = -ERESTARTSYS; + + while (1) { + set_current_state(TASK_INTERRUPTIBLE); + data = xchg(&gen_rtc_irq_data, 0); + if (data) + break; + if (signal_pending(current)) + goto out; + schedule(); + } + + retval = put_user(data, (unsigned long *)buf); + if (!retval) + retval = sizeof(unsigned long); + out: + current->state = TASK_RUNNING; + remove_wait_queue(&gen_rtc_wait, &wait); + + 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; + genrtc_task.routine = genrtc_troutine; + oldsecs = get_rtc_ss(); + init_timer(&timer_task); + + stask_active = 1; + if (schedule_task(&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 inode *inode, struct file *file, + unsigned int cmd, unsigned long arg) +{ + struct rtc_time wtime; + struct rtc_pll_info pll; + + switch (cmd) { + + case RTC_PLL_GET: + if (get_rtc_pll(&pll)) + return -EINVAL; + else + return copy_to_user((void *)arg, &pll, sizeof pll) ? -EFAULT : 0; + + case RTC_PLL_SET: + if (!capable(CAP_SYS_TIME)) + return -EACCES; + if (copy_from_user(&pll, (struct rtc_pll_info*)arg, + 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((void *)arg, &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, (struct rtc_time *)arg, + 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; + + set_rtc_time(&wtime); + return 0; + } + } + + return -EINVAL; +} + +/* + * 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) +{ + if (gen_rtc_status & RTC_IS_OPEN) + return -EBUSY; + + MOD_INC_USE_COUNT; + + gen_rtc_status |= RTC_IS_OPEN; + gen_rtc_irq_data = 0; + irq_active = 0; + + 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; + MOD_DEC_USE_COUNT; + + return 0; +} + +static int gen_rtc_read_proc(char *page, char **start, off_t off, + int count, int *eof, void *data); + + +/* + * The various file operations we support. + */ + +static struct file_operations gen_rtc_fops = { + .owner = THIS_MODULE, +#ifdef CONFIG_GEN_RTC_X + .read = gen_rtc_read, + .poll = gen_rtc_poll, +#endif + .ioctl = gen_rtc_ioctl, + .open = gen_rtc_open, + .release = gen_rtc_release +}; + +static struct miscdevice rtc_gen_dev = +{ + RTC_MINOR, + "rtc", + &gen_rtc_fops +}; + +int __init rtc_generic_init(void) +{ + + printk(KERN_INFO "Generic RTC Driver v%s\n", RTC_VERSION); + + misc_register(&rtc_gen_dev); + create_proc_read_entry ("driver/rtc", 0, 0, gen_rtc_read_proc, NULL); + + 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); +EXPORT_NO_SYMBOLS; + + +/* + * Info exported via "/proc/rtc". + */ + +int gen_rtc_proc_output(char *buf) +{ + char *p; + struct rtc_time tm; + unsigned tmp; + struct rtc_pll_info pll; + + p = buf; + + get_rtc_time(&tm); + + p += sprintf(p, + "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=0;tm.tm_min=0;tm.tm_sec=0; + + p += sprintf(p, "alarm\t\t: "); + 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:", tm.tm_min); + else + p += sprintf(p, "**:"); + + if (tm.tm_sec <= 59) + p += sprintf(p, "%02d\n", tm.tm_sec); + else + p += sprintf(p, "**\n"); + + tmp= RTC_24H ; + p += sprintf(p, + "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", + (tmp & RTC_DST_EN) ? "yes" : "no", + (tmp & RTC_DM_BINARY) ? "no" : "yes", + (tmp & RTC_24H) ? "yes" : "no", + (tmp & RTC_SQWE) ? "yes" : "no", + (tmp & RTC_AIE) ? "yes" : "no", + irq_active ? "yes" : "no", + (tmp & RTC_PIE) ? "yes" : "no", + 0L /* freq */, + "okay" ); + if (!get_rtc_pll(&pll)) + p += sprintf(p, + "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 p - buf; +} + +static int gen_rtc_read_proc(char *page, char **start, off_t off, + int count, int *eof, void *data) +{ + int len = gen_rtc_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; +} + + +MODULE_AUTHOR("Richard Zidlicky"); +MODULE_LICENSE("GPL"); - 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/