[PATCH][RESEND x 2] A generic RTC driver [3/3]

Tom Rini (trini@kernel.crashing.org)
Wed, 7 Aug 2002 09:49:48 -0700


This is part 3 of 3 of the genrtc patches. This is my own slight bit
of work, as well as some work by Randolph Chung. This changes
set_rtc_time(struct *rtc_time) to return an int instead of void.
This was done so that the arch-specific code here could do additional
checks on the time and return an error if needed. This then introduces
include/asm-generic/rtc.h, include/asm-i386/rtc.h and
include/asm-alpha/rtc.h. include/asm-generic/rtc.h contains the
get_rtc_time and set_rtc_time logic that is in drivers/char/rtc.c and
has been tested on SMP i386. This also modifies include/asm-ppc/rtc.h
to return -ENODEV if no rtc hardware is present.

Additionally, Dave Jones pointed out to me a place where we might not be
safe when jiffies wraps, so this switches that to time_after().

>From Randolph Chung, is supprt for a 64bit kernel and a 32bit userland.

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

--- linux-2.5/include/asm-ppc/rtc.h 2002-07-24 13:25:15.000000000 -0700 +++ linux-2.5/include/asm-ppc/rtc.h 2002-07-24 13:25:36.000000000 -0700 @@ -68,7 +68,10 @@ time->tm_sec); (ppc_md.set_rtc_time)(nowtime); - } + + return 0; + } else + return -EINVAL; } static inline unsigned int get_rtc_ss(void) --- /dev/null 1969-12-31 17:00:00.000000000 -0700 +++ linux-2.5/include/asm-generic/rtc.h 2002-07-24 11:06:48.000000000 -0700 @@ -0,0 +1,211 @@ +/* + * inclue/asm-generic/rtc.h + * + * Author: Tom Rini <trini@mvista.com> + * + * Based on: + * drivers/char/rtc.c + * + * Please read the COPYING file for all license details. + */ + +#ifndef __ASM_RTC_H__ +#define __ASM_RTC_H__ + +#ifdef __KERNEL__ + +#include <linux/mc146818rtc.h> +#include <linux/rtc.h> + +#define RTC_PIE 0x40 /* periodic interrupt enable */ +#define RTC_AIE 0x20 /* alarm interrupt enable */ +#define RTC_UIE 0x10 /* update-finished interrupt enable */ + +extern void gen_rtc_interrupt(unsigned long); + +/* some dummy definitions */ +#define RTC_SQWE 0x08 /* enable square-wave output */ +#define RTC_DM_BINARY 0x04 /* all time/date values are BCD if clear */ +#define RTC_24H 0x02 /* 24 hour mode - else hours bit 7 means pm */ +#define RTC_DST_EN 0x01 /* auto switch DST - works f. USA only */ + +/* + * Returns true if a clock update is in progress + */ +static inline unsigned char rtc_is_updating(void) +{ + unsigned char uip; + + spin_lock_irq(&rtc_lock); + uip = (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP); + spin_unlock_irq(&rtc_lock); + return uip; +} + +static inline void get_rtc_time(struct rtc_time *time) +{ + unsigned long uip_watchdog = jiffies; + unsigned char ctrl; +#ifdef CONFIG_DECSTATION + unsigned int real_year; +#endif + + /* + * 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 (rtc_is_updating() != 0) + while (jiffies - uip_watchdog < 2*HZ/100) { + barrier(); + cpu_relax(); + } + + /* + * 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_irq(&rtc_lock); + time->tm_sec = CMOS_READ(RTC_SECONDS); + time->tm_min = CMOS_READ(RTC_MINUTES); + time->tm_hour = CMOS_READ(RTC_HOURS); + time->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH); + time->tm_mon = CMOS_READ(RTC_MONTH); + time->tm_year = CMOS_READ(RTC_YEAR); +#ifdef CONFIG_DECSTATION + real_year = CMOS_READ(RTC_DEC_YEAR); +#endif + ctrl = CMOS_READ(RTC_CONTROL); + spin_unlock_irq(&rtc_lock); + + if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD) + { + BCD_TO_BIN(time->tm_sec); + BCD_TO_BIN(time->tm_min); + BCD_TO_BIN(time->tm_hour); + BCD_TO_BIN(time->tm_mday); + BCD_TO_BIN(time->tm_mon); + BCD_TO_BIN(time->tm_year); + } + +#ifdef CONFIG_DECSTATION + time->tm_year += real_year - 72; +#endif + + /* + * Account for differences between how the RTC uses the values + * and how they are defined in a struct rtc_time; + */ + if (time->tm_year <= 69) + time->tm_year += 100; + + time->tm_mon--; +} + +/* Set the current date and time in the real time clock. */ +static inline int set_rtc_time(struct rtc_time *time) +{ + unsigned char mon, day, hrs, min, sec; + unsigned char save_control, save_freq_select; + unsigned int yrs; +#ifdef CONFIG_DECSTATION + unsigned int real_yrs, leap_yr; +#endif + + yrs = time->tm_year; + mon = time->tm_mon + 1; /* tm_mon starts at zero */ + day = time->tm_mday; + hrs = time->tm_hour; + min = time->tm_min; + sec = time->tm_sec; + + if (yrs > 255) /* They are unsigned */ + return -EINVAL; + + spin_lock_irq(&rtc_lock); +#ifdef CONFIG_DECSTATION + real_yrs = yrs; + leap_yr = ((!((yrs + 1900) % 4) && ((yrs + 1900) % 100)) || + !((yrs + 1900) % 400)); + yrs = 72; + + /* + * We want to keep the year set to 73 until March + * for non-leap years, so that Feb, 29th is handled + * correctly. + */ + if (!leap_yr && mon < 3) { + real_yrs--; + yrs = 73; + } +#endif + /* These limits and adjustments are independant of + * whether the chip is in binary mode or not. + */ + if (yrs > 169) { + spin_unlock_irq(&rtc_lock); + return -EINVAL; + } + + if (yrs >= 100) + yrs -= 100; + + if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) + || RTC_ALWAYS_BCD) { + BIN_TO_BCD(sec); + BIN_TO_BCD(min); + BIN_TO_BCD(hrs); + BIN_TO_BCD(day); + BIN_TO_BCD(mon); + BIN_TO_BCD(yrs); + } + + save_control = CMOS_READ(RTC_CONTROL); + CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL); + save_freq_select = CMOS_READ(RTC_FREQ_SELECT); + CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT); + +#ifdef CONFIG_DECSTATION + CMOS_WRITE(real_yrs, RTC_DEC_YEAR); +#endif + CMOS_WRITE(yrs, RTC_YEAR); + CMOS_WRITE(mon, RTC_MONTH); + CMOS_WRITE(day, RTC_DAY_OF_MONTH); + CMOS_WRITE(hrs, RTC_HOURS); + CMOS_WRITE(min, RTC_MINUTES); + CMOS_WRITE(sec, RTC_SECONDS); + + CMOS_WRITE(save_control, RTC_CONTROL); + CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT); + + spin_unlock_irq(&rtc_lock); + + return 0; +} + +static inline unsigned int get_rtc_ss(void) +{ + struct rtc_time h; + + get_rtc_time(&h); + return h.tm_sec; +} + +static inline int get_rtc_pll(struct rtc_pll_info *pll) +{ + return -EINVAL; +} +static inline int set_rtc_pll(struct rtc_pll_info *pll) +{ + return -EINVAL; +} + +#endif /* __KERNEL__ */ +#endif /* __ASM_RTC_H__ */ --- /dev/null 1969-12-31 17:00:00.000000000 -0700 +++ linux-2.5/include/asm-i386/rtc.h 2002-07-23 10:38:32.000000000 -0700 @@ -0,0 +1,10 @@ +#ifndef _I386_RTC_H +#define _I386_RTC_H + +/* + * x86 uses the default access methods for the RTC. + */ + +#include <asm-generic/rtc.h> + +#endif --- /dev/null 1969-12-31 17:00:00.000000000 -0700 +++ linux-2.5/include/asm-alpha/rtc.h 2002-07-23 10:38:32.000000000 -0700 @@ -0,0 +1,10 @@ +#ifndef _ALPHA_RTC_H +#define _ALPHA_RTC_H + +/* + * Alpha uses the default access methods for the RTC. + */ + +#include <asm-generic/rtc.h> + +#endif --- /dev/null 1969-12-31 17:00:00.000000000 -0700 +++ linux-2.5/include/asm-parisc/rtc.h 2002-08-02 08:22:16.000000000 -0700 @@ -0,0 +1,131 @@ +/* + * inclue/asm-parisc/rtc.h + * + * Copyright 2002 Randolph CHung <tausq@debian.org> + * + * Based on: include/asm-ppc/rtc.h and the genrtc driver in the + * 2.4 parisc linux tree + */ + +#ifndef __ASM_RTC_H__ +#define __ASM_RTC_H__ + +#ifdef __KERNEL__ + +#include <linux/rtc.h> + +#include <asm/pdc.h> + +#define SECS_PER_HOUR (60 * 60) +#define SECS_PER_DAY (SECS_PER_HOUR * 24) + + +#define RTC_PIE 0x40 /* periodic interrupt enable */ +#define RTC_AIE 0x20 /* alarm interrupt enable */ +#define RTC_UIE 0x10 /* update-finished interrupt enable */ + +extern void gen_rtc_interrupt(unsigned long); + +/* some dummy definitions */ +#define RTC_SQWE 0x08 /* enable square-wave output */ +#define RTC_DM_BINARY 0x04 /* all time/date values are BCD if clear */ +#define RTC_24H 0x02 /* 24 hour mode - else hours bit 7 means pm */ +#define RTC_DST_EN 0x01 /* auto switch DST - works f. USA only */ + +# define __isleap(year) \ + ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0)) + +/* How many days come before each month (0-12). */ +static const unsigned short int __mon_yday[2][13] = +{ + /* Normal years. */ + { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 }, + /* Leap years. */ + { 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 } +}; + +static int get_rtc_time(struct rtc_time *wtime) +{ + struct pdc_tod tod_data; + long int days, rem, y; + const unsigned short int *ip; + + if(pdc_tod_read(&tod_data) < 0) + return -1; + + + // most of the remainder of this function is: +// Copyright (C) 1991, 1993, 1997, 1998 Free Software Foundation, Inc. +// This was originally a part of the GNU C Library. +// It is distributed under the GPL, and was swiped from offtime.c + + + days = tod_data.tod_sec / SECS_PER_DAY; + rem = tod_data.tod_sec % SECS_PER_DAY; + + wtime->tm_hour = rem / SECS_PER_HOUR; + rem %= SECS_PER_HOUR; + wtime->tm_min = rem / 60; + wtime->tm_sec = rem % 60; + + y = 1970; + +#define DIV(a, b) ((a) / (b) - ((a) % (b) < 0)) +#define LEAPS_THRU_END_OF(y) (DIV (y, 4) - DIV (y, 100) + DIV (y, 400)) + + while (days < 0 || days >= (__isleap (y) ? 366 : 365)) + { + /* Guess a corrected year, assuming 365 days per year. */ + long int yg = y + days / 365 - (days % 365 < 0); + + /* Adjust DAYS and Y to match the guessed year. */ + days -= ((yg - y) * 365 + + LEAPS_THRU_END_OF (yg - 1) + - LEAPS_THRU_END_OF (y - 1)); + y = yg; + } + wtime->tm_year = y - 1900; + + ip = __mon_yday[__isleap(y)]; + for (y = 11; days < (long int) ip[y]; --y) + continue; + days -= ip[y]; + wtime->tm_mon = y; + wtime->tm_mday = days + 1; + + return 0; +} + +static int set_rtc_time(struct rtc_time *wtime) +{ + u_int32_t secs; + + secs = mktime(wtime->tm_year + 1900, wtime->tm_mon + 1, wtime->tm_mday, + wtime->tm_hour, wtime->tm_min, wtime->tm_sec); + + if(pdc_tod_set(secs, 0) < 0) + return -1; + else + return 0; + +} + +static inline unsigned int get_rtc_ss(void) +{ + struct rtc_time h; + + get_rtc_time(&h); + return h.tm_sec; +} + +static inline int get_rtc_pll(struct rtc_pll_info *pll) +{ + return -EINVAL; +} +static inline int set_rtc_pll(struct rtc_pll_info *pll) +{ + return -EINVAL; +} + +#endif /* __KERNEL__ */ +#endif /* __ASM_RTC_H__ */ --- linux-2.5/drivers/char/genrtc.c 2002-08-02 08:24:32.000000000 -0700 +++ linux-2.5/drivers/char/genrtc.c 2002-08-02 09:01:59.000000000 -0700 @@ -33,9 +33,10 @@ * 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 */ -#define RTC_VERSION "1.05" +#define RTC_VERSION "1.06" #include <linux/module.h> #include <linux/config.h> @@ -128,8 +129,8 @@ 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", + 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; @@ -174,7 +175,7 @@ unsigned long data; ssize_t retval; - if (count < sizeof(unsigned long)) + if (count != sizeof (unsigned int) && count != sizeof (unsigned long)) return -EINVAL; if (file->f_flags & O_NONBLOCK && !gen_rtc_irq_data) @@ -193,7 +194,14 @@ schedule(); } - retval = put_user(data, (unsigned long *)buf); + /* 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 long *)buf); + } + else { + retval = put_user(data, (unsigned long *)buf); + } if (!retval) retval = sizeof(unsigned long); out: @@ -326,8 +334,7 @@ wtime.tm_sec < 0 || wtime.tm_sec >= 60) return -EINVAL; - set_rtc_time(&wtime); - return 0; + return set_rtc_time(&wtime); } } - 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/