[POWERPC] Implement {read,update}_persistent_clock

With these functions implemented we cooperate better with the generic
timekeeping code.  This obsoletes the need for the timer sysdev as a bonus.

Signed-off-by: Tony Breeds <tony@bakeyournoodle.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 26 insertions, 59 deletions

diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index d95e68c0a6b3..b94e4dffba19 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -73,16 +73,11 @@
 #include <asm/iseries/hv_call_xm.h>
 #endif
 
-/* keep track of when we need to update the rtc */
-time_t last_rtc_update;
 #ifdef CONFIG_PPC_ISERIES
 static unsigned long __initdata iSeries_recal_titan;
 static signed long __initdata iSeries_recal_tb;
 #endif
 
-/* The decrementer counts down by 128 every 128ns on a 601. */
-#define DECREMENTER_COUNT_601   (1000000000 / HZ)
-
 #define XSEC_PER_SEC (1024*1024)
 
 #ifdef CONFIG_PPC64
@@ -348,39 +343,6 @@ void udelay(unsigned long usecs)
 }
 EXPORT_SYMBOL(udelay);
 
-static __inline__ void timer_check_rtc(void)
-{
-        /*
-         * update the rtc when needed, this should be performed on the
-         * right fraction of a second. Half or full second ?
-         * Full second works on mk48t59 clocks, others need testing.
-         * Note that this update is basically only used through 
-         * the adjtimex system calls. Setting the HW clock in
-         * any other way is a /dev/rtc and userland business.
-         * This is still wrong by -0.5/+1.5 jiffies because of the
-         * timer interrupt resolution and possible delay, but here we 
-         * hit a quantization limit which can only be solved by higher
-         * resolution timers and decoupling time management from timer
-         * interrupts. This is also wrong on the clocks
-         * which require being written at the half second boundary.
-         * We should have an rtc call that only sets the minutes and
-         * seconds like on Intel to avoid problems with non UTC clocks.
-         */
-        if (ppc_md.set_rtc_time && ntp_synced() &&
-            xtime.tv_sec - last_rtc_update >= 659 &&
-            abs((xtime.tv_nsec/1000) - (1000000-1000000/HZ)) < 500000/HZ) {
-                struct rtc_time tm;
-                to_tm(xtime.tv_sec + 1 + timezone_offset, &tm);
-                tm.tm_year -= 1900;
-                tm.tm_mon -= 1;
-                if (ppc_md.set_rtc_time(&tm) == 0)
-                        last_rtc_update = xtime.tv_sec + 1;
-                else
-                        /* Try again one minute later */
-                        last_rtc_update += 60;
-        }
-}
-
 /*
  * This version of gettimeofday has microsecond resolution.
  */
@@ -689,7 +651,6 @@ void timer_interrupt(struct pt_regs * regs)
                         tb_last_jiffy = tb_next_jiffy;
                         do_timer(1);
                         timer_recalc_offset(tb_last_jiffy);
-                        timer_check_rtc();
                 }
                 write_sequnlock(&xtime_lock);
         }
@@ -801,11 +762,6 @@ int do_settimeofday(struct timespec *tv)
         set_normalized_timespec(&xtime, new_sec, new_nsec);
         set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
 
-        /* In case of a large backwards jump in time with NTP, we want the 
-         * clock to be updated as soon as the PLL is again in lock.
-         */
-        last_rtc_update = new_sec - 658;
-
         ntp_clear();
 
         new_xsec = xtime.tv_nsec;
@@ -881,12 +837,35 @@ void __init generic_calibrate_decr(void)
 #endif
 }
 
-unsigned long get_boot_time(void)
+int update_persistent_clock(struct timespec now)
+{
+        struct rtc_time tm;
+
+        if (!ppc_md.set_rtc_time)
+                return 0;
+
+        to_tm(now.tv_sec + 1 + timezone_offset, &tm);
+        tm.tm_year -= 1900;
+        tm.tm_mon -= 1;
+
+        return ppc_md.set_rtc_time(&tm);
+}
+
+unsigned long read_persistent_clock(void)
 {
         struct rtc_time tm;
+        static int first = 1;
+
+        /* XXX this is a litle fragile but will work okay in the short term */
+        if (first) {
+                first = 0;
+                if (ppc_md.time_init)
+                        timezone_offset = ppc_md.time_init();
 
-        if (ppc_md.get_boot_time)
-                return ppc_md.get_boot_time();
+                /* get_boot_time() isn't guaranteed to be safe to call late */
+                if (ppc_md.get_boot_time)
+                        return ppc_md.get_boot_time() -timezone_offset;
+        }
         if (!ppc_md.get_rtc_time)
                 return 0;
         ppc_md.get_rtc_time(&tm);
@@ -898,14 +877,10 @@ unsigned long get_boot_time(void)
 void __init time_init(void)
 {
         unsigned long flags;
-        unsigned long tm = 0;
         struct div_result res;
         u64 scale, x;
         unsigned shift;
 
-        if (ppc_md.time_init != NULL)
-                timezone_offset = ppc_md.time_init();
-
         if (__USE_RTC()) {
                 /* 601 processor: dec counts down by 128 every 128ns */
                 ppc_tb_freq = 1000000000;
@@ -980,19 +955,14 @@ void __init time_init(void)
         /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */
         boot_tb = get_tb_or_rtc();
 
-        tm = get_boot_time();
-
         write_seqlock_irqsave(&xtime_lock, flags);
 
         /* If platform provided a timezone (pmac), we correct the time */
         if (timezone_offset) {
                 sys_tz.tz_minuteswest = -timezone_offset / 60;
                 sys_tz.tz_dsttime = 0;
-                tm -= timezone_offset;
         }
 
-        xtime.tv_sec = tm;
-        xtime.tv_nsec = 0;
         do_gtod.varp = &do_gtod.vars[0];
         do_gtod.var_idx = 0;
         do_gtod.varp->tb_orig_stamp = tb_last_jiffy;
@@ -1010,9 +980,6 @@ void __init time_init(void)
 
         time_freq = 0;
 
-        last_rtc_update = xtime.tv_sec;
-        set_normalized_timespec(&wall_to_monotonic,
-                                -xtime.tv_sec, -xtime.tv_nsec);
         write_sequnlock_irqrestore(&xtime_lock, flags);
 
         /* Not exact, but the timer interrupt takes care of this */