sparc: convert to arch_gettimeoffset()

This patch converts sparc (specifically sparc32) to use GENERIC_TIME via
the arch_getoffset() infrastructure, reducing the amount of arch
specific code we need to maintain.

The sparc architecture is one of the last 3 arches that need to be
converted.

This patch applies on top of Linus' current -git tree

I've taken my best swing at converting this, but I'm not 100% confident
I got it right. My cross-compiler is now out of date (gcc4.2) so I
wasn't able to check if it compiled. Any assistance from arch
maintainers or testers to get this merged would be great.

Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 41 insertions, 178 deletions

diff --git a/arch/sparc/kernel/pcic.c b/arch/sparc/kernel/pcic.c
index 85e7037429b9..4e2724ec2bb6 100644
--- a/arch/sparc/kernel/pcic.c
+++ b/arch/sparc/kernel/pcic.c
@@ -30,6 +30,7 @@
 #include <asm/oplib.h>
 #include <asm/prom.h>
 #include <asm/pcic.h>
+#include <asm/timex.h>
 #include <asm/timer.h>
 #include <asm/uaccess.h>
 #include <asm/irq_regs.h>
@@ -163,8 +164,6 @@ void __iomem *pcic_regs;
 volatile int pcic_speculative;
 volatile int pcic_trapped;
 
-static void pci_do_gettimeofday(struct timeval *tv);
-static int pci_do_settimeofday(struct timespec *tv);
 
 #define CONFIG_CMD(bus, device_fn, where) (0x80000000 | (((unsigned int)bus) << 16) | (((unsigned int)device_fn) << 8) | (where & ~3))
 
@@ -716,19 +715,27 @@ static irqreturn_t pcic_timer_handler (int irq, void *h)
 #define USECS_PER_JIFFY  10000  /* We have 100HZ "standard" timer for sparc */
 #define TICK_TIMER_LIMIT ((100*1000000/4)/100)
 
+u32 pci_gettimeoffset(void)
+{
+        /*
+         * We divide all by 100
+         * to have microsecond resolution and to avoid overflow
+         */
+        unsigned long count =
+            readl(pcic0.pcic_regs+PCI_SYS_COUNTER) & ~PCI_SYS_COUNTER_OVERFLOW;
+        count = ((count/100)*USECS_PER_JIFFY) / (TICK_TIMER_LIMIT/100);
+        return count * 1000;
+}
+
+
 void __init pci_time_init(void)
 {
         struct linux_pcic *pcic = &pcic0;
         unsigned long v;
         int timer_irq, irq;
 
-        /* A hack until do_gettimeofday prototype is moved to arch specific headers
-           and btfixupped. Patch do_gettimeofday with ba pci_do_gettimeofday; nop */
-        ((unsigned int *)do_gettimeofday)[0] = 
-            0x10800000 | ((((unsigned long)pci_do_gettimeofday -
-             (unsigned long)do_gettimeofday) >> 2) & 0x003fffff);
-        ((unsigned int *)do_gettimeofday)[1] = 0x01000000;
-        BTFIXUPSET_CALL(bus_do_settimeofday, pci_do_settimeofday, BTFIXUPCALL_NORM);
+        do_arch_gettimeoffset = pci_gettimeoffset;
+
         btfixup();
 
         writel (TICK_TIMER_LIMIT, pcic->pcic_regs+PCI_SYS_LIMIT);
@@ -746,84 +753,6 @@ void __init pci_time_init(void)
         local_irq_enable();
 }
 
-static inline unsigned long do_gettimeoffset(void)
-{
-        /*
-         * We divide all by 100
-         * to have microsecond resolution and to avoid overflow
-         */
-        unsigned long count =
-            readl(pcic0.pcic_regs+PCI_SYS_COUNTER) & ~PCI_SYS_COUNTER_OVERFLOW;
-        count = ((count/100)*USECS_PER_JIFFY) / (TICK_TIMER_LIMIT/100);
-        return count;
-}
-
-static void pci_do_gettimeofday(struct timeval *tv)
-{
-        unsigned long flags;
-        unsigned long seq;
-        unsigned long usec, sec;
-        unsigned long max_ntp_tick = tick_usec - tickadj;
-
-        do {
-                seq = read_seqbegin_irqsave(&xtime_lock, flags);
-                usec = do_gettimeoffset();
-
-                /*
-                 * If time_adjust is negative then NTP is slowing the clock
-                 * so make sure not to go into next possible interval.
-                 * Better to lose some accuracy than have time go backwards..
-                 */
-                if (unlikely(time_adjust < 0))
-                        usec = min(usec, max_ntp_tick);
-
-                sec = xtime.tv_sec;
-                usec += (xtime.tv_nsec / 1000);
-        } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
-
-        while (usec >= 1000000) {
-                usec -= 1000000;
-                sec++;
-        }
-
-        tv->tv_sec = sec;
-        tv->tv_usec = usec;
-}
-
-static int pci_do_settimeofday(struct timespec *tv)
-{
-        if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
-                return -EINVAL;
-
-        /*
-         * This is revolting. We need to set "xtime" correctly. However, the
-         * value in this location is the value at the most recent update of
-         * wall time.  Discover what correction gettimeofday() would have
-         * made, and then undo it!
-         */
-        tv->tv_nsec -= 1000 * do_gettimeoffset();
-        while (tv->tv_nsec < 0) {
-                tv->tv_nsec += NSEC_PER_SEC;
-                tv->tv_sec--;
-        }
-
-        wall_to_monotonic.tv_sec += xtime.tv_sec - tv->tv_sec;
-        wall_to_monotonic.tv_nsec += xtime.tv_nsec - tv->tv_nsec;
-
-        if (wall_to_monotonic.tv_nsec > NSEC_PER_SEC) {
-                wall_to_monotonic.tv_nsec -= NSEC_PER_SEC;
-                wall_to_monotonic.tv_sec++;
-        }
-        if (wall_to_monotonic.tv_nsec < 0) {
-                wall_to_monotonic.tv_nsec += NSEC_PER_SEC;
-                wall_to_monotonic.tv_sec--;
-        }
-
-        xtime.tv_sec = tv->tv_sec;
-        xtime.tv_nsec = tv->tv_nsec;
-        ntp_clear();
-        return 0;
-}
 
 #if 0
 static void watchdog_reset() {
diff --git a/arch/sparc/kernel/time_32.c b/arch/sparc/kernel/time_32.c
index 5b2f595fe65b..0d4c09b15efc 100644
--- a/arch/sparc/kernel/time_32.c
+++ b/arch/sparc/kernel/time_32.c
@@ -35,6 +35,7 @@
 #include <linux/platform_device.h>
 
 #include <asm/oplib.h>
+#include <asm/timex.h>
 #include <asm/timer.h>
 #include <asm/system.h>
 #include <asm/irq.h>
@@ -51,7 +52,6 @@ DEFINE_SPINLOCK(rtc_lock);
 EXPORT_SYMBOL(rtc_lock);
 
 static int set_rtc_mmss(unsigned long);
-static int sbus_do_settimeofday(struct timespec *tv);
 
 unsigned long profile_pc(struct pt_regs *regs)
 {
@@ -76,6 +76,8 @@ EXPORT_SYMBOL(profile_pc);
 
 __volatile__ unsigned int *master_l10_counter;
 
+u32 (*do_arch_gettimeoffset)(void);
+
 /*
  * timer_interrupt() needs to keep up the real-time clock,
  * as well as call the "do_timer()" routine every clocktick
@@ -196,35 +198,14 @@ static int __init clock_init(void)
 {
         return of_register_driver(&clock_driver, &of_platform_bus_type);
 }
-
 /* Must be after subsys_initcall() so that busses are probed.  Must
  * be before device_initcall() because things like the RTC driver
  * need to see the clock registers.
  */
 fs_initcall(clock_init);
 
-static void __init sbus_time_init(void)
-{
-
-        BTFIXUPSET_CALL(bus_do_settimeofday, sbus_do_settimeofday, BTFIXUPCALL_NORM);
-        btfixup();
-
-        sparc_init_timers(timer_interrupt);
-}
-
-void __init time_init(void)
-{
-#ifdef CONFIG_PCI
-        extern void pci_time_init(void);
-        if (pcic_present()) {
-                pci_time_init();
-                return;
-        }
-#endif
-        sbus_time_init();
-}
 
-static inline unsigned long do_gettimeoffset(void)
+u32 sbus_do_gettimeoffset(void)
 {
         unsigned long val = *master_l10_counter;
         unsigned long usec = (val >> 10) & 0x1fffff;
@@ -233,86 +214,39 @@ static inline unsigned long do_gettimeoffset(void)
         if (val & 0x80000000)
                 usec += 1000000 / HZ;
 
-        return usec;
+        return usec * 1000;
 }
 
-/* Ok, my cute asm atomicity trick doesn't work anymore.
- * There are just too many variables that need to be protected
- * now (both members of xtime, et al.)
- */
-void do_gettimeofday(struct timeval *tv)
-{
-        unsigned long flags;
-        unsigned long seq;
-        unsigned long usec, sec;
-        unsigned long max_ntp_tick = tick_usec - tickadj;
-
-        do {
-                seq = read_seqbegin_irqsave(&xtime_lock, flags);
-                usec = do_gettimeoffset();
-
-                /*
-                 * If time_adjust is negative then NTP is slowing the clock
-                 * so make sure not to go into next possible interval.
-                 * Better to lose some accuracy than have time go backwards..
-                 */
-                if (unlikely(time_adjust < 0))
-                        usec = min(usec, max_ntp_tick);
-
-                sec = xtime.tv_sec;
-                usec += (xtime.tv_nsec / 1000);
-        } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
-
-        while (usec >= 1000000) {
-                usec -= 1000000;
-                sec++;
-        }
 
-        tv->tv_sec = sec;
-        tv->tv_usec = usec;
-}
-
-EXPORT_SYMBOL(do_gettimeofday);
-
-int do_settimeofday(struct timespec *tv)
+u32 arch_gettimeoffset(void)
 {
-        int ret;
-
-        write_seqlock_irq(&xtime_lock);
-        ret = bus_do_settimeofday(tv);
-        write_sequnlock_irq(&xtime_lock);
-        clock_was_set();
-        return ret;
+        if (unlikely(!do_arch_gettimeoffset))
+                return 0;
+        return do_arch_gettimeoffset();
 }
 
-EXPORT_SYMBOL(do_settimeofday);
-
-static int sbus_do_settimeofday(struct timespec *tv)
+static void __init sbus_time_init(void)
 {
-        time_t wtm_sec, sec = tv->tv_sec;
-        long wtm_nsec, nsec = tv->tv_nsec;
+        do_arch_gettimeoffset = sbus_do_gettimeoffset;
 
-        if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
-                return -EINVAL;
-
-        /*
-         * This is revolting. We need to set "xtime" correctly. However, the
-         * value in this location is the value at the most recent update of
-         * wall time.  Discover what correction gettimeofday() would have
-         * made, and then undo it!
-         */
-        nsec -= 1000 * do_gettimeoffset();
-
-        wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
-        wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
+        btfixup();
 
-        set_normalized_timespec(&xtime, sec, nsec);
-        set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
+        sparc_init_timers(timer_interrupt);
+}
 
-        ntp_clear();
-        return 0;
+void __init time_init(void)
+{
+#ifdef CONFIG_PCI
+        extern void pci_time_init(void);
+        if (pcic_present()) {
+                pci_time_init();
+                return;
+        }
+#endif
+        sbus_time_init();
 }
 
+
 static int set_rtc_mmss(unsigned long secs)
 {
         struct rtc_device *rtc = rtc_class_open("rtc0");