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authorPaul Mackerras <paulus@samba.org>2005-10-23 17:14:56 +1000
committerPaul Mackerras <paulus@samba.org>2005-10-23 17:14:56 +1000
commit96c44507601d64f29b8ccc867637292e326c7019 (patch)
tree1fbdb6f4a3c2d99afaa6a244161518ec78f31048 /arch/powerpc/kernel
parent985990137e81ca9fd6561cd0f7d1a9695ec57d5a (diff)
powerpc: Fix time code for 601 processors
The 601 doesn't have the timebase register; instead it has an RTCL register that counts nanoseconds and wraps at 1000000000, and an RTCU register that counts seconds. This makes the necessary changes for the merged time code to use the RTCL/U registers when the kernel is running on a 601. Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch/powerpc/kernel')
-rw-r--r--arch/powerpc/kernel/time.c79
1 files changed, 56 insertions, 23 deletions
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index b635c7de669..ad501d62aa6 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -126,6 +126,16 @@ unsigned long ppc_tb_freq;
#define boot_cpuid 0
#endif
+u64 tb_last_jiffy __cacheline_aligned_in_smp;
+unsigned long tb_last_stamp;
+
+/*
+ * Note that on ppc32 this only stores the bottom 32 bits of
+ * the timebase value, but that's enough to tell when a jiffy
+ * has passed.
+ */
+DEFINE_PER_CPU(unsigned long, last_jiffy);
+
static __inline__ void timer_check_rtc(void)
{
/*
@@ -191,6 +201,26 @@ static inline void __do_gettimeofday(struct timeval *tv, u64 tb_val)
void do_gettimeofday(struct timeval *tv)
{
+ if (__USE_RTC()) {
+ /* do this the old way */
+ unsigned long flags, seq;
+ unsigned int sec, nsec, usec, lost;
+
+ do {
+ seq = read_seqbegin_irqsave(&xtime_lock, flags);
+ sec = xtime.tv_sec;
+ nsec = xtime.tv_nsec + tb_ticks_since(tb_last_stamp);
+ lost = jiffies - wall_jiffies;
+ } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
+ usec = nsec / 1000 + lost * (1000000 / HZ);
+ while (usec >= 1000000) {
+ usec -= 1000000;
+ ++sec;
+ }
+ tv->tv_sec = sec;
+ tv->tv_usec = usec;
+ return;
+ }
__do_gettimeofday(tv, get_tb());
}
@@ -272,6 +302,8 @@ static __inline__ void timer_recalc_offset(u64 cur_tb)
unsigned long offset;
u64 new_stamp_xsec;
+ if (__USE_RTC())
+ return;
offset = cur_tb - do_gtod.varp->tb_orig_stamp;
if ((offset & 0x80000000u) == 0)
return;
@@ -357,15 +389,6 @@ static void iSeries_tb_recal(void)
* call will not be needed)
*/
-u64 tb_last_stamp __cacheline_aligned_in_smp;
-
-/*
- * Note that on ppc32 this only stores the bottom 32 bits of
- * the timebase value, but that's enough to tell when a jiffy
- * has passed.
- */
-DEFINE_PER_CPU(unsigned long, last_jiffy);
-
/*
* timer_interrupt - gets called when the decrementer overflows,
* with interrupts disabled.
@@ -415,10 +438,11 @@ void timer_interrupt(struct pt_regs * regs)
continue;
write_seqlock(&xtime_lock);
- tb_last_stamp += tb_ticks_per_jiffy;
- timer_recalc_offset(tb_last_stamp);
+ tb_last_jiffy += tb_ticks_per_jiffy;
+ tb_last_stamp = per_cpu(last_jiffy, cpu);
+ timer_recalc_offset(tb_last_jiffy);
do_timer(regs);
- timer_sync_xtime(tb_last_stamp);
+ timer_sync_xtime(tb_last_jiffy);
timer_check_rtc();
write_sequnlock(&xtime_lock);
if (adjusting_time && (time_adjust == 0))
@@ -453,7 +477,7 @@ void wakeup_decrementer(void)
* We don't expect this to be called on a machine with a 601,
* so using get_tbl is fine.
*/
- tb_last_stamp = get_tb();
+ tb_last_stamp = tb_last_jiffy = get_tb();
for_each_cpu(i)
per_cpu(last_jiffy, i) = tb_last_stamp;
}
@@ -483,6 +507,8 @@ void __init smp_space_timers(unsigned int max_cpus)
*/
unsigned long long sched_clock(void)
{
+ if (__USE_RTC())
+ return get_rtc();
return mulhdu(get_tb(), tb_to_ns_scale) << tb_to_ns_shift;
}
@@ -534,7 +560,7 @@ int do_settimeofday(struct timespec *tv)
new_xsec = (u64)new_nsec * XSEC_PER_SEC;
do_div(new_xsec, NSEC_PER_SEC);
new_xsec += (u64)new_sec * XSEC_PER_SEC;
- update_gtod(tb_last_stamp, new_xsec, do_gtod.varp->tb_to_xs);
+ update_gtod(tb_last_jiffy, new_xsec, do_gtod.varp->tb_to_xs);
#ifdef CONFIG_PPC64
systemcfg->tz_minuteswest = sys_tz.tz_minuteswest;
@@ -616,12 +642,20 @@ void __init time_init(void)
if (ppc_md.time_init != NULL)
timezone_offset = ppc_md.time_init();
- ppc_md.calibrate_decr();
-
- printk(KERN_INFO "time_init: decrementer frequency = %lu.%.6lu MHz\n",
- ppc_tb_freq / 1000000, ppc_tb_freq % 1000000);
- printk(KERN_INFO "time_init: processor frequency = %lu.%.6lu MHz\n",
- ppc_proc_freq / 1000000, ppc_proc_freq % 1000000);
+ if (__USE_RTC()) {
+ /* 601 processor: dec counts down by 128 every 128ns */
+ ppc_tb_freq = 1000000000;
+ tb_last_stamp = get_rtcl();
+ tb_last_jiffy = tb_last_stamp;
+ } else {
+ /* Normal PowerPC with timebase register */
+ ppc_md.calibrate_decr();
+ printk(KERN_INFO "time_init: decrementer frequency = %lu.%.6lu MHz\n",
+ ppc_tb_freq / 1000000, ppc_tb_freq % 1000000);
+ printk(KERN_INFO "time_init: processor frequency = %lu.%.6lu MHz\n",
+ ppc_proc_freq / 1000000, ppc_proc_freq % 1000000);
+ tb_last_stamp = tb_last_jiffy = get_tb();
+ }
tb_ticks_per_jiffy = ppc_tb_freq / HZ;
tb_ticks_per_sec = tb_ticks_per_jiffy * HZ;
@@ -661,17 +695,16 @@ void __init time_init(void)
write_seqlock_irqsave(&xtime_lock, flags);
xtime.tv_sec = tm;
xtime.tv_nsec = 0;
- tb_last_stamp = get_tb();
do_gtod.varp = &do_gtod.vars[0];
do_gtod.var_idx = 0;
- do_gtod.varp->tb_orig_stamp = tb_last_stamp;
+ do_gtod.varp->tb_orig_stamp = tb_last_jiffy;
__get_cpu_var(last_jiffy) = tb_last_stamp;
do_gtod.varp->stamp_xsec = (u64) xtime.tv_sec * XSEC_PER_SEC;
do_gtod.tb_ticks_per_sec = tb_ticks_per_sec;
do_gtod.varp->tb_to_xs = tb_to_xs;
do_gtod.tb_to_us = tb_to_us;
#ifdef CONFIG_PPC64
- systemcfg->tb_orig_stamp = tb_last_stamp;
+ systemcfg->tb_orig_stamp = tb_last_jiffy;
systemcfg->tb_update_count = 0;
systemcfg->tb_ticks_per_sec = tb_ticks_per_sec;
systemcfg->stamp_xsec = xtime.tv_sec * XSEC_PER_SEC;