[PATCH] x86_64: Don't need to read PIT in timer handler when PM timer is used

[mv-sheeva.git] / arch / x86_64 / kernel / time.c

diff --git a/arch/x86_64/kernel/time.c b/arch/x86_64/kernel/time.c
index dba7237be5c1c2b2b2e8ae28a5ca5a5ecf34aa65..86039baaaf185872fe68e23a639b1d34105f557b 100644 (file)
--- a/arch/x86_64/kernel/time.c
+++ b/arch/x86_64/kernel/time.c
@@ -48,6 +48,8 @@ static void cpufreq_delayed_get(void);
 extern void i8254_timer_resume(void);
 extern int using_apic_timer;
 
+static char *time_init_gtod(void);
+
 DEFINE_SPINLOCK(rtc_lock);
 DEFINE_SPINLOCK(i8253_lock);
 
@@ -59,7 +61,7 @@ static int notsc __initdata = 0;
 unsigned int cpu_khz;                                  /* TSC clocks / usec, not used here */
 static unsigned long hpet_period;                      /* fsecs / HPET clock */
 unsigned long hpet_tick;                               /* HPET clocks / interrupt */
-static int hpet_use_timer;                             /* Use counter of hpet for time keeping, otherwise PIT */
+int hpet_use_timer;                            /* Use counter of hpet for time keeping, otherwise PIT */
 unsigned long vxtime_hz = PIT_TICK_RATE;
 int report_lost_ticks;                         /* command line option */
 unsigned long long monotonic_base;
@@ -326,7 +328,10 @@ static noinline void handle_lost_ticks(int lost, struct pt_regs *regs)
            print_symbol("rip %s\n", regs->rip);
            if (vxtime.mode == VXTIME_TSC && vxtime.hpet_address) {
                    printk(KERN_WARNING "Falling back to HPET\n");
-                   vxtime.last = hpet_readl(HPET_T0_CMP) - hpet_tick;
+                   if (hpet_use_timer)
+                       vxtime.last = hpet_readl(HPET_T0_CMP) - hpet_tick;
+                   else
+                       vxtime.last = hpet_readl(HPET_COUNTER);
                    vxtime.mode = VXTIME_HPET;
                    do_gettimeoffset = do_gettimeoffset_hpet;
            }
@@ -349,7 +354,7 @@ void main_timer_handler(struct pt_regs *regs)
 {
        static unsigned long rtc_update = 0;
        unsigned long tsc;
-       int delay, offset = 0, lost = 0;
+       int delay = 0, offset = 0, lost = 0;
 
 /*
  * Here we are in the timer irq handler. We have irqs locally disabled (so we
@@ -370,7 +375,7 @@ void main_timer_handler(struct pt_regs *regs)
                 */
                offset = hpet_readl(HPET_T0_CMP) - hpet_tick;
                delay = hpet_readl(HPET_COUNTER) - offset;
-       } else {
+       } else if (!pmtmr_ioport) {
                spin_lock(&i8253_lock);
                outb_p(0x00, 0x43);
                delay = inb_p(0x40);
@@ -472,7 +477,7 @@ static irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
        return IRQ_HANDLED;
 }
 
-static unsigned int cyc2ns_scale;
+static unsigned int cyc2ns_scale __read_mostly;
 #define CYC2NS_SCALE_FACTOR 10 /* 2^10, carefully chosen */
 
 static inline void set_cyc2ns_scale(unsigned long cpu_khz)
@@ -898,6 +903,7 @@ static struct irqaction irq0 = {
 void __init time_init(void)
 {
        char *timename;
+       char *gtod;
 
 #ifdef HPET_HACK_ENABLE_DANGEROUS
         if (!vxtime.hpet_address) {
@@ -942,21 +948,19 @@ void __init time_init(void)
                timename = "PIT";
        }
 
-       printk(KERN_INFO "time.c: Using %ld.%06ld MHz %s timer.\n",
-              vxtime_hz / 1000000, vxtime_hz % 1000000, timename);
+       vxtime.mode = VXTIME_TSC;
+       gtod = time_init_gtod();
+
+       printk(KERN_INFO "time.c: Using %ld.%06ld MHz WALL %s GTOD %s timer.\n",
+              vxtime_hz / 1000000, vxtime_hz % 1000000, timename, gtod);
        printk(KERN_INFO "time.c: Detected %d.%03d MHz processor.\n",
                cpu_khz / 1000, cpu_khz % 1000);
-       vxtime.mode = VXTIME_TSC;
        vxtime.quot = (1000000L << 32) / vxtime_hz;
        vxtime.tsc_quot = (1000L << 32) / cpu_khz;
        vxtime.last_tsc = get_cycles_sync();
        setup_irq(0, &irq0);
 
        set_cyc2ns_scale(cpu_khz);
-
-#ifndef CONFIG_SMP
-       time_init_gtod();
-#endif
 }
 
 /*
@@ -978,9 +982,9 @@ __cpuinit int unsynchronized_tsc(void)
 }
 
 /*
- * Decide after all CPUs are booted what mode gettimeofday should use.
+ * Decide what mode gettimeofday should use.
  */
-void __init time_init_gtod(void)
+__init static char *time_init_gtod(void)
 {
        char *timetype;
 
@@ -988,7 +992,10 @@ void __init time_init_gtod(void)
                notsc = 1;
        if (vxtime.hpet_address && notsc) {
                timetype = hpet_use_timer ? "HPET" : "PIT/HPET";
-               vxtime.last = hpet_readl(HPET_T0_CMP) - hpet_tick;
+               if (hpet_use_timer)
+                       vxtime.last = hpet_readl(HPET_T0_CMP) - hpet_tick;
+               else
+                       vxtime.last = hpet_readl(HPET_COUNTER);
                vxtime.mode = VXTIME_HPET;
                do_gettimeoffset = do_gettimeoffset_hpet;
 #ifdef CONFIG_X86_PM_TIMER
@@ -1005,8 +1012,7 @@ void __init time_init_gtod(void)
                timetype = hpet_use_timer ? "HPET/TSC" : "PIT/TSC";
                vxtime.mode = VXTIME_TSC;
        }
-
-       printk(KERN_INFO "time.c: Using %s based timekeeping.\n", timetype);
+       return timetype;
 }
 
 __setup("report_lost_ticks", time_setup);
@@ -1321,8 +1327,7 @@ static int __init nohpet_setup(char *s)
 
 __setup("nohpet", nohpet_setup);
 
-
-static int __init notsc_setup(char *s)
+int __init notsc_setup(char *s)
 {
        notsc = 1;
        return 0;