* Author: Jun Sun, jsun@mvista.com or jsun@junsun.net
* Copyright (c) 2003, 2004 Maciej W. Rozycki
*
- * Common time service routines for MIPS machines. See
- * Documentation/mips/time.README.
+ * Common time service routines for MIPS machines.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/param.h>
-#include <linux/profile.h>
#include <linux/time.h>
#include <linux/timex.h>
#include <linux/smp.h>
-#include <linux/kernel_stat.h>
#include <linux/spinlock.h>
-#include <linux/interrupt.h>
#include <linux/module.h>
-#include <linux/kallsyms.h>
-#include <asm/bootinfo.h>
-#include <asm/cache.h>
-#include <asm/compiler.h>
-#include <asm/cpu.h>
#include <asm/cpu-features.h>
#include <asm/div64.h>
-#include <asm/sections.h>
#include <asm/smtc_ipi.h>
#include <asm/time.h>
-#include <irq.h>
-
/*
* forward reference
*/
{
return 0;
}
-EXPORT_SYMBOL(rtc_mips_set_time);
int __weak rtc_mips_set_mmss(unsigned long nowtime)
{
return rtc_mips_set_mmss(now.tv_sec);
}
-/*
- * Null high precision timer functions for systems lacking one.
- */
-static cycle_t null_hpt_read(void)
-{
- return 0;
-}
-
-/*
- * High precision timer functions for a R4k-compatible timer.
- */
-static cycle_t c0_hpt_read(void)
-{
- return read_c0_count();
-}
-
-int (*mips_timer_state)(void);
-
-int null_perf_irq(void)
+static int null_perf_irq(void)
{
return 0;
}
-EXPORT_SYMBOL(null_perf_irq);
-
int (*perf_irq)(void) = null_perf_irq;
EXPORT_SYMBOL(perf_irq);
unsigned int mips_hpt_frequency;
-static unsigned int __init calibrate_hpt(void)
-{
- cycle_t frequency, hpt_start, hpt_end, hpt_count, hz;
-
- const int loops = HZ / 10;
- int log_2_loops = 0;
- int i;
-
- /*
- * We want to calibrate for 0.1s, but to avoid a 64-bit
- * division we round the number of loops up to the nearest
- * power of 2.
- */
- while (loops > 1 << log_2_loops)
- log_2_loops++;
- i = 1 << log_2_loops;
-
- /*
- * Wait for a rising edge of the timer interrupt.
- */
- while (mips_timer_state());
- while (!mips_timer_state());
-
- /*
- * Now see how many high precision timer ticks happen
- * during the calculated number of periods between timer
- * interrupts.
- */
- hpt_start = clocksource_mips.read();
- do {
- while (mips_timer_state());
- while (!mips_timer_state());
- } while (--i);
- hpt_end = clocksource_mips.read();
-
- hpt_count = (hpt_end - hpt_start) & clocksource_mips.mask;
- hz = HZ;
- frequency = hpt_count * hz;
-
- return frequency >> log_2_loops;
-}
-
-struct clocksource clocksource_mips = {
- .name = "MIPS",
- .mask = CLOCKSOURCE_MASK(32),
- .flags = CLOCK_SOURCE_IS_CONTINUOUS,
-};
-
void __init clocksource_set_clock(struct clocksource *cs, unsigned int clock)
{
u64 temp;
cd->mult = (u32) temp;
}
-static void __init init_mips_clocksource(void)
-{
- if (!mips_hpt_frequency || clocksource_mips.read == null_hpt_read)
- return;
-
- /* Calclate a somewhat reasonable rating value */
- clocksource_mips.rating = 200 + mips_hpt_frequency / 10000000;
-
- clocksource_set_clock(&clocksource_mips, mips_hpt_frequency);
-
- clocksource_register(&clocksource_mips);
-}
-
-void __init __weak plat_time_init(void)
-{
-}
-
/*
* This function exists in order to cause an error due to a duplicate
* definition if platform code should have its own implementation. The hook
* setup_irq calls and each clock_event_device should use its own
* struct irqrequest.
*/
-void __init plat_timer_setup(struct irqaction *irq)
+void __init plat_timer_setup(void)
{
BUG();
}
+static __init int cpu_has_mfc0_count_bug(void)
+{
+ switch (current_cpu_type()) {
+ case CPU_R4000PC:
+ case CPU_R4000SC:
+ case CPU_R4000MC:
+ /*
+ * V3.0 is documented as suffering from the mfc0 from count bug.
+ * Afaik this is the last version of the R4000. Later versions
+ * were marketed as R4400.
+ */
+ return 1;
+
+ case CPU_R4400PC:
+ case CPU_R4400SC:
+ case CPU_R4400MC:
+ /*
+ * The published errata for the R4400 upto 3.0 say the CPU
+ * has the mfc0 from count bug.
+ */
+ if ((current_cpu_data.processor_id & 0xff) <= 0x30)
+ return 1;
+
+ /*
+ * we assume newer revisions are ok
+ */
+ return 0;
+ }
+
+ return 0;
+}
+
void __init time_init(void)
{
plat_time_init();
- /* Choose appropriate high precision timer routines. */
- if (!cpu_has_counter && !clocksource_mips.read)
- /* No high precision timer -- sorry. */
- clocksource_mips.read = null_hpt_read;
- else if (!mips_hpt_frequency && !mips_timer_state) {
- /* A high precision timer of unknown frequency. */
- if (!clocksource_mips.read)
- /* No external high precision timer -- use R4k. */
- clocksource_mips.read = c0_hpt_read;
- } else {
- /* We know counter frequency. Or we can get it. */
- if (!clocksource_mips.read) {
- /* No external high precision timer -- use R4k. */
- clocksource_mips.read = c0_hpt_read;
- }
- if (!mips_hpt_frequency)
- mips_hpt_frequency = calibrate_hpt();
-
- /* Report the high precision timer rate for a reference. */
- printk("Using %u.%03u MHz high precision timer.\n",
- ((mips_hpt_frequency + 500) / 1000) / 1000,
- ((mips_hpt_frequency + 500) / 1000) % 1000);
- }
-
- init_mips_clocksource();
- mips_clockevent_init();
+ if (!mips_clockevent_init() || !cpu_has_mfc0_count_bug())
+ init_mips_clocksource();
}
projects / linux-2.6-omap-h63xx.git / blobdiff