From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/drivers/clocksource/mips-gic-timer.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++----------
1 files changed, 50 insertions(+), 10 deletions(-)
diff --git a/kernel/drivers/clocksource/mips-gic-timer.c b/kernel/drivers/clocksource/mips-gic-timer.c
index 54f8a33..be4175f 100644
--- a/kernel/drivers/clocksource/mips-gic-timer.c
+++ b/kernel/drivers/clocksource/mips-gic-timer.c
@@ -16,6 +16,7 @@
#include <linux/notifier.h>
#include <linux/of_irq.h>
#include <linux/percpu.h>
+#include <linux/sched_clock.h>
#include <linux/smp.h>
#include <linux/time.h>
#include <asm/mips-cps.h>
@@ -23,13 +24,13 @@
static DEFINE_PER_CPU(struct clock_event_device, gic_clockevent_device);
static int gic_timer_irq;
static unsigned int gic_frequency;
+static bool __read_mostly gic_clock_unstable;
-static u64 notrace gic_read_count(void)
+static void gic_clocksource_unstable(char *reason);
+
+static u64 notrace gic_read_count_2x32(void)
{
unsigned int hi, hi2, lo;
-
- if (mips_cm_is64)
- return read_gic_counter();
do {
hi = read_gic_counter_32h();
@@ -38,6 +39,19 @@
} while (hi2 != hi);
return (((u64) hi) << 32) + lo;
+}
+
+static u64 notrace gic_read_count_64(void)
+{
+ return read_gic_counter();
+}
+
+static u64 notrace gic_read_count(void)
+{
+ if (mips_cm_is64)
+ return gic_read_count_64();
+
+ return gic_read_count_2x32();
}
static int gic_next_event(unsigned long delta, struct clock_event_device *evt)
@@ -67,7 +81,7 @@
return IRQ_HANDLED;
}
-struct irqaction gic_compare_irqaction = {
+static struct irqaction gic_compare_irqaction = {
.handler = gic_compare_interrupt,
.percpu_dev_id = &gic_clockevent_device,
.flags = IRQF_PERCPU | IRQF_TIMER,
@@ -114,8 +128,10 @@
{
struct clk_notifier_data *cnd = data;
- if (action == POST_RATE_CHANGE)
+ if (action == POST_RATE_CHANGE) {
+ gic_clocksource_unstable("ref clock rate change");
on_each_cpu(gic_update_frequency, (void *)cnd->new_rate, 1);
+ }
return NOTIFY_OK;
}
@@ -155,11 +171,23 @@
}
static struct clocksource gic_clocksource = {
- .name = "GIC",
- .read = gic_hpt_read,
- .flags = CLOCK_SOURCE_IS_CONTINUOUS,
- .archdata = { .vdso_clock_mode = VDSO_CLOCK_GIC },
+ .name = "GIC",
+ .read = gic_hpt_read,
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+ .vdso_clock_mode = VDSO_CLOCKMODE_GIC,
};
+
+static void gic_clocksource_unstable(char *reason)
+{
+ if (gic_clock_unstable)
+ return;
+
+ gic_clock_unstable = true;
+
+ pr_info("GIC timer is unstable due to %s\n", reason);
+
+ clocksource_mark_unstable(&gic_clocksource);
+}
static int __init __gic_clocksource_init(void)
{
@@ -228,6 +256,18 @@
/* And finally start the counter */
clear_gic_config(GIC_CONFIG_COUNTSTOP);
+ /*
+ * It's safe to use the MIPS GIC timer as a sched clock source only if
+ * its ticks are stable, which is true on either the platforms with
+ * stable CPU frequency or on the platforms with CM3 and CPU frequency
+ * change performed by the CPC core clocks divider.
+ */
+ if (mips_cm_revision() >= CM_REV_CM3 || !IS_ENABLED(CONFIG_CPU_FREQ)) {
+ sched_clock_register(mips_cm_is64 ?
+ gic_read_count_64 : gic_read_count_2x32,
+ 64, gic_frequency);
+ }
+
return 0;
}
TIMER_OF_DECLARE(mips_gic_timer, "mti,gic-timer",
--
Gitblit v1.6.2