[PATCH v5] ARC: clockevent: DT based probe
Vineet Gupta
Vineet.Gupta1 at synopsys.com
Sun Apr 17 23:46:10 PDT 2016
- timer frequency is derived from DT (no longer rely on top level
DT "clock-frequency" probed early and exported by asm/clk.h)
- TIMER0_IRQ need not be exported across arch code, confined to intc as
it is property of same
- Any failures in clockevent setup are considered pedantic and system
panic()'s as there is no generic fallback (unlike clocksource where
a jiffies based soft clocksource always exists)
Cc: Daniel Lezcano <daniel.lezcano at linaro.org>
Signed-off-by: Vineet Gupta <vgupta at synopsys.com>
---
Changes since v4 [*]
- clockevent setup failure panic()s bubbled up to top level function [Daniel]
- arc_get_timer_clk() returns error status vs. void [Daniel]
- For consistency, straggler pr_err() in setup function also converted to panic
[*] http://lists.infradead.org/pipermail/linux-snps-arc/2016-April/000903.html
---
arch/arc/include/asm/irq.h | 9 -------
arch/arc/kernel/intc-compact.c | 2 ++
arch/arc/kernel/time.c | 58 ++++++++++++++++++++++++++++++------------
3 files changed, 44 insertions(+), 25 deletions(-)
diff --git a/arch/arc/include/asm/irq.h b/arch/arc/include/asm/irq.h
index 5c0b5abda67a..a6ac89dc228f 100644
--- a/arch/arc/include/asm/irq.h
+++ b/arch/arc/include/asm/irq.h
@@ -12,15 +12,6 @@
#define NR_CPU_IRQS 32 /* number of interrupt lines of ARC770 CPU */
#define NR_IRQS 128 /* allow some CPU external IRQ handling */
-/* Platform Independent IRQs */
-#ifdef CONFIG_ISA_ARCOMPACT
-#define TIMER0_IRQ 3
-#define TIMER1_IRQ 4
-#else
-#define TIMER0_IRQ 16
-#define TIMER1_IRQ 17
-#endif
-
#include <linux/interrupt.h>
#include <asm-generic/irq.h>
diff --git a/arch/arc/kernel/intc-compact.c b/arch/arc/kernel/intc-compact.c
index 4195eedeb6d1..d31bc647146d 100644
--- a/arch/arc/kernel/intc-compact.c
+++ b/arch/arc/kernel/intc-compact.c
@@ -14,6 +14,8 @@
#include <linux/irqchip.h>
#include <asm/irq.h>
+#define TIMER0_IRQ 3 /* Fixed by ISA */
+
/*
* Early Hardware specific Interrupt setup
* -Platform independent, needed for each CPU (not foldable into init_IRQ)
diff --git a/arch/arc/kernel/time.c b/arch/arc/kernel/time.c
index 848353a27ac8..83e2c0eb2d68 100644
--- a/arch/arc/kernel/time.c
+++ b/arch/arc/kernel/time.c
@@ -30,19 +30,15 @@
*/
#include <linux/interrupt.h>
-#include <linux/module.h>
-#include <linux/kernel.h>
-#include <linux/time.h>
-#include <linux/init.h>
#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/clocksource.h>
#include <linux/clockchips.h>
#include <linux/cpu.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
#include <asm/irq.h>
#include <asm/arcregs.h>
-#include <asm/clk.h>
-#include <asm/mach_desc.h>
#include <asm/mcip.h>
@@ -59,6 +55,29 @@
#define ARC_TIMER_MAX 0xFFFFFFFF
+static unsigned long arc_timer_freq;
+
+static int noinline arc_get_timer_clk(struct device_node *node)
+{
+ struct clk *clk;
+ int ret = -1;
+
+ clk = of_clk_get(node, 0);
+ if (IS_ERR(clk)) {
+ pr_err("timer missing clk");
+ return ret;
+ }
+
+ ret = clk_prepare_enable(clk);
+ if (ret) {
+ pr_err("Couldn't enable parent clk\n");
+ return ret;
+ }
+
+ arc_timer_freq = clk_get_rate(clk);
+ return ret;
+}
+
/********** Clock Source Device *********/
#ifdef CONFIG_ARC_HAS_GFRC
@@ -182,7 +201,7 @@ static struct clocksource arc_counter = {
/********** Clock Event Device *********/
-static int arc_timer_irq = TIMER0_IRQ;
+static int arc_timer_irq;
/*
* Arm the timer to interrupt after @cycles
@@ -210,7 +229,7 @@ static int arc_clkevent_set_periodic(struct clock_event_device *dev)
* At X Hz, 1 sec = 1000ms -> X cycles;
* 10ms -> X / 100 cycles
*/
- arc_timer_event_setup(arc_get_core_freq() / HZ);
+ arc_timer_event_setup(arc_timer_freq / HZ);
return 0;
}
@@ -253,7 +272,7 @@ static int arc_timer_cpu_notify(struct notifier_block *self,
switch (action & ~CPU_TASKS_FROZEN) {
case CPU_STARTING:
- clockevents_config_and_register(evt, arc_get_core_freq(),
+ clockevents_config_and_register(evt, arc_timer_freq,
0, ULONG_MAX);
enable_percpu_irq(arc_timer_irq, 0);
break;
@@ -272,25 +291,35 @@ static struct notifier_block arc_timer_cpu_nb = {
/*
* clockevent setup for boot CPU
*/
-static void __init arc_clockevent_setup(void)
+static void __init arc_clockevent_setup(struct device_node *node)
{
struct clock_event_device *evt = this_cpu_ptr(&arc_clockevent_device);
int ret;
register_cpu_notifier(&arc_timer_cpu_nb);
+ arc_timer_irq = irq_of_parse_and_map(node, 0);
+ if (arc_timer_irq <= 0)
+ panic("clockevent: missing irq");
+
+ ret = arc_get_timer_clk(node);
+ if (ret)
+ panic("clockevent: missing clk");
+
+ evt->irq = arc_timer_irq;
evt->cpumask = cpumask_of(smp_processor_id());
- clockevents_config_and_register(evt, arc_get_core_freq(),
+ clockevents_config_and_register(evt, arc_timer_freq,
0, ARC_TIMER_MAX);
/* Needs apriori irq_set_percpu_devid() done in intc map function */
ret = request_percpu_irq(arc_timer_irq, timer_irq_handler,
"Timer0 (per-cpu-tick)", evt);
if (ret)
- pr_err("Unable to register interrupt\n");
+ panic("clockevent: unable to request irq\n");
enable_percpu_irq(arc_timer_irq, 0);
}
+CLOCKSOURCE_OF_DECLARE(arc_clkevt, "snps,arc-timer", arc_clockevent_setup);
/*
* Called from start_kernel() - boot CPU only
@@ -299,7 +328,6 @@ static void __init arc_clockevent_setup(void)
* -Also sets up any global state needed for timer subsystem:
* - for "counting" timer, registers a clocksource, usable across CPUs
* (provided that underlying counter h/w is synchronized across cores)
- * - for "event" timer, sets up TIMER0 IRQ (as that is platform agnostic)
*/
void __init time_init(void)
{
@@ -315,7 +343,5 @@ void __init time_init(void)
* CLK upto 4.29 GHz can be safely represented in 32 bits
* because Max 32 bit number is 4,294,967,295
*/
- clocksource_register_hz(&arc_counter, arc_get_core_freq());
-
- arc_clockevent_setup();
+ clocksource_register_hz(&arc_counter, arc_timer_freq);
}
--
2.5.0
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