Re: dw_apb_timer_of.c: remove parts that were picoxcell-specific

Pavel Machek
2013-05-07T20:11:36Z

Hi!

> >>>So I guess it should go through the timekeeping tree...?
> >>I would prefer that, but we can also take it through arm-soc, it doesn't
> >>really matter.
> >I see no response from timekeeping people... so if you could take it,
> >that would be great.
>
> I don't think the original patch ever made it to my inbox.

For some reason, I cced johnstul@us.ibm.com. (I guess
get_maintainer.pl? But it seems to behave now.) Anyway, patch is
below...

It would be great if you could apply it... Thanks,
Pavel

----

It seems we made a mistake when creating dw_apb_timer_of.c:
picoxcell sched_clock had parts that were not related to
dw_apb_timer, yet we moved them to dw_apb_timer_of, and tried to
use them on socfpga.

This results in system where user/system time is not measured
properly, as demonstrated by

time dd if=/dev/urandom of=/dev/zero bs=100000 count=100

So this patch switches sched_clock to hardware that exists on both
platforms, and adds missing of_node_put() in dw_apb_timer_init().

Signed-off-by: Pavel Machek <pavel@denx.de>
Acked-by: Jamie Iles <jamie@jamieiles.com>

diff --git a/arch/arm/mach-picoxcell/common.h b/arch/arm/mach-picoxcell/common.h
index 481b42a..237fb3b 100644
--- a/arch/arm/mach-picoxcell/common.h
+++ b/arch/arm/mach-picoxcell/common.h
@@ -12,6 +12,4 @@

#include <asm/mach/time.h>

-extern void dw_apb_timer_init(void);
-
#endif /* __PICOXCELL_COMMON_H__ */
diff --git a/drivers/clocksource/dw_apb_timer.c b/drivers/clocksource/dw_apb_timer.c
index 8c2a35f..460ac99 100644
--- a/drivers/clocksource/dw_apb_timer.c
+++ b/drivers/clocksource/dw_apb_timer.c
@@ -21,12 +21,6 @@
#define APBT_MIN_PERIOD 4
#define APBT_MIN_DELTA_USEC 200

-#define APBTMR_N_LOAD_COUNT 0x00
-#define APBTMR_N_CURRENT_VALUE 0x04
-#define APBTMR_N_CONTROL 0x08
-#define APBTMR_N_EOI 0x0c
-#define APBTMR_N_INT_STATUS 0x10
-
#define APBTMRS_INT_STATUS 0xa0
#define APBTMRS_EOI 0xa4
#define APBTMRS_RAW_INT_STATUS 0xa8
diff --git a/drivers/clocksource/dw_apb_timer_of.c b/drivers/clocksource/dw_apb_timer_of.c
index ab09ed3..0fa3104 100644
--- a/drivers/clocksource/dw_apb_timer_of.c
+++ b/drivers/clocksource/dw_apb_timer_of.c
@@ -57,6 +57,15 @@ static void add_clockevent(struct device_node *event_timer)
dw_apb_clockevent_register(ced);
}

+static void __iomem *sched_io_base;
+
+/* This is actually same as __apbt_read_clocksource(), but with
+ different interface */
+static u32 read_sched_clock_sptimer(void)
+{
+ return ~__raw_readl(sched_io_base + APBTMR_N_CURRENT_VALUE);
+}
+
static void add_clocksource(struct device_node *source_timer)
{
void __iomem *iobase;
@@ -71,41 +80,27 @@ static void add_clocksource(struct device_node *source_timer)

dw_apb_clocksource_start(cs);
dw_apb_clocksource_register(cs);
-}

-static void __iomem *sched_io_base;
-
-static u32 read_sched_clock(void)
-{
- return __raw_readl(sched_io_base);
+ sched_io_base = iobase;
+ setup_sched_clock(read_sched_clock_sptimer, 32, rate);
}

-static const struct of_device_id sptimer_ids[] __initconst = {
- { .compatible = "picochip,pc3x2-rtc" },
+static const struct of_device_id osctimer_ids[] __initconst = {
+ { .compatible = "picochip,pc3x2-timer" },
+ { .compatible = "snps,dw-apb-timer-osc" },
{ .compatible = "snps,dw-apb-timer-sp" },
- { /* Sentinel */ },
+ { /* Sentinel */ },
};

-static void init_sched_clock(void)
-{
- struct device_node *sched_timer;
- u32 rate;
-
- sched_timer = of_find_matching_node(NULL, sptimer_ids);
- if (!sched_timer)
- panic("No RTC for sched clock to use");
+/*
+ You don't have to use dw_apb_timer for scheduler clock,
+ this should also work fine on arm:

- timer_get_base_and_rate(sched_timer, &sched_io_base, &rate);
- of_node_put(sched_timer);
+ twd_local_timer_of_register();
+ arch_timer_of_register();
+ arch_timer_sched_clock_init();
+*/

- setup_sched_clock(read_sched_clock, 32, rate);
-}
-
-static const struct of_device_id osctimer_ids[] __initconst = {
- { .compatible = "picochip,pc3x2-timer" },
- { .compatible = "snps,dw-apb-timer-osc" },
- {},
-};

void __init dw_apb_timer_init(void)
{
@@ -121,7 +116,6 @@ void __init dw_apb_timer_init(void)
panic("No timer for clocksource");
add_clocksource(source_timer);

+ of_node_put(event_timer);
of_node_put(source_timer);
-
- init_sched_clock();
}
diff --git a/include/linux/dw_apb_timer.h b/include/linux/dw_apb_timer.h
index dd755ce..a64c987 100644
--- a/include/linux/dw_apb_timer.h
+++ b/include/linux/dw_apb_timer.h
@@ -17,6 +17,12 @@
#include <linux/clocksource.h>
#include <linux/interrupt.h>

+#define APBTMR_N_LOAD_COUNT 0x00
+#define APBTMR_N_CURRENT_VALUE 0x04
+#define APBTMR_N_CONTROL 0x08
+#define APBTMR_N_EOI 0x0c
+#define APBTMR_N_INT_STATUS 0x10
+
#define APBTMRS_REG_SIZE 0x14

struct dw_apb_timer {