* [PATCH 2/9] clocksource/drivers/mediatek: Use GPT as sched clock source
2015-10-19 20:59 ` [PATCH 1/9] clockevents/drivers/mtk: Fix spurious interrupt leading to crash Daniel Lezcano
@ 2015-10-19 20:59 ` Daniel Lezcano
2015-10-19 20:59 ` [PATCH 6/9] clocksource/drivers/exynos_mct: Use container_of() instead of this_cpu_ptr() Daniel Lezcano
2015-10-22 19:50 ` [PATCH 1/9] clockevents/drivers/mtk: Fix spurious interrupt leading to crash Matthias Brugger
2 siblings, 0 replies; 4+ messages in thread
From: Daniel Lezcano @ 2015-10-19 20:59 UTC (permalink / raw)
To: linux-arm-kernel
From: Yingjoe Chen <yingjoe.chen@mediatek.com>
When cpu is in deep idle, arch timer will stop counting. Setup GPT as
sched clock source so it can keep counting in idle.
Signed-off-by: Yingjoe Chen <yingjoe.chen@mediatek.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: Matthias Brugger <matthias.bgg@gmail.com>
---
drivers/clocksource/mtk_timer.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/drivers/clocksource/mtk_timer.c b/drivers/clocksource/mtk_timer.c
index c8badc4..fbfc746 100644
--- a/drivers/clocksource/mtk_timer.c
+++ b/drivers/clocksource/mtk_timer.c
@@ -24,6 +24,7 @@
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
+#include <linux/sched_clock.h>
#include <linux/slab.h>
#define GPT_IRQ_EN_REG 0x00
@@ -59,6 +60,13 @@ struct mtk_clock_event_device {
struct clock_event_device dev;
};
+static void __iomem *gpt_sched_reg __read_mostly;
+
+static u64 notrace mtk_read_sched_clock(void)
+{
+ return readl_relaxed(gpt_sched_reg);
+}
+
static inline struct mtk_clock_event_device *to_mtk_clk(
struct clock_event_device *c)
{
@@ -230,6 +238,8 @@ static void __init mtk_timer_init(struct device_node *node)
mtk_timer_setup(evt, GPT_CLK_SRC, TIMER_CTRL_OP_FREERUN);
clocksource_mmio_init(evt->gpt_base + TIMER_CNT_REG(GPT_CLK_SRC),
node->name, rate, 300, 32, clocksource_mmio_readl_up);
+ gpt_sched_reg = evt->gpt_base + TIMER_CNT_REG(GPT_CLK_SRC);
+ sched_clock_register(mtk_read_sched_clock, 32, rate);
/* Configure clock event */
mtk_timer_setup(evt, GPT_CLK_EVT, TIMER_CTRL_OP_REPEAT);
--
1.9.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH 6/9] clocksource/drivers/exynos_mct: Use container_of() instead of this_cpu_ptr()
2015-10-19 20:59 ` [PATCH 1/9] clockevents/drivers/mtk: Fix spurious interrupt leading to crash Daniel Lezcano
2015-10-19 20:59 ` [PATCH 2/9] clocksource/drivers/mediatek: Use GPT as sched clock source Daniel Lezcano
@ 2015-10-19 20:59 ` Daniel Lezcano
2015-10-22 19:50 ` [PATCH 1/9] clockevents/drivers/mtk: Fix spurious interrupt leading to crash Matthias Brugger
2 siblings, 0 replies; 4+ messages in thread
From: Daniel Lezcano @ 2015-10-19 20:59 UTC (permalink / raw)
To: linux-arm-kernel
From: Alexey Klimov <alexey.klimov@linaro.org>
Since evt structure is embedded in per-CPU mevt structure it's
definitely faster to use container_of() to get access to mevt
if we have evt (for example as incoming function argument) instead
of more expensive approach with this_cpu_ptr(&percpu_mct_tick).
this_cpu_ptr() on per-CPU mevt structure leads to access to cp15
to get cpu id and arithmetic operations.
Container_of() is cheaper since it's just one asm instruction.
This should work if used evt pointer is correct and owned by
local mevt structure.
For example, before this patch set_state_shutdown() looks like:
4a4: e92d4010 push {r4, lr}
4a8: e3004000 movw r4, #0
4ac: ebfffffe bl 0 <debug_smp_processor_id>
4b0: e3003000 movw r3, #0
4b4: e3404000 movt r4, #0
4b8: e3403000 movt r3, #0
4bc: e7933100 ldr r3, [r3, r0, lsl #2]
4c0: e0844003 add r4, r4, r3
4c4: e59400c0 ldr r0, [r4, #192] ; 0xc0
4c8: ebffffd4 bl 420 <exynos4_mct_tick_stop.isra.1>
4cc: e3a00000 mov r0, #0
4d0: e8bd8010 pop {r4, pc}
With this patch:
4a4: e92d4010 push {r4, lr}
4a8: e59000c0 ldr r0, [r0, #192] ; 0xc0
4ac: ebffffdb bl 420 <exynos4_mct_tick_stop.isra.1>
4b0: e3a00000 mov r0, #0
4b4: e8bd8010 pop {r4, pc}
Also, for me size of exynos_mct.o decreased from 84588 bytes
to 83956.
Signed-off-by: Alexey Klimov <alexey.klimov@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
---
drivers/clocksource/exynos_mct.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/drivers/clocksource/exynos_mct.c b/drivers/clocksource/exynos_mct.c
index 029f96a..ff44082 100644
--- a/drivers/clocksource/exynos_mct.c
+++ b/drivers/clocksource/exynos_mct.c
@@ -382,24 +382,28 @@ static void exynos4_mct_tick_start(unsigned long cycles,
static int exynos4_tick_set_next_event(unsigned long cycles,
struct clock_event_device *evt)
{
- struct mct_clock_event_device *mevt = this_cpu_ptr(&percpu_mct_tick);
+ struct mct_clock_event_device *mevt;
+ mevt = container_of(evt, struct mct_clock_event_device, evt);
exynos4_mct_tick_start(cycles, mevt);
-
return 0;
}
static int set_state_shutdown(struct clock_event_device *evt)
{
- exynos4_mct_tick_stop(this_cpu_ptr(&percpu_mct_tick));
+ struct mct_clock_event_device *mevt;
+
+ mevt = container_of(evt, struct mct_clock_event_device, evt);
+ exynos4_mct_tick_stop(mevt);
return 0;
}
static int set_state_periodic(struct clock_event_device *evt)
{
- struct mct_clock_event_device *mevt = this_cpu_ptr(&percpu_mct_tick);
+ struct mct_clock_event_device *mevt;
unsigned long cycles_per_jiffy;
+ mevt = container_of(evt, struct mct_clock_event_device, evt);
cycles_per_jiffy = (((unsigned long long)NSEC_PER_SEC / HZ * evt->mult)
>> evt->shift);
exynos4_mct_tick_stop(mevt);
--
1.9.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH 1/9] clockevents/drivers/mtk: Fix spurious interrupt leading to crash
2015-10-19 20:59 ` [PATCH 1/9] clockevents/drivers/mtk: Fix spurious interrupt leading to crash Daniel Lezcano
2015-10-19 20:59 ` [PATCH 2/9] clocksource/drivers/mediatek: Use GPT as sched clock source Daniel Lezcano
2015-10-19 20:59 ` [PATCH 6/9] clocksource/drivers/exynos_mct: Use container_of() instead of this_cpu_ptr() Daniel Lezcano
@ 2015-10-22 19:50 ` Matthias Brugger
2 siblings, 0 replies; 4+ messages in thread
From: Matthias Brugger @ 2015-10-22 19:50 UTC (permalink / raw)
To: linux-arm-kernel
2015-10-19 22:59 GMT+02:00 Daniel Lezcano <daniel.lezcano@linaro.org>:
> After analysis done by Yingjoe Chen, the timer appears to have a pending
> interrupt when it is enabled.
>
> Fix this by acknowledging the pending interrupt when enabling the timer
> interrupt.
>
> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
> Tested-by: Yingjoe Chen <yingjoe.chen@mediatek.com>
Acked-by: Matthias Brugger <matthias.bgg@gmail.com>
> ---
> drivers/clocksource/mtk_timer.c | 16 ++++++----------
> 1 file changed, 6 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/clocksource/mtk_timer.c b/drivers/clocksource/mtk_timer.c
> index 50f0641..c8badc4 100644
> --- a/drivers/clocksource/mtk_timer.c
> +++ b/drivers/clocksource/mtk_timer.c
> @@ -141,14 +141,6 @@ static irqreturn_t mtk_timer_interrupt(int irq, void *dev_id)
> return IRQ_HANDLED;
> }
>
> -static void mtk_timer_global_reset(struct mtk_clock_event_device *evt)
> -{
> - /* Disable all interrupts */
> - writel(0x0, evt->gpt_base + GPT_IRQ_EN_REG);
> - /* Acknowledge all interrupts */
> - writel(0x3f, evt->gpt_base + GPT_IRQ_ACK_REG);
> -}
> -
> static void
> mtk_timer_setup(struct mtk_clock_event_device *evt, u8 timer, u8 option)
> {
> @@ -168,6 +160,12 @@ static void mtk_timer_enable_irq(struct mtk_clock_event_device *evt, u8 timer)
> {
> u32 val;
>
> + /* Disable all interrupts */
> + writel(0x0, evt->gpt_base + GPT_IRQ_EN_REG);
> +
> + /* Acknowledge all spurious pending interrupts */
> + writel(0x3f, evt->gpt_base + GPT_IRQ_ACK_REG);
> +
> val = readl(evt->gpt_base + GPT_IRQ_EN_REG);
> writel(val | GPT_IRQ_ENABLE(timer),
> evt->gpt_base + GPT_IRQ_EN_REG);
> @@ -220,8 +218,6 @@ static void __init mtk_timer_init(struct device_node *node)
> }
> rate = clk_get_rate(clk);
>
> - mtk_timer_global_reset(evt);
> -
> if (request_irq(evt->dev.irq, mtk_timer_interrupt,
> IRQF_TIMER | IRQF_IRQPOLL, "mtk_timer", evt)) {
> pr_warn("failed to setup irq %d\n", evt->dev.irq);
> --
> 1.9.1
>
--
motzblog.wordpress.com
^ permalink raw reply [flat|nested] 4+ messages in thread