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[PATCH v5 0/8] Implement clocksource for rockchip SoC using rockchip timer

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  [PATCH v5 0/8] Implement clocksource for rockchip SoC using rockchip timer Alexander Kochetkov <al.kochet@gmail.com> - 2017-01-24 13:20 +0100
    [PATCH v5 4/8] ARM: dts: rockchip: disable arm-global-timer for rk3188 Alexander Kochetkov <al.kochet@gmail.com> - 2017-01-24 13:20 +0100
      Re: [PATCH v5 4/8] ARM: dts: rockchip: disable arm-global-timer for  rk3188 Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-01-30 11:30 +0100
    [PATCH v5 6/8] clocksource/drivers/rockchip_timer: low level routines take rk_timer as parameter Alexander Kochetkov <al.kochet@gmail.com> - 2017-01-24 13:20 +0100
    [PATCH v5 7/8] clocksource/drivers/rockchip_timer: move TIMER_INT_UNMASK out of rk_timer_enable() Alexander Kochetkov <al.kochet@gmail.com> - 2017-01-24 13:20 +0100

#1565818 — [PATCH v5 0/8] Implement clocksource for rockchip SoC using rockchip timer

Hello,

This patch series contain:
- devicetree bindings clarification for rockchip timers
- dts files fixes for rk3228-evb, rk3229-evb and rk3188
- implementation of clocksource and sched clock for rockchip SoC

The clock supplying the arm-global-timer on the rk3188 is coming from the
the cpu clock itself and thus changes its rate everytime cpufreq adjusts
the cpu frequency making this timer unsuitable as a stable clocksource.

The rk3188, rk3288 and following socs share a separate timer block already
handled by the rockchip-timer driver. Therefore adapt this driver to also
be able to act as clocksource on rk3188.

In order to test clocksource you can run following commands and check
how much time it take in real. On rk3188 it take about ~45 seconds.

       cpufreq-set -f 1.6GHZ
       date; sleep 60; date

rk3288 (and probably anything newer) is irrelevant to this patch,
as it has the arch timer interface. This patch may be usefull
for Cortex-A9/A5 based parts.

Regards,
Alexander.

Changes in v5:
- Add 'Acked-by: Rob Herring <robh@kernel.org>' to 1/8
  http://lists.infradead.org/pipermail/linux-rockchip/2016-December/013308.html
- Add 'Reviwed-by: Heiko Stübner <heiko@sntech.de>' to series
- change timer compatible property in the rk322x.dtsi 2/8
  http://lists.infradead.org/pipermail/linux-rockchip/2017-January/013784.html
- updated comment message for 4/8
  http://lists.infradead.org/pipermail/linux-rockchip/2017-January/013786.html
- updated comment message for 5/8
  http://lists.infradead.org/pipermail/linux-rockchip/2017-January/013787.html
- fixed build error for 8/8
  http://lists.infradead.org/pipermail/linux-rockchip/2017-January/013789.html

Changes in v4:
merged 7 and 8 from series 3
merged 10, 11, 12, 13 from series 3
fixed commit message

Changes in v3:
added patches:
ARM: dts: rockchip: disable arm-global-timer for rk3188
clocksource/drivers/rockchip_timer: Prevent ftrace recursion

devicetree v1 patches:
https://patchwork.ozlabs.org/patch/699019/
https://patchwork.ozlabs.org/patch/699020/

kernel v1 patches:
https://patchwork.kernel.org/patch/9443975/
https://patchwork.kernel.org/patch/9443971/
https://patchwork.kernel.org/patch/9443959/
https://patchwork.kernel.org/patch/9443963/
https://patchwork.kernel.org/patch/9443979/
https://patchwork.kernel.org/patch/9443989/
https://patchwork.kernel.org/patch/9443987/
https://patchwork.kernel.org/patch/9443977/
https://patchwork.kernel.org/patch/9443991/

Alexander Kochetkov (8):
  dt-bindings: clarify compatible property for rockchip timers
  ARM: dts: rockchip: update compatible property for rk322x timer
  ARM: dts: rockchip: add timer entries to rk3188 SoC
  ARM: dts: rockchip: disable arm-global-timer for rk3188
  clocksource/drivers/rockchip_timer: split bc_timer into rk_timer and
    rk_clock_event_device
  clocksource/drivers/rockchip_timer: low level routines take rk_timer
    as parameter
  clocksource/drivers/rockchip_timer: move TIMER_INT_UNMASK out of
    rk_timer_enable()
  clocksource/drivers/rockchip_timer: implement clocksource timer

 .../bindings/timer/rockchip,rk-timer.txt           |   12 +-
 arch/arm/boot/dts/rk3188.dtsi                      |   17 ++
 arch/arm/boot/dts/rk322x.dtsi                      |    2 +-
 drivers/clocksource/rockchip_timer.c               |  207 +++++++++++++++-----
 4 files changed, 183 insertions(+), 55 deletions(-)

-- 
1.7.9.5

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#1565819 — [PATCH v5 4/8] ARM: dts: rockchip: disable arm-global-timer for rk3188

clocksource and shed_clock provided by arm-global-timer is quite
unstable, because their rate depends on cpu frequency.
So disable arm-global-timer and use clocksource and sched_clock
from rockchip_timer.

It is impossible get stable clocksource having rockchip_timer and
arm-global-timer enabled at the same time. Because arm-global-timer
looks like a better candidate for the kernel: it has higher
frequency and rating.

Disabling arm-global-timer doesn't leave kernel without
clockevents as there is another clockevent provider (smp-twd).

Signed-off-by: Alexander Kochetkov <al.kochet@gmail.com>
Reviwed-by: Heiko Stübner <heiko@sntech.de>
---
 arch/arm/boot/dts/rk3188.dtsi |    1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm/boot/dts/rk3188.dtsi b/arch/arm/boot/dts/rk3188.dtsi
index bcf8e03..f677130 100644
--- a/arch/arm/boot/dts/rk3188.dtsi
+++ b/arch/arm/boot/dts/rk3188.dtsi
@@ -546,6 +546,7 @@
 
 &global_timer {
 	interrupts = <GIC_PPI 11 0xf04>;
+	status = "disabled";
 };
 
 &local_timer {
-- 
1.7.9.5

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#1569554 — Re: [PATCH v5 4/8] ARM: dts: rockchip: disable arm-global-timer for rk3188

On Tue, Jan 24, 2017 at 03:16:39PM +0300, Alexander Kochetkov wrote:
> clocksource and shed_clock provided by arm-global-timer is quite
> unstable, because their rate depends on cpu frequency.
> So disable arm-global-timer and use clocksource and sched_clock
> from rockchip_timer.
> It is impossible get stable clocksource having rockchip_timer and
> arm-global-timer enabled at the same time. Because arm-global-timer
> looks like a better candidate for the kernel: it has higher
> frequency and rating.
> 
> Disabling arm-global-timer doesn't leave kernel without
> clockevents as there is another clockevent provider (smp-twd).

Hi Alexander,

sorry, I will rewrite the description because of the grammatical errors. I
don't want to give you the feeling I'm lecturing you, my English is not perfect
but it will be simpler to give the full descr with the typos fixed.

"
The clocksource and the sched_clock provided by the arm_global_timer are quite
unstable because their rates depend on the cpu frequency.

On the other side, the arm_global_timer has a higher rating than the
rockchip_timer, it will be selected by default by the time framework while
we want to use the stable rockchip clocksource.

Let's disable the arm_global_timer in order to have the rockchip clocksource
selected by default.
"

This patch should go at the end of the patchset when the clocksource is
implemented in the rockchip_timer.

> Signed-off-by: Alexander Kochetkov <al.kochet@gmail.com>
> Reviwed-by: Heiko Stübner <heiko@sntech.de>
> ---
>  arch/arm/boot/dts/rk3188.dtsi |    1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arch/arm/boot/dts/rk3188.dtsi b/arch/arm/boot/dts/rk3188.dtsi
> index bcf8e03..f677130 100644
> --- a/arch/arm/boot/dts/rk3188.dtsi
> +++ b/arch/arm/boot/dts/rk3188.dtsi
> @@ -546,6 +546,7 @@
>  
>  &global_timer {
>  	interrupts = <GIC_PPI 11 0xf04>;
> +	status = "disabled";
>  };
>  
>  &local_timer {
> -- 
> 1.7.9.5
> 

-- 

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#1565821 — [PATCH v5 6/8] clocksource/drivers/rockchip_timer: low level routines take rk_timer as parameter

Pass rk_timer instead of clock_event_device to low lever timer routines.
So that code could be reused by clocksource implementation.

Drop rk_base() and rk_ctrl().

This is refactoring step without functional changes.

Signed-off-by: Alexander Kochetkov <al.kochet@gmail.com>
Reviwed-by: Heiko Stübner <heiko@sntech.de>
---
 drivers/clocksource/rockchip_timer.c |   57 ++++++++++++++++------------------
 1 file changed, 27 insertions(+), 30 deletions(-)

diff --git a/drivers/clocksource/rockchip_timer.c b/drivers/clocksource/rockchip_timer.c
index 6d68d4c..a17dc61 100644
--- a/drivers/clocksource/rockchip_timer.c
+++ b/drivers/clocksource/rockchip_timer.c
@@ -53,70 +53,67 @@ static inline struct rk_timer *rk_timer(struct clock_event_device *ce)
 	return &rk_clock_event_device(ce)->timer;
 }
 
-static inline void __iomem *rk_base(struct clock_event_device *ce)
+static inline void rk_timer_disable(struct rk_timer *timer)
 {
-	return rk_timer(ce)->base;
+	writel_relaxed(TIMER_DISABLE, timer->ctrl);
 }
 
-static inline void __iomem *rk_ctrl(struct clock_event_device *ce)
-{
-	return rk_timer(ce)->ctrl;
-}
-
-static inline void rk_timer_disable(struct clock_event_device *ce)
-{
-	writel_relaxed(TIMER_DISABLE, rk_ctrl(ce));
-}
-
-static inline void rk_timer_enable(struct clock_event_device *ce, u32 flags)
+static inline void rk_timer_enable(struct rk_timer *timer, u32 flags)
 {
 	writel_relaxed(TIMER_ENABLE | TIMER_INT_UNMASK | flags,
-		       rk_ctrl(ce));
+		       timer->ctrl);
 }
 
 static void rk_timer_update_counter(unsigned long cycles,
-				    struct clock_event_device *ce)
+				    struct rk_timer *timer)
 {
-	writel_relaxed(cycles, rk_base(ce) + TIMER_LOAD_COUNT0);
-	writel_relaxed(0, rk_base(ce) + TIMER_LOAD_COUNT1);
+	writel_relaxed(cycles, timer->base + TIMER_LOAD_COUNT0);
+	writel_relaxed(0, timer->base + TIMER_LOAD_COUNT1);
 }
 
-static void rk_timer_interrupt_clear(struct clock_event_device *ce)
+static void rk_timer_interrupt_clear(struct rk_timer *timer)
 {
-	writel_relaxed(1, rk_base(ce) + TIMER_INT_STATUS);
+	writel_relaxed(1, timer->base + TIMER_INT_STATUS);
 }
 
 static inline int rk_timer_set_next_event(unsigned long cycles,
 					  struct clock_event_device *ce)
 {
-	rk_timer_disable(ce);
-	rk_timer_update_counter(cycles, ce);
-	rk_timer_enable(ce, TIMER_MODE_USER_DEFINED_COUNT);
+	struct rk_timer *timer = rk_timer(ce);
+
+	rk_timer_disable(timer);
+	rk_timer_update_counter(cycles, timer);
+	rk_timer_enable(timer, TIMER_MODE_USER_DEFINED_COUNT);
 	return 0;
 }
 
 static int rk_timer_shutdown(struct clock_event_device *ce)
 {
-	rk_timer_disable(ce);
+	struct rk_timer *timer = rk_timer(ce);
+
+	rk_timer_disable(timer);
 	return 0;
 }
 
 static int rk_timer_set_periodic(struct clock_event_device *ce)
 {
-	rk_timer_disable(ce);
-	rk_timer_update_counter(rk_timer(ce)->freq / HZ - 1, ce);
-	rk_timer_enable(ce, TIMER_MODE_FREE_RUNNING);
+	struct rk_timer *timer = rk_timer(ce);
+
+	rk_timer_disable(timer);
+	rk_timer_update_counter(timer->freq / HZ - 1, timer);
+	rk_timer_enable(timer, TIMER_MODE_FREE_RUNNING);
 	return 0;
 }
 
 static irqreturn_t rk_timer_interrupt(int irq, void *dev_id)
 {
 	struct clock_event_device *ce = dev_id;
+	struct rk_timer *timer = rk_timer(ce);
 
-	rk_timer_interrupt_clear(ce);
+	rk_timer_interrupt_clear(timer);
 
 	if (clockevent_state_oneshot(ce))
-		rk_timer_disable(ce);
+		rk_timer_disable(timer);
 
 	ce->event_handler(ce);
 
@@ -183,8 +180,8 @@ static int __init rk_timer_init(struct device_node *np, u32 ctrl_reg)
 	ce->cpumask = cpu_possible_mask;
 	ce->rating = 250;
 
-	rk_timer_interrupt_clear(ce);
-	rk_timer_disable(ce);
+	rk_timer_interrupt_clear(timer);
+	rk_timer_disable(timer);
 
 	ret = request_irq(irq, rk_timer_interrupt, IRQF_TIMER, TIMER_NAME, ce);
 	if (ret) {
-- 
1.7.9.5

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#1565822 — [PATCH v5 7/8] clocksource/drivers/rockchip_timer: move TIMER_INT_UNMASK out of rk_timer_enable()

This allow to enable timer without enabling interrupts from it.
As that mode will be used in clocksource implementation.

This is refactoring step without functional changes.

Signed-off-by: Alexander Kochetkov <al.kochet@gmail.com>
Reviwed-by: Heiko Stübner <heiko@sntech.de>
---
 drivers/clocksource/rockchip_timer.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/clocksource/rockchip_timer.c b/drivers/clocksource/rockchip_timer.c
index a17dc61..61c3bb1 100644
--- a/drivers/clocksource/rockchip_timer.c
+++ b/drivers/clocksource/rockchip_timer.c
@@ -60,8 +60,7 @@ static inline void rk_timer_disable(struct rk_timer *timer)
 
 static inline void rk_timer_enable(struct rk_timer *timer, u32 flags)
 {
-	writel_relaxed(TIMER_ENABLE | TIMER_INT_UNMASK | flags,
-		       timer->ctrl);
+	writel_relaxed(TIMER_ENABLE | flags, timer->ctrl);
 }
 
 static void rk_timer_update_counter(unsigned long cycles,
@@ -83,7 +82,8 @@ static inline int rk_timer_set_next_event(unsigned long cycles,
 
 	rk_timer_disable(timer);
 	rk_timer_update_counter(cycles, timer);
-	rk_timer_enable(timer, TIMER_MODE_USER_DEFINED_COUNT);
+	rk_timer_enable(timer, TIMER_MODE_USER_DEFINED_COUNT |
+			       TIMER_INT_UNMASK);
 	return 0;
 }
 
@@ -101,7 +101,7 @@ static int rk_timer_set_periodic(struct clock_event_device *ce)
 
 	rk_timer_disable(timer);
 	rk_timer_update_counter(timer->freq / HZ - 1, timer);
-	rk_timer_enable(timer, TIMER_MODE_FREE_RUNNING);
+	rk_timer_enable(timer, TIMER_MODE_FREE_RUNNING | TIMER_INT_UNMASK);
 	return 0;
 }
 
-- 
1.7.9.5

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