clocksource; armada-370: implement ARM delay timer

PATCH New Russell King 4 participants 4 messages Oct 19, 2015

Subsystems (4)

Arm (32-bit) Arm sub-architectures Clocksource, clockevent drivers Arm/Marvell Dove/MV78xx0/Orion SoC support

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Russell King

author

2015-10-19 15:03 UTC #0 lore raw

PATCH 1/1 clocksource; armada-370: implement ARM delay timer

Implement an ARM delay timer to be used for udelay() on Armada 37x platforms. This allows us to skip the delay loop calibration at boot, saving 180ms on the boot time of the kernel (which is around 10%).

It also means that udelay() will be unaffected by CPU frequency changes when cpufreq is enabled on these platforms.

Signed-off-by Russell King <[email protected]>

---
 arch/arm/Kconfig                         |  1 +
 arch/arm/plat-orion/time.c               | 13 +++++++++++++
 drivers/clocksource/time-armada-370-xp.c | 14 ++++++++++++++
 3 files changed, 28 insertions(+)

arch/arm/Kconfig +1 -0

index f3dfca632a8a..194569c23271 100644
@@ -10,6 +10,7 @@ config ARM
 	select ARCH_SUPPORTS_ATOMIC_RMW
 	select ARCH_USE_BUILTIN_BSWAP
 	select ARCH_USE_CMPXCHG_LOCKREF
+	select ARCH_WANT_FRAME_POINTERS
 	select ARCH_WANT_IPC_PARSE_VERSION
 	select BUILDTIME_EXTABLE_SORT if MMU
 	select CLONE_BACKWARDS

arch/arm/plat-orion/time.c +13 -0

index 8085a8aac812..ffb93db68e9c 100644
@@ -18,6 +18,7 @@
 #include <linux/irq.h>
 #include <linux/sched_clock.h>
 #include <plat/time.h>
+#include <asm/delay.h>
 
 /*
  * MBus bridge block registers.

@@ -188,6 +189,15 @@ orion_time_set_base(void __iomem *_timer_base)
 	timer_base = _timer_base;
 }
 
+static unsigned long orion_delay_timer_read(void)
+{
+	return ~readl(timer_base + TIMER0_VAL_OFF);
+}
+
+static struct delay_timer orion_delay_timer = {
+	.read_current_timer = orion_delay_timer_read,
+};
+
 void __init
 orion_time_init(void __iomem *_bridge_base, u32 _bridge_timer1_clr_mask,
 		unsigned int irq, unsigned int tclk)

@@ -202,6 +212,9 @@ orion_time_init(void __iomem *_bridge_base, u32 _bridge_timer1_clr_mask,
 
 	ticks_per_jiffy = (tclk + HZ/2) / HZ;
 
+	orion_delay_timer.freq = tclk;
+	register_current_timer_delay(&orion_delay_timer);
+
 	/*
 	 * Set scale and timer for sched_clock.
 	 */

drivers/clocksource/time-armada-370-xp.c +14 -0

index 2162796fd504..d93ec3c4f139 100644
@@ -45,6 +45,8 @@
 #include <linux/percpu.h>
 #include <linux/syscore_ops.h>
 
+#include <asm/delay.h>
+
 /*
  * Timer block registers.
  */

@@ -249,6 +251,15 @@ struct syscore_ops armada_370_xp_timer_syscore_ops = {
 	.resume		= armada_370_xp_timer_resume,
 };
 
+static unsigned long armada_370_delay_timer_read(void)
+{
+	return ~readl(timer_base + TIMER0_VAL_OFF);
+}
+
+static struct delay_timer armada_370_delay_timer = {
+	.read_current_timer = armada_370_delay_timer_read,
+};
+
 static void __init armada_370_xp_timer_common_init(struct device_node *np)
 {
 	u32 clr = 0, set = 0;

@@ -287,6 +298,9 @@ static void __init armada_370_xp_timer_common_init(struct device_node *np)
 		TIMER0_RELOAD_EN | enable_mask,
 		TIMER0_RELOAD_EN | enable_mask);
 
+	armada_370_delay_timer.freq = timer_clk;
+	register_current_timer_delay(&armada_370_delay_timer);
+
 	/*
 	 * Set scale and timer for sched_clock.
 	 */

Signature · 1 line

2.1.0

Andrew Lunn

maintainer

2015-10-19 15:15 UTC #1 lore raw

PATCH 1/1 clocksource; armada-370: implement ARM delay timer

Quoted 19 lines · Russell King

Implement an ARM delay timer to be used for udelay() on Armada 37x platforms. This allows us to skip the delay loop calibration at boot, saving 180ms on the boot time of the kernel (which is around 10%).
It also means that udelay() will be unaffected by CPU frequency changes when cpufreq is enabled on these platforms.
Signed-off-by Russell King <[email protected]>
---
 arch/arm/Kconfig                         |  1 +
 arch/arm/plat-orion/time.c               | 13 +++++++++++++
 drivers/clocksource/time-armada-370-xp.c | 14 ++++++++++++++
 3 files changed, 28 insertions(+)
arch/arm/Kconfig +0 -0
index f3dfca632a8a..194569c23271 100644

arch/arm/Kconfig config ARM · line 16

Quoted 7 lines

arch/arm/Kconfig +1 -0

@@ -10,6 +10,7 @@ config ARM
 	select ARCH_SUPPORTS_ATOMIC_RMW
 	select ARCH_USE_BUILTIN_BSWAP
 	select ARCH_USE_CMPXCHG_LOCKREF
+	select ARCH_WANT_FRAME_POINTERS
 	select ARCH_WANT_IPC_PARSE_VERSION
 	select BUILDTIME_EXTABLE_SORT if MMU
 	select CLONE_BACKWARDS

Hi Russell

Does this hunk belong in the patch?

Thanks
Andrew

Russell King - ARM Linux

2015-10-19 15:18 UTC #2 lore raw

PATCH 1/1 clocksource; armada-370: implement ARM delay timer

Quoted 30 lines · Andrew Lunn

Quoted 19 lines · Russell King
Implement an ARM delay timer to be used for udelay() on Armada 37x platforms. This allows us to skip the delay loop calibration at boot, saving 180ms on the boot time of the kernel (which is around 10%).
It also means that udelay() will be unaffected by CPU frequency changes when cpufreq is enabled on these platforms.
Signed-off-by Russell King <[email protected]>
---
 arch/arm/Kconfig                         |  1 +
 arch/arm/plat-orion/time.c               | 13 +++++++++++++
 drivers/clocksource/time-armada-370-xp.c | 14 ++++++++++++++
 3 files changed, 28 insertions(+)
arch/arm/Kconfig +0 -0
index f3dfca632a8a..194569c23271 100644
arch/arm/Kconfig config ARM · line 16
Quoted 7 lines
arch/arm/Kconfig +1 -0
@@ -10,6 +10,7 @@ config ARM
 	select ARCH_SUPPORTS_ATOMIC_RMW
 	select ARCH_USE_BUILTIN_BSWAP
 	select ARCH_USE_CMPXCHG_LOCKREF
+	select ARCH_WANT_FRAME_POINTERS
 	select ARCH_WANT_IPC_PARSE_VERSION
 	select BUILDTIME_EXTABLE_SORT if MMU
 	select CLONE_BACKWARDS
Hi Russell

Quoted 1 line

Does this hunk belong in the patch?

Bah. Neither does the other change to arch/arm/mach-mvebu/time.c ! Slip up using git commit -a after _manually_ adding just the clocksource file.

Signature · 2 lines

FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.

Gregory CLEMENT

2015-10-19 15:19 UTC #3 lore raw

PATCH 1/1 clocksource; armada-370: implement ARM delay timer

In reply to Russell King

Hi Russell,

Quoted 11 lines · Russell King

Implement an ARM delay timer to be used for udelay() on Armada 37x platforms. This allows us to skip the delay loop calibration at boot, saving 180ms on the boot time of the kernel (which is around 10%).
It also means that udelay() will be unaffected by CPU frequency changes when cpufreq is enabled on these platforms.
Signed-off-by Russell King <[email protected]>
---
 arch/arm/Kconfig                         |  1 +
 arch/arm/plat-orion/time.c               | 13 +++++++++++++

You spoke only about the armada37x but you also modified the timer of the orion platforms.

Could you split your patch in two part?

Then the arch/arm/plat-orion/time.c related part would be applied through the mvebu tree and the drivers/clocksource/time-armada-370-xp.c through the clocksource tree.

arch/arm/Kconfig config ARM · line 13

Quoted 12 lines

 drivers/clocksource/time-armada-370-xp.c | 14 ++++++++++++++
 3 files changed, 28 insertions(+)

arch/arm/Kconfig +1 -0

index f3dfca632a8a..194569c23271 100644
@@ -10,6 +10,7 @@ config ARM
 	select ARCH_SUPPORTS_ATOMIC_RMW
 	select ARCH_USE_BUILTIN_BSWAP
 	select ARCH_USE_CMPXCHG_LOCKREF
+	select ARCH_WANT_FRAME_POINTERS

Is it related to this patch?

Thanks,

Gregory

Quoted 3 lines

arch/arm/Kconfig +0 -0

 	select ARCH_WANT_IPC_PARSE_VERSION
 	select BUILDTIME_EXTABLE_SORT if MMU
 	select CLONE_BACKWARDS

Signature · 4 lines

Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com