[RFC PATCH 00/12] Make SMP timers standalone

[RFC PATCH 00/12] Make SMP timers standalone

[Marc Zyngier]

The LOCAL_TIMERS infrastructure has a few limitations:
- It only allows one implementation to be compiled in, hence
  preventing a single kernel image to be booted hardware with
  different requirements (Tegra and MSM, for example).
- It is only supported on SMP, which is a problem on platforms where
  the local timer can be used on UP platforms (Cortex A15 being one).

The proposal is to convert local timer drivers to be "standalone" (not
relying on the local timer infrastructure) and to use a CPU notifier
to have the timer brought up or down on non-boot CPUs.

The SMP support code can then be simplified to only manage the
boadcast timer, which is always installed, and leave the generic
kernel code to pick the highest priority timer. CONFIG_LOCAL_TIMERS
disappears in the process.

This patch series is based on my earlier series ("Consolidating GIC
per-cpu interrupts"). Tested on EB11MP, VE A15, OMAP4 and Tegra.

Marc Zyngier (12):
  ARM: local timers: allow smp_twd to be used standalone
  ARM: local timers: switch realview to standalone smp_twd
  ARM: local timers: switch vexpress to standalone smp_twd
  ARM: local timers: remove localtimer.c from plat-versatile
  ARM: local timers: switch tegra to standalone smp_twd
  ARM: local timers: switch omap4 to standalone smp_twd
  ARM: local timers: switch shmobile to standalone smp_twd
  ARM: local timers: switch ux500 to standalone smp_twd
  ARM: smp_twd: remove support for non-standalone version
  ARM: local timers: make MSM timers standalone
  ARM: local timers: make MCT timer standalone
  ARM: local timers: Remove CONFIG_LOCAL_TIMERS support

 arch/arm/Kconfig                             |   15 +----
 arch/arm/include/asm/localtimer.h            |   56 -----------------
 arch/arm/include/asm/smp_twd.h               |   14 +++--
 arch/arm/kernel/smp.c                        |   56 +++++-------------
 arch/arm/kernel/smp_twd.c                    |   82 ++++++++++++++++++++++++--
 arch/arm/mach-exynos4/mct.c                  |   75 ++++++++++++++++++------
 arch/arm/mach-msm/timer.c                    |   64 +++++++++++++++-----
 arch/arm/mach-omap2/Kconfig                  |    2 +-
 arch/arm/mach-omap2/Makefile                 |    1 -
 arch/arm/mach-omap2/timer-mpu.c              |   39 ------------
 arch/arm/mach-omap2/timer.c                  |   38 ++++++++++--
 arch/arm/mach-realview/Kconfig               |    3 +
 arch/arm/mach-realview/realview_eb.c         |   33 +++++++++-
 arch/arm/mach-realview/realview_pb11mp.c     |   31 +++++++++-
 arch/arm/mach-realview/realview_pbx.c        |   30 +++++++++-
 arch/arm/mach-shmobile/Kconfig               |    1 +
 arch/arm/mach-shmobile/Makefile              |    1 -
 arch/arm/mach-shmobile/include/mach/common.h |    3 +
 arch/arm/mach-shmobile/localtimer.c          |   26 --------
 arch/arm/mach-shmobile/platsmp.c             |    1 -
 arch/arm/mach-shmobile/smp-sh73a0.c          |   32 +++++++++-
 arch/arm/mach-shmobile/timer.c               |   10 +++
 arch/arm/mach-tegra/Kconfig                  |    1 +
 arch/arm/mach-tegra/Makefile                 |    2 +-
 arch/arm/mach-tegra/localtimer.c             |   26 --------
 arch/arm/mach-tegra/timer.c                  |   34 +++++++++--
 arch/arm/mach-ux500/Kconfig                  |    1 +
 arch/arm/mach-ux500/Makefile                 |    1 -
 arch/arm/mach-ux500/cpu.c                    |   40 ++++++++++--
 arch/arm/mach-ux500/localtimer.c             |   29 ---------
 arch/arm/mach-vexpress/Kconfig               |    1 +
 arch/arm/mach-vexpress/ct-ca9x4.c            |   29 ++++++++-
 arch/arm/plat-versatile/Makefile             |    1 -
 arch/arm/plat-versatile/localtimer.c         |   27 ---------
 34 files changed, 462 insertions(+), 343 deletions(-)
 delete mode 100644 arch/arm/include/asm/localtimer.h
 delete mode 100644 arch/arm/mach-omap2/timer-mpu.c
 delete mode 100644 arch/arm/mach-shmobile/localtimer.c
 delete mode 100644 arch/arm/mach-tegra/localtimer.c
 delete mode 100644 arch/arm/mach-ux500/localtimer.c
 delete mode 100644 arch/arm/plat-versatile/localtimer.c

[RFC PATCH 01/12] ARM: local timers: allow smp_twd to be used standalone

[Marc Zyngier]

Allow smp_twd to be built in a "standalone" version,
without relying on the CONFIG_LOCAL_TIMER infrastructure.
It mainly relies on a CPU notifier block to stop or start
the timer on the right CPU.

The CONFIG_ARM_SMP_TWD option selects the new behaviour.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/Kconfig               |    6 +++-
 arch/arm/include/asm/smp_twd.h |    9 +++++
 arch/arm/kernel/smp_twd.c      |   76 +++++++++++++++++++++++++++++++++++++++-
 3 files changed, 89 insertions(+), 2 deletions(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 2c71a8f..7ac28a3 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1394,6 +1394,10 @@ config HAVE_ARM_TWD
 	help
 	  This options enables support for the ARM timer and watchdog unit
 
+config ARM_SMP_TWD
+	bool
+	select HAVE_ARM_TWD if SMP
+
 choice
 	prompt "Memory split"
 	default VMSPLIT_3G
@@ -1432,7 +1436,7 @@ config HOTPLUG_CPU
 
 config LOCAL_TIMERS
 	bool "Use local timer interrupts"
-	depends on SMP
+	depends on SMP && !ARM_SMP_TWD
 	default y
 	select HAVE_ARM_TWD if (!ARCH_MSM_SCORPIONMP && !EXYNOS4_MCT)
 	help
diff --git a/arch/arm/include/asm/smp_twd.h b/arch/arm/include/asm/smp_twd.h
index ef9ffba..934f1bc 100644
--- a/arch/arm/include/asm/smp_twd.h
+++ b/arch/arm/include/asm/smp_twd.h
@@ -19,10 +19,19 @@
 #define TWD_TIMER_CONTROL_IT_ENABLE	(1 << 2)
 
 struct clock_event_device;
+struct resource;
 
 extern void __iomem *twd_base;
 
 void twd_timer_setup(struct clock_event_device *);
 void twd_timer_stop(struct clock_event_device *);
+#ifdef CONFIG_HAVE_ARM_TWD
+int twd_timer_register(struct resource *res, int res_nr);
+#else
+static inline int twd_timer_register(struct resource *res, int res_nr)
+{
+	return 0;
+}
+#endif
 
 #endif
diff --git a/arch/arm/kernel/smp_twd.c b/arch/arm/kernel/smp_twd.c
index 7156f09..5b6d99b 100644
--- a/arch/arm/kernel/smp_twd.c
+++ b/arch/arm/kernel/smp_twd.c
@@ -13,6 +13,7 @@
 #include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/smp.h>
+#include <linux/cpu.h>
 #include <linux/jiffies.h>
 #include <linux/clockchips.h>
 #include <linux/irq.h>
@@ -135,7 +136,7 @@ void __cpuinit twd_timer_setup(struct clock_event_device *clk)
 	clk->name = "local_timer";
 	clk->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT |
 			CLOCK_EVT_FEAT_C3STOP;
-	clk->rating = 350;
+	clk->rating = 450;	/* Make sure this is higher than broadcast */
 	clk->set_mode = twd_set_mode;
 	clk->set_next_event = twd_set_next_event;
 	clk->shift = 20;
@@ -150,3 +151,76 @@ void __cpuinit twd_timer_setup(struct clock_event_device *clk)
 		pr_err("%s: can't register interrupt %d on cpu %d (%d)\n",
 		       clk->name, clk->irq, smp_processor_id(), err);
 }
+
+#ifdef CONFIG_ARM_SMP_TWD
+static struct clock_event_device __percpu *twd_evt;
+static int twd_ppi;
+
+static void __cpuinit twd_setup(void *data)
+{
+	struct clock_event_device *clk = data;
+	clk->cpumask = cpumask_of(smp_processor_id());
+	clk->irq = twd_ppi;
+	twd_timer_setup(clk);
+}
+
+static void __cpuinit twd_teardown(void *data)
+{
+	struct clock_event_device *clk = data;
+	twd_timer_stop(clk);
+}
+
+static int __cpuinit twd_cpu_notify(struct notifier_block *self,
+				    unsigned long action, void *data)
+{
+	int cpu = (int)data;
+	struct clock_event_device *clk = per_cpu_ptr(twd_evt, cpu);
+
+	switch (action) {
+	case CPU_STARTING:
+	case CPU_STARTING_FROZEN:
+		smp_call_function_single(cpu, twd_setup, clk, 1);
+		break;
+
+	case CPU_DOWN_PREPARE:
+	case CPU_DOWN_PREPARE_FROZEN:
+		smp_call_function_single(cpu, twd_teardown, clk, 1);
+		break;
+	}
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block __cpuinitdata twd_cpu_nb = {
+	.notifier_call = twd_cpu_notify,
+};
+
+int twd_timer_register(struct resource *res, int res_nr)
+{
+	struct clock_event_device *clk;
+
+	if (res_nr != 2 || res[1].start < 0)
+		return -EINVAL;
+
+	if (twd_base)
+		return -EBUSY;
+
+	twd_ppi		= res[1].start;
+	twd_base	= ioremap(res[0].start, resource_size(&res[0]));
+	twd_evt		= alloc_percpu(struct clock_event_device);
+	if (!twd_base || !twd_evt) {
+		iounmap(twd_base);
+		twd_base = NULL;
+		free_percpu(twd_evt);
+		return -ENOMEM;
+	}
+
+	/* Immediately configure the timer on the boot CPU */
+	clk = per_cpu_ptr(twd_evt, smp_processor_id());
+	twd_setup(clk);
+
+	register_cpu_notifier(&twd_cpu_nb);
+
+	return 0;
+}
+#endif
-- 
1.7.0.4

[RFC PATCH 02/12] ARM: local timers: switch realview to standalone smp_twd

[Marc Zyngier]

Convert the SMP RealView platforms to the standalone version
of smp_twd.c. Since the timer calibration code requires another
timer to be up and running, the actual initialisation is left
to the late_timer_init hook.

Tested on EB-11MP.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/mach-realview/Kconfig           |    3 ++
 arch/arm/mach-realview/realview_eb.c     |   33 ++++++++++++++++++++++++++---
 arch/arm/mach-realview/realview_pb11mp.c |   31 ++++++++++++++++++++++++---
 arch/arm/mach-realview/realview_pbx.c    |   30 ++++++++++++++++++++++++--
 4 files changed, 86 insertions(+), 11 deletions(-)

diff --git a/arch/arm/mach-realview/Kconfig b/arch/arm/mach-realview/Kconfig
index dba6d0c..135a7ea 100644
--- a/arch/arm/mach-realview/Kconfig
+++ b/arch/arm/mach-realview/Kconfig
@@ -4,6 +4,7 @@ menu "RealView platform type"
 config MACH_REALVIEW_EB
 	bool "Support RealView(R) Emulation Baseboard"
 	select ARM_GIC
+	select ARM_SMP_TWD if SMP
 	help
 	  Include support for the ARM(R) RealView(R) Emulation Baseboard
 	  platform.
@@ -40,6 +41,7 @@ config MACH_REALVIEW_PB11MP
 	select ARM_GIC
 	select HAVE_PATA_PLATFORM
 	select ARCH_HAS_BARRIERS if SMP
+	select ARM_SMP_TWD if SMP
 	help
 	  Include support for the ARM(R) RealView(R) Platform Baseboard for
 	  the ARM11MPCore.  This platform has an on-board ARM11MPCore and has
@@ -80,6 +82,7 @@ config MACH_REALVIEW_PBX
 	select HAVE_PATA_PLATFORM
 	select ARCH_SPARSEMEM_ENABLE if CPU_V7 && !REALVIEW_HIGH_PHYS_OFFSET
 	select ZONE_DMA if SPARSEMEM
+	select ARM_SMP_TWD if SMP
 	help
 	  Include support for the ARM(R) RealView(R) Platform Baseboard
 	  Explore.
diff --git a/arch/arm/mach-realview/realview_eb.c b/arch/arm/mach-realview/realview_eb.c
index 7a4e3b1..420cc1c 100644
--- a/arch/arm/mach-realview/realview_eb.c
+++ b/arch/arm/mach-realview/realview_eb.c
@@ -36,7 +36,7 @@
 #include <asm/pgtable.h>
 #include <asm/hardware/gic.h>
 #include <asm/hardware/cache-l2x0.h>
-#include <asm/localtimer.h>
+#include <asm/smp_twd.h>
 
 #include <asm/mach/arch.h>
 #include <asm/mach/map.h>
@@ -391,6 +391,33 @@ static void realview_eb11mp_fixup(void)
 	realview_eb_isp1761_resources[1].end	= IRQ_EB11MP_USB;
 }
 
+#ifdef CONFIG_ARM_SMP_TWD
+static struct resource twd_resources[] __initdata = {
+	{
+		.start	= REALVIEW_EB11MP_TWD_BASE,
+		.end	= REALVIEW_EB11MP_TWD_BASE + 0xff,
+		.flags	= IORESOURCE_MEM,
+	},
+	{
+		.start	= IRQ_LOCALTIMER,
+		.end	= IRQ_LOCALTIMER,
+		.flags	= IORESOURCE_IRQ,
+	},
+};
+
+static void __init realview_eb_twd_init(void)
+{
+	if (core_tile_eb11mp() || core_tile_a9mp()) {
+		int err = twd_timer_register(twd_resources,
+					     ARRAY_SIZE(twd_resources));
+		if (err)
+			pr_err("twd_timer_register failed %d\n", err);
+	}
+}
+#else
+#define realview_eb_twd_init	NULL
+#endif
+
 static void __init realview_eb_timer_init(void)
 {
 	unsigned int timer_irq;
@@ -401,9 +428,7 @@ static void __init realview_eb_timer_init(void)
 	timer3_va_base = __io_address(REALVIEW_EB_TIMER2_3_BASE) + 0x20;
 
 	if (core_tile_eb11mp() || core_tile_a9mp()) {
-#ifdef CONFIG_LOCAL_TIMERS
-		twd_base = __io_address(REALVIEW_EB11MP_TWD_BASE);
-#endif
+		late_time_init = realview_eb_twd_init;
 		timer_irq = IRQ_EB11MP_TIMER0_1;
 	} else
 		timer_irq = IRQ_EB_TIMER0_1;
diff --git a/arch/arm/mach-realview/realview_pb11mp.c b/arch/arm/mach-realview/realview_pb11mp.c
index b43644b..8185022 100644
--- a/arch/arm/mach-realview/realview_pb11mp.c
+++ b/arch/arm/mach-realview/realview_pb11mp.c
@@ -36,7 +36,7 @@
 #include <asm/pgtable.h>
 #include <asm/hardware/gic.h>
 #include <asm/hardware/cache-l2x0.h>
-#include <asm/localtimer.h>
+#include <asm/smp_twd.h>
 
 #include <asm/mach/arch.h>
 #include <asm/mach/flash.h>
@@ -298,6 +298,31 @@ static void __init gic_init_irq(void)
 	gic_cascade_irq(1, IRQ_TC11MP_PB_IRQ1);
 }
 
+#ifdef CONFIG_ARM_SMP_TWD
+static struct resource realview_pb11mp_twd_resources[] __initdata = {
+	{
+		.start	= REALVIEW_TC11MP_TWD_BASE,
+		.end	= REALVIEW_TC11MP_TWD_BASE + 0x10,
+		.flags	= IORESOURCE_MEM,
+	},
+	{
+		.start	= IRQ_LOCALTIMER,
+		.end	= IRQ_LOCALTIMER,
+		.flags	= IORESOURCE_IRQ,
+	},
+};
+
+static void __init realview_pb11mp_twd_init(void)
+{
+	int err = twd_timer_register(realview_pb11mp_twd_resources,
+				     ARRAY_SIZE(realview_pb11mp_twd_resources));
+	if (err)
+		pr_err("twd_timer_register failed %d\n", err);
+}
+#else
+#define realview_pb11mp_twd_init	NULL
+#endif
+
 static void __init realview_pb11mp_timer_init(void)
 {
 	timer0_va_base = __io_address(REALVIEW_PB11MP_TIMER0_1_BASE);
@@ -305,10 +330,8 @@ static void __init realview_pb11mp_timer_init(void)
 	timer2_va_base = __io_address(REALVIEW_PB11MP_TIMER2_3_BASE);
 	timer3_va_base = __io_address(REALVIEW_PB11MP_TIMER2_3_BASE) + 0x20;
 
-#ifdef CONFIG_LOCAL_TIMERS
-	twd_base = __io_address(REALVIEW_TC11MP_TWD_BASE);
-#endif
 	realview_timer_init(IRQ_TC11MP_TIMER0_1);
+	late_time_init = realview_pb11mp_twd_init;
 }
 
 static struct sys_timer realview_pb11mp_timer = {
diff --git a/arch/arm/mach-realview/realview_pbx.c b/arch/arm/mach-realview/realview_pbx.c
index 363b0ab..bbe4534 100644
--- a/arch/arm/mach-realview/realview_pbx.c
+++ b/arch/arm/mach-realview/realview_pbx.c
@@ -301,6 +301,31 @@ static void __init gic_init_irq(void)
 	}
 }
 
+#ifdef CONFIG_ARM_SMP_TWD
+static struct resource realview_pbx_twd_resources[] __initdata = {
+	{
+		.start	= REALVIEW_PBX_TILE_TWD_BASE,
+		.end	= REALVIEW_PBX_TILE_TWD_BASE + 0x10,
+		.flags	= IORESOURCE_MEM,
+	},
+	{
+		.start	= IRQ_LOCALTIMER,
+		.end	= IRQ_LOCALTIMER,
+		.flags	= IORESOURCE_IRQ,
+	},
+};
+
+static void __init realview_pbx_twd_init(void)
+{
+	int err = twd_timer_register(realview_pbx_twd_resources,
+				     ARRAY_SIZE(realview_pbx_twd_resources));
+	if (err)
+		pr_err("twd_timer_register failed %d\n", err);
+}
+#else
+#define realview_pbx_twd_init	NULL
+#endif
+
 static void __init realview_pbx_timer_init(void)
 {
 	timer0_va_base = __io_address(REALVIEW_PBX_TIMER0_1_BASE);
@@ -308,10 +333,9 @@ static void __init realview_pbx_timer_init(void)
 	timer2_va_base = __io_address(REALVIEW_PBX_TIMER2_3_BASE);
 	timer3_va_base = __io_address(REALVIEW_PBX_TIMER2_3_BASE) + 0x20;
 
-#ifdef CONFIG_LOCAL_TIMERS
 	if (core_tile_pbx11mp() || core_tile_pbxa9mp())
-		twd_base = __io_address(REALVIEW_PBX_TILE_TWD_BASE);
-#endif
+		late_time_init = realview_pbx_twd_init;
+
 	realview_timer_init(IRQ_PBX_TIMER0_1);
 }
 
-- 
1.7.0.4

[RFC PATCH 03/12] ARM: local timers: switch vexpress to standalone smp_twd

[Marc Zyngier]

Convert the Versatile Express platform to the standalone version
of smp_twd.c. Since the timer calibration code requires another
timer to be up and running, the actual initialisation is left
to the late_timer_init hook.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/mach-vexpress/Kconfig    |    1 +
 arch/arm/mach-vexpress/ct-ca9x4.c |   29 ++++++++++++++++++++++++++---
 2 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/arch/arm/mach-vexpress/Kconfig b/arch/arm/mach-vexpress/Kconfig
index 9311484..13f1606 100644
--- a/arch/arm/mach-vexpress/Kconfig
+++ b/arch/arm/mach-vexpress/Kconfig
@@ -5,6 +5,7 @@ config ARCH_VEXPRESS_CA9X4
 	bool "Versatile Express Cortex-A9x4 tile"
 	select CPU_V7
 	select ARM_GIC
+	select ARM_SMP_TWD
 	select ARM_ERRATA_720789
 	select ARM_ERRATA_751472
 	select ARM_ERRATA_753970
diff --git a/arch/arm/mach-vexpress/ct-ca9x4.c b/arch/arm/mach-vexpress/ct-ca9x4.c
index bfd32f5..7141d73 100644
--- a/arch/arm/mach-vexpress/ct-ca9x4.c
+++ b/arch/arm/mach-vexpress/ct-ca9x4.c
@@ -53,9 +53,6 @@ static struct map_desc ct_ca9x4_io_desc[] __initdata = {
 
 static void __init ct_ca9x4_map_io(void)
 {
-#ifdef CONFIG_LOCAL_TIMERS
-	twd_base = MMIO_P2V(A9_MPCORE_TWD);
-#endif
 	iotable_init(ct_ca9x4_io_desc, ARRAY_SIZE(ct_ca9x4_io_desc));
 }
 
@@ -191,9 +188,35 @@ static struct platform_device pmu_device = {
 	.resource	= pmu_resources,
 };
 
+#ifdef CONFIG_ARM_SMP_TWD
+static struct resource ca9x4_twd_resources[] __initdata = {
+	{
+		.start	= A9_MPCORE_TWD,
+		.end	= A9_MPCORE_TWD + 0x10,
+		.flags	= IORESOURCE_MEM,
+	},
+	{
+		.start	= IRQ_LOCALTIMER,
+		.end	= IRQ_LOCALTIMER,
+		.flags	= IORESOURCE_IRQ,
+	},
+};
+
+static void __init ca9x4_twd_init(void)
+{
+	int err = twd_timer_register(ca9x4_twd_resources,
+				     ARRAY_SIZE(ca9x4_twd_resources));
+	if (err)
+		pr_err("twd_timer_register failed %d\n", err);
+}
+#else
+#define ca9x4_twd_init	NULL
+#endif
+
 static void __init ct_ca9x4_init_early(void)
 {
 	clkdev_add_table(lookups, ARRAY_SIZE(lookups));
+	late_time_init = ca9x4_twd_init;
 }
 
 static void __init ct_ca9x4_init(void)
-- 
1.7.0.4

[RFC PATCH 04/12] ARM: local timers: remove localtimer.c from plat-versatile

[Marc Zyngier]

As the localtimer infrastructure is not use anymore by any of
the Versatile platforms, remove localtimer.c.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/plat-versatile/Makefile     |    1 -
 arch/arm/plat-versatile/localtimer.c |   27 ---------------------------
 2 files changed, 0 insertions(+), 28 deletions(-)
 delete mode 100644 arch/arm/plat-versatile/localtimer.c

diff --git a/arch/arm/plat-versatile/Makefile b/arch/arm/plat-versatile/Makefile
index 69714db..a5cb194 100644
--- a/arch/arm/plat-versatile/Makefile
+++ b/arch/arm/plat-versatile/Makefile
@@ -1,5 +1,4 @@
 obj-y	:= clock.o
-obj-$(CONFIG_LOCAL_TIMERS) += localtimer.o
 obj-$(CONFIG_PLAT_VERSATILE_CLCD) += clcd.o
 obj-$(CONFIG_PLAT_VERSATILE_FPGA_IRQ) += fpga-irq.o
 obj-$(CONFIG_PLAT_VERSATILE_LEDS) += leds.o
diff --git a/arch/arm/plat-versatile/localtimer.c b/arch/arm/plat-versatile/localtimer.c
deleted file mode 100644
index 0fb3961..0000000
--- a/arch/arm/plat-versatile/localtimer.c
+++ /dev/null
@@ -1,27 +0,0 @@
-/*
- *  linux/arch/arm/plat-versatile/localtimer.c
- *
- *  Copyright (C) 2002 ARM Ltd.
- *  All Rights Reserved
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
-#include <linux/init.h>
-#include <linux/smp.h>
-#include <linux/clockchips.h>
-
-#include <asm/smp_twd.h>
-#include <asm/localtimer.h>
-#include <mach/irqs.h>
-
-/*
- * Setup the local clock events for a CPU.
- */
-int __cpuinit local_timer_setup(struct clock_event_device *evt)
-{
-	evt->irq = IRQ_LOCALTIMER;
-	twd_timer_setup(evt);
-	return 0;
-}
-- 
1.7.0.4

[RFC PATCH 05/12] ARM: local timers: switch tegra to standalone smp_twd

[Marc Zyngier]

Convert the Tegra-2 platforms to the standalone version
of smp_twd.c. Since the timer calibration code requires another
timer to be up and running, the actual initialisation is left
to the late_timer_init hook.

Tested on Harmony.

Cc: Colin Cross <ccross@android.com>
Cc: Erik Gilling <konkers@android.com>
Cc: Olof Johansson <olof@lixom.net>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/mach-tegra/Kconfig      |    1 +
 arch/arm/mach-tegra/Makefile     |    2 +-
 arch/arm/mach-tegra/localtimer.c |   26 --------------------------
 arch/arm/mach-tegra/timer.c      |   34 +++++++++++++++++++++++++++++-----
 4 files changed, 31 insertions(+), 32 deletions(-)
 delete mode 100644 arch/arm/mach-tegra/localtimer.c

diff --git a/arch/arm/mach-tegra/Kconfig b/arch/arm/mach-tegra/Kconfig
index d82ebab..6d6c396 100644
--- a/arch/arm/mach-tegra/Kconfig
+++ b/arch/arm/mach-tegra/Kconfig
@@ -9,6 +9,7 @@ config ARCH_TEGRA_2x_SOC
 	bool "Tegra 2 family"
 	select CPU_V7
 	select ARM_GIC
+	select ARM_SMP_TWD
 	select ARCH_REQUIRE_GPIOLIB
 	select USB_ARCH_HAS_EHCI if USB_SUPPORT
 	select USB_ULPI if USB_SUPPORT
diff --git a/arch/arm/mach-tegra/Makefile b/arch/arm/mach-tegra/Makefile
index f11b910..c6b305f 100644
--- a/arch/arm/mach-tegra/Makefile
+++ b/arch/arm/mach-tegra/Makefile
@@ -11,7 +11,7 @@ obj-$(CONFIG_ARCH_TEGRA_2x_SOC)         += clock.o
 obj-$(CONFIG_ARCH_TEGRA_2x_SOC)         += tegra2_clocks.o
 obj-$(CONFIG_ARCH_TEGRA_2x_SOC)		+= tegra2_emc.o
 obj-$(CONFIG_ARCH_TEGRA_2x_SOC)		+= pinmux-t2-tables.o
-obj-$(CONFIG_SMP)                       += platsmp.o localtimer.o headsmp.o
+obj-$(CONFIG_SMP)                       += platsmp.o headsmp.o
 obj-$(CONFIG_HOTPLUG_CPU)               += hotplug.o
 obj-$(CONFIG_TEGRA_SYSTEM_DMA)		+= dma.o
 obj-$(CONFIG_CPU_FREQ)                  += cpu-tegra.o
diff --git a/arch/arm/mach-tegra/localtimer.c b/arch/arm/mach-tegra/localtimer.c
deleted file mode 100644
index e91d681..0000000
--- a/arch/arm/mach-tegra/localtimer.c
+++ /dev/null
@@ -1,26 +0,0 @@
-/*
- *  arch/arm/mach-tegra/localtimer.c
- *
- *  Copyright (C) 2002 ARM Ltd.
- *  All Rights Reserved
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
-#include <linux/init.h>
-#include <linux/smp.h>
-#include <linux/clockchips.h>
-#include <asm/irq.h>
-#include <asm/smp_twd.h>
-#include <asm/localtimer.h>
-
-/*
- * Setup the local clock events for a CPU.
- */
-int __cpuinit local_timer_setup(struct clock_event_device *evt)
-{
-	evt->irq = IRQ_LOCALTIMER;
-	twd_timer_setup(evt);
-	return 0;
-}
diff --git a/arch/arm/mach-tegra/timer.c b/arch/arm/mach-tegra/timer.c
index 9035042..d8e26c4 100644
--- a/arch/arm/mach-tegra/timer.c
+++ b/arch/arm/mach-tegra/timer.c
@@ -27,9 +27,10 @@
 #include <linux/clocksource.h>
 #include <linux/clk.h>
 #include <linux/io.h>
+#include <linux/ioport.h>
 
 #include <asm/mach/time.h>
-#include <asm/localtimer.h>
+#include <asm/smp_twd.h>
 #include <asm/sched_clock.h>
 
 #include <mach/iomap.h>
@@ -179,6 +180,31 @@ static struct irqaction tegra_timer_irq = {
 	.irq		= INT_TMR3,
 };
 
+#ifdef CONFIG_ARM_SMP_TWD
+static struct resource tegra_twd_resources[] __initdata = {
+	{
+		.start	= TEGRA_ARM_PERIF_BASE + 0x600,
+		.end	= TEGRA_ARM_PERIF_BASE + 0x610,
+		.flags	= IORESOURCE_MEM,
+	},
+	{
+		.start	= IRQ_LOCALTIMER,
+		.end	= IRQ_LOCALTIMER,
+		.flags	= IORESOURCE_IRQ,
+	},
+};
+
+static void __init tegra_twd_init(void)
+{
+	int err = twd_timer_register(tegra_twd_resources,
+				     ARRAY_SIZE(tegra_twd_resources));
+	if (err)
+		pr_err("twd_timer_register failed %d\n", err);
+}
+#else
+#define tegra_twd_init	NULL
+#endif
+
 static void __init tegra_init_timer(void)
 {
 	struct clk *clk;
@@ -197,10 +223,6 @@ static void __init tegra_init_timer(void)
 	BUG_ON(IS_ERR(clk));
 	clk_enable(clk);
 
-#ifdef CONFIG_HAVE_ARM_TWD
-	twd_base = IO_ADDRESS(TEGRA_ARM_PERIF_BASE + 0x600);
-#endif
-
 	switch (rate) {
 	case 12000000:
 		timer_writel(0x000b, TIMERUS_USEC_CFG);
@@ -241,6 +263,8 @@ static void __init tegra_init_timer(void)
 	tegra_clockevent.cpumask = cpu_all_mask;
 	tegra_clockevent.irq = tegra_timer_irq.irq;
 	clockevents_register_device(&tegra_clockevent);
+
+	late_time_init = tegra_twd_init;
 }
 
 struct sys_timer tegra_timer = {
-- 
1.7.0.4

[RFC PATCH 06/12] ARM: local timers: switch omap4 to standalone smp_twd

[Marc Zyngier]

Convert the OMAP4 platforms to the standalone version
of smp_twd.c. Since the timer calibration code requires another
timer to be up and running, the actual initialisation is left
to the late_timer_init hook.

Tested on a Pandaboard.

Cc: Tony Lindgren <tony@atomide.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/mach-omap2/Kconfig     |    2 +-
 arch/arm/mach-omap2/Makefile    |    1 -
 arch/arm/mach-omap2/timer-mpu.c |   39 ---------------------------------------
 arch/arm/mach-omap2/timer.c     |   38 +++++++++++++++++++++++++++++++++-----
 4 files changed, 34 insertions(+), 46 deletions(-)
 delete mode 100644 arch/arm/mach-omap2/timer-mpu.c

diff --git a/arch/arm/mach-omap2/Kconfig b/arch/arm/mach-omap2/Kconfig
index 4ae6257..f8c0eb7 100644
--- a/arch/arm/mach-omap2/Kconfig
+++ b/arch/arm/mach-omap2/Kconfig
@@ -44,7 +44,7 @@ config ARCH_OMAP4
 	depends on ARCH_OMAP2PLUS
 	select CPU_V7
 	select ARM_GIC
-	select LOCAL_TIMERS if SMP
+	select ARM_SMP_TWD
 	select PL310_ERRATA_588369
 	select PL310_ERRATA_727915
 	select ARM_ERRATA_720789
diff --git a/arch/arm/mach-omap2/Makefile b/arch/arm/mach-omap2/Makefile
index f343365..40ea7e2 100644
--- a/arch/arm/mach-omap2/Makefile
+++ b/arch/arm/mach-omap2/Makefile
@@ -22,7 +22,6 @@ obj-$(CONFIG_TWL4030_CORE) += omap_twl.o
 
 # SMP support ONLY available for OMAP4
 obj-$(CONFIG_SMP)			+= omap-smp.o omap-headsmp.o
-obj-$(CONFIG_LOCAL_TIMERS)		+= timer-mpu.o
 obj-$(CONFIG_HOTPLUG_CPU)		+= omap-hotplug.o
 obj-$(CONFIG_ARCH_OMAP4)		+= omap44xx-smc.o omap4-common.o
 
diff --git a/arch/arm/mach-omap2/timer-mpu.c b/arch/arm/mach-omap2/timer-mpu.c
deleted file mode 100644
index 31c0ac4..0000000
--- a/arch/arm/mach-omap2/timer-mpu.c
+++ /dev/null
@@ -1,39 +0,0 @@
-/*
- * The MPU local timer source file. In OMAP4, both cortex-a9 cores have
- * own timer in it's MPU domain. These timers will be driving the
- * linux kernel SMP tick framework when active. These timers are not
- * part of the wake up domain.
- *
- * Copyright (C) 2009 Texas Instruments, Inc.
- *
- * Author:
- *      Santosh Shilimkar <santosh.shilimkar@ti.com>
- *
- * This file is based on arm realview smp platform file.
- * Copyright (C) 2002 ARM Ltd.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
-#include <linux/init.h>
-#include <linux/smp.h>
-#include <linux/clockchips.h>
-#include <asm/irq.h>
-#include <asm/smp_twd.h>
-#include <asm/localtimer.h>
-
-/*
- * Setup the local clock events for a CPU.
- */
-int __cpuinit local_timer_setup(struct clock_event_device *evt)
-{
-	/* Local timers are not supprted on OMAP4430 ES1.0 */
-	if (omap_rev() == OMAP4430_REV_ES1_0)
-		return -ENXIO;
-
-	evt->irq = OMAP44XX_IRQ_LOCALTIMER;
-	twd_timer_setup(evt);
-	return 0;
-}
-
diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c
index e964072..5a4ce50 100644
--- a/arch/arm/mach-omap2/timer.c
+++ b/arch/arm/mach-omap2/timer.c
@@ -38,7 +38,7 @@
 
 #include <asm/mach/time.h>
 #include <plat/dmtimer.h>
-#include <asm/localtimer.h>
+#include <asm/smp_twd.h>
 #include <asm/sched_clock.h>
 #include <plat/common.h>
 #include <plat/omap_hwmod.h>
@@ -328,15 +328,43 @@ OMAP_SYS_TIMER_INIT(3_secure, OMAP3_SECURE_TIMER, OMAP3_CLKEV_SOURCE,
 OMAP_SYS_TIMER(3_secure)
 #endif
 
+#ifdef CONFIG_ARM_SMP_TWD
+static struct resource omap4_twd_resources[] __initdata = {
+	{
+		.start	= OMAP44XX_LOCAL_TWD_BASE,
+		.end	= OMAP44XX_LOCAL_TWD_BASE + 0x10,
+		.flags	= IORESOURCE_MEM,
+	},
+	{
+		.start	= OMAP44XX_IRQ_LOCALTIMER,
+		.end	= OMAP44XX_IRQ_LOCALTIMER,
+		.flags	= IORESOURCE_IRQ,
+	},
+};
+
+static void __init omap4_twd_init(void)
+{
+	int err;
+
+	/* Local timers are not supprted on OMAP4430 ES1.0 */
+	if (omap_rev() == OMAP4430_REV_ES1_0)
+		return;
+
+	err = twd_timer_register(omap4_twd_resources,
+				 ARRAY_SIZE(omap4_twd_resources));
+	if (err)
+		pr_err("twd_timer_register failed %d\n", err);
+}
+#else
+#define omap4_twd_init	NULL
+#endif
+
 #ifdef CONFIG_ARCH_OMAP4
 static void __init omap4_timer_init(void)
 {
-#ifdef CONFIG_LOCAL_TIMERS
-	twd_base = ioremap(OMAP44XX_LOCAL_TWD_BASE, SZ_256);
-	BUG_ON(!twd_base);
-#endif
 	omap2_gp_clockevent_init(1, OMAP4_CLKEV_SOURCE);
 	omap2_gp_clocksource_init(2, OMAP4_MPU_SOURCE);
+	late_time_init = omap4_twd_init;
 }
 OMAP_SYS_TIMER(4)
 #endif
-- 
1.7.0.4

[RFC PATCH 07/12] ARM: local timers: switch shmobile to standalone smp_twd

[Marc Zyngier]

Convert the SMP shmobile platforms to the standalone version
of smp_twd.c. As shmobile is already using the late_time_init
hook, a private hook is added to initialise the TWD driver
once the platform timer is up and running.

Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Magnus Damm <magnus.damm@gmail.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/mach-shmobile/Kconfig               |    1 +
 arch/arm/mach-shmobile/Makefile              |    1 -
 arch/arm/mach-shmobile/include/mach/common.h |    3 ++
 arch/arm/mach-shmobile/localtimer.c          |   26 ---------------------
 arch/arm/mach-shmobile/platsmp.c             |    1 -
 arch/arm/mach-shmobile/smp-sh73a0.c          |   32 +++++++++++++++++++++++--
 arch/arm/mach-shmobile/timer.c               |   10 ++++++++
 7 files changed, 43 insertions(+), 31 deletions(-)
 delete mode 100644 arch/arm/mach-shmobile/localtimer.c

diff --git a/arch/arm/mach-shmobile/Kconfig b/arch/arm/mach-shmobile/Kconfig
index 0c8f6cf..c2999b6 100644
--- a/arch/arm/mach-shmobile/Kconfig
+++ b/arch/arm/mach-shmobile/Kconfig
@@ -23,6 +23,7 @@ config ARCH_SH7372
 config ARCH_SH73A0
 	bool "SH-Mobile AG5 (R8A73A00)"
 	select CPU_V7
+	select ARM_SMP_TWD
 	select SH_CLK_CPG
 	select ARCH_WANT_OPTIONAL_GPIOLIB
 	select ARM_GIC
diff --git a/arch/arm/mach-shmobile/Makefile b/arch/arm/mach-shmobile/Makefile
index 612b270..82ec6e9 100644
--- a/arch/arm/mach-shmobile/Makefile
+++ b/arch/arm/mach-shmobile/Makefile
@@ -14,7 +14,6 @@ obj-$(CONFIG_ARCH_SH73A0)	+= setup-sh73a0.o clock-sh73a0.o intc-sh73a0.o
 # SMP objects
 smp-y				:= platsmp.o headsmp.o
 smp-$(CONFIG_HOTPLUG_CPU)	+= hotplug.o
-smp-$(CONFIG_LOCAL_TIMERS)	+= localtimer.o
 smp-$(CONFIG_ARCH_SH73A0)	+= smp-sh73a0.o
 
 # Pinmux setup
diff --git a/arch/arm/mach-shmobile/include/mach/common.h b/arch/arm/mach-shmobile/include/mach/common.h
index 06aecb3..39a2637 100644
--- a/arch/arm/mach-shmobile/include/mach/common.h
+++ b/arch/arm/mach-shmobile/include/mach/common.h
@@ -53,4 +53,7 @@ extern void sh73a0_secondary_init(unsigned int cpu);
 extern int sh73a0_boot_secondary(unsigned int cpu);
 extern void sh73a0_smp_prepare_cpus(void);
 
+struct resource;
+extern void shmobile_local_timer_register(void (*)(void));
+
 #endif /* __ARCH_MACH_COMMON_H */
diff --git a/arch/arm/mach-shmobile/localtimer.c b/arch/arm/mach-shmobile/localtimer.c
deleted file mode 100644
index ad9ccc9..0000000
--- a/arch/arm/mach-shmobile/localtimer.c
+++ /dev/null
@@ -1,26 +0,0 @@
-/*
- * SMP support for R-Mobile / SH-Mobile - local timer portion
- *
- * Copyright (C) 2010  Magnus Damm
- *
- * Based on vexpress, Copyright (C) 2002 ARM Ltd, All Rights Reserved
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
-#include <linux/init.h>
-#include <linux/smp.h>
-#include <linux/clockchips.h>
-#include <asm/smp_twd.h>
-#include <asm/localtimer.h>
-
-/*
- * Setup the local clock events for a CPU.
- */
-int __cpuinit local_timer_setup(struct clock_event_device *evt)
-{
-	evt->irq = 29;
-	twd_timer_setup(evt);
-	return 0;
-}
diff --git a/arch/arm/mach-shmobile/platsmp.c b/arch/arm/mach-shmobile/platsmp.c
index 66f9806..b5dcc57 100644
--- a/arch/arm/mach-shmobile/platsmp.c
+++ b/arch/arm/mach-shmobile/platsmp.c
@@ -17,7 +17,6 @@
 #include <linux/smp.h>
 #include <linux/io.h>
 #include <asm/hardware/gic.h>
-#include <asm/localtimer.h>
 #include <asm/mach-types.h>
 #include <mach/common.h>
 
diff --git a/arch/arm/mach-shmobile/smp-sh73a0.c b/arch/arm/mach-shmobile/smp-sh73a0.c
index 3ffdbc9..8506437 100644
--- a/arch/arm/mach-shmobile/smp-sh73a0.c
+++ b/arch/arm/mach-shmobile/smp-sh73a0.c
@@ -22,6 +22,7 @@
 #include <linux/smp.h>
 #include <linux/spinlock.h>
 #include <linux/io.h>
+#include <linux/ioport.h>
 #include <mach/common.h>
 #include <asm/smp_scu.h>
 #include <asm/smp_twd.h>
@@ -41,6 +42,31 @@ static void __iomem *scu_base_addr(void)
 static DEFINE_SPINLOCK(scu_lock);
 static unsigned long tmp;
 
+#ifdef CONFIG_ARM_SMP_TWD
+static struct resource sh73a0_twd_resources[] __initdata = {
+	{
+		.start	= 0xf0000600,
+		.end	= 0xf0000600 + 0x10,
+		.flags	= IORESOURCE_MEM,
+	},
+	{
+		.start	= 29,
+		.end	= 29,
+		.flags	= IORESOURCE_IRQ,
+	},
+};
+
+static void __init sh73a0_twd_init(void)
+{
+	int err = twd_timer_register(sh73a0_twd_resources,
+				     ARRAY_SIZE(sh73a0_twd_resources));
+	if (err)
+		pr_err("twd_timer_register failed %d\n", err);
+}
+#else
+#define sh73a0_twd_init	NULL
+#endif
+
 static void modify_scu_cpu_psr(unsigned long set, unsigned long clr)
 {
 	void __iomem *scu_base = scu_base_addr();
@@ -59,9 +85,9 @@ unsigned int __init sh73a0_get_core_count(void)
 {
 	void __iomem *scu_base = scu_base_addr();
 
-#ifdef CONFIG_HAVE_ARM_TWD
-	/* twd_base needs to be initialized before percpu_timer_setup() */
-	twd_base = (void __iomem *)0xf0000600;
+
+#ifdef CONFIG_ARM_SMP_TWD
+	shmobile_local_timer_register(sh73a0_twd_init);
 #endif
 
 	return scu_get_core_count(scu_base);
diff --git a/arch/arm/mach-shmobile/timer.c b/arch/arm/mach-shmobile/timer.c
index 895794b..fad385d 100644
--- a/arch/arm/mach-shmobile/timer.c
+++ b/arch/arm/mach-shmobile/timer.c
@@ -19,8 +19,11 @@
  *
  */
 #include <linux/platform_device.h>
+#include <mach/common.h>
 #include <asm/mach/time.h>
 
+static void (*local_timer_hook)(void) __initdata;
+
 static void __init shmobile_late_time_init(void)
 {
 	/*
@@ -34,6 +37,8 @@ static void __init shmobile_late_time_init(void)
 	 */
 	early_platform_driver_register_all("earlytimer");
 	early_platform_driver_probe("earlytimer", 2, 0);
+	if (local_timer_hook)
+		local_timer_hook();
 }
 
 static void __init shmobile_timer_init(void)
@@ -41,6 +46,11 @@ static void __init shmobile_timer_init(void)
 	late_time_init = shmobile_late_time_init;
 }
 
+void __init shmobile_local_timer_register(void (*hook)(void))
+{
+	local_timer_hook = hook;
+}
+
 struct sys_timer shmobile_timer = {
 	.init		= shmobile_timer_init,
 };
-- 
1.7.0.4

[RFC PATCH 08/12] ARM: local timers: switch ux500 to standalone smp_twd

[Marc Zyngier]

Convert the ux500 platforms to the standalone version of smp_twd.c.
Since the timer calibration code requires another timer to be up
and running, the actual initialisation is left to the late_timer_init
hook.

Cc: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/mach-ux500/Kconfig      |    1 +
 arch/arm/mach-ux500/Makefile     |    1 -
 arch/arm/mach-ux500/cpu.c        |   40 +++++++++++++++++++++++++++++++------
 arch/arm/mach-ux500/localtimer.c |   29 ---------------------------
 4 files changed, 34 insertions(+), 37 deletions(-)
 delete mode 100644 arch/arm/mach-ux500/localtimer.c

diff --git a/arch/arm/mach-ux500/Kconfig b/arch/arm/mach-ux500/Kconfig
index 4210cb4..3b1f972 100644
--- a/arch/arm/mach-ux500/Kconfig
+++ b/arch/arm/mach-ux500/Kconfig
@@ -4,6 +4,7 @@ config UX500_SOC_COMMON
 	bool
 	default y
 	select ARM_GIC
+	select ARM_SMP_TWD
 	select HAS_MTU
 	select ARM_ERRATA_753970
 
diff --git a/arch/arm/mach-ux500/Makefile b/arch/arm/mach-ux500/Makefile
index 1694916..2e30a80 100644
--- a/arch/arm/mach-ux500/Makefile
+++ b/arch/arm/mach-ux500/Makefile
@@ -14,7 +14,6 @@ obj-$(CONFIG_MACH_U8500)	+= board-mop500.o board-mop500-sdi.o \
 obj-$(CONFIG_MACH_U5500)	+= board-u5500.o board-u5500-sdi.o
 obj-$(CONFIG_SMP)		+= platsmp.o headsmp.o
 obj-$(CONFIG_HOTPLUG_CPU)	+= hotplug.o
-obj-$(CONFIG_LOCAL_TIMERS)	+= localtimer.o
 obj-$(CONFIG_U5500_MODEM_IRQ)	+= modem-irq-db5500.o
 obj-$(CONFIG_U5500_MBOX)	+= mbox-db5500.o
 
diff --git a/arch/arm/mach-ux500/cpu.c b/arch/arm/mach-ux500/cpu.c
index 1da23bb..ec622b6 100644
--- a/arch/arm/mach-ux500/cpu.c
+++ b/arch/arm/mach-ux500/cpu.c
@@ -15,7 +15,7 @@
 #include <asm/hardware/cache-l2x0.h>
 #include <asm/hardware/gic.h>
 #include <asm/mach/map.h>
-#include <asm/localtimer.h>
+#include <asm/smp_twd.h>
 
 #include <plat/mtu.h>
 #include <mach/hardware.h>
@@ -120,15 +120,40 @@ static int ux500_l2x0_init(void)
 early_initcall(ux500_l2x0_init);
 #endif
 
+#ifdef CONFIG_ARM_SMP_TWD
+static struct resource ux500_twd_resources[] __initdata = {
+	{
+		.flags	= IORESOURCE_MEM,
+	},
+	{
+		.start	= IRQ_LOCALTIMER,
+		.end	= IRQ_LOCALTIMER,
+		.flags	= IORESOURCE_IRQ,
+	},
+};
+
+static void __init ux500_twd_init(void)
+{
+	int err = twd_timer_register(ux500_twd_resources,
+				     ARRAY_SIZE(ux500_twd_resources));
+	if (err)
+		pr_err("twd_timer_register failed %d\n", err);
+}
+#else
+#define ux500_twd_init	NULL
+#endif
+
 static void __init ux500_timer_init(void)
 {
-#ifdef CONFIG_LOCAL_TIMERS
+#ifdef CONFIG_ARM_SMP_TWD
 	/* Setup the local timer base */
-	if (cpu_is_u5500())
-		twd_base = __io_address(U5500_TWD_BASE);
-	else if (cpu_is_u8500())
-		twd_base = __io_address(U8500_TWD_BASE);
-	else
+	if (cpu_is_u5500()) {
+		ux500_twd_resources[0].start = U5500_TWD_BASE;
+		ux500_twd_resources[0]end = U5500_TWD_BASE + 0x10;
+	} else if (cpu_is_u8500()) {
+		ux500_twd_resources[0].start = U8500_TWD_BASE;
+		ux500_twd_resources[0]end = U8500_TWD_BASE + 0x10;
+	} else
 		ux500_unknown_soc();
 #endif
 	if (cpu_is_u5500())
@@ -141,6 +166,7 @@ static void __init ux500_timer_init(void)
 		ux500_unknown_soc();
 
 	nmdk_timer_init();
+	late_time_init = ux500_twd_init;
 }
 
 struct sys_timer ux500_timer = {
diff --git a/arch/arm/mach-ux500/localtimer.c b/arch/arm/mach-ux500/localtimer.c
deleted file mode 100644
index 5ba1133..0000000
--- a/arch/arm/mach-ux500/localtimer.c
+++ /dev/null
@@ -1,29 +0,0 @@
-/*
- * Copyright (C) 2008-2009 ST-Ericsson
- * Srinidhi Kasagar <srinidhi.kasagar@stericsson.com>
- *
- * This file is heavily based on relaview platform, almost a copy.
- *
- * Copyright (C) 2002 ARM Ltd.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
-#include <linux/init.h>
-#include <linux/smp.h>
-#include <linux/clockchips.h>
-
-#include <asm/irq.h>
-#include <asm/smp_twd.h>
-#include <asm/localtimer.h>
-
-/*
- * Setup the local clock events for a CPU.
- */
-int __cpuinit local_timer_setup(struct clock_event_device *evt)
-{
-	evt->irq = IRQ_LOCALTIMER;
-	twd_timer_setup(evt);
-	return 0;
-}
-- 
1.7.0.4

[RFC PATCH 09/12] ARM: smp_twd: remove support for non-standalone version

[Marc Zyngier]

There is no in-tree platform using both CONFIG_LOCAL_TIMERS and
CONFIG_HAVE_ARM_TWD. As such, some code can be removed and some
exported function of smp_twd.c can be made static.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/Kconfig                  |    1 -
 arch/arm/include/asm/localtimer.h |   10 ----------
 arch/arm/include/asm/smp_twd.h    |    5 -----
 arch/arm/kernel/smp_twd.c         |   10 +++-------
 4 files changed, 3 insertions(+), 23 deletions(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 7ac28a3..12cbeba 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1438,7 +1438,6 @@ config LOCAL_TIMERS
 	bool "Use local timer interrupts"
 	depends on SMP && !ARM_SMP_TWD
 	default y
-	select HAVE_ARM_TWD if (!ARCH_MSM_SCORPIONMP && !EXYNOS4_MCT)
 	help
 	  Enable support for local timers on SMP platforms, rather then the
 	  legacy IPI broadcast method.  Local timers allows the system
diff --git a/arch/arm/include/asm/localtimer.h b/arch/arm/include/asm/localtimer.h
index f5e1cec..af5c371 100644
--- a/arch/arm/include/asm/localtimer.h
+++ b/arch/arm/include/asm/localtimer.h
@@ -21,21 +21,11 @@ void percpu_timer_setup(void);
 
 #ifdef CONFIG_LOCAL_TIMERS
 
-#ifdef CONFIG_HAVE_ARM_TWD
-
-#include "smp_twd.h"
-
-#define local_timer_stop(c)	twd_timer_stop((c))
-
-#else
-
 /*
  * Stop the local timer
  */
 void local_timer_stop(struct clock_event_device *);
 
-#endif
-
 /*
  * Setup a local timer interrupt for a CPU.
  */
diff --git a/arch/arm/include/asm/smp_twd.h b/arch/arm/include/asm/smp_twd.h
index 934f1bc..0da6438 100644
--- a/arch/arm/include/asm/smp_twd.h
+++ b/arch/arm/include/asm/smp_twd.h
@@ -18,13 +18,8 @@
 #define TWD_TIMER_CONTROL_PERIODIC	(1 << 1)
 #define TWD_TIMER_CONTROL_IT_ENABLE	(1 << 2)
 
-struct clock_event_device;
 struct resource;
 
-extern void __iomem *twd_base;
-
-void twd_timer_setup(struct clock_event_device *);
-void twd_timer_stop(struct clock_event_device *);
 #ifdef CONFIG_HAVE_ARM_TWD
 int twd_timer_register(struct resource *res, int res_nr);
 #else
diff --git a/arch/arm/kernel/smp_twd.c b/arch/arm/kernel/smp_twd.c
index 5b6d99b..0a9106d 100644
--- a/arch/arm/kernel/smp_twd.c
+++ b/arch/arm/kernel/smp_twd.c
@@ -20,11 +20,9 @@
 #include <linux/io.h>
 
 #include <asm/smp_twd.h>
-#include <asm/localtimer.h>
 #include <asm/hardware/gic.h>
 
-/* set up by the platform code */
-void __iomem *twd_base;
+static void __iomem *twd_base;
 
 static unsigned long twd_timer_rate;
 
@@ -79,7 +77,7 @@ static irqreturn_t twd_timer_handler(int irq, void *dev_id)
 	return IRQ_NONE;
 }
 
-void twd_timer_stop(struct clock_event_device *clk)
+static void twd_timer_stop(struct clock_event_device *clk)
 {
 	twd_set_mode(CLOCK_EVT_MODE_UNUSED, clk);
 	gic_free_ppi(clk->irq, clk);
@@ -127,7 +125,7 @@ static void __cpuinit twd_calibrate_rate(void)
 /*
  * Setup the local clock events for a CPU.
  */
-void __cpuinit twd_timer_setup(struct clock_event_device *clk)
+static void __cpuinit twd_timer_setup(struct clock_event_device *clk)
 {
 	int err;
 
@@ -152,7 +150,6 @@ void __cpuinit twd_timer_setup(struct clock_event_device *clk)
 		       clk->name, clk->irq, smp_processor_id(), err);
 }
 
-#ifdef CONFIG_ARM_SMP_TWD
 static struct clock_event_device __percpu *twd_evt;
 static int twd_ppi;
 
@@ -223,4 +220,3 @@ int twd_timer_register(struct resource *res, int res_nr)
 
 	return 0;
 }
-#endif
-- 
1.7.0.4

[RFC PATCH 10/12] ARM: local timers: make MSM timers standalone

[Marc Zyngier]

Following the same pattern used for smp_twd, allow the MSM timers
to be built in standalone, without relying on the CONFIG_LOCAL_TIMER
infrastructure and use a CPU notifier block to stop or start
the timer on the secondary CPU.

Cc: David Brown <davidb@codeaurora.org>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/Kconfig          |    2 +-
 arch/arm/mach-msm/timer.c |   64 +++++++++++++++++++++++++++++++++------------
 2 files changed, 48 insertions(+), 18 deletions(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 12cbeba..13cdba4 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1436,7 +1436,7 @@ config HOTPLUG_CPU
 
 config LOCAL_TIMERS
 	bool "Use local timer interrupts"
-	depends on SMP && !ARM_SMP_TWD
+	depends on SMP && !ARM_SMP_TWD && !ARCH_MSM
 	default y
 	help
 	  Enable support for local timers on SMP platforms, rather then the
diff --git a/arch/arm/mach-msm/timer.c b/arch/arm/mach-msm/timer.c
index 94e6fc5..f67ff1c 100644
--- a/arch/arm/mach-msm/timer.c
+++ b/arch/arm/mach-msm/timer.c
@@ -21,6 +21,7 @@
 #include <linux/clockchips.h>
 #include <linux/delay.h>
 #include <linux/io.h>
+#include <linux/cpu.h>
 
 #include <asm/mach/time.h>
 #include <asm/hardware/gic.h>
@@ -110,15 +111,7 @@ static cycle_t msm_read_timer_count(struct clocksource *cs)
 
 static struct msm_clock *clockevent_to_clock(struct clock_event_device *evt)
 {
-#ifdef CONFIG_SMP
-	int i;
-	for (i = 0; i < NR_TIMERS; i++)
-		if (evt == &(msm_clocks[i].clockevent))
-			return &msm_clocks[i];
-	return &msm_clocks[MSM_GLOBAL_TIMER];
-#else
 	return container_of(evt, struct msm_clock, clockevent);
-#endif
 }
 
 static int msm_timer_set_next_event(unsigned long cycles,
@@ -193,7 +186,7 @@ static struct msm_clock msm_clocks[] = {
 	}
 };
 
-static void __init msm_timer_init(void)
+static void __init msm_timer_primary_setup(void)
 {
 	int i;
 	int res;
@@ -263,16 +256,13 @@ static void __init msm_timer_init(void)
 }
 
 #ifdef CONFIG_SMP
-int __cpuinit local_timer_setup(struct clock_event_device *evt)
+static void __cpuinit msm_timer_secondary_setup(void *data)
 {
 	static bool local_timer_inited;
+	struct clock_event_device *evt = data;
 	struct msm_clock *clock = &msm_clocks[MSM_GLOBAL_TIMER];
 	int res;
 
-	/* Use existing clock_event for cpu 0 */
-	if (!smp_processor_id())
-		return 0;
-
 	writel(DGT_CLK_CTL_DIV_4, MSM_TMR_BASE + DGT_CLK_CTL);
 
 	if (!local_timer_inited) {
@@ -292,25 +282,65 @@ int __cpuinit local_timer_setup(struct clock_event_device *evt)
 	evt->max_delta_ns =
 		clockevent_delta2ns(0xf0000000 >> clock->shift, evt);
 	evt->min_delta_ns = clockevent_delta2ns(4, evt);
+	evt->cpumask = cpumask_of(smp_processor_id());
 
 	res = gic_request_ppi(evt->irq, msm_timer_interrupt, evt);
 	if (res) {
 		pr_err("local_timer_setup: request_irq failed for %s\n",
 			       clock->clockevent.name);
-		return res;
+		return;
 	}
 
 	clockevents_register_device(evt);
-	return 0;
 }
 
-void local_timer_stop(struct clock_event_device *evt)
+void msm_timer_secondary_teardown(void *data)
 {
+	struct clock_event_device *evt = data;
 	evt->set_mode(CLOCK_EVT_MODE_UNUSED, evt);
 	gic_free_ppi(evt->irq, evt);
 }
+
+static int __cpuinit msm_timer_cpu_notify(struct notifier_block *self,
+					  unsigned long action, void *data)
+{
+	int cpu = (int)data;
+	struct clock_event_device *clk;
+
+	clk = &msm_clocks[MSM_GLOBAL_TIMER].clockevent;
+
+	switch (action) {
+	case CPU_STARTING:
+	case CPU_STARTING_FROZEN:
+		smp_call_function_single(cpu, msm_timer_secondary_setup,
+					 clk, 1);
+		break;
+
+	case CPU_DOWN_PREPARE:
+	case CPU_DOWN_PREPARE_FROZEN:
+		smp_call_function_single(cpu, msm_timer_secondary_teardown,
+					 clk, 1);
+		break;
+	}
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block __cpuinitdata msm_timer_cpu_nb = {
+	.notifier_call = msm_timer_cpu_notify,
+};
 #endif
 
+static void __init msm_timer_init(void)
+{
+	/* Immediately configure the timer on the boot CPU */
+	msm_timer_primary_setup();
+
+#ifdef CONFIG_SMP
+	register_cpu_notifier(&msm_timer_cpu_nb);
+#endif
+}
+
 struct sys_timer msm_timer = {
 	.init = msm_timer_init
 };
-- 
1.7.0.4

[RFC PATCH 11/12] ARM: local timers: make MCT timer standalone

[Marc Zyngier]

Following the same pattern used for smp_twd, allow the MCT timers
to be built in standalone, without relying on the CONFIG_LOCAL_TIMER
infrastructure and use a CPU notifier block to stop or start
the timer on the right CPU.

Cc: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/Kconfig            |    2 +-
 arch/arm/mach-exynos4/mct.c |   75 ++++++++++++++++++++++++++++++++----------
 2 files changed, 58 insertions(+), 19 deletions(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 13cdba4..ef67b64 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1436,7 +1436,7 @@ config HOTPLUG_CPU
 
 config LOCAL_TIMERS
 	bool "Use local timer interrupts"
-	depends on SMP && !ARM_SMP_TWD && !ARCH_MSM
+	depends on SMP && !ARM_SMP_TWD && !ARCH_MSM && !EXYNOS4_MCT
 	default y
 	help
 	  Enable support for local timers on SMP platforms, rather then the
diff --git a/arch/arm/mach-exynos4/mct.c b/arch/arm/mach-exynos4/mct.c
index 194fc6d..abe92cf 100644
--- a/arch/arm/mach-exynos4/mct.c
+++ b/arch/arm/mach-exynos4/mct.c
@@ -19,6 +19,7 @@
 #include <linux/platform_device.h>
 #include <linux/delay.h>
 #include <linux/percpu.h>
+#include <linux/cpu.h>
 
 #include <mach/map.h>
 #include <mach/regs-mct.h>
@@ -28,11 +29,11 @@ static unsigned long clk_cnt_per_tick;
 static unsigned long clk_rate;
 
 struct mct_clock_event_device {
-	struct clock_event_device *evt;
+	struct clock_event_device evt;
 	void __iomem *base;
 };
 
-struct mct_clock_event_device mct_tick[2];
+static struct mct_clock_event_device __percpu *mct_tick;
 
 static void exynos4_mct_write(unsigned int value, void *addr)
 {
@@ -249,10 +250,10 @@ static void exynos4_clockevent_init(void)
 	setup_irq(IRQ_MCT_G0, &mct_comp_event_irq);
 }
 
-#ifdef CONFIG_LOCAL_TIMERS
 /* Clock event handling */
-static void exynos4_mct_tick_stop(struct mct_clock_event_device *mevt)
+static void exynos4_mct_tick_stop(void *data)
 {
+	struct mct_clock_event_device *mevt = data;
 	unsigned long tmp;
 	unsigned long mask = MCT_L_TCON_INT_START | MCT_L_TCON_TIMER_START;
 	void __iomem *addr = mevt->base + MCT_L_TCON_OFFSET;
@@ -288,8 +289,9 @@ 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 = &mct_tick[smp_processor_id()];
+	struct mct_clock_event_device *mevt;
 
+	mevt = container_of(evt, struct mct_clock_event_device, evt);
 	exynos4_mct_tick_start(cycles, mevt);
 
 	return 0;
@@ -298,8 +300,9 @@ static int exynos4_tick_set_next_event(unsigned long cycles,
 static inline void exynos4_tick_set_mode(enum clock_event_mode mode,
 					 struct clock_event_device *evt)
 {
-	struct mct_clock_event_device *mevt = &mct_tick[smp_processor_id()];
+	struct mct_clock_event_device *mevt;
 
+	mevt = container_of(evt, struct mct_clock_event_device, evt);
 	exynos4_mct_tick_stop(mevt);
 
 	switch (mode) {
@@ -318,7 +321,7 @@ static inline void exynos4_tick_set_mode(enum clock_event_mode mode,
 static irqreturn_t exynos4_mct_tick_isr(int irq, void *dev_id)
 {
 	struct mct_clock_event_device *mevt = dev_id;
-	struct clock_event_device *evt = mevt->evt;
+	struct clock_event_device *evt = &mevt->evt;
 
 	/*
 	 * This is for supporting oneshot mode.
@@ -348,17 +351,17 @@ static struct irqaction mct_tick1_event_irq = {
 	.handler	= exynos4_mct_tick_isr,
 };
 
-static void exynos4_mct_tick_init(struct clock_event_device *evt)
+static void __cpuinit exynos4_mct_tick_init(void *data)
 {
+	struct mct_clock_event_device *mevt = data;
+	struct clock_event_device *evt = &mevt->evt;
 	unsigned int cpu = smp_processor_id();
 
-	mct_tick[cpu].evt = evt;
-
 	if (cpu == 0) {
-		mct_tick[cpu].base = EXYNOS4_MCT_L0_BASE;
+		mct_tick->base = EXYNOS4_MCT_L0_BASE;
 		evt->name = "mct_tick0";
 	} else {
-		mct_tick[cpu].base = EXYNOS4_MCT_L1_BASE;
+		mct_tick->base = EXYNOS4_MCT_L1_BASE;
 		evt->name = "mct_tick1";
 	}
 
@@ -379,21 +382,56 @@ static void exynos4_mct_tick_init(struct clock_event_device *evt)
 	exynos4_mct_write(0x1, mct_tick[cpu].base + MCT_L_TCNTB_OFFSET);
 
 	if (cpu == 0) {
-		mct_tick0_event_irq.dev_id = &mct_tick[cpu];
+		mct_tick0_event_irq.dev_id = mevt;
 		setup_irq(IRQ_MCT_L0, &mct_tick0_event_irq);
 	} else {
-		mct_tick1_event_irq.dev_id = &mct_tick[cpu];
+		mct_tick1_event_irq.dev_id = mevt;
 		setup_irq(IRQ_MCT_L1, &mct_tick1_event_irq);
 		irq_set_affinity(IRQ_MCT_L1, cpumask_of(1));
 	}
 }
 
-/* Setup the local clock events for a CPU */
-void __cpuinit local_timer_setup(struct clock_event_device *evt)
+static int __cpuinit exynos4_mct_cpu_notify(struct notifier_block *self,
+					    unsigned long action, void *data)
 {
-	exynos4_mct_tick_init(evt);
+	int cpu = (int)data;
+	struct mct_clock_event_device *mevt = per_cpu_ptr(mct_tick, cpu);
+
+	switch (action) {
+	case CPU_STARTING:
+	case CPU_STARTING_FROZEN:
+		smp_call_function_single(cpu, exynos4_mct_tick_init, mevt, 1);
+		break;
+
+	case CPU_DOWN_PREPARE:
+	case CPU_DOWN_PREPARE_FROZEN:
+		smp_call_function_single(cpu, exynos4_mct_tick_stop, mevt, 1);
+		break;
+	}
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block __cpuinitdata exynos4_mct_cpu_nb = {
+	.notifier_call = exynos4_mct_cpu_notify,
+};
+
+static void __init exynos4_mct_init(void)
+{
+	struct mct_clock_event_device *mevt;
+
+	mct_tick = alloc_percpu(struct mct_clock_event_device);
+	if (!mct_tick) {
+		pr_err("exynos4_mct_init: can't allocate memory\n");
+		return;
+	}
+
+	/* Immediately configure the timer on the boot CPU */
+	mevt = per_cpu_ptr(mct_tick, smp_processor_id());
+	exynos4_mct_tick_init(mevt);
+
+	register_cpu_notifier(&exynos4_mct_cpu_nb);
 }
-#endif /* CONFIG_LOCAL_TIMERS */
 
 static void __init exynos4_timer_resources(void)
 {
@@ -408,6 +446,7 @@ static void __init exynos4_timer_init(void)
 	exynos4_timer_resources();
 	exynos4_clocksource_init();
 	exynos4_clockevent_init();
+	exynos4_mct_init();
 }
 
 struct sys_timer exynos4_timer = {
-- 
1.7.0.4

[RFC PATCH 12/12] ARM: local timers: Remove CONFIG_LOCAL_TIMERS support

[Marc Zyngier]

Local timer support in arch/arm is now completely unused, as all
in-tree platforms are using standalone timers.

It allows us to simplify the code, only preserving the broadcast
timer. The broadcast timer is always installed, and we leave it up
to the kernel to pick the more suitable timer (usually the one with
the highest priority).

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/Kconfig                  |   10 ------
 arch/arm/include/asm/localtimer.h |   46 ------------------------------
 arch/arm/kernel/smp.c             |   56 +++++++++---------------------------
 3 files changed, 14 insertions(+), 98 deletions(-)
 delete mode 100644 arch/arm/include/asm/localtimer.h

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index ef67b64..9aba6c2 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1434,16 +1434,6 @@ config HOTPLUG_CPU
 	  Say Y here to experiment with turning CPUs off and on.  CPUs
 	  can be controlled through /sys/devices/system/cpu.
 
-config LOCAL_TIMERS
-	bool "Use local timer interrupts"
-	depends on SMP && !ARM_SMP_TWD && !ARCH_MSM && !EXYNOS4_MCT
-	default y
-	help
-	  Enable support for local timers on SMP platforms, rather then the
-	  legacy IPI broadcast method.  Local timers allows the system
-	  accounting to be spread across the timer interval, preventing a
-	  "thundering herd" at every timer tick.
-
 source kernel/Kconfig.preempt
 
 config HZ
diff --git a/arch/arm/include/asm/localtimer.h b/arch/arm/include/asm/localtimer.h
deleted file mode 100644
index af5c371..0000000
--- a/arch/arm/include/asm/localtimer.h
+++ /dev/null
@@ -1,46 +0,0 @@
-/*
- *  arch/arm/include/asm/localtimer.h
- *
- *  Copyright (C) 2004-2005 ARM Ltd.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
-#ifndef __ASM_ARM_LOCALTIMER_H
-#define __ASM_ARM_LOCALTIMER_H
-
-#include <linux/interrupt.h>
-
-struct clock_event_device;
-
-/*
- * Setup a per-cpu timer, whether it be a local timer or dummy broadcast
- */
-void percpu_timer_setup(void);
-
-#ifdef CONFIG_LOCAL_TIMERS
-
-/*
- * Stop the local timer
- */
-void local_timer_stop(struct clock_event_device *);
-
-/*
- * Setup a local timer interrupt for a CPU.
- */
-int local_timer_setup(struct clock_event_device *);
-
-#else
-
-static inline int local_timer_setup(struct clock_event_device *evt)
-{
-	return -ENXIO;
-}
-
-static inline void local_timer_stop(struct clock_event_device *evt)
-{
-}
-#endif
-
-#endif
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 5d1f2e2..32471ac 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -38,7 +38,6 @@
 #include <asm/sections.h>
 #include <asm/tlbflush.h>
 #include <asm/ptrace.h>
-#include <asm/localtimer.h>
 
 /*
  * as from 2.5, kernels no longer have an init_tasks structure
@@ -154,8 +153,6 @@ int __cpuinit __cpu_up(unsigned int cpu)
 }
 
 #ifdef CONFIG_HOTPLUG_CPU
-static void percpu_timer_stop(void);
-
 /*
  * __cpu_disable runs on the processor to be shutdown.
  */
@@ -181,11 +178,6 @@ int __cpu_disable(void)
 	migrate_irqs();
 
 	/*
-	 * Stop the local timer for this CPU.
-	 */
-	percpu_timer_stop();
-
-	/*
 	 * Flush user cache and TLB mappings, and then remove this CPU
 	 * from the vm mask set of all processes.
 	 */
@@ -286,6 +278,8 @@ static void __cpuinit smp_store_cpu_info(unsigned int cpuid)
 	cpu_info->loops_per_jiffy = loops_per_jiffy;
 }
 
+static void broadcast_timer_setup(void);
+
 /*
  * This is the secondary CPU boot entry.  We're using this CPUs
  * idle thread stack, but a set of temporary page tables.
@@ -325,9 +319,9 @@ asmlinkage void __cpuinit secondary_start_kernel(void)
 	local_fiq_enable();
 
 	/*
-	 * Setup the percpu timer for this CPU.
+	 * Setup the broadcast timer for this CPU.
 	 */
-	percpu_timer_setup();
+	broadcast_timer_setup();
 
 	calibrate_delay();
 
@@ -383,10 +377,10 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
 		max_cpus = ncores;
 	if (ncores > 1 && max_cpus) {
 		/*
-		 * Enable the local timer or broadcast device for the
-		 * boot CPU, but only if we have more than one CPU.
+		 * Enable the broadcast device for the boot CPU, but
+		 * only if we have more than one CPU.
 		 */
-		percpu_timer_setup();
+		broadcast_timer_setup();
 
 		/*
 		 * Initialise the present map, which describes the set of CPUs
@@ -457,7 +451,7 @@ u64 smp_irq_stat_cpu(unsigned int cpu)
 }
 
 /*
- * Timer (local or broadcast) support
+ * Broadcast timer support
  */
 static DEFINE_PER_CPU(struct clock_event_device, percpu_clockevent);
 
@@ -483,8 +477,11 @@ static void broadcast_timer_set_mode(enum clock_event_mode mode,
 {
 }
 
-static void __cpuinit broadcast_timer_setup(struct clock_event_device *evt)
+static void __cpuinit broadcast_timer_setup(void)
 {
+	unsigned int cpu = smp_processor_id();
+	struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu);
+
 	evt->name	= "dummy_timer";
 	evt->features	= CLOCK_EVT_FEAT_ONESHOT |
 			  CLOCK_EVT_FEAT_PERIODIC |
@@ -492,37 +489,12 @@ static void __cpuinit broadcast_timer_setup(struct clock_event_device *evt)
 	evt->rating	= 400;
 	evt->mult	= 1;
 	evt->set_mode	= broadcast_timer_set_mode;
+	evt->cpumask	= cpumask_of(cpu);
+	evt->broadcast	= smp_timer_broadcast;
 
 	clockevents_register_device(evt);
 }
 
-void __cpuinit percpu_timer_setup(void)
-{
-	unsigned int cpu = smp_processor_id();
-	struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu);
-
-	evt->cpumask = cpumask_of(cpu);
-	evt->broadcast = smp_timer_broadcast;
-
-	if (local_timer_setup(evt))
-		broadcast_timer_setup(evt);
-}
-
-#ifdef CONFIG_HOTPLUG_CPU
-/*
- * The generic clock events code purposely does not stop the local timer
- * on CPU_DEAD/CPU_DEAD_FROZEN hotplug events, so we have to do it
- * manually here.
- */
-static void percpu_timer_stop(void)
-{
-	unsigned int cpu = smp_processor_id();
-	struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu);
-
-	local_timer_stop(evt);
-}
-#endif
-
 static DEFINE_SPINLOCK(stop_lock);
 
 /*
-- 
1.7.0.4

[RFC PATCH 08/12] ARM: local timers: switch ux500 to standalone smp_twd

[Linus Walleij]

On 08/09/2011 12:46 PM, Marc Zyngier wrote:
> Convert the ux500 platforms to the standalone version of smp_twd.c.
> Since the timer calibration code requires another timer to be up
> and running, the actual initialisation is left to the late_timer_init
> hook.
>
> Cc: Linus Walleij<linus.walleij@stericsson.com>
> Signed-off-by: Marc Zyngier<marc.zyngier@arm.com>
>    

So it switch to ioremap():ing the TWD too.
Seems like a pretty good idea.
Acked-by: Linus Walleij <linus.walleij@linaro.org>

Yours,
Linus Walleij