[PATCH v9 0/2] J-Core timer support

[PATCH v9 0/2] J-Core timer support

[Rich Felker]

This version of the patch makes the changes requested by Daniel
Lezcano in review of v8.

Rich Felker (2):
  of: add J-Core timer bindings
  clocksource: add J-Core timer/clocksource driver

 .../devicetree/bindings/timer/jcore,pit.txt        |  24 ++
 drivers/clocksource/Kconfig                        |  10 +
 drivers/clocksource/Makefile                       |   1 +
 drivers/clocksource/jcore-pit.c                    | 249 +++++++++++++++++++++
 include/linux/cpuhotplug.h                         |   1 +
 5 files changed, 285 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/timer/jcore,pit.txt
 create mode 100644 drivers/clocksource/jcore-pit.c

-- 
2.10.0

[PATCH v9 1/2] of: add J-Core timer bindings

[Rich Felker]

Signed-off-by: Rich Felker <dalias@libc.org>
Acked-by: Rob Herring <robh@kernel.org>
---
 .../devicetree/bindings/timer/jcore,pit.txt        | 24 ++++++++++++++++++++++
 1 file changed, 24 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/timer/jcore,pit.txt

diff --git a/Documentation/devicetree/bindings/timer/jcore,pit.txt b/Documentation/devicetree/bindings/timer/jcore,pit.txt
new file mode 100644
index 0000000..af5dd35
--- /dev/null
+++ b/Documentation/devicetree/bindings/timer/jcore,pit.txt
@@ -0,0 +1,24 @@
+J-Core Programmable Interval Timer and Clocksource
+
+Required properties:
+
+- compatible: Must be "jcore,pit".
+
+- reg: Memory region(s) for timer/clocksource registers. For SMP,
+  there should be one region per cpu, indexed by the sequential,
+  zero-based hardware cpu number.
+
+- interrupts: An interrupt to assign for the timer. The actual pit
+  core is integrated with the aic and allows the timer interrupt
+  assignment to be programmed by software, but this property is
+  required in order to reserve an interrupt number that doesn't
+  conflict with other devices.
+
+
+Example:
+
+timer@200 {
+	compatible = "jcore,pit";
+	reg = < 0x200 0x30 0x500 0x30 >;
+	interrupts = < 0x48 >;
+};
-- 
2.10.0

[tip:timers/urgent] of: Add J-Core timer bindings

[tip-bot for Rich Felker]

Commit-ID:  a2ce092be34c4951e23104a0bfdec08f9577fada
Gitweb:     http://git.kernel.org/tip/a2ce092be34c4951e23104a0bfdec08f9577fada
Author:     Rich Felker <dalias@libc.org>
AuthorDate: Thu, 13 Oct 2016 21:51:06 +0000
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Thu, 20 Oct 2016 20:10:17 +0200

of: Add J-Core timer bindings

Signed-off-by: Rich Felker <dalias@libc.org>
Acked-by: Rob Herring <robh@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: devicetree@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Rob Herring <robh+dt@kernel.org>
Link: http://lkml.kernel.org/r/8b107c292ed8cf8eed0fa283071fc8a930098628.1476393790.git.dalias@libc.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

---
 .../devicetree/bindings/timer/jcore,pit.txt        | 24 ++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/Documentation/devicetree/bindings/timer/jcore,pit.txt b/Documentation/devicetree/bindings/timer/jcore,pit.txt
new file mode 100644
index 0000000..af5dd35
--- /dev/null
+++ b/Documentation/devicetree/bindings/timer/jcore,pit.txt
@@ -0,0 +1,24 @@
+J-Core Programmable Interval Timer and Clocksource
+
+Required properties:
+
+- compatible: Must be "jcore,pit".
+
+- reg: Memory region(s) for timer/clocksource registers. For SMP,
+  there should be one region per cpu, indexed by the sequential,
+  zero-based hardware cpu number.
+
+- interrupts: An interrupt to assign for the timer. The actual pit
+  core is integrated with the aic and allows the timer interrupt
+  assignment to be programmed by software, but this property is
+  required in order to reserve an interrupt number that doesn't
+  conflict with other devices.
+
+
+Example:
+
+timer@200 {
+	compatible = "jcore,pit";
+	reg = < 0x200 0x30 0x500 0x30 >;
+	interrupts = < 0x48 >;
+};

[PATCH v9 2/2] clocksource: add J-Core timer/clocksource driver

[Rich Felker]

At the hardware level, the J-Core PIT is integrated with the interrupt
controller, but it is represented as its own device and has an
independent programming interface. It provides a 12-bit countdown
timer, which is not presently used, and a periodic timer. The interval
length for the latter is programmable via a 32-bit throttle register
whose units are determined by a bus-period register. The periodic
timer is used to implement both periodic and oneshot clock event
modes; in oneshot mode the interrupt handler simply disables the timer
as soon as it fires.

Despite its device tree node representing an interrupt for the PIT,
the actual irq generated is programmable, not hard-wired. The driver
is responsible for programming the PIT to generate the hardware irq
number that the DT assigns to it.

On SMP configurations, J-Core provides cpu-local instances of the PIT;
no broadcast timer is needed. This driver supports the creation of the
necessary per-cpu clock_event_device instances.

A nanosecond-resolution clocksource is provided using the J-Core "RTC"
registers, which give a 64-bit seconds count and 32-bit nanoseconds
that wrap every second. The driver converts these to a full-range
32-bit nanoseconds count.

Signed-off-by: Rich Felker <dalias@libc.org>
---
 drivers/clocksource/Kconfig     |  10 ++
 drivers/clocksource/Makefile    |   1 +
 drivers/clocksource/jcore-pit.c | 249 ++++++++++++++++++++++++++++++++++++++++
 include/linux/cpuhotplug.h      |   1 +
 4 files changed, 261 insertions(+)
 create mode 100644 drivers/clocksource/jcore-pit.c

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 5677886..eec5731 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -407,6 +407,16 @@ config SYS_SUPPORTS_SH_TMU
 config SYS_SUPPORTS_EM_STI
         bool
 
+config CLKSRC_JCORE_PIT
+	bool "J-Core PIT timer driver" if COMPILE_TEST
+	depends on OF
+	depends on GENERIC_CLOCKEVENTS
+	depends on HAS_IOMEM
+	select CLKSRC_MMIO
+	help
+	  This enables build of clocksource and clockevent driver for
+	  the integrated PIT in the J-Core synthesizable, open source SoC.
+
 config SH_TIMER_CMT
 	bool "Renesas CMT timer driver" if COMPILE_TEST
 	depends on GENERIC_CLOCKEVENTS
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index fd9d6df..cf87f40 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -5,6 +5,7 @@ obj-$(CONFIG_ATMEL_TCB_CLKSRC)	+= tcb_clksrc.o
 obj-$(CONFIG_X86_PM_TIMER)	+= acpi_pm.o
 obj-$(CONFIG_SCx200HR_TIMER)	+= scx200_hrt.o
 obj-$(CONFIG_CS5535_CLOCK_EVENT_SRC)	+= cs5535-clockevt.o
+obj-$(CONFIG_CLKSRC_JCORE_PIT)		+= jcore-pit.o
 obj-$(CONFIG_SH_TIMER_CMT)	+= sh_cmt.o
 obj-$(CONFIG_SH_TIMER_MTU2)	+= sh_mtu2.o
 obj-$(CONFIG_SH_TIMER_TMU)	+= sh_tmu.o
diff --git a/drivers/clocksource/jcore-pit.c b/drivers/clocksource/jcore-pit.c
new file mode 100644
index 0000000..16eb5d9
--- /dev/null
+++ b/drivers/clocksource/jcore-pit.c
@@ -0,0 +1,249 @@
+/*
+ * J-Core SoC PIT/clocksource driver
+ *
+ * Copyright (C) 2015-2016 Smart Energy Instruments, Inc.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/clockchips.h>
+#include <linux/clocksource.h>
+#include <linux/sched_clock.h>
+#include <linux/cpu.h>
+#include <linux/cpuhotplug.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+
+#define PIT_IRQ_SHIFT		12
+#define PIT_PRIO_SHIFT		20
+#define PIT_ENABLE_SHIFT	26
+#define PIT_PRIO_MASK		0xf
+
+#define REG_PITEN		0x00
+#define REG_THROT		0x10
+#define REG_COUNT		0x14
+#define REG_BUSPD		0x18
+#define REG_SECHI		0x20
+#define REG_SECLO		0x24
+#define REG_NSEC		0x28
+
+struct jcore_pit {
+	struct clock_event_device	ced;
+	void __iomem			*base;
+	unsigned long			periodic_delta;
+	u32				enable_val;
+};
+
+static void __iomem *jcore_pit_base;
+static struct jcore_pit __percpu *jcore_pit_percpu;
+
+static notrace u64 jcore_sched_clock_read(void)
+{
+	u32 seclo, nsec, seclo0;
+	__iomem void *base = jcore_pit_base;
+
+	seclo = readl(base + REG_SECLO);
+	do {
+		seclo0 = seclo;
+		nsec  = readl(base + REG_NSEC);
+		seclo = readl(base + REG_SECLO);
+	} while (seclo0 != seclo);
+
+	return seclo * NSEC_PER_SEC + nsec;
+}
+
+static cycle_t jcore_clocksource_read(struct clocksource *cs)
+{
+	return jcore_sched_clock_read();
+}
+
+static int jcore_pit_disable(struct jcore_pit *pit)
+{
+	writel(0, pit->base + REG_PITEN);
+	return 0;
+}
+
+static int jcore_pit_set(unsigned long delta, struct jcore_pit *pit)
+{
+	jcore_pit_disable(pit);
+	writel(delta, pit->base + REG_THROT);
+	writel(pit->enable_val, pit->base + REG_PITEN);
+	return 0;
+}
+
+static int jcore_pit_set_state_shutdown(struct clock_event_device *ced)
+{
+	struct jcore_pit *pit = container_of(ced, struct jcore_pit, ced);
+
+	return jcore_pit_disable(pit);
+}
+
+static int jcore_pit_set_state_oneshot(struct clock_event_device *ced)
+{
+	struct jcore_pit *pit = container_of(ced, struct jcore_pit, ced);
+
+	return jcore_pit_disable(pit);
+}
+
+static int jcore_pit_set_state_periodic(struct clock_event_device *ced)
+{
+	struct jcore_pit *pit = container_of(ced, struct jcore_pit, ced);
+
+	return jcore_pit_set(pit->periodic_delta, pit);
+}
+
+static int jcore_pit_set_next_event(unsigned long delta,
+				    struct clock_event_device *ced)
+{
+	struct jcore_pit *pit = container_of(ced, struct jcore_pit, ced);
+
+	return jcore_pit_set(delta, pit);
+}
+
+static int jcore_pit_local_init(unsigned cpu)
+{
+	struct jcore_pit *pit = this_cpu_ptr(jcore_pit_percpu);
+	unsigned buspd, freq;
+
+	pr_info("Local J-Core PIT init on cpu %u\n", cpu);
+
+	buspd = readl(pit->base + REG_BUSPD);
+	freq = DIV_ROUND_CLOSEST(NSEC_PER_SEC, buspd);
+	pit->periodic_delta = DIV_ROUND_CLOSEST(NSEC_PER_SEC, HZ * buspd);
+
+	clockevents_config_and_register(&pit->ced, freq, 1, ULONG_MAX);
+
+	return 0;
+}
+
+static irqreturn_t jcore_timer_interrupt(int irq, void *dev_id)
+{
+	struct jcore_pit *pit = this_cpu_ptr(dev_id);
+
+	if (clockevent_state_oneshot(&pit->ced))
+		jcore_pit_disable(pit);
+
+	pit->ced.event_handler(&pit->ced);
+
+	return IRQ_HANDLED;
+}
+
+static int __init jcore_pit_init(struct device_node *node)
+{
+	int err;
+	unsigned pit_irq, cpu;
+	unsigned long hwirq;
+	u32 irqprio, enable_val;
+
+	jcore_pit_base = of_iomap(node, 0);
+	if (!jcore_pit_base) {
+		pr_err("Error: Cannot map base address for J-Core PIT\n");
+		return -ENXIO;
+	}
+
+	pit_irq = irq_of_parse_and_map(node, 0);
+	if (!pit_irq) {
+		pr_err("Error: J-Core PIT has no IRQ\n");
+		return -ENXIO;
+	}
+
+	pr_info("Initializing J-Core PIT at %p IRQ %d\n",
+		jcore_pit_base, pit_irq);
+
+	err = clocksource_mmio_init(jcore_pit_base, "jcore_pit_cs",
+				    NSEC_PER_SEC, 400, 32,
+				    jcore_clocksource_read);
+	if (err) {
+		pr_err("Error registering clocksource device: %d\n", err);
+		return err;
+	}
+
+	sched_clock_register(jcore_sched_clock_read, 32, NSEC_PER_SEC);
+
+	jcore_pit_percpu = alloc_percpu(struct jcore_pit);
+	if (!jcore_pit_percpu) {
+		pr_err("Failed to allocate memory for clock event device\n");
+		return -ENOMEM;
+	}
+
+	err = request_irq(pit_irq, jcore_timer_interrupt,
+			  IRQF_TIMER | IRQF_PERCPU,
+			  "jcore_pit", jcore_pit_percpu);
+	if (err) {
+		pr_err("pit irq request failed: %d\n", err);
+		free_percpu(jcore_pit_percpu);
+		return err;
+	}
+
+	/*
+	 * The J-Core PIT is not hard-wired to a particular IRQ, but
+	 * integrated with the interrupt controller such that the IRQ it
+	 * generates is programmable, as follows:
+	 *
+	 * The bit layout of the PIT enable register is:
+	 *
+	 *	.....e..ppppiiiiiiii............
+	 * 
+	 * where the .'s indicate unrelated/unused bits, e is enable,
+	 * p is priority, and i is hard irq number.
+	 *
+	 * For the PIT included in AIC1 (obsolete but still in use),
+	 * any hard irq (trap number) can be programmed via the 8
+	 * iiiiiiii bits, and a priority (0-15) is programmable
+	 * separately in the pppp bits.
+	 *
+	 * For the PIT included in AIC2 (current), the programming
+	 * interface is equivalent modulo interrupt mapping. This is
+	 * why a different compatible tag was not used. However only
+	 * traps 64-127 (the ones actually intended to be used for
+	 * interrupts, rather than syscalls/exceptions/etc.) can be
+	 * programmed (the high 2 bits of i are ignored) and the
+	 * priority pppp is <<2'd and or'd onto the irq number. This
+	 * choice seems to have been made on the hardware engineering
+	 * side under an assumption that preserving old AIC1 priority
+	 * mappings was important. Future models will likely ignore
+	 * the pppp field.
+	 */
+	hwirq = irq_get_irq_data(pit_irq)->hwirq;
+	irqprio = (hwirq >> 2) & PIT_PRIO_MASK;
+	enable_val = (1U << PIT_ENABLE_SHIFT)
+		   | (hwirq << PIT_IRQ_SHIFT)
+		   | (irqprio << PIT_PRIO_SHIFT);
+
+	for_each_present_cpu(cpu) {
+		struct jcore_pit *pit = per_cpu_ptr(jcore_pit_percpu, cpu);
+
+		pit->base = of_iomap(node, cpu);
+		if (!pit->base) {
+			pr_err("Unable to map PIT for cpu %u\n", cpu);
+			continue;
+		}
+
+		pit->ced.name = "jcore_pit";
+		pit->ced.features = CLOCK_EVT_FEAT_PERIODIC
+				  | CLOCK_EVT_FEAT_ONESHOT
+				  | CLOCK_EVT_FEAT_PERCPU;
+		pit->ced.cpumask = cpumask_of(cpu);
+		pit->ced.rating = 400;
+		pit->ced.irq = pit_irq;
+		pit->ced.set_state_shutdown = jcore_pit_set_state_shutdown;
+		pit->ced.set_state_periodic = jcore_pit_set_state_periodic;
+		pit->ced.set_state_oneshot = jcore_pit_set_state_oneshot;
+		pit->ced.set_next_event = jcore_pit_set_next_event;
+
+		pit->enable_val = enable_val;
+	}
+
+	cpuhp_setup_state(CPUHP_AP_JCORE_TIMER_STARTING,
+			  "AP_JCORE_TIMER_STARTING",
+			  jcore_pit_local_init, NULL);
+
+	return 0;
+}
+
+CLOCKSOURCE_OF_DECLARE(jcore_pit, "jcore,pit", jcore_pit_init);
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 34bd805..e2e6c8c 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -52,6 +52,7 @@ enum cpuhp_state {
 	CPUHP_AP_ARM_ARCH_TIMER_STARTING,
 	CPUHP_AP_ARM_GLOBAL_TIMER_STARTING,
 	CPUHP_AP_DUMMY_TIMER_STARTING,
+	CPUHP_AP_JCORE_TIMER_STARTING,
 	CPUHP_AP_EXYNOS4_MCT_TIMER_STARTING,
 	CPUHP_AP_ARM_TWD_STARTING,
 	CPUHP_AP_METAG_TIMER_STARTING,
-- 
2.10.0

[tip:timers/urgent] clocksource: Add J-Core timer/clocksource driver

[tip-bot for Rich Felker]

Commit-ID:  9995f4f184613fb02ee73092b03545520a72b104
Gitweb:     http://git.kernel.org/tip/9995f4f184613fb02ee73092b03545520a72b104
Author:     Rich Felker <dalias@libc.org>
AuthorDate: Thu, 13 Oct 2016 21:51:06 +0000
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Thu, 20 Oct 2016 20:10:17 +0200

clocksource: Add J-Core timer/clocksource driver

At the hardware level, the J-Core PIT is integrated with the interrupt
controller, but it is represented as its own device and has an
independent programming interface. It provides a 12-bit countdown
timer, which is not presently used, and a periodic timer. The interval
length for the latter is programmable via a 32-bit throttle register
whose units are determined by a bus-period register. The periodic
timer is used to implement both periodic and oneshot clock event
modes; in oneshot mode the interrupt handler simply disables the timer
as soon as it fires.

Despite its device tree node representing an interrupt for the PIT,
the actual irq generated is programmable, not hard-wired. The driver
is responsible for programming the PIT to generate the hardware irq
number that the DT assigns to it.

On SMP configurations, J-Core provides cpu-local instances of the PIT;
no broadcast timer is needed. This driver supports the creation of the
necessary per-cpu clock_event_device instances.

A nanosecond-resolution clocksource is provided using the J-Core "RTC"
registers, which give a 64-bit seconds count and 32-bit nanoseconds
that wrap every second. The driver converts these to a full-range
32-bit nanoseconds count.

Signed-off-by: Rich Felker <dalias@libc.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: devicetree@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Rob Herring <robh+dt@kernel.org>
Link: http://lkml.kernel.org/r/b591ff12cc5ebf63d1edc98da26046f95a233814.1476393790.git.dalias@libc.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

---
 drivers/clocksource/Kconfig     |  10 ++
 drivers/clocksource/Makefile    |   1 +
 drivers/clocksource/jcore-pit.c | 249 ++++++++++++++++++++++++++++++++++++++++
 include/linux/cpuhotplug.h      |   1 +
 4 files changed, 261 insertions(+)

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 2451908..e2c6e43 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -417,6 +417,16 @@ config SYS_SUPPORTS_SH_TMU
 config SYS_SUPPORTS_EM_STI
         bool
 
+config CLKSRC_JCORE_PIT
+	bool "J-Core PIT timer driver" if COMPILE_TEST
+	depends on OF
+	depends on GENERIC_CLOCKEVENTS
+	depends on HAS_IOMEM
+	select CLKSRC_MMIO
+	help
+	  This enables build of clocksource and clockevent driver for
+	  the integrated PIT in the J-Core synthesizable, open source SoC.
+
 config SH_TIMER_CMT
 	bool "Renesas CMT timer driver" if COMPILE_TEST
 	depends on GENERIC_CLOCKEVENTS
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index fd9d6df..cf87f40 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -5,6 +5,7 @@ obj-$(CONFIG_ATMEL_TCB_CLKSRC)	+= tcb_clksrc.o
 obj-$(CONFIG_X86_PM_TIMER)	+= acpi_pm.o
 obj-$(CONFIG_SCx200HR_TIMER)	+= scx200_hrt.o
 obj-$(CONFIG_CS5535_CLOCK_EVENT_SRC)	+= cs5535-clockevt.o
+obj-$(CONFIG_CLKSRC_JCORE_PIT)		+= jcore-pit.o
 obj-$(CONFIG_SH_TIMER_CMT)	+= sh_cmt.o
 obj-$(CONFIG_SH_TIMER_MTU2)	+= sh_mtu2.o
 obj-$(CONFIG_SH_TIMER_TMU)	+= sh_tmu.o
diff --git a/drivers/clocksource/jcore-pit.c b/drivers/clocksource/jcore-pit.c
new file mode 100644
index 0000000..54e1665
--- /dev/null
+++ b/drivers/clocksource/jcore-pit.c
@@ -0,0 +1,249 @@
+/*
+ * J-Core SoC PIT/clocksource driver
+ *
+ * Copyright (C) 2015-2016 Smart Energy Instruments, Inc.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/clockchips.h>
+#include <linux/clocksource.h>
+#include <linux/sched_clock.h>
+#include <linux/cpu.h>
+#include <linux/cpuhotplug.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+
+#define PIT_IRQ_SHIFT		12
+#define PIT_PRIO_SHIFT		20
+#define PIT_ENABLE_SHIFT	26
+#define PIT_PRIO_MASK		0xf
+
+#define REG_PITEN		0x00
+#define REG_THROT		0x10
+#define REG_COUNT		0x14
+#define REG_BUSPD		0x18
+#define REG_SECHI		0x20
+#define REG_SECLO		0x24
+#define REG_NSEC		0x28
+
+struct jcore_pit {
+	struct clock_event_device	ced;
+	void __iomem			*base;
+	unsigned long			periodic_delta;
+	u32				enable_val;
+};
+
+static void __iomem *jcore_pit_base;
+static struct jcore_pit __percpu *jcore_pit_percpu;
+
+static notrace u64 jcore_sched_clock_read(void)
+{
+	u32 seclo, nsec, seclo0;
+	__iomem void *base = jcore_pit_base;
+
+	seclo = readl(base + REG_SECLO);
+	do {
+		seclo0 = seclo;
+		nsec  = readl(base + REG_NSEC);
+		seclo = readl(base + REG_SECLO);
+	} while (seclo0 != seclo);
+
+	return seclo * NSEC_PER_SEC + nsec;
+}
+
+static cycle_t jcore_clocksource_read(struct clocksource *cs)
+{
+	return jcore_sched_clock_read();
+}
+
+static int jcore_pit_disable(struct jcore_pit *pit)
+{
+	writel(0, pit->base + REG_PITEN);
+	return 0;
+}
+
+static int jcore_pit_set(unsigned long delta, struct jcore_pit *pit)
+{
+	jcore_pit_disable(pit);
+	writel(delta, pit->base + REG_THROT);
+	writel(pit->enable_val, pit->base + REG_PITEN);
+	return 0;
+}
+
+static int jcore_pit_set_state_shutdown(struct clock_event_device *ced)
+{
+	struct jcore_pit *pit = container_of(ced, struct jcore_pit, ced);
+
+	return jcore_pit_disable(pit);
+}
+
+static int jcore_pit_set_state_oneshot(struct clock_event_device *ced)
+{
+	struct jcore_pit *pit = container_of(ced, struct jcore_pit, ced);
+
+	return jcore_pit_disable(pit);
+}
+
+static int jcore_pit_set_state_periodic(struct clock_event_device *ced)
+{
+	struct jcore_pit *pit = container_of(ced, struct jcore_pit, ced);
+
+	return jcore_pit_set(pit->periodic_delta, pit);
+}
+
+static int jcore_pit_set_next_event(unsigned long delta,
+				    struct clock_event_device *ced)
+{
+	struct jcore_pit *pit = container_of(ced, struct jcore_pit, ced);
+
+	return jcore_pit_set(delta, pit);
+}
+
+static int jcore_pit_local_init(unsigned cpu)
+{
+	struct jcore_pit *pit = this_cpu_ptr(jcore_pit_percpu);
+	unsigned buspd, freq;
+
+	pr_info("Local J-Core PIT init on cpu %u\n", cpu);
+
+	buspd = readl(pit->base + REG_BUSPD);
+	freq = DIV_ROUND_CLOSEST(NSEC_PER_SEC, buspd);
+	pit->periodic_delta = DIV_ROUND_CLOSEST(NSEC_PER_SEC, HZ * buspd);
+
+	clockevents_config_and_register(&pit->ced, freq, 1, ULONG_MAX);
+
+	return 0;
+}
+
+static irqreturn_t jcore_timer_interrupt(int irq, void *dev_id)
+{
+	struct jcore_pit *pit = this_cpu_ptr(dev_id);
+
+	if (clockevent_state_oneshot(&pit->ced))
+		jcore_pit_disable(pit);
+
+	pit->ced.event_handler(&pit->ced);
+
+	return IRQ_HANDLED;
+}
+
+static int __init jcore_pit_init(struct device_node *node)
+{
+	int err;
+	unsigned pit_irq, cpu;
+	unsigned long hwirq;
+	u32 irqprio, enable_val;
+
+	jcore_pit_base = of_iomap(node, 0);
+	if (!jcore_pit_base) {
+		pr_err("Error: Cannot map base address for J-Core PIT\n");
+		return -ENXIO;
+	}
+
+	pit_irq = irq_of_parse_and_map(node, 0);
+	if (!pit_irq) {
+		pr_err("Error: J-Core PIT has no IRQ\n");
+		return -ENXIO;
+	}
+
+	pr_info("Initializing J-Core PIT at %p IRQ %d\n",
+		jcore_pit_base, pit_irq);
+
+	err = clocksource_mmio_init(jcore_pit_base, "jcore_pit_cs",
+				    NSEC_PER_SEC, 400, 32,
+				    jcore_clocksource_read);
+	if (err) {
+		pr_err("Error registering clocksource device: %d\n", err);
+		return err;
+	}
+
+	sched_clock_register(jcore_sched_clock_read, 32, NSEC_PER_SEC);
+
+	jcore_pit_percpu = alloc_percpu(struct jcore_pit);
+	if (!jcore_pit_percpu) {
+		pr_err("Failed to allocate memory for clock event device\n");
+		return -ENOMEM;
+	}
+
+	err = request_irq(pit_irq, jcore_timer_interrupt,
+			  IRQF_TIMER | IRQF_PERCPU,
+			  "jcore_pit", jcore_pit_percpu);
+	if (err) {
+		pr_err("pit irq request failed: %d\n", err);
+		free_percpu(jcore_pit_percpu);
+		return err;
+	}
+
+	/*
+	 * The J-Core PIT is not hard-wired to a particular IRQ, but
+	 * integrated with the interrupt controller such that the IRQ it
+	 * generates is programmable, as follows:
+	 *
+	 * The bit layout of the PIT enable register is:
+	 *
+	 *	.....e..ppppiiiiiiii............
+	 *
+	 * where the .'s indicate unrelated/unused bits, e is enable,
+	 * p is priority, and i is hard irq number.
+	 *
+	 * For the PIT included in AIC1 (obsolete but still in use),
+	 * any hard irq (trap number) can be programmed via the 8
+	 * iiiiiiii bits, and a priority (0-15) is programmable
+	 * separately in the pppp bits.
+	 *
+	 * For the PIT included in AIC2 (current), the programming
+	 * interface is equivalent modulo interrupt mapping. This is
+	 * why a different compatible tag was not used. However only
+	 * traps 64-127 (the ones actually intended to be used for
+	 * interrupts, rather than syscalls/exceptions/etc.) can be
+	 * programmed (the high 2 bits of i are ignored) and the
+	 * priority pppp is <<2'd and or'd onto the irq number. This
+	 * choice seems to have been made on the hardware engineering
+	 * side under an assumption that preserving old AIC1 priority
+	 * mappings was important. Future models will likely ignore
+	 * the pppp field.
+	 */
+	hwirq = irq_get_irq_data(pit_irq)->hwirq;
+	irqprio = (hwirq >> 2) & PIT_PRIO_MASK;
+	enable_val = (1U << PIT_ENABLE_SHIFT)
+		   | (hwirq << PIT_IRQ_SHIFT)
+		   | (irqprio << PIT_PRIO_SHIFT);
+
+	for_each_present_cpu(cpu) {
+		struct jcore_pit *pit = per_cpu_ptr(jcore_pit_percpu, cpu);
+
+		pit->base = of_iomap(node, cpu);
+		if (!pit->base) {
+			pr_err("Unable to map PIT for cpu %u\n", cpu);
+			continue;
+		}
+
+		pit->ced.name = "jcore_pit";
+		pit->ced.features = CLOCK_EVT_FEAT_PERIODIC
+				  | CLOCK_EVT_FEAT_ONESHOT
+				  | CLOCK_EVT_FEAT_PERCPU;
+		pit->ced.cpumask = cpumask_of(cpu);
+		pit->ced.rating = 400;
+		pit->ced.irq = pit_irq;
+		pit->ced.set_state_shutdown = jcore_pit_set_state_shutdown;
+		pit->ced.set_state_periodic = jcore_pit_set_state_periodic;
+		pit->ced.set_state_oneshot = jcore_pit_set_state_oneshot;
+		pit->ced.set_next_event = jcore_pit_set_next_event;
+
+		pit->enable_val = enable_val;
+	}
+
+	cpuhp_setup_state(CPUHP_AP_JCORE_TIMER_STARTING,
+			  "AP_JCORE_TIMER_STARTING",
+			  jcore_pit_local_init, NULL);
+
+	return 0;
+}
+
+CLOCKSOURCE_OF_DECLARE(jcore_pit, "jcore,pit", jcore_pit_init);
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 9b207a8..afe641c 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -81,6 +81,7 @@ enum cpuhp_state {
 	CPUHP_AP_ARM_ARCH_TIMER_STARTING,
 	CPUHP_AP_ARM_GLOBAL_TIMER_STARTING,
 	CPUHP_AP_DUMMY_TIMER_STARTING,
+	CPUHP_AP_JCORE_TIMER_STARTING,
 	CPUHP_AP_EXYNOS4_MCT_TIMER_STARTING,
 	CPUHP_AP_ARM_TWD_STARTING,
 	CPUHP_AP_METAG_TIMER_STARTING,

Re: [PATCH v9 0/2] J-Core timer support

[Daniel Lezcano]

On Thu, Oct 13, 2016 at 09:51:06PM +0000, Rich Felker wrote:
> This version of the patch makes the changes requested by Daniel
> Lezcano in review of v8.
> 
> Rich Felker (2):
>   of: add J-Core timer bindings
>   clocksource: add J-Core timer/clocksource driver
> 
>  .../devicetree/bindings/timer/jcore,pit.txt        |  24 ++
>  drivers/clocksource/Kconfig                        |  10 +
>  drivers/clocksource/Makefile                       |   1 +
>  drivers/clocksource/jcore-pit.c                    | 249 +++++++++++++++++++++
>  include/linux/cpuhotplug.h                         |   1 +
>  5 files changed, 285 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/timer/jcore,pit.txt
>  create mode 100644 drivers/clocksource/jcore-pit.c

Hi Rich,

I applied your patches on my tree.

Thanks !

  -- Daniel

Re: [PATCH v9 0/2] J-Core timer support

[Rich Felker]

On Mon, Oct 17, 2016 at 11:30:13AM +0200, Daniel Lezcano wrote:
> On Thu, Oct 13, 2016 at 09:51:06PM +0000, Rich Felker wrote:
> > This version of the patch makes the changes requested by Daniel
> > Lezcano in review of v8.
> > 
> > Rich Felker (2):
> >   of: add J-Core timer bindings
> >   clocksource: add J-Core timer/clocksource driver
> > 
> >  .../devicetree/bindings/timer/jcore,pit.txt        |  24 ++
> >  drivers/clocksource/Kconfig                        |  10 +
> >  drivers/clocksource/Makefile                       |   1 +
> >  drivers/clocksource/jcore-pit.c                    | 249 +++++++++++++++++++++
> >  include/linux/cpuhotplug.h                         |   1 +
> >  5 files changed, 285 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/timer/jcore,pit.txt
> >  create mode 100644 drivers/clocksource/jcore-pit.c
> 
> Hi Rich,
> 
> I applied your patches on my tree.
> 
> Thanks !

Thanks! Which is your current tree? I was looking and couldn't find
it. This is the one thing (and it's a boot blocker) keeping Linux on
J2 from working out of the box and I'd really love to see it go in
4.9.

Rich

Re: [PATCH v9 0/2] J-Core timer support

[Daniel Lezcano]

On Wed, Oct 19, 2016 at 09:22:25PM -0400, Rich Felker wrote:
> On Mon, Oct 17, 2016 at 11:30:13AM +0200, Daniel Lezcano wrote:
> > On Thu, Oct 13, 2016 at 09:51:06PM +0000, Rich Felker wrote:
> > > This version of the patch makes the changes requested by Daniel
> > > Lezcano in review of v8.
> > > 
> > > Rich Felker (2):
> > >   of: add J-Core timer bindings
> > >   clocksource: add J-Core timer/clocksource driver
> > > 
> > >  .../devicetree/bindings/timer/jcore,pit.txt        |  24 ++
> > >  drivers/clocksource/Kconfig                        |  10 +
> > >  drivers/clocksource/Makefile                       |   1 +
> > >  drivers/clocksource/jcore-pit.c                    | 249 +++++++++++++++++++++
> > >  include/linux/cpuhotplug.h                         |   1 +
> > >  5 files changed, 285 insertions(+)
> > >  create mode 100644 Documentation/devicetree/bindings/timer/jcore,pit.txt
> > >  create mode 100644 drivers/clocksource/jcore-pit.c
> > 
> > Hi Rich,
> > 
> > I applied your patches on my tree.
> > 
> > Thanks !
> 
> Thanks! Which is your current tree? 

http://git.linaro.org/people/daniel.lezcano/linux.git clockevents/4.10

> I was looking and couldn't find
> it. This is the one thing (and it's a boot blocker) keeping Linux on
> J2 from working out of the box and I'd really love to see it go in
> 4.9.

Unfortunately it won't happen. v4.9-rc1 is already out. The driver will be
in v4.10.

If you wanted patches merged for v4.9, they should have been merged in the
downstream tree before v4.8-rc5, so they hit the upstream tree for v4.9's merge
window.

  -- Daniel

Re: [PATCH v9 0/2] J-Core timer support

[Rich Felker]

On Thu, Oct 20, 2016 at 09:32:40AM +0200, Daniel Lezcano wrote:
> On Wed, Oct 19, 2016 at 09:22:25PM -0400, Rich Felker wrote:
> > On Mon, Oct 17, 2016 at 11:30:13AM +0200, Daniel Lezcano wrote:
> > > On Thu, Oct 13, 2016 at 09:51:06PM +0000, Rich Felker wrote:
> > > > This version of the patch makes the changes requested by Daniel
> > > > Lezcano in review of v8.
> > > > 
> > > > Rich Felker (2):
> > > >   of: add J-Core timer bindings
> > > >   clocksource: add J-Core timer/clocksource driver
> > > > 
> > > >  .../devicetree/bindings/timer/jcore,pit.txt        |  24 ++
> > > >  drivers/clocksource/Kconfig                        |  10 +
> > > >  drivers/clocksource/Makefile                       |   1 +
> > > >  drivers/clocksource/jcore-pit.c                    | 249 +++++++++++++++++++++
> > > >  include/linux/cpuhotplug.h                         |   1 +
> > > >  5 files changed, 285 insertions(+)
> > > >  create mode 100644 Documentation/devicetree/bindings/timer/jcore,pit.txt
> > > >  create mode 100644 drivers/clocksource/jcore-pit.c
> > > 
> > > Hi Rich,
> > > 
> > > I applied your patches on my tree.
> > > 
> > > Thanks !
> > 
> > Thanks! Which is your current tree? 
> 
> http://git.linaro.org/people/daniel.lezcano/linux.git clockevents/4.10
> 
> > I was looking and couldn't find
> > it. This is the one thing (and it's a boot blocker) keeping Linux on
> > J2 from working out of the box and I'd really love to see it go in
> > 4.9.
> 
> Unfortunately it won't happen. v4.9-rc1 is already out. The driver will be
> in v4.10.
> 
> If you wanted patches merged for v4.9, they should have been merged in the
> downstream tree before v4.8-rc5, so they hit the upstream tree for v4.9's merge
> window.

I've been trying to get what's essentially the same patch merged since
before the 4.8 merge window. I would be more understanding if this
were something new that's not upstream, but broken support for the
hardware (that, from a user perspective, is a bug, since they can
select the target but then it doesn't boot) has already been in one
release due to missing core drivers, and the irq patches have already
been merged in this release (post-rc1 even).

Rich

Re: [PATCH v9 0/2] J-Core timer support

[Thomas Gleixner]

Daniel,

On Thu, 20 Oct 2016, Rich Felker wrote:
> On Thu, Oct 20, 2016 at 09:32:40AM +0200, Daniel Lezcano wrote:
> > Unfortunately it won't happen. v4.9-rc1 is already out. The driver will be
> > in v4.10.
> > 
> > If you wanted patches merged for v4.9, they should have been merged in the
> > downstream tree before v4.8-rc5, so they hit the upstream tree for v4.9's merge
> > window.
> 
> I've been trying to get what's essentially the same patch merged since
> before the 4.8 merge window. I would be more understanding if this
> were something new that's not upstream, but broken support for the
> hardware (that, from a user perspective, is a bug, since they can
> select the target but then it doesn't boot) has already been in one
> release due to missing core drivers, and the irq patches have already
> been merged in this release (post-rc1 even).

It's hardware enablement and not a new feature, so it's fine to merge it
now. I'll pick it up later tonight.

Thanks,

	tglx

Re: [PATCH v9 0/2] J-Core timer support

[Thomas Gleixner]

On Thu, 20 Oct 2016, Thomas Gleixner wrote:
> Daniel,
> 
> On Thu, 20 Oct 2016, Rich Felker wrote:
> > On Thu, Oct 20, 2016 at 09:32:40AM +0200, Daniel Lezcano wrote:
> > > Unfortunately it won't happen. v4.9-rc1 is already out. The driver will be
> > > in v4.10.
> > > 
> > > If you wanted patches merged for v4.9, they should have been merged in the
> > > downstream tree before v4.8-rc5, so they hit the upstream tree for v4.9's merge
> > > window.
> > 
> > I've been trying to get what's essentially the same patch merged since
> > before the 4.8 merge window. I would be more understanding if this
> > were something new that's not upstream, but broken support for the
> > hardware (that, from a user perspective, is a bug, since they can
> > select the target but then it doesn't boot) has already been in one
> > release due to missing core drivers, and the irq patches have already
> > been merged in this release (post-rc1 even).
> 
> It's hardware enablement and not a new feature, so it's fine to merge it
> now. I'll pick it up later tonight.

Daniel, it's the top two commits in your 4.10 branch. So it's not a big
deal to zap them.

Thanks,

	tglx

Re: [PATCH v9 0/2] J-Core timer support

[Rich Felker]

On Thu, Oct 20, 2016 at 07:56:09PM +0200, Thomas Gleixner wrote:
> Daniel,
> 
> On Thu, 20 Oct 2016, Rich Felker wrote:
> > On Thu, Oct 20, 2016 at 09:32:40AM +0200, Daniel Lezcano wrote:
> > > Unfortunately it won't happen. v4.9-rc1 is already out. The driver will be
> > > in v4.10.
> > > 
> > > If you wanted patches merged for v4.9, they should have been merged in the
> > > downstream tree before v4.8-rc5, so they hit the upstream tree for v4.9's merge
> > > window.
> > 
> > I've been trying to get what's essentially the same patch merged since
> > before the 4.8 merge window. I would be more understanding if this
> > were something new that's not upstream, but broken support for the
> > hardware (that, from a user perspective, is a bug, since they can
> > select the target but then it doesn't boot) has already been in one
> > release due to missing core drivers, and the irq patches have already
> > been merged in this release (post-rc1 even).
> 
> It's hardware enablement and not a new feature, so it's fine to merge it
> now. I'll pick it up later tonight.

Thanks Thomas. Daniel, sorry if my above reply was harsh and thanks
again for all your help reviewing and getting this upstream.

Rich