[PATCH v7 0/3] clocksource/drivers/atcpit100: Add andestech atcpit100 timer

[PATCH v7 0/3] clocksource/drivers/atcpit100: Add andestech atcpit100 timer

[Greentime Hu]

Hi, all:

ATCPIT100 is often used on the Andes architecture,
This timer provide 4 PIT channels. Each PIT channel is a
multi-function timer, can be configured as 32,16,8 bit timers
or PWM as well.

For system timer it will set channel 1 32-bit timer0 as clock
source and count downwards until underflow and restart again.

It also set channel 0 32-bit timer0 as clock event and count
downwards until condition match. It will generate an interrupt
for handling periodically.

Changes in v7:
 - Fix atcpit100_clkevt_next_event(), before set reload register,
   clock source timer shall disable. And re-enable it after the setting.
   Without this modification, the test case 'clock_nanosleep02' of ltp_20170929
   will fail.

Changes in v6:
 - To select TIMER_OF in drivers/clocksource/Kconfig instead of arch/nds32/Kconfig
 - Refine Kconfig
 - Update license format to SPDX-License-Identifier


Rick Chen (3):
  clocksource/drivers/atcpit100: Add andestech atcpit100 timer
  clocksource/drivers/atcpit100: VDSO support
  dt-bindings: timer: Add andestech atcpit100 timer binding doc

 .../bindings/timer/andestech,atcpit100-timer.txt   |  33 +++
 drivers/clocksource/Kconfig                        |   9 +
 drivers/clocksource/Makefile                       |   1 +
 drivers/clocksource/timer-atcpit100.c              | 266 +++++++++++++++++++++
 4 files changed, 309 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/timer/andestech,atcpit100-timer.txt
 create mode 100644 drivers/clocksource/timer-atcpit100.c

-- 
2.16.1

[PATCH v7 1/3] clocksource/drivers/atcpit100: Add andestech atcpit100 timer

[Greentime Hu]

From: Rick Chen <rickchen36@gmail.com>

ATCPIT100 is often used on the Andes architecture,
This timer provide 4 PIT channels. Each PIT channel is a
multi-function timer, can be configured as 32,16,8 bit timers
or PWM as well.

For system timer it will set channel 1 32-bit timer0 as clock
source and count downwards until underflow and restart again.

It also set channel 0 32-bit timer0 as clock event and count
downwards until condition match. It will generate an interrupt
for handling periodically.

Signed-off-by: Rick Chen <rickchen36@gmail.com>
Signed-off-by: Greentime Hu <green.hu@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Add andestech atcpit100 timer
---
 drivers/clocksource/Kconfig           |   9 ++
 drivers/clocksource/Makefile          |   1 +
 drivers/clocksource/timer-atcpit100.c | 248 ++++++++++++++++++++++++++++++++++
 3 files changed, 258 insertions(+)
 create mode 100644 drivers/clocksource/timer-atcpit100.c

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index b3b4ed9b6874..19d65fe0627e 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -591,4 +591,13 @@ config CLKSRC_ST_LPC
 	  Enable this option to use the Low Power controller timer
 	  as clocksource.
 
+config ATCPIT100_TIMER
+	bool "ATCPIT100 timer driver"
+	depends on NDS32 || COMPILE_TEST
+	depends on HAS_IOMEM
+	select TIMER_OF
+	default NDS32
+	help
+	  This option enables support for the Andestech ATCPIT100 timers.
+
 endmenu
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index d6dec4489d66..a79523b22e52 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -76,3 +76,4 @@ obj-$(CONFIG_H8300_TMR16)		+= h8300_timer16.o
 obj-$(CONFIG_H8300_TPU)			+= h8300_tpu.o
 obj-$(CONFIG_CLKSRC_ST_LPC)		+= clksrc_st_lpc.o
 obj-$(CONFIG_X86_NUMACHIP)		+= numachip.o
+obj-$(CONFIG_ATCPIT100_TIMER)		+= timer-atcpit100.o
diff --git a/drivers/clocksource/timer-atcpit100.c b/drivers/clocksource/timer-atcpit100.c
new file mode 100644
index 000000000000..2190096cffa3
--- /dev/null
+++ b/drivers/clocksource/timer-atcpit100.c
@@ -0,0 +1,248 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2005-2017 Andes Technology Corporation
+/*
+ *  Andestech ATCPIT100 Timer Device Driver Implementation
+ * Rick Chen, Andes Technology Corporation <rick@andestech.com>
+ *
+ */
+
+#include <linux/irq.h>
+#include <linux/clocksource.h>
+#include <linux/clockchips.h>
+#include <linux/interrupt.h>
+#include <linux/ioport.h>
+#include <linux/cpufreq.h>
+#include <linux/sched.h>
+#include <linux/sched_clock.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+#include "timer-of.h"
+
+/*
+ * Definition of register offsets
+ */
+
+/* ID and Revision Register */
+#define ID_REV		0x0
+
+/* Configuration Register */
+#define CFG		0x10
+
+/* Interrupt Enable Register */
+#define INT_EN		0x14
+#define CH_INT_EN(c, i)	((1<<i)<<(4*c))
+#define CH0INT0EN	0x01
+
+/* Interrupt Status Register */
+#define INT_STA		0x18
+#define CH0INT0		0x01
+
+/* Channel Enable Register */
+#define CH_EN		0x1C
+#define CH0TMR0EN	0x1
+#define CH1TMR0EN	0x10
+
+/* Channel 0 , 1 Control Register */
+#define CH0_CTL		(0x20)
+#define CH1_CTL		(0x20 + 0x10)
+
+/* Channel clock source , bit 3 , 0:External clock , 1:APB clock */
+#define APB_CLK		BIT(3)
+
+/* Channel mode , bit 0~2 */
+#define TMR_32		0x1
+#define TMR_16		0x2
+#define TMR_8		0x3
+
+/* Channel 0 , 1 Reload Register */
+#define CH0_REL		(0x24)
+#define CH1_REL		(0x24 + 0x10)
+
+/* Channel 0 , 1 Counter Register */
+#define CH0_CNT		(0x28)
+#define CH1_CNT		(0x28 + 0x10)
+
+#define TIMER_SYNC_TICKS	3
+
+static void atcpit100_ch1_tmr0_en(void __iomem *base)
+{
+	writel(~0, base + CH1_REL);
+	writel(APB_CLK|TMR_32, base + CH1_CTL);
+}
+
+static void atcpit100_ch0_tmr0_en(void __iomem *base)
+{
+	writel(APB_CLK|TMR_32, base + CH0_CTL);
+}
+
+static void atcpit100_clkevt_time_setup(void __iomem *base, unsigned long delay)
+{
+	writel(delay, base + CH0_CNT);
+	writel(delay, base + CH0_REL);
+}
+
+static void atcpit100_timer_clear_interrupt(void __iomem *base)
+{
+	u32 val;
+
+	val = readl(base + INT_STA);
+	writel(val | CH0INT0, base + INT_STA);
+}
+
+static void atcpit100_clocksource_start(void __iomem *base)
+{
+	u32 val;
+
+	val = readl(base + CH_EN);
+	writel(val | CH1TMR0EN, base + CH_EN);
+}
+
+static void atcpit100_clkevt_time_start(void __iomem *base)
+{
+	u32 val;
+
+	val = readl(base + CH_EN);
+	writel(val | CH0TMR0EN, base + CH_EN);
+}
+
+static void atcpit100_clkevt_time_stop(void __iomem *base)
+{
+	u32 val;
+
+	atcpit100_timer_clear_interrupt(base);
+	val = readl(base + CH_EN);
+	writel(val & ~CH0TMR0EN, base + CH_EN);
+}
+
+static int atcpit100_clkevt_next_event(unsigned long evt,
+	struct clock_event_device *clkevt)
+{
+	u32 val;
+	struct timer_of *to = to_timer_of(clkevt);
+
+	val = readl(timer_of_base(to) + CH_EN);
+	writel(val & ~CH0TMR0EN, timer_of_base(to) + CH_EN);
+	writel(evt, timer_of_base(to) + CH0_REL);
+	writel(val | CH0TMR0EN, timer_of_base(to) + CH_EN);
+
+	return 0;
+}
+
+static int atcpit100_clkevt_set_periodic(struct clock_event_device *evt)
+{
+	struct timer_of *to = to_timer_of(evt);
+
+	atcpit100_clkevt_time_setup(timer_of_base(to), timer_of_period(to));
+	atcpit100_clkevt_time_start(timer_of_base(to));
+
+	return 0;
+}
+static int atcpit100_clkevt_shutdown(struct clock_event_device *evt)
+{
+	struct timer_of *to = to_timer_of(evt);
+
+	atcpit100_clkevt_time_stop(timer_of_base(to));
+
+	return 0;
+}
+static int atcpit100_clkevt_set_oneshot(struct clock_event_device *evt)
+{
+	struct timer_of *to = to_timer_of(evt);
+	u32 val;
+
+	writel(~0x0, timer_of_base(to) + CH0_REL);
+	val = readl(timer_of_base(to) + CH_EN);
+	writel(val | CH0TMR0EN, timer_of_base(to) + CH_EN);
+
+	return 0;
+}
+
+static irqreturn_t atcpit100_timer_interrupt(int irq, void *dev_id)
+{
+	struct clock_event_device *evt = (struct clock_event_device *)dev_id;
+	struct timer_of *to = to_timer_of(evt);
+
+	atcpit100_timer_clear_interrupt(timer_of_base(to));
+
+	evt->event_handler(evt);
+
+	return IRQ_HANDLED;
+}
+
+static struct timer_of to = {
+	.flags = TIMER_OF_IRQ | TIMER_OF_CLOCK | TIMER_OF_BASE,
+
+	.clkevt = {
+		.name = "atcpit100_tick",
+		.rating = 300,
+		.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
+		.set_state_shutdown = atcpit100_clkevt_shutdown,
+		.set_state_periodic = atcpit100_clkevt_set_periodic,
+		.set_state_oneshot = atcpit100_clkevt_set_oneshot,
+		.tick_resume = atcpit100_clkevt_shutdown,
+		.set_next_event = atcpit100_clkevt_next_event,
+		.cpumask = cpu_all_mask,
+	},
+
+	.of_irq = {
+		.handler = atcpit100_timer_interrupt,
+		.flags = IRQF_TIMER | IRQF_IRQPOLL,
+	},
+
+	/*
+	 * FIXME: we currently only support clocking using PCLK
+	 * and using EXTCLK is not supported in the driver.
+	 */
+	.of_clk = {
+		.name = "PCLK",
+	}
+};
+
+static u64 notrace atcpit100_timer_sched_read(void)
+{
+	return ~readl(timer_of_base(&to) + CH1_CNT);
+}
+
+static int __init atcpit100_timer_init(struct device_node *node)
+{
+	int ret;
+	u32 val;
+	void __iomem *base;
+
+	ret = timer_of_init(node, &to);
+	if (ret)
+		return ret;
+
+	base = timer_of_base(&to);
+
+	sched_clock_register(atcpit100_timer_sched_read, 32,
+		timer_of_rate(&to));
+
+	ret = clocksource_mmio_init(base + CH1_CNT,
+		node->name, timer_of_rate(&to), 300, 32,
+		clocksource_mmio_readl_down);
+
+	if (ret) {
+		pr_err("Failed to register clocksource\n");
+		return ret;
+	}
+
+	/* clear channel 0 timer0 interrupt */
+	atcpit100_timer_clear_interrupt(base);
+
+	clockevents_config_and_register(&to.clkevt, timer_of_rate(&to),
+					TIMER_SYNC_TICKS, 0xffffffff);
+	atcpit100_ch0_tmr0_en(base);
+	atcpit100_ch1_tmr0_en(base);
+	atcpit100_clocksource_start(base);
+	atcpit100_clkevt_time_start(base);
+
+	/* Enable channel 0 timer0 interrupt */
+	val = readl(base + INT_EN);
+	writel(val | CH0INT0EN, base + INT_EN);
+
+	return ret;
+}
+
+TIMER_OF_DECLARE(atcpit100, "andestech,atcpit100", atcpit100_timer_init);
-- 
2.16.1

[PATCH v7 2/3] clocksource/drivers/atcpit100: VDSO support

[Greentime Hu]

From: Rick Chen <rickchen36@gmail.com>

VDSO needs real-time cycle count to ensure the time accuracy.
Unlike others, nds32 architecture does not define clock source,
hence VDSO needs atcpit100 offering real-time cycle count
to derive the correct time.

Signed-off-by: Vincent Chen <vincentc@andestech.com>
Signed-off-by: Rick Chen <rickchen36@gmail.com>
Signed-off-by: Greentime Hu <green.hu@gmail.com>
---
 drivers/clocksource/timer-atcpit100.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/clocksource/timer-atcpit100.c b/drivers/clocksource/timer-atcpit100.c
index 2190096cffa3..5e23d7b4a722 100644
--- a/drivers/clocksource/timer-atcpit100.c
+++ b/drivers/clocksource/timer-atcpit100.c
@@ -18,6 +18,9 @@
 #include <linux/of_irq.h>
 #include <linux/of_platform.h>
 #include "timer-of.h"
+#ifdef CONFIG_NDS32
+#include <asm/vdso_timer_info.h>
+#endif
 
 /*
  * Definition of register offsets
@@ -204,6 +207,17 @@ static u64 notrace atcpit100_timer_sched_read(void)
 	return ~readl(timer_of_base(&to) + CH1_CNT);
 }
 
+#ifdef CONFIG_NDS32
+static void fill_vdso_need_info(struct device_node *node)
+{
+	struct resource timer_res;
+	of_address_to_resource(node, 0, &timer_res);
+	timer_info.mapping_base = (unsigned long)timer_res.start;
+	timer_info.cycle_count_down = true;
+	timer_info.cycle_count_reg_offset = CH1_CNT;
+}
+#endif
+
 static int __init atcpit100_timer_init(struct device_node *node)
 {
 	int ret;
@@ -242,6 +256,10 @@ static int __init atcpit100_timer_init(struct device_node *node)
 	val = readl(base + INT_EN);
 	writel(val | CH0INT0EN, base + INT_EN);
 
+#ifdef CONFIG_NDS32
+	fill_vdso_need_info(node);
+#endif
+
 	return ret;
 }
 
-- 
2.16.1

[PATCH v7 3/3] dt-bindings: timer: Add andestech atcpit100 timer binding doc

[Greentime Hu]

From: Rick Chen <rickchen36@gmail.com>

Add a document to describe Andestech atcpit100 timer and
binding information.

Signed-off-by: Rick Chen <rickchen36@gmail.com>
Signed-off-by: Greentime Hu <green.hu@gmail.com>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
---
 .../bindings/timer/andestech,atcpit100-timer.txt   | 33 ++++++++++++++++++++++
 1 file changed, 33 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/timer/andestech,atcpit100-timer.txt

diff --git a/Documentation/devicetree/bindings/timer/andestech,atcpit100-timer.txt b/Documentation/devicetree/bindings/timer/andestech,atcpit100-timer.txt
new file mode 100644
index 000000000000..4c9ea5989e35
--- /dev/null
+++ b/Documentation/devicetree/bindings/timer/andestech,atcpit100-timer.txt
@@ -0,0 +1,33 @@
+Andestech ATCPIT100 timer
+------------------------------------------------------------------
+ATCPIT100 is a generic IP block from Andes Technology, embedded in
+Andestech AE3XX platforms and other designs.
+
+This timer is a set of compact multi-function timers, which can be
+used as pulse width modulators (PWM) as well as simple timers.
+
+It supports up to 4 PIT channels. Each PIT channel is a
+multi-function timer and provide the following usage scenarios:
+One 32-bit timer
+Two 16-bit timers
+Four 8-bit timers
+One 16-bit PWM
+One 16-bit timer and one 8-bit PWM
+Two 8-bit timer and one 8-bit PWM
+
+Required properties:
+- compatible	: Should be "andestech,atcpit100"
+- reg		: Address and length of the register set
+- interrupts	: Reference to the timer interrupt
+- clocks 	: a clock to provide the tick rate for "andestech,atcpit100"
+- clock-names 	: should be "PCLK" for the peripheral clock source.
+
+Examples:
+
+timer0: timer@f0400000 {
+	compatible = "andestech,atcpit100";
+	reg = <0xf0400000 0x1000>;
+	interrupts = <2>;
+	clocks = <&apb>;
+	clock-names = "PCLK";
+};
-- 
2.16.1