Thread (16 messages) 16 messages, 3 authors, 2014-10-19
STALE4268d
Revisions (6)
  1. v3 [diff vs current]
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  3. v5 current
  4. v6 [diff vs current]
  5. v7 [diff vs current]
  6. v8 [diff vs current]

[PATCH v5 06/10] ARM: clocksource: add asm9260_timer driver

From: Oleksij Rempel <hidden>
Date: 2014-10-14 08:03:34
Subsystem: arm/alphascale architecture, clocksource, clockevent drivers, the rest · Maintainers: Krzysztof Kozlowski, Daniel Lezcano, Thomas Gleixner, Linus Torvalds

In some cases asm9260 looks similar to iMX2x. One of exceptions is
timer controller. So this patch introduces new driver for this special case.

Signed-off-by: Oleksij Rempel <redacted>
---
 drivers/clocksource/Kconfig         |   4 +
 drivers/clocksource/Makefile        |   1 +
 drivers/clocksource/asm9260_timer.c | 234 ++++++++++++++++++++++++++++++++++++
 3 files changed, 239 insertions(+)
 create mode 100644 drivers/clocksource/asm9260_timer.c
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index cfd6519..6a03d34 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -216,4 +216,8 @@ config CLKSRC_VERSATILE
 	  ARM Versatile, RealView and Versatile Express reference
 	  platforms.
 
+config ASM9260_TIMER
+	select CLKSRC_MMIO
+	bool
+
 endmenu
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index 7fd9fd1..fc93854 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -44,3 +44,4 @@ obj-$(CONFIG_CLKSRC_METAG_GENERIC)	+= metag_generic.o
 obj-$(CONFIG_ARCH_HAS_TICK_BROADCAST)	+= dummy_timer.o
 obj-$(CONFIG_ARCH_KEYSTONE)		+= timer-keystone.o
 obj-$(CONFIG_CLKSRC_VERSATILE)		+= versatile.o
+obj-$(CONFIG_ASM9260_TIMER)		+= asm9260_timer.o
diff --git a/drivers/clocksource/asm9260_timer.c b/drivers/clocksource/asm9260_timer.c
new file mode 100644
index 0000000..1b16e00
--- /dev/null
+++ b/drivers/clocksource/asm9260_timer.c
@@ -0,0 +1,234 @@
+/*
+ * Copyright (C) 2014 Oleksij Rempel <linux@rempel-privat.de>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/sched.h>
+#include <linux/clk.h>
+#include <linux/clocksource.h>
+#include <linux/clockchips.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/bitops.h>
+
+
+/*
+ * this device provide 4 offsets for each register:
+ * 0x0 - plain read write mode
+ * 0x4 - set mode, OR logic.
+ * 0x8 - clr mode, XOR logic.
+ * 0xc - togle mode.
+ */
+#define SET_REG 4
+#define CLR_REG 8
+
+#define HW_IR           0x0000 /* RW. Interrupt */
+#define BM_IR_CR0	BIT(4)
+#define BM_IR_MR3	BIT(3)
+#define BM_IR_MR2	BIT(2)
+#define BM_IR_MR1	BIT(1)
+#define BM_IR_MR0	BIT(0)
+
+#define HW_TCR		0x0010 /* RW. Timer controller */
+/* BM_C*_RST
+ * Timer Counter and the Prescale Counter are synchronously reset on the
+ * next positive edge of PCLK. The counters remain reset until TCR[1] is
+ * returned to zero. */
+#define BM_C3_RST	BIT(7)
+#define BM_C2_RST	BIT(6)
+#define BM_C1_RST	BIT(5)
+#define BM_C0_RST	BIT(4)
+/* BM_C*_EN
+ * 1 - Timer Counter and Prescale Counter are enabled for counting
+ * 0 - counters are disabled */
+#define BM_C3_EN	BIT(3)
+#define BM_C2_EN	BIT(2)
+#define BM_C1_EN	BIT(1)
+#define BM_C0_EN	BIT(0)
+
+#define HW_DIR		0x0020 /* RW. Direction? */
+/* 00 - count up
+ * 01 - count down
+ * 10 - ?? 2^n/2 */
+#define BM_DIR0_SHIFT	0
+#define BM_DIR1_SHIFT	4
+#define BM_DIR2_SHIFT	8
+#define BM_DIR3_SHIFT	12
+
+#define HW_TC0		0x0030 /* RO. Timer counter 0 */
+/* HW_TC*. Timer counter owerflow (0xffff.ffff to 0x0000.0000) do not generate
+ * interrupt. This registers can be used to detect overflow */
+#define HW_TC1          0x0040
+#define HW_TC2		0x0050
+#define HW_TC3		0x0060
+
+#define HW_PR		0x0070 /* RW. prescaler */
+#define HW_PC		0x0080 /* RO. Prescaler counter */
+#define HW_MCR		0x0090 /* RW. Match control */
+/* enable interrupt on match */
+#define BM_MCR_INT_EN(n)	(1 << (n * 3 + 0))
+/* enable TC reset on match */
+#define BM_MCR_RES_EN(n)	(1 << (n * 3 + 1))
+/* enable stop TC on match */
+#define BM_MCR_STOP_EN(n)	(1 << (n * 3 + 2))
+
+#define HW_MR0		0x00a0 /* RW. Match reg */
+#define HW_MR1		0x00b0
+#define HW_MR2		0x00C0
+#define HW_MR3		0x00D0
+#define HW_CCR		0x00E0 /* RW. Capture control */
+#define HW_CR0		0x00F0 /* RO. Capture reg */
+#define HW_CR1		0x0100
+#define HW_CR2		0x0110
+#define HW_CR3		0x0120
+#define HW_EMR		0x0130 /* RW. External Match */
+#define HW_PWMTH0	0x0140 /* RW. PWM width */
+#define HW_PWMTH1	0x0150
+#define HW_PWMTH2	0x0160
+#define HW_PWMTH3	0x0170
+#define HW_CTCR		0x0180 /* Counter control */
+#define HW_PWMC		0x0190 /* PWM control */
+
+static void __iomem *base;
+static unsigned long ticks_per_jiffy;
+
+static int asm9260_timer_set_next_event(unsigned long delta,
+					 struct clock_event_device *dev)
+{
+	/* configure match count for TC0 */
+	writel_relaxed(delta, base + HW_MR0);
+	/* enable TC0 */
+	writel_relaxed(BM_C0_EN, base + HW_TCR + SET_REG);
+	return 0;
+}
+
+static void asm9260_timer_set_mode(enum clock_event_mode mode,
+				    struct clock_event_device *evt)
+{
+	/* stop timer0 */
+	writel_relaxed(BM_C0_EN, base + HW_TCR + CLR_REG);
+
+	switch (mode) {
+	case CLOCK_EVT_MODE_PERIODIC:
+		/* disable reset and stop on match */
+		writel_relaxed(BM_MCR_RES_EN(0) | BM_MCR_STOP_EN(0),
+				base + HW_MCR + CLR_REG);
+		/* configure match count for TC0 */
+		writel_relaxed(ticks_per_jiffy, base + HW_MR0);
+		/* enable TC0 */
+		writel_relaxed(BM_C0_EN, base + HW_TCR + SET_REG);
+		break;
+	case CLOCK_EVT_MODE_ONESHOT:
+		/* enable reset and stop on match */
+		writel_relaxed(BM_MCR_RES_EN(0) | BM_MCR_STOP_EN(0),
+				base + HW_MCR + SET_REG);
+		break;
+	default:
+		break;
+	}
+}
+
+static struct clock_event_device asm9260_clockevent_device = {
+	.name		= "asm9260-clockevent-dev",
+	.rating		= 200,
+	.features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
+	.set_next_event	= asm9260_timer_set_next_event,
+	.set_mode	= asm9260_timer_set_mode,
+};
+
+static irqreturn_t asm9260_timer_interrupt(int irq, void *dev_id)
+{
+	struct clock_event_device *evt = &asm9260_clockevent_device;
+
+	evt->event_handler(evt);
+
+	writel_relaxed(BM_IR_MR0, base + HW_IR);
+
+	return IRQ_HANDLED;
+}
+
+static struct irqaction asm9260_timer_irq = {
+	.name		= "asm9260-clockevent-dev",
+	.flags		= IRQF_TIMER | IRQF_IRQPOLL,
+	.handler	= asm9260_timer_interrupt,
+};
+
+/*
+ * ---------------------------------------------------------------------------
+ * Timer initialization
+ * ---------------------------------------------------------------------------
+ */
+
+static void __init asm9260_clockevent_init(struct clk *clk)
+{
+	unsigned long rate = clk_get_rate(clk);
+
+	ticks_per_jiffy = DIV_ROUND_CLOSEST(rate, HZ);
+	asm9260_clockevent_device.cpumask = cpumask_of(0);
+	clockevents_config_and_register(&asm9260_clockevent_device,
+					rate, 0x2c00, 0xfffffffe);
+}
+
+static void __init asm9260_clocksource_init(struct clk *clk)
+{
+	unsigned long hz = clk_get_rate(clk);
+
+	clocksource_mmio_init(base + HW_TC1,
+			"asm9260-clocksource", hz,
+			200, 32, clocksource_mmio_readl_up);
+
+	/* Seems like we can't use counter without match register even if
+	 * actions for MR are disabled. */
+	writel_relaxed(0xffffffff, base + HW_MR1);
+	/* enable TC1 */
+	writel_relaxed(BM_C1_EN, base + HW_TCR + SET_REG);
+}
+
+static void __init asm9260_timer_init(struct device_node *np)
+{
+	int irq;
+	struct clk *clk;
+	struct resource res;
+	int ret;
+
+	of_address_to_resource(np, 0, &res);
+	if (!request_mem_region(res.start, resource_size(&res),
+				"asm9260-timer"))
+		panic("%s: unable to request mem region", np->name);
+
+	base = ioremap_nocache(res.start, resource_size(&res));
+	if (!base)
+		panic("%s: unable to map resource", np->name);
+
+	clk = of_clk_get(np, 0);
+
+	ret = clk_prepare_enable(clk);
+	if (ret)
+		panic("Failed to enable clk!\n");
+
+	irq = irq_of_parse_and_map(np, 0);
+	setup_irq(irq, &asm9260_timer_irq);
+
+	/* set all timers for count-up */
+	writel_relaxed(0, base + HW_DIR);
+	/* disable divider */
+	writel_relaxed(0, base + HW_PR);
+	/* make sure all timers use every rising PCLK edge. */
+	writel_relaxed(0, base + HW_CTCR);
+	/* enable interrupt for TC0 and clean setting for all other lines */
+	writel_relaxed(BM_MCR_INT_EN(0) , base + HW_MCR);
+
+	asm9260_clocksource_init(clk);
+	asm9260_clockevent_init(clk);
+}
+CLOCKSOURCE_OF_DECLARE(asm9260_timer, "alphascale,asm9260-timer",
+		asm9260_timer_init);
-- 
1.9.1
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