[ARM] msm: irq and timer support for ARCH_MSM7X00A

- Vectored Interrupt Controller support
- Timer support using the GPT and DGT timers

Signed-off-by: Brian Swetland <swetland@google.com>

1 files changed, 205 insertions, 0 deletions

diff --git a/arch/arm/mach-msm/timer.c b/arch/arm/mach-msm/timer.c
new file mode 100644
index 00000000000..bd4732d1ab3
--- /dev/null
+++ b/arch/arm/mach-msm/timer.c
@@ -0,0 +1,205 @@
+/* linux/arch/arm/mach-msm/timer.c
+ *
+ * Copyright (C) 2007 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/time.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/clk.h>
+#include <linux/clockchips.h>
+#include <linux/delay.h>
+
+#include <asm/mach/time.h>
+#include <asm/arch/msm_iomap.h>
+
+#include <asm/io.h>
+
+#define MSM_DGT_BASE (MSM_GPT_BASE + 0x10)
+#define MSM_DGT_SHIFT (5)
+
+#define TIMER_MATCH_VAL         0x0000
+#define TIMER_COUNT_VAL         0x0004
+#define TIMER_ENABLE            0x0008
+#define TIMER_ENABLE_CLR_ON_MATCH_EN    2
+#define TIMER_ENABLE_EN                 1
+#define TIMER_CLEAR             0x000C
+
+#define CSR_PROTECTION          0x0020
+#define CSR_PROTECTION_EN               1
+
+#define GPT_HZ 32768
+#define DGT_HZ 19200000 /* 19.2 MHz or 600 KHz after shift */
+
+struct msm_clock {
+	struct clock_event_device   clockevent;
+	struct clocksource          clocksource;
+	struct irqaction            irq;
+	uint32_t                    regbase;
+	uint32_t                    freq;
+	uint32_t                    shift;
+};
+
+static irqreturn_t msm_timer_interrupt(int irq, void *dev_id)
+{
+	struct clock_event_device *evt = dev_id;
+	evt->event_handler(evt);
+	return IRQ_HANDLED;
+}
+
+static cycle_t msm_gpt_read(void)
+{
+	return readl(MSM_GPT_BASE + TIMER_COUNT_VAL);
+}
+
+static cycle_t msm_dgt_read(void)
+{
+	return readl(MSM_DGT_BASE + TIMER_COUNT_VAL) >> MSM_DGT_SHIFT;
+}
+
+static int msm_timer_set_next_event(unsigned long cycles,
+				    struct clock_event_device *evt)
+{
+	struct msm_clock *clock = container_of(evt, struct msm_clock, clockevent);
+	uint32_t now = readl(clock->regbase + TIMER_COUNT_VAL);
+	uint32_t alarm = now + (cycles << clock->shift);
+	int late;
+
+	writel(alarm, clock->regbase + TIMER_MATCH_VAL);
+	now = readl(clock->regbase + TIMER_COUNT_VAL);
+	late = now - alarm;
+	if (late >= (-2 << clock->shift) && late < DGT_HZ*5) {
+		printk(KERN_NOTICE "msm_timer_set_next_event(%lu) clock %s, "
+		       "alarm already expired, now %x, alarm %x, late %d\n",
+		       cycles, clock->clockevent.name, now, alarm, late);
+		return -ETIME;
+	}
+	return 0;
+}
+
+static void msm_timer_set_mode(enum clock_event_mode mode,
+			      struct clock_event_device *evt)
+{
+	struct msm_clock *clock = container_of(evt, struct msm_clock, clockevent);
+	switch (mode) {
+	case CLOCK_EVT_MODE_RESUME:
+	case CLOCK_EVT_MODE_PERIODIC:
+		break;
+	case CLOCK_EVT_MODE_ONESHOT:
+		writel(TIMER_ENABLE_EN, clock->regbase + TIMER_ENABLE);
+		break;
+	case CLOCK_EVT_MODE_UNUSED:
+	case CLOCK_EVT_MODE_SHUTDOWN:
+		writel(0, clock->regbase + TIMER_ENABLE);
+		break;
+	}
+}
+
+static struct msm_clock msm_clocks[] = {
+	{
+		.clockevent = {
+			.name           = "gp_timer",
+			.features       = CLOCK_EVT_FEAT_ONESHOT,
+			.shift          = 32,
+			.rating         = 200,
+			.set_next_event = msm_timer_set_next_event,
+			.set_mode       = msm_timer_set_mode,
+		},
+		.clocksource = {
+			.name           = "gp_timer",
+			.rating         = 200,
+			.read           = msm_gpt_read,
+			.mask           = CLOCKSOURCE_MASK(32),
+			.shift          = 24,
+			.flags          = CLOCK_SOURCE_IS_CONTINUOUS,
+		},
+		.irq = {
+			.name    = "gp_timer",
+			.flags   = IRQF_DISABLED | IRQF_TIMER | IRQF_TRIGGER_RISING,
+			.handler = msm_timer_interrupt,
+			.dev_id  = &msm_clocks[0].clockevent,
+			.irq     = INT_GP_TIMER_EXP
+		},
+		.regbase = MSM_GPT_BASE,
+		.freq = GPT_HZ
+	},
+	{
+		.clockevent = {
+			.name           = "dg_timer",
+			.features       = CLOCK_EVT_FEAT_ONESHOT,
+			.shift          = 32 + MSM_DGT_SHIFT,
+			.rating         = 300,
+			.set_next_event = msm_timer_set_next_event,
+			.set_mode       = msm_timer_set_mode,
+		},
+		.clocksource = {
+			.name           = "dg_timer",
+			.rating         = 300,
+			.read           = msm_dgt_read,
+			.mask           = CLOCKSOURCE_MASK((32 - MSM_DGT_SHIFT)),
+			.shift          = 24 - MSM_DGT_SHIFT,
+			.flags          = CLOCK_SOURCE_IS_CONTINUOUS,
+		},
+		.irq = {
+			.name    = "dg_timer",
+			.flags   = IRQF_DISABLED | IRQF_TIMER | IRQF_TRIGGER_RISING,
+			.handler = msm_timer_interrupt,
+			.dev_id  = &msm_clocks[1].clockevent,
+			.irq     = INT_DEBUG_TIMER_EXP
+		},
+		.regbase = MSM_DGT_BASE,
+		.freq = DGT_HZ >> MSM_DGT_SHIFT,
+		.shift = MSM_DGT_SHIFT
+	}
+};
+
+static void __init msm_timer_init(void)
+{
+	int i;
+	int res;
+
+	for (i = 0; i < ARRAY_SIZE(msm_clocks); i++) {
+		struct msm_clock *clock = &msm_clocks[i];
+		struct clock_event_device *ce = &clock->clockevent;
+		struct clocksource *cs = &clock->clocksource;
+		writel(0, clock->regbase + TIMER_ENABLE);
+		writel(0, clock->regbase + TIMER_CLEAR);
+		writel(~0, clock->regbase + TIMER_MATCH_VAL);
+
+		ce->mult = div_sc(clock->freq, NSEC_PER_SEC, ce->shift);
+		/* allow at least 10 seconds to notice that the timer wrapped */
+		ce->max_delta_ns =
+			clockevent_delta2ns(0xf0000000 >> clock->shift, ce);
+		/* 4 gets rounded down to 3 */
+		ce->min_delta_ns = clockevent_delta2ns(4, ce);
+		ce->cpumask = cpumask_of_cpu(0);
+
+		cs->mult = clocksource_hz2mult(clock->freq, cs->shift);
+		res = clocksource_register(cs);
+		if (res)
+			printk(KERN_ERR "msm_timer_init: clocksource_register "
+			       "failed for %s\n", cs->name);
+
+		res = setup_irq(clock->irq.irq, &clock->irq);
+		if (res)
+			printk(KERN_ERR "msm_timer_init: setup_irq "
+			       "failed for %s\n", cs->name);
+
+		clockevents_register_device(ce);
+	}
+}
+
+struct sys_timer msm_timer = {
+	.init = msm_timer_init
+};