[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 000000000000..bd4732d1ab3e
--- /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
+};