--- /dev/null
+/*
+ * arch/arm/mach-pxa/time.c
+ *
+ * PXA clocksource, clockevents, and OST interrupt handlers.
+ * Copyright (c) 2007 by Bill Gatliff <bgat@billgatliff.com>.
+ *
+ * Derived from Nicolas Pitre's PXA timer handler Copyright (c) 2001
+ * by MontaVista Software, Inc. (Nico, your code rocks!)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/clk.h>
+#include <linux/clockchips.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/sched_clock.h>
+
+#include <asm/div64.h>
+
+#define OSMR0 0x00 /* OS Timer 0 Match Register */
+#define OSMR1 0x04 /* OS Timer 1 Match Register */
+#define OSMR2 0x08 /* OS Timer 2 Match Register */
+#define OSMR3 0x0C /* OS Timer 3 Match Register */
+
+#define OSCR 0x10 /* OS Timer Counter Register */
+#define OSSR 0x14 /* OS Timer Status Register */
+#define OWER 0x18 /* OS Timer Watchdog Enable Register */
+#define OIER 0x1C /* OS Timer Interrupt Enable Register */
+
+#define OSSR_M3 (1 << 3) /* Match status channel 3 */
+#define OSSR_M2 (1 << 2) /* Match status channel 2 */
+#define OSSR_M1 (1 << 1) /* Match status channel 1 */
+#define OSSR_M0 (1 << 0) /* Match status channel 0 */
+
+#define OIER_E0 (1 << 0) /* Interrupt enable channel 0 */
+
+/*
+ * This is PXA's sched_clock implementation. This has a resolution
+ * of at least 308 ns and a maximum value of 208 days.
+ *
+ * The return value is guaranteed to be monotonic in that range as
+ * long as there is always less than 582 seconds between successive
+ * calls to sched_clock() which should always be the case in practice.
+ */
+
+#define timer_readl(reg) readl_relaxed(timer_base + (reg))
+#define timer_writel(val, reg) writel_relaxed((val), timer_base + (reg))
+
+static void __iomem *timer_base;
+
+static u64 notrace pxa_read_sched_clock(void)
+{
+ return timer_readl(OSCR);
+}
+
+
+#define MIN_OSCR_DELTA 16
+
+static irqreturn_t
+pxa_ost0_interrupt(int irq, void *dev_id)
+{
+ struct clock_event_device *c = dev_id;
+
+ /* Disarm the compare/match, signal the event. */
+ timer_writel(timer_readl(OIER) & ~OIER_E0, OIER);
+ timer_writel(OSSR_M0, OSSR);
+ c->event_handler(c);
+
+ return IRQ_HANDLED;
+}
+
+static int
+pxa_osmr0_set_next_event(unsigned long delta, struct clock_event_device *dev)
+{
+ unsigned long next, oscr;
+
+ timer_writel(timer_readl(OIER) | OIER_E0, OIER);
+ next = timer_readl(OSCR) + delta;
+ timer_writel(next, OSMR0);
+ oscr = timer_readl(OSCR);
+
+ return (signed)(next - oscr) <= MIN_OSCR_DELTA ? -ETIME : 0;
+}
+
+static void
+pxa_osmr0_set_mode(enum clock_event_mode mode, struct clock_event_device *dev)
+{
+ switch (mode) {
+ case CLOCK_EVT_MODE_ONESHOT:
+ timer_writel(timer_readl(OIER) & ~OIER_E0, OIER);
+ timer_writel(OSSR_M0, OSSR);
+ break;
+
+ case CLOCK_EVT_MODE_UNUSED:
+ case CLOCK_EVT_MODE_SHUTDOWN:
+ /* initializing, released, or preparing for suspend */
+ timer_writel(timer_readl(OIER) & ~OIER_E0, OIER);
+ timer_writel(OSSR_M0, OSSR);
+ break;
+
+ case CLOCK_EVT_MODE_RESUME:
+ case CLOCK_EVT_MODE_PERIODIC:
+ break;
+ }
+}
+
+#ifdef CONFIG_PM
+static unsigned long osmr[4], oier, oscr;
+
+static void pxa_timer_suspend(struct clock_event_device *cedev)
+{
+ osmr[0] = timer_readl(OSMR0);
+ osmr[1] = timer_readl(OSMR1);
+ osmr[2] = timer_readl(OSMR2);
+ osmr[3] = timer_readl(OSMR3);
+ oier = timer_readl(OIER);
+ oscr = timer_readl(OSCR);
+}
+
+static void pxa_timer_resume(struct clock_event_device *cedev)
+{
+ /*
+ * Ensure that we have at least MIN_OSCR_DELTA between match
+ * register 0 and the OSCR, to guarantee that we will receive
+ * the one-shot timer interrupt. We adjust OSMR0 in preference
+ * to OSCR to guarantee that OSCR is monotonically incrementing.
+ */
+ if (osmr[0] - oscr < MIN_OSCR_DELTA)
+ osmr[0] += MIN_OSCR_DELTA;
+
+ timer_writel(osmr[0], OSMR0);
+ timer_writel(osmr[1], OSMR1);
+ timer_writel(osmr[2], OSMR2);
+ timer_writel(osmr[3], OSMR3);
+ timer_writel(oier, OIER);
+ timer_writel(oscr, OSCR);
+}
+#else
+#define pxa_timer_suspend NULL
+#define pxa_timer_resume NULL
+#endif
+
+static struct clock_event_device ckevt_pxa_osmr0 = {
+ .name = "osmr0",
+ .features = CLOCK_EVT_FEAT_ONESHOT,
+ .rating = 200,
+ .set_next_event = pxa_osmr0_set_next_event,
+ .set_mode = pxa_osmr0_set_mode,
+ .suspend = pxa_timer_suspend,
+ .resume = pxa_timer_resume,
+};
+
+static struct irqaction pxa_ost0_irq = {
+ .name = "ost0",
+ .flags = IRQF_TIMER | IRQF_IRQPOLL,
+ .handler = pxa_ost0_interrupt,
+ .dev_id = &ckevt_pxa_osmr0,
+};
+
+static void __init pxa_timer_common_init(int irq, unsigned long clock_tick_rate)
+{
+ timer_writel(0, OIER);
+ timer_writel(OSSR_M0 | OSSR_M1 | OSSR_M2 | OSSR_M3, OSSR);
+
+ sched_clock_register(pxa_read_sched_clock, 32, clock_tick_rate);
+
+ ckevt_pxa_osmr0.cpumask = cpumask_of(0);
+
+ setup_irq(irq, &pxa_ost0_irq);
+
+ clocksource_mmio_init(timer_base + OSCR, "oscr0", clock_tick_rate, 200,
+ 32, clocksource_mmio_readl_up);
+ clockevents_config_and_register(&ckevt_pxa_osmr0, clock_tick_rate,
+ MIN_OSCR_DELTA * 2, 0x7fffffff);
+}
+
+static void __init pxa_timer_dt_init(struct device_node *np)
+{
+ struct clk *clk;
+ int irq;
+
+ /* timer registers are shared with watchdog timer */
+ timer_base = of_iomap(np, 0);
+ if (!timer_base)
+ panic("%s: unable to map resource\n", np->name);
+
+ clk = of_clk_get(np, 0);
+ if (IS_ERR(clk)) {
+ pr_crit("%s: unable to get clk\n", np->name);
+ return;
+ }
+ clk_prepare_enable(clk);
+
+ /* we are only interested in OS-timer0 irq */
+ irq = irq_of_parse_and_map(np, 0);
+ if (irq <= 0) {
+ pr_crit("%s: unable to parse OS-timer0 irq\n", np->name);
+ return;
+ }
+
+ pxa_timer_common_init(irq, clk_get_rate(clk));
+}
+CLOCKSOURCE_OF_DECLARE(pxa_timer, "marvell,pxa-timer", pxa_timer_dt_init);
+
+/*
+ * Legacy timer init for non device-tree boards.
+ */
+void __init pxa_timer_nodt_init(int irq, void __iomem *base,
+ unsigned long clock_tick_rate)
+{
+ struct clk *clk;
+
+ timer_base = base;
+ clk = clk_get(NULL, "OSTIMER0");
+ if (clk && !IS_ERR(clk))
+ clk_prepare_enable(clk);
+ else
+ pr_crit("%s: unable to get clk\n", __func__);
+
+ pxa_timer_common_init(irq, clock_tick_rate);
+}
Code Review / kvmfornfv.git / blobdiff