+++ /dev/null
-/*
- * arch/arm/mach-vt8500/timer.c
- *
- * Copyright (C) 2012 Tony Prisk <linux@prisktech.co.nz>
- * Copyright (C) 2010 Alexey Charkov <alchark@gmail.com>
- *
- * 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.
- *
- * 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.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
- */
-
-/*
- * This file is copied and modified from the original timer.c provided by
- * Alexey Charkov. Minor changes have been made for Device Tree Support.
- */
-
-#include <linux/io.h>
-#include <linux/irq.h>
-#include <linux/interrupt.h>
-#include <linux/clocksource.h>
-#include <linux/clockchips.h>
-#include <linux/delay.h>
-#include <asm/mach/time.h>
-
-#include <linux/of.h>
-#include <linux/of_address.h>
-#include <linux/of_irq.h>
-
-#define VT8500_TIMER_OFFSET 0x0100
-#define VT8500_TIMER_HZ 3000000
-#define TIMER_MATCH_VAL 0x0000
-#define TIMER_COUNT_VAL 0x0010
-#define TIMER_STATUS_VAL 0x0014
-#define TIMER_IER_VAL 0x001c /* interrupt enable */
-#define TIMER_CTRL_VAL 0x0020
-#define TIMER_AS_VAL 0x0024 /* access status */
-#define TIMER_COUNT_R_ACTIVE (1 << 5) /* not ready for read */
-#define TIMER_COUNT_W_ACTIVE (1 << 4) /* not ready for write */
-#define TIMER_MATCH_W_ACTIVE (1 << 0) /* not ready for write */
-
-#define msecs_to_loops(t) (loops_per_jiffy / 1000 * HZ * t)
-
-static void __iomem *regbase;
-
-static cycle_t vt8500_timer_read(struct clocksource *cs)
-{
- int loops = msecs_to_loops(10);
- writel(3, regbase + TIMER_CTRL_VAL);
- while ((readl((regbase + TIMER_AS_VAL)) & TIMER_COUNT_R_ACTIVE)
- && --loops)
- cpu_relax();
- return readl(regbase + TIMER_COUNT_VAL);
-}
-
-static struct clocksource clocksource = {
- .name = "vt8500_timer",
- .rating = 200,
- .read = vt8500_timer_read,
- .mask = CLOCKSOURCE_MASK(32),
- .flags = CLOCK_SOURCE_IS_CONTINUOUS,
-};
-
-static int vt8500_timer_set_next_event(unsigned long cycles,
- struct clock_event_device *evt)
-{
- int loops = msecs_to_loops(10);
- cycle_t alarm = clocksource.read(&clocksource) + cycles;
- while ((readl(regbase + TIMER_AS_VAL) & TIMER_MATCH_W_ACTIVE)
- && --loops)
- cpu_relax();
- writel((unsigned long)alarm, regbase + TIMER_MATCH_VAL);
-
- if ((signed)(alarm - clocksource.read(&clocksource)) <= 16)
- return -ETIME;
-
- writel(1, regbase + TIMER_IER_VAL);
-
- return 0;
-}
-
-static void vt8500_timer_set_mode(enum clock_event_mode mode,
- struct clock_event_device *evt)
-{
- switch (mode) {
- case CLOCK_EVT_MODE_RESUME:
- case CLOCK_EVT_MODE_PERIODIC:
- break;
- case CLOCK_EVT_MODE_ONESHOT:
- case CLOCK_EVT_MODE_UNUSED:
- case CLOCK_EVT_MODE_SHUTDOWN:
- writel(readl(regbase + TIMER_CTRL_VAL) | 1,
- regbase + TIMER_CTRL_VAL);
- writel(0, regbase + TIMER_IER_VAL);
- break;
- }
-}
-
-static struct clock_event_device clockevent = {
- .name = "vt8500_timer",
- .features = CLOCK_EVT_FEAT_ONESHOT,
- .rating = 200,
- .set_next_event = vt8500_timer_set_next_event,
- .set_mode = vt8500_timer_set_mode,
-};
-
-static irqreturn_t vt8500_timer_interrupt(int irq, void *dev_id)
-{
- struct clock_event_device *evt = dev_id;
- writel(0xf, regbase + TIMER_STATUS_VAL);
- evt->event_handler(evt);
-
- return IRQ_HANDLED;
-}
-
-static struct irqaction irq = {
- .name = "vt8500_timer",
- .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
- .handler = vt8500_timer_interrupt,
- .dev_id = &clockevent,
-};
-
-static struct of_device_id vt8500_timer_ids[] = {
- { .compatible = "via,vt8500-timer" },
- { }
-};
-
-void __init vt8500_timer_init(void)
-{
- struct device_node *np;
- int timer_irq;
-
- np = of_find_matching_node(NULL, vt8500_timer_ids);
- if (!np) {
- pr_err("%s: Timer description missing from Device Tree\n",
- __func__);
- return;
- }
- regbase = of_iomap(np, 0);
- if (!regbase) {
- pr_err("%s: Missing iobase description in Device Tree\n",
- __func__);
- of_node_put(np);
- return;
- }
- timer_irq = irq_of_parse_and_map(np, 0);
- if (!timer_irq) {
- pr_err("%s: Missing irq description in Device Tree\n",
- __func__);
- of_node_put(np);
- return;
- }
-
- writel(1, regbase + TIMER_CTRL_VAL);
- writel(0xf, regbase + TIMER_STATUS_VAL);
- writel(~0, regbase + TIMER_MATCH_VAL);
-
- if (clocksource_register_hz(&clocksource, VT8500_TIMER_HZ))
- pr_err("%s: vt8500_timer_init: clocksource_register failed for %s\n",
- __func__, clocksource.name);
-
- clockevents_calc_mult_shift(&clockevent, VT8500_TIMER_HZ, 4);
-
- /* copy-pasted from mach-msm; no idea */
- clockevent.max_delta_ns =
- clockevent_delta2ns(0xf0000000, &clockevent);
- clockevent.min_delta_ns = clockevent_delta2ns(4, &clockevent);
- clockevent.cpumask = cpumask_of(0);
-
- if (setup_irq(timer_irq, &irq))
- pr_err("%s: setup_irq failed for %s\n", __func__,
- clockevent.name);
- clockevents_register_device(&clockevent);
-}
-
projects / firefly-linux-kernel-4.4.55.git / blobdiff