1727339590
The CLOCKSOURCE_OF_DECLARE macro is used widely for the timers to declare the clocksource at early stage. However, this macro is also used to initialize the clockevent if any, or the clockevent only. It was originally suggested to declare another macro to initialize a clockevent, so in order to separate the two entities even they belong to the same IP. This was not accepted because of the impact on the DT where splitting a clocksource/clockevent definition does not make sense as it is a Linux concept not a hardware description. On the other side, the clocksource has not interrupt declared while the clockevent has, so it is easy from the driver to know if the description is for a clockevent or a clocksource, IOW it could be implemented at the driver level. So instead of dealing with a named clocksource macro, let's use a more generic one: TIMER_OF_DECLARE. The patch has not functional changes. Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Acked-by: Heiko Stuebner <heiko@sntech.de> Acked-by: Neil Armstrong <narmstrong@baylibre.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Matthias Brugger <matthias.bgg@gmail.com> Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
169 lines
4.6 KiB
C
169 lines
4.6 KiB
C
/*
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* arch/arm/mach-vt8500/timer.c
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*
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* Copyright (C) 2012 Tony Prisk <linux@prisktech.co.nz>
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* Copyright (C) 2010 Alexey Charkov <alchark@gmail.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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/*
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* This file is copied and modified from the original timer.c provided by
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* Alexey Charkov. Minor changes have been made for Device Tree Support.
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*/
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#include <linux/io.h>
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#include <linux/irq.h>
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#include <linux/interrupt.h>
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#include <linux/clocksource.h>
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#include <linux/clockchips.h>
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#include <linux/delay.h>
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#include <linux/of.h>
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#include <linux/of_address.h>
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#include <linux/of_irq.h>
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#define VT8500_TIMER_OFFSET 0x0100
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#define VT8500_TIMER_HZ 3000000
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#define TIMER_MATCH_VAL 0x0000
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#define TIMER_COUNT_VAL 0x0010
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#define TIMER_STATUS_VAL 0x0014
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#define TIMER_IER_VAL 0x001c /* interrupt enable */
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#define TIMER_CTRL_VAL 0x0020
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#define TIMER_AS_VAL 0x0024 /* access status */
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#define TIMER_COUNT_R_ACTIVE (1 << 5) /* not ready for read */
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#define TIMER_COUNT_W_ACTIVE (1 << 4) /* not ready for write */
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#define TIMER_MATCH_W_ACTIVE (1 << 0) /* not ready for write */
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#define msecs_to_loops(t) (loops_per_jiffy / 1000 * HZ * t)
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#define MIN_OSCR_DELTA 16
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static void __iomem *regbase;
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static u64 vt8500_timer_read(struct clocksource *cs)
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{
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int loops = msecs_to_loops(10);
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writel(3, regbase + TIMER_CTRL_VAL);
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while ((readl((regbase + TIMER_AS_VAL)) & TIMER_COUNT_R_ACTIVE)
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&& --loops)
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cpu_relax();
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return readl(regbase + TIMER_COUNT_VAL);
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}
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static struct clocksource clocksource = {
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.name = "vt8500_timer",
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.rating = 200,
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.read = vt8500_timer_read,
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.mask = CLOCKSOURCE_MASK(32),
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.flags = CLOCK_SOURCE_IS_CONTINUOUS,
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};
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static int vt8500_timer_set_next_event(unsigned long cycles,
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struct clock_event_device *evt)
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{
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int loops = msecs_to_loops(10);
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u64 alarm = clocksource.read(&clocksource) + cycles;
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while ((readl(regbase + TIMER_AS_VAL) & TIMER_MATCH_W_ACTIVE)
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&& --loops)
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cpu_relax();
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writel((unsigned long)alarm, regbase + TIMER_MATCH_VAL);
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if ((signed)(alarm - clocksource.read(&clocksource)) <= MIN_OSCR_DELTA)
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return -ETIME;
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writel(1, regbase + TIMER_IER_VAL);
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return 0;
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}
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static int vt8500_shutdown(struct clock_event_device *evt)
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{
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writel(readl(regbase + TIMER_CTRL_VAL) | 1, regbase + TIMER_CTRL_VAL);
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writel(0, regbase + TIMER_IER_VAL);
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return 0;
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}
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static struct clock_event_device clockevent = {
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.name = "vt8500_timer",
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.features = CLOCK_EVT_FEAT_ONESHOT,
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.rating = 200,
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.set_next_event = vt8500_timer_set_next_event,
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.set_state_shutdown = vt8500_shutdown,
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.set_state_oneshot = vt8500_shutdown,
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};
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static irqreturn_t vt8500_timer_interrupt(int irq, void *dev_id)
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{
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struct clock_event_device *evt = dev_id;
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writel(0xf, regbase + TIMER_STATUS_VAL);
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evt->event_handler(evt);
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return IRQ_HANDLED;
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}
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static struct irqaction irq = {
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.name = "vt8500_timer",
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.flags = IRQF_TIMER | IRQF_IRQPOLL,
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.handler = vt8500_timer_interrupt,
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.dev_id = &clockevent,
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};
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static int __init vt8500_timer_init(struct device_node *np)
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{
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int timer_irq, ret;
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regbase = of_iomap(np, 0);
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if (!regbase) {
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pr_err("%s: Missing iobase description in Device Tree\n",
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__func__);
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return -ENXIO;
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}
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timer_irq = irq_of_parse_and_map(np, 0);
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if (!timer_irq) {
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pr_err("%s: Missing irq description in Device Tree\n",
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__func__);
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return -EINVAL;
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}
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writel(1, regbase + TIMER_CTRL_VAL);
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writel(0xf, regbase + TIMER_STATUS_VAL);
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writel(~0, regbase + TIMER_MATCH_VAL);
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ret = clocksource_register_hz(&clocksource, VT8500_TIMER_HZ);
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if (ret) {
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pr_err("%s: vt8500_timer_init: clocksource_register failed for %s\n",
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__func__, clocksource.name);
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return ret;
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}
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clockevent.cpumask = cpumask_of(0);
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ret = setup_irq(timer_irq, &irq);
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if (ret) {
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pr_err("%s: setup_irq failed for %s\n", __func__,
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clockevent.name);
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return ret;
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}
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clockevents_config_and_register(&clockevent, VT8500_TIMER_HZ,
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MIN_OSCR_DELTA * 2, 0xf0000000);
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return 0;
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}
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TIMER_OF_DECLARE(vt8500, "via,vt8500-timer", vt8500_timer_init);
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