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![Guo Ren](/assets/img/avatar_default.png)
The driver is for gx6605s SOC system timer and there are two same timers in gx6605s. We use one for clkevt and another one for clksrc. The timer is mmio map to access, so we need give mmio address in dts. The counter at 0x0 offset is clock event. The counter at 0x40 offset is clock source. Signed-off-by: Guo Ren <ren_guo@c-sky.com> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
154 lines
4 KiB
C
154 lines
4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/sched_clock.h>
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#include "timer-of.h"
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#define CLKSRC_OFFSET 0x40
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#define TIMER_STATUS 0x00
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#define TIMER_VALUE 0x04
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#define TIMER_CONTRL 0x10
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#define TIMER_CONFIG 0x20
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#define TIMER_DIV 0x24
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#define TIMER_INI 0x28
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#define GX6605S_STATUS_CLR BIT(0)
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#define GX6605S_CONTRL_RST BIT(0)
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#define GX6605S_CONTRL_START BIT(1)
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#define GX6605S_CONFIG_EN BIT(0)
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#define GX6605S_CONFIG_IRQ_EN BIT(1)
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static irqreturn_t gx6605s_timer_interrupt(int irq, void *dev)
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{
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struct clock_event_device *ce = dev;
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void __iomem *base = timer_of_base(to_timer_of(ce));
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writel_relaxed(GX6605S_STATUS_CLR, base + TIMER_STATUS);
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ce->event_handler(ce);
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return IRQ_HANDLED;
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}
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static int gx6605s_timer_set_oneshot(struct clock_event_device *ce)
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{
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void __iomem *base = timer_of_base(to_timer_of(ce));
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/* reset and stop counter */
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writel_relaxed(GX6605S_CONTRL_RST, base + TIMER_CONTRL);
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/* enable with irq and start */
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writel_relaxed(GX6605S_CONFIG_EN | GX6605S_CONFIG_IRQ_EN,
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base + TIMER_CONFIG);
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return 0;
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}
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static int gx6605s_timer_set_next_event(unsigned long delta,
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struct clock_event_device *ce)
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{
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void __iomem *base = timer_of_base(to_timer_of(ce));
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/* use reset to pause timer */
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writel_relaxed(GX6605S_CONTRL_RST, base + TIMER_CONTRL);
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/* config next timeout value */
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writel_relaxed(ULONG_MAX - delta, base + TIMER_INI);
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writel_relaxed(GX6605S_CONTRL_START, base + TIMER_CONTRL);
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return 0;
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}
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static int gx6605s_timer_shutdown(struct clock_event_device *ce)
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{
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void __iomem *base = timer_of_base(to_timer_of(ce));
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writel_relaxed(0, base + TIMER_CONTRL);
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writel_relaxed(0, base + TIMER_CONFIG);
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return 0;
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}
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static struct timer_of to = {
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.flags = TIMER_OF_IRQ | TIMER_OF_BASE | TIMER_OF_CLOCK,
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.clkevt = {
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.rating = 300,
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.features = CLOCK_EVT_FEAT_DYNIRQ |
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CLOCK_EVT_FEAT_ONESHOT,
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.set_state_shutdown = gx6605s_timer_shutdown,
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.set_state_oneshot = gx6605s_timer_set_oneshot,
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.set_next_event = gx6605s_timer_set_next_event,
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.cpumask = cpu_possible_mask,
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},
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.of_irq = {
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.handler = gx6605s_timer_interrupt,
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.flags = IRQF_TIMER | IRQF_IRQPOLL,
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},
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};
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static u64 notrace gx6605s_sched_clock_read(void)
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{
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void __iomem *base;
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base = timer_of_base(&to) + CLKSRC_OFFSET;
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return (u64)readl_relaxed(base + TIMER_VALUE);
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}
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static void gx6605s_clkevt_init(void __iomem *base)
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{
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writel_relaxed(0, base + TIMER_DIV);
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writel_relaxed(0, base + TIMER_CONFIG);
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clockevents_config_and_register(&to.clkevt, timer_of_rate(&to), 2,
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ULONG_MAX);
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}
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static int gx6605s_clksrc_init(void __iomem *base)
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{
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writel_relaxed(0, base + TIMER_DIV);
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writel_relaxed(0, base + TIMER_INI);
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writel_relaxed(GX6605S_CONTRL_RST, base + TIMER_CONTRL);
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writel_relaxed(GX6605S_CONFIG_EN, base + TIMER_CONFIG);
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writel_relaxed(GX6605S_CONTRL_START, base + TIMER_CONTRL);
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sched_clock_register(gx6605s_sched_clock_read, 32, timer_of_rate(&to));
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return clocksource_mmio_init(base + TIMER_VALUE, "gx6605s",
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timer_of_rate(&to), 200, 32, clocksource_mmio_readl_up);
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}
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static int __init gx6605s_timer_init(struct device_node *np)
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{
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int ret;
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/*
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* The timer driver is for nationalchip gx6605s SOC and there are two
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* same timer in gx6605s. We use one for clkevt and another for clksrc.
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*
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* The timer is mmio map to access, so we need give mmio address in dts.
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*
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* It provides a 32bit countup timer and interrupt will be caused by
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* count-overflow.
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* So we need set-next-event by ULONG_MAX - delta in TIMER_INI reg.
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*
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* The counter at 0x0 offset is clock event.
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* The counter at 0x40 offset is clock source.
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* They are the same in hardware, just different used by driver.
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*/
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ret = timer_of_init(np, &to);
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if (ret)
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return ret;
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gx6605s_clkevt_init(timer_of_base(&to));
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return gx6605s_clksrc_init(timer_of_base(&to) + CLKSRC_OFFSET);
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}
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TIMER_OF_DECLARE(csky_gx6605s_timer, "csky,gx6605s-timer", gx6605s_timer_init);
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