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9eded23215
The name AUTORELOAD was actually pretty bad since it doesn't make the register reload the previous interval when it expires, but setting this value pushes the new programmed interval to the internal timer counter. Rename it to RELOAD instead. Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
148 lines
3.8 KiB
C
148 lines
3.8 KiB
C
/*
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* Allwinner A1X SoCs timer handling.
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*
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* Copyright (C) 2012 Maxime Ripard
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*
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* Maxime Ripard <maxime.ripard@free-electrons.com>
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*
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* Based on code from
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* Allwinner Technology Co., Ltd. <www.allwinnertech.com>
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* Benn Huang <benn@allwinnertech.com>
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*
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* This file is licensed under the terms of the GNU General Public
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* License version 2. This program is licensed "as is" without any
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* warranty of any kind, whether express or implied.
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*/
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#include <linux/clk.h>
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#include <linux/clockchips.h>
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#include <linux/interrupt.h>
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#include <linux/irq.h>
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#include <linux/irqreturn.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 TIMER_IRQ_EN_REG 0x00
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#define TIMER_IRQ_EN(val) BIT(val)
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#define TIMER_IRQ_ST_REG 0x04
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#define TIMER_CTL_REG(val) (0x10 * val + 0x10)
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#define TIMER_CTL_ENABLE BIT(0)
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#define TIMER_CTL_RELOAD BIT(1)
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#define TIMER_CTL_ONESHOT BIT(7)
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#define TIMER_INTVAL_REG(val) (0x10 * (val) + 0x14)
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#define TIMER_CNTVAL_REG(val) (0x10 * (val) + 0x18)
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#define TIMER_SCAL 16
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static void __iomem *timer_base;
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static void sun4i_clkevt_mode(enum clock_event_mode mode,
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struct clock_event_device *clk)
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{
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u32 u = readl(timer_base + TIMER_CTL_REG(0));
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switch (mode) {
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case CLOCK_EVT_MODE_PERIODIC:
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u &= ~(TIMER_CTL_ONESHOT);
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writel(u | TIMER_CTL_ENABLE, timer_base + TIMER_CTL_REG(0));
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break;
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case CLOCK_EVT_MODE_ONESHOT:
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writel(u | TIMER_CTL_ONESHOT, timer_base + TIMER_CTL_REG(0));
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break;
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case CLOCK_EVT_MODE_UNUSED:
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case CLOCK_EVT_MODE_SHUTDOWN:
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default:
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writel(u & ~(TIMER_CTL_ENABLE), timer_base + TIMER_CTL_REG(0));
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break;
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}
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}
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static int sun4i_clkevt_next_event(unsigned long evt,
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struct clock_event_device *unused)
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{
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u32 u = readl(timer_base + TIMER_CTL_REG(0));
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writel(evt, timer_base + TIMER_CNTVAL_REG(0));
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writel(u | TIMER_CTL_ENABLE | TIMER_CTL_AUTORELOAD,
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timer_base + TIMER_CTL_REG(0));
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return 0;
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}
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static struct clock_event_device sun4i_clockevent = {
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.name = "sun4i_tick",
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.rating = 300,
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.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
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.set_mode = sun4i_clkevt_mode,
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.set_next_event = sun4i_clkevt_next_event,
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};
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static irqreturn_t sun4i_timer_interrupt(int irq, void *dev_id)
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{
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struct clock_event_device *evt = (struct clock_event_device *)dev_id;
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writel(0x1, timer_base + TIMER_IRQ_ST_REG);
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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 sun4i_timer_irq = {
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.name = "sun4i_timer0",
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.flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
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.handler = sun4i_timer_interrupt,
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.dev_id = &sun4i_clockevent,
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};
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static void __init sun4i_timer_init(struct device_node *node)
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{
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unsigned long rate = 0;
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struct clk *clk;
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int ret, irq;
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u32 val;
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timer_base = of_iomap(node, 0);
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if (!timer_base)
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panic("Can't map registers");
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irq = irq_of_parse_and_map(node, 0);
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if (irq <= 0)
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panic("Can't parse IRQ");
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clk = of_clk_get(node, 0);
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if (IS_ERR(clk))
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panic("Can't get timer clock");
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rate = clk_get_rate(clk);
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writel(rate / (TIMER_SCAL * HZ),
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timer_base + TIMER_INTVAL_REG(0));
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/* set clock source to HOSC, 16 pre-division */
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val = readl(timer_base + TIMER_CTL_REG(0));
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val &= ~(0x07 << 4);
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val &= ~(0x03 << 2);
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val |= (4 << 4) | (1 << 2);
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writel(val, timer_base + TIMER_CTL_REG(0));
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/* set mode to auto reload */
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val = readl(timer_base + TIMER_CTL_REG(0));
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writel(val | TIMER_CTL_RELOAD, timer_base + TIMER_CTL_REG(0));
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ret = setup_irq(irq, &sun4i_timer_irq);
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if (ret)
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pr_warn("failed to setup irq %d\n", irq);
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/* Enable timer0 interrupt */
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val = readl(timer_base + TIMER_IRQ_EN_REG);
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writel(val | TIMER_IRQ_EN(0), timer_base + TIMER_IRQ_EN_REG);
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sun4i_clockevent.cpumask = cpumask_of(0);
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clockevents_config_and_register(&sun4i_clockevent, rate / TIMER_SCAL,
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0x1, 0xff);
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}
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CLOCKSOURCE_OF_DECLARE(sun4i, "allwinner,sun4i-timer",
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sun4i_timer_init);
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