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220 lines
5.7 KiB
220 lines
5.7 KiB
/*
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* linux/drivers/clocksource/zevio-timer.c
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*
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* Copyright (C) 2013 Daniel Tang <tangrs@tangrs.id.au>
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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 version 2, as
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* published by the Free Software Foundation.
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*
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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/of.h>
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#include <linux/of_address.h>
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#include <linux/of_irq.h>
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#include <linux/clk.h>
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#include <linux/clockchips.h>
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#include <linux/cpumask.h>
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#include <linux/interrupt.h>
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#include <linux/slab.h>
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#define IO_CURRENT_VAL 0x00
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#define IO_DIVIDER 0x04
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#define IO_CONTROL 0x08
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#define IO_TIMER1 0x00
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#define IO_TIMER2 0x0C
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#define IO_MATCH_BEGIN 0x18
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#define IO_MATCH(x) (IO_MATCH_BEGIN + ((x) << 2))
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#define IO_INTR_STS 0x00
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#define IO_INTR_ACK 0x00
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#define IO_INTR_MSK 0x04
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#define CNTL_STOP_TIMER (1 << 4)
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#define CNTL_RUN_TIMER (0 << 4)
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#define CNTL_INC (1 << 3)
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#define CNTL_DEC (0 << 3)
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#define CNTL_TOZERO 0
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#define CNTL_MATCH(x) ((x) + 1)
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#define CNTL_FOREVER 7
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/* There are 6 match registers but we only use one. */
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#define TIMER_MATCH 0
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#define TIMER_INTR_MSK (1 << (TIMER_MATCH))
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#define TIMER_INTR_ALL 0x3F
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struct zevio_timer {
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void __iomem *base;
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void __iomem *timer1, *timer2;
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void __iomem *interrupt_regs;
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struct clk *clk;
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struct clock_event_device clkevt;
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struct irqaction clkevt_irq;
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char clocksource_name[64];
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char clockevent_name[64];
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};
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static int zevio_timer_set_event(unsigned long delta,
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struct clock_event_device *dev)
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{
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struct zevio_timer *timer = container_of(dev, struct zevio_timer,
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clkevt);
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writel(delta, timer->timer1 + IO_CURRENT_VAL);
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writel(CNTL_RUN_TIMER | CNTL_DEC | CNTL_MATCH(TIMER_MATCH),
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timer->timer1 + IO_CONTROL);
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return 0;
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}
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static void zevio_timer_set_mode(enum clock_event_mode mode,
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struct clock_event_device *dev)
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{
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struct zevio_timer *timer = container_of(dev, struct zevio_timer,
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clkevt);
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switch (mode) {
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case CLOCK_EVT_MODE_RESUME:
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case CLOCK_EVT_MODE_ONESHOT:
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/* Enable timer interrupts */
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writel(TIMER_INTR_MSK, timer->interrupt_regs + IO_INTR_MSK);
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writel(TIMER_INTR_ALL, timer->interrupt_regs + IO_INTR_ACK);
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break;
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case CLOCK_EVT_MODE_SHUTDOWN:
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case CLOCK_EVT_MODE_UNUSED:
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/* Disable timer interrupts */
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writel(0, timer->interrupt_regs + IO_INTR_MSK);
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writel(TIMER_INTR_ALL, timer->interrupt_regs + IO_INTR_ACK);
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/* Stop timer */
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writel(CNTL_STOP_TIMER, timer->timer1 + IO_CONTROL);
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break;
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case CLOCK_EVT_MODE_PERIODIC:
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default:
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/* Unsupported */
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break;
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}
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}
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static irqreturn_t zevio_timer_interrupt(int irq, void *dev_id)
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{
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struct zevio_timer *timer = dev_id;
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u32 intr;
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intr = readl(timer->interrupt_regs + IO_INTR_ACK);
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if (!(intr & TIMER_INTR_MSK))
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return IRQ_NONE;
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writel(TIMER_INTR_MSK, timer->interrupt_regs + IO_INTR_ACK);
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writel(CNTL_STOP_TIMER, timer->timer1 + IO_CONTROL);
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if (timer->clkevt.event_handler)
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timer->clkevt.event_handler(&timer->clkevt);
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return IRQ_HANDLED;
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}
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static int __init zevio_timer_add(struct device_node *node)
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{
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struct zevio_timer *timer;
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struct resource res;
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int irqnr, ret;
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timer = kzalloc(sizeof(*timer), GFP_KERNEL);
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if (!timer)
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return -ENOMEM;
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timer->base = of_iomap(node, 0);
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if (!timer->base) {
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ret = -EINVAL;
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goto error_free;
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}
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timer->timer1 = timer->base + IO_TIMER1;
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timer->timer2 = timer->base + IO_TIMER2;
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timer->clk = of_clk_get(node, 0);
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if (IS_ERR(timer->clk)) {
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ret = PTR_ERR(timer->clk);
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pr_err("Timer clock not found! (error %d)\n", ret);
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goto error_unmap;
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}
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timer->interrupt_regs = of_iomap(node, 1);
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irqnr = irq_of_parse_and_map(node, 0);
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of_address_to_resource(node, 0, &res);
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scnprintf(timer->clocksource_name, sizeof(timer->clocksource_name),
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"%llx.%s_clocksource",
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(unsigned long long)res.start, node->name);
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scnprintf(timer->clockevent_name, sizeof(timer->clockevent_name),
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"%llx.%s_clockevent",
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(unsigned long long)res.start, node->name);
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if (timer->interrupt_regs && irqnr) {
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timer->clkevt.name = timer->clockevent_name;
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timer->clkevt.set_next_event = zevio_timer_set_event;
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timer->clkevt.set_mode = zevio_timer_set_mode;
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timer->clkevt.rating = 200;
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timer->clkevt.cpumask = cpu_all_mask;
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timer->clkevt.features = CLOCK_EVT_FEAT_ONESHOT;
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timer->clkevt.irq = irqnr;
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writel(CNTL_STOP_TIMER, timer->timer1 + IO_CONTROL);
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writel(0, timer->timer1 + IO_DIVIDER);
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/* Start with timer interrupts disabled */
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writel(0, timer->interrupt_regs + IO_INTR_MSK);
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writel(TIMER_INTR_ALL, timer->interrupt_regs + IO_INTR_ACK);
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/* Interrupt to occur when timer value matches 0 */
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writel(0, timer->base + IO_MATCH(TIMER_MATCH));
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timer->clkevt_irq.name = timer->clockevent_name;
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timer->clkevt_irq.handler = zevio_timer_interrupt;
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timer->clkevt_irq.dev_id = timer;
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timer->clkevt_irq.flags = IRQF_TIMER | IRQF_IRQPOLL;
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setup_irq(irqnr, &timer->clkevt_irq);
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clockevents_config_and_register(&timer->clkevt,
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clk_get_rate(timer->clk), 0x0001, 0xffff);
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pr_info("Added %s as clockevent\n", timer->clockevent_name);
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}
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writel(CNTL_STOP_TIMER, timer->timer2 + IO_CONTROL);
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writel(0, timer->timer2 + IO_CURRENT_VAL);
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writel(0, timer->timer2 + IO_DIVIDER);
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writel(CNTL_RUN_TIMER | CNTL_FOREVER | CNTL_INC,
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timer->timer2 + IO_CONTROL);
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clocksource_mmio_init(timer->timer2 + IO_CURRENT_VAL,
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timer->clocksource_name,
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clk_get_rate(timer->clk),
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200, 16,
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clocksource_mmio_readw_up);
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pr_info("Added %s as clocksource\n", timer->clocksource_name);
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return 0;
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error_unmap:
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iounmap(timer->base);
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error_free:
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kfree(timer);
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return ret;
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}
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static void __init zevio_timer_init(struct device_node *node)
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{
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BUG_ON(zevio_timer_add(node));
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}
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CLOCKSOURCE_OF_DECLARE(zevio_timer, "lsi,zevio-timer", zevio_timer_init);
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