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![Daniel Lezcano](/assets/img/avatar_default.png)
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>
249 lines
6.7 KiB
C
249 lines
6.7 KiB
C
/*
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* System timer for CSR SiRFprimaII
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*
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* Copyright (c) 2011 Cambridge Silicon Radio Limited, a CSR plc group company.
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*
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* Licensed under GPLv2 or later.
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*/
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#include <linux/kernel.h>
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#include <linux/interrupt.h>
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#include <linux/clockchips.h>
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#include <linux/clocksource.h>
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#include <linux/bitops.h>
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#include <linux/irq.h>
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#include <linux/clk.h>
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#include <linux/err.h>
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#include <linux/slab.h>
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#include <linux/of.h>
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#include <linux/of_irq.h>
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#include <linux/of_address.h>
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#include <linux/sched_clock.h>
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#define PRIMA2_CLOCK_FREQ 1000000
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#define SIRFSOC_TIMER_COUNTER_LO 0x0000
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#define SIRFSOC_TIMER_COUNTER_HI 0x0004
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#define SIRFSOC_TIMER_MATCH_0 0x0008
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#define SIRFSOC_TIMER_MATCH_1 0x000C
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#define SIRFSOC_TIMER_MATCH_2 0x0010
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#define SIRFSOC_TIMER_MATCH_3 0x0014
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#define SIRFSOC_TIMER_MATCH_4 0x0018
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#define SIRFSOC_TIMER_MATCH_5 0x001C
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#define SIRFSOC_TIMER_STATUS 0x0020
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#define SIRFSOC_TIMER_INT_EN 0x0024
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#define SIRFSOC_TIMER_WATCHDOG_EN 0x0028
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#define SIRFSOC_TIMER_DIV 0x002C
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#define SIRFSOC_TIMER_LATCH 0x0030
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#define SIRFSOC_TIMER_LATCHED_LO 0x0034
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#define SIRFSOC_TIMER_LATCHED_HI 0x0038
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#define SIRFSOC_TIMER_WDT_INDEX 5
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#define SIRFSOC_TIMER_LATCH_BIT BIT(0)
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#define SIRFSOC_TIMER_REG_CNT 11
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static const u32 sirfsoc_timer_reg_list[SIRFSOC_TIMER_REG_CNT] = {
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SIRFSOC_TIMER_MATCH_0, SIRFSOC_TIMER_MATCH_1, SIRFSOC_TIMER_MATCH_2,
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SIRFSOC_TIMER_MATCH_3, SIRFSOC_TIMER_MATCH_4, SIRFSOC_TIMER_MATCH_5,
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SIRFSOC_TIMER_INT_EN, SIRFSOC_TIMER_WATCHDOG_EN, SIRFSOC_TIMER_DIV,
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SIRFSOC_TIMER_LATCHED_LO, SIRFSOC_TIMER_LATCHED_HI,
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};
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static u32 sirfsoc_timer_reg_val[SIRFSOC_TIMER_REG_CNT];
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static void __iomem *sirfsoc_timer_base;
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/* timer0 interrupt handler */
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static irqreturn_t sirfsoc_timer_interrupt(int irq, void *dev_id)
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{
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struct clock_event_device *ce = dev_id;
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WARN_ON(!(readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_STATUS) &
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BIT(0)));
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/* clear timer0 interrupt */
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writel_relaxed(BIT(0), sirfsoc_timer_base + SIRFSOC_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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/* read 64-bit timer counter */
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static u64 notrace sirfsoc_timer_read(struct clocksource *cs)
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{
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u64 cycles;
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/* latch the 64-bit timer counter */
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writel_relaxed(SIRFSOC_TIMER_LATCH_BIT,
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sirfsoc_timer_base + SIRFSOC_TIMER_LATCH);
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cycles = readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_LATCHED_HI);
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cycles = (cycles << 32) |
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readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_LATCHED_LO);
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return cycles;
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}
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static int sirfsoc_timer_set_next_event(unsigned long delta,
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struct clock_event_device *ce)
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{
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unsigned long now, next;
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writel_relaxed(SIRFSOC_TIMER_LATCH_BIT,
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sirfsoc_timer_base + SIRFSOC_TIMER_LATCH);
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now = readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_LATCHED_LO);
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next = now + delta;
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writel_relaxed(next, sirfsoc_timer_base + SIRFSOC_TIMER_MATCH_0);
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writel_relaxed(SIRFSOC_TIMER_LATCH_BIT,
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sirfsoc_timer_base + SIRFSOC_TIMER_LATCH);
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now = readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_LATCHED_LO);
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return next - now > delta ? -ETIME : 0;
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}
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static int sirfsoc_timer_shutdown(struct clock_event_device *evt)
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{
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u32 val = readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_INT_EN);
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writel_relaxed(val & ~BIT(0),
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sirfsoc_timer_base + SIRFSOC_TIMER_INT_EN);
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return 0;
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}
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static int sirfsoc_timer_set_oneshot(struct clock_event_device *evt)
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{
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u32 val = readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_INT_EN);
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writel_relaxed(val | BIT(0), sirfsoc_timer_base + SIRFSOC_TIMER_INT_EN);
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return 0;
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}
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static void sirfsoc_clocksource_suspend(struct clocksource *cs)
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{
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int i;
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writel_relaxed(SIRFSOC_TIMER_LATCH_BIT,
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sirfsoc_timer_base + SIRFSOC_TIMER_LATCH);
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for (i = 0; i < SIRFSOC_TIMER_REG_CNT; i++)
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sirfsoc_timer_reg_val[i] =
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readl_relaxed(sirfsoc_timer_base +
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sirfsoc_timer_reg_list[i]);
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}
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static void sirfsoc_clocksource_resume(struct clocksource *cs)
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{
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int i;
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for (i = 0; i < SIRFSOC_TIMER_REG_CNT - 2; i++)
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writel_relaxed(sirfsoc_timer_reg_val[i],
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sirfsoc_timer_base + sirfsoc_timer_reg_list[i]);
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writel_relaxed(sirfsoc_timer_reg_val[SIRFSOC_TIMER_REG_CNT - 2],
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sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_LO);
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writel_relaxed(sirfsoc_timer_reg_val[SIRFSOC_TIMER_REG_CNT - 1],
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sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_HI);
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}
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static struct clock_event_device sirfsoc_clockevent = {
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.name = "sirfsoc_clockevent",
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.rating = 200,
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.features = CLOCK_EVT_FEAT_ONESHOT,
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.set_state_shutdown = sirfsoc_timer_shutdown,
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.set_state_oneshot = sirfsoc_timer_set_oneshot,
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.set_next_event = sirfsoc_timer_set_next_event,
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};
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static struct clocksource sirfsoc_clocksource = {
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.name = "sirfsoc_clocksource",
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.rating = 200,
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.mask = CLOCKSOURCE_MASK(64),
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.flags = CLOCK_SOURCE_IS_CONTINUOUS,
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.read = sirfsoc_timer_read,
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.suspend = sirfsoc_clocksource_suspend,
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.resume = sirfsoc_clocksource_resume,
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};
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static struct irqaction sirfsoc_timer_irq = {
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.name = "sirfsoc_timer0",
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.flags = IRQF_TIMER,
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.irq = 0,
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.handler = sirfsoc_timer_interrupt,
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.dev_id = &sirfsoc_clockevent,
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};
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/* Overwrite weak default sched_clock with more precise one */
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static u64 notrace sirfsoc_read_sched_clock(void)
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{
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return sirfsoc_timer_read(NULL);
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}
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static void __init sirfsoc_clockevent_init(void)
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{
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sirfsoc_clockevent.cpumask = cpumask_of(0);
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clockevents_config_and_register(&sirfsoc_clockevent, PRIMA2_CLOCK_FREQ,
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2, -2);
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}
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/* initialize the kernel jiffy timer source */
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static int __init sirfsoc_prima2_timer_init(struct device_node *np)
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{
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unsigned long rate;
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struct clk *clk;
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int ret;
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clk = of_clk_get(np, 0);
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if (IS_ERR(clk)) {
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pr_err("Failed to get clock\n");
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return PTR_ERR(clk);
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}
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ret = clk_prepare_enable(clk);
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if (ret) {
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pr_err("Failed to enable clock\n");
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return ret;
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}
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rate = clk_get_rate(clk);
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if (rate < PRIMA2_CLOCK_FREQ || rate % PRIMA2_CLOCK_FREQ) {
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pr_err("Invalid clock rate\n");
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return -EINVAL;
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}
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sirfsoc_timer_base = of_iomap(np, 0);
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if (!sirfsoc_timer_base) {
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pr_err("unable to map timer cpu registers\n");
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return -ENXIO;
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}
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sirfsoc_timer_irq.irq = irq_of_parse_and_map(np, 0);
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writel_relaxed(rate / PRIMA2_CLOCK_FREQ / 2 - 1,
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sirfsoc_timer_base + SIRFSOC_TIMER_DIV);
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writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_LO);
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writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_HI);
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writel_relaxed(BIT(0), sirfsoc_timer_base + SIRFSOC_TIMER_STATUS);
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ret = clocksource_register_hz(&sirfsoc_clocksource, PRIMA2_CLOCK_FREQ);
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if (ret) {
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pr_err("Failed to register clocksource\n");
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return ret;
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}
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sched_clock_register(sirfsoc_read_sched_clock, 64, PRIMA2_CLOCK_FREQ);
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ret = setup_irq(sirfsoc_timer_irq.irq, &sirfsoc_timer_irq);
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if (ret) {
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pr_err("Failed to setup irq\n");
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return ret;
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}
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sirfsoc_clockevent_init();
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return 0;
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}
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TIMER_OF_DECLARE(sirfsoc_prima2_timer,
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"sirf,prima2-tick", sirfsoc_prima2_timer_init);
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