e4db9253d6
In preparation for making the clockevents core NTP correction aware, all clockevent device drivers must set ->min_delta_ticks and ->max_delta_ticks rather than ->min_delta_ns and ->max_delta_ns: a clockevent device's rate is going to change dynamically and thus, the ratio of ns to ticks ceases to stay invariant. Make the MIPS arch's clockevent drivers initialize these fields properly. This patch alone doesn't introduce any change in functionality as the clockevents core still looks exclusively at the (untouched) ->min_delta_ns and ->max_delta_ns. As soon as this has changed, a followup patch will purge the initialization of ->min_delta_ns and ->max_delta_ns from these drivers. Cc: Ingo Molnar <mingo@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Keguang Zhang <keguang.zhang@gmail.com> Cc: John Crispin <john@phrozen.org> Acked-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Nicolai Stange <nicstange@gmail.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
156 lines
3.8 KiB
C
156 lines
3.8 KiB
C
/*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Copyright (C) 2013 by John Crispin <john@phrozen.org>
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*/
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#include <linux/clockchips.h>
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#include <linux/clocksource.h>
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#include <linux/interrupt.h>
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#include <linux/reset.h>
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#include <linux/init.h>
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#include <linux/time.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 <asm/mach-ralink/ralink_regs.h>
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#define SYSTICK_FREQ (50 * 1000)
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#define SYSTICK_CONFIG 0x00
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#define SYSTICK_COMPARE 0x04
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#define SYSTICK_COUNT 0x08
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/* route systick irq to mips irq 7 instead of the r4k-timer */
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#define CFG_EXT_STK_EN 0x2
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/* enable the counter */
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#define CFG_CNT_EN 0x1
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struct systick_device {
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void __iomem *membase;
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struct clock_event_device dev;
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int irq_requested;
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int freq_scale;
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};
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static int systick_set_oneshot(struct clock_event_device *evt);
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static int systick_shutdown(struct clock_event_device *evt);
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static int systick_next_event(unsigned long delta,
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struct clock_event_device *evt)
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{
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struct systick_device *sdev;
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u32 count;
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sdev = container_of(evt, struct systick_device, dev);
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count = ioread32(sdev->membase + SYSTICK_COUNT);
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count = (count + delta) % SYSTICK_FREQ;
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iowrite32(count, sdev->membase + SYSTICK_COMPARE);
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return 0;
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}
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static void systick_event_handler(struct clock_event_device *dev)
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{
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/* noting to do here */
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}
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static irqreturn_t systick_interrupt(int irq, void *dev_id)
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{
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struct clock_event_device *dev = (struct clock_event_device *) dev_id;
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dev->event_handler(dev);
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return IRQ_HANDLED;
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}
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static struct systick_device systick = {
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.dev = {
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/*
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* cevt-r4k uses 300, make sure systick
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* gets used if available
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*/
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.rating = 310,
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.features = CLOCK_EVT_FEAT_ONESHOT,
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.set_next_event = systick_next_event,
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.set_state_shutdown = systick_shutdown,
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.set_state_oneshot = systick_set_oneshot,
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.event_handler = systick_event_handler,
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},
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};
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static struct irqaction systick_irqaction = {
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.handler = systick_interrupt,
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.flags = IRQF_PERCPU | IRQF_TIMER,
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.dev_id = &systick.dev,
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};
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static int systick_shutdown(struct clock_event_device *evt)
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{
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struct systick_device *sdev;
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sdev = container_of(evt, struct systick_device, dev);
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if (sdev->irq_requested)
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free_irq(systick.dev.irq, &systick_irqaction);
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sdev->irq_requested = 0;
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iowrite32(0, systick.membase + SYSTICK_CONFIG);
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return 0;
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}
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static int systick_set_oneshot(struct clock_event_device *evt)
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{
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struct systick_device *sdev;
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sdev = container_of(evt, struct systick_device, dev);
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if (!sdev->irq_requested)
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setup_irq(systick.dev.irq, &systick_irqaction);
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sdev->irq_requested = 1;
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iowrite32(CFG_EXT_STK_EN | CFG_CNT_EN,
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systick.membase + SYSTICK_CONFIG);
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return 0;
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}
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static int __init ralink_systick_init(struct device_node *np)
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{
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int ret;
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systick.membase = of_iomap(np, 0);
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if (!systick.membase)
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return -ENXIO;
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systick_irqaction.name = np->name;
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systick.dev.name = np->name;
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clockevents_calc_mult_shift(&systick.dev, SYSTICK_FREQ, 60);
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systick.dev.max_delta_ns = clockevent_delta2ns(0x7fff, &systick.dev);
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systick.dev.max_delta_ticks = 0x7fff;
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systick.dev.min_delta_ns = clockevent_delta2ns(0x3, &systick.dev);
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systick.dev.min_delta_ticks = 0x3;
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systick.dev.irq = irq_of_parse_and_map(np, 0);
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if (!systick.dev.irq) {
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pr_err("%s: request_irq failed", np->name);
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return -EINVAL;
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}
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ret = clocksource_mmio_init(systick.membase + SYSTICK_COUNT, np->name,
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SYSTICK_FREQ, 301, 16,
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clocksource_mmio_readl_up);
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if (ret)
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return ret;
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clockevents_register_device(&systick.dev);
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pr_info("%s: running - mult: %d, shift: %d\n",
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np->name, systick.dev.mult, systick.dev.shift);
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return 0;
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}
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CLOCKSOURCE_OF_DECLARE(systick, "ralink,cevt-systick", ralink_systick_init);
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