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1727339590
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>
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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TIMER_OF_DECLARE(systick, "ralink,cevt-systick", ralink_systick_init);
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