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![Geert Uytterhoeven](/assets/img/avatar_default.png)
Currently all OSTM devices are called "ostm", also in kernel messages. As there can be multiple instances in an SoC, this can confuse the user. Hence construct a unique name from the DT node name, like is done for platform devices. On RSK+RZA1, the boot log changes like: -clocksource: ostm: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 57352151442 ns +clocksource: timer@fcfec000: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 57352151442 ns sched_clock: 32 bits at 33MHz, resolution 30ns, wraps every 64440619504ns -ostm: used for clocksource -ostm: used for clock events +/soc/timer@fcfec000: used for clocksource +/soc/timer@fcfec400: used for clock events ... -clocksource: Switched to clocksource ostm +clocksource: Switched to clocksource timer@fcfec000 Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Link: https://lore.kernel.org/r/20191016144747.29538-5-geert+renesas@glider.be
211 lines
4.8 KiB
C
211 lines
4.8 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Renesas Timer Support - OSTM
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*
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* Copyright (C) 2017 Renesas Electronics America, Inc.
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* Copyright (C) 2017 Chris Brandt
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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/sched_clock.h>
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#include <linux/slab.h>
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#include "timer-of.h"
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/*
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* The OSTM contains independent channels.
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* The first OSTM channel probed will be set up as a free running
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* clocksource. Additionally we will use this clocksource for the system
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* schedule timer sched_clock().
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*
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* The second (or more) channel probed will be set up as an interrupt
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* driven clock event.
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*/
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static void __iomem *system_clock; /* For sched_clock() */
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/* OSTM REGISTERS */
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#define OSTM_CMP 0x000 /* RW,32 */
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#define OSTM_CNT 0x004 /* R,32 */
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#define OSTM_TE 0x010 /* R,8 */
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#define OSTM_TS 0x014 /* W,8 */
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#define OSTM_TT 0x018 /* W,8 */
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#define OSTM_CTL 0x020 /* RW,8 */
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#define TE 0x01
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#define TS 0x01
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#define TT 0x01
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#define CTL_PERIODIC 0x00
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#define CTL_ONESHOT 0x02
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#define CTL_FREERUN 0x02
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static void ostm_timer_stop(struct timer_of *to)
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{
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if (readb(timer_of_base(to) + OSTM_TE) & TE) {
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writeb(TT, timer_of_base(to) + OSTM_TT);
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/*
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* Read back the register simply to confirm the write operation
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* has completed since I/O writes can sometimes get queued by
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* the bus architecture.
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*/
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while (readb(timer_of_base(to) + OSTM_TE) & TE)
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;
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}
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}
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static int __init ostm_init_clksrc(struct timer_of *to)
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{
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ostm_timer_stop(to);
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writel(0, timer_of_base(to) + OSTM_CMP);
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writeb(CTL_FREERUN, timer_of_base(to) + OSTM_CTL);
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writeb(TS, timer_of_base(to) + OSTM_TS);
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return clocksource_mmio_init(timer_of_base(to) + OSTM_CNT,
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to->np->full_name, timer_of_rate(to), 300,
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32, clocksource_mmio_readl_up);
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}
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static u64 notrace ostm_read_sched_clock(void)
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{
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return readl(system_clock);
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}
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static void __init ostm_init_sched_clock(struct timer_of *to)
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{
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system_clock = timer_of_base(to) + OSTM_CNT;
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sched_clock_register(ostm_read_sched_clock, 32, timer_of_rate(to));
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}
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static int ostm_clock_event_next(unsigned long delta,
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struct clock_event_device *ced)
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{
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struct timer_of *to = to_timer_of(ced);
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ostm_timer_stop(to);
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writel(delta, timer_of_base(to) + OSTM_CMP);
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writeb(CTL_ONESHOT, timer_of_base(to) + OSTM_CTL);
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writeb(TS, timer_of_base(to) + OSTM_TS);
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return 0;
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}
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static int ostm_shutdown(struct clock_event_device *ced)
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{
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struct timer_of *to = to_timer_of(ced);
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ostm_timer_stop(to);
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return 0;
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}
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static int ostm_set_periodic(struct clock_event_device *ced)
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{
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struct timer_of *to = to_timer_of(ced);
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if (clockevent_state_oneshot(ced) || clockevent_state_periodic(ced))
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ostm_timer_stop(to);
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writel(timer_of_period(to) - 1, timer_of_base(to) + OSTM_CMP);
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writeb(CTL_PERIODIC, timer_of_base(to) + OSTM_CTL);
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writeb(TS, timer_of_base(to) + OSTM_TS);
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return 0;
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}
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static int ostm_set_oneshot(struct clock_event_device *ced)
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{
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struct timer_of *to = to_timer_of(ced);
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ostm_timer_stop(to);
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return 0;
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}
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static irqreturn_t ostm_timer_interrupt(int irq, void *dev_id)
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{
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struct clock_event_device *ced = dev_id;
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if (clockevent_state_oneshot(ced))
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ostm_timer_stop(to_timer_of(ced));
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/* notify clockevent layer */
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if (ced->event_handler)
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ced->event_handler(ced);
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return IRQ_HANDLED;
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}
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static int __init ostm_init_clkevt(struct timer_of *to)
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{
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struct clock_event_device *ced = &to->clkevt;
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ced->features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC;
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ced->set_state_shutdown = ostm_shutdown;
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ced->set_state_periodic = ostm_set_periodic;
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ced->set_state_oneshot = ostm_set_oneshot;
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ced->set_next_event = ostm_clock_event_next;
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ced->shift = 32;
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ced->rating = 300;
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ced->cpumask = cpumask_of(0);
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clockevents_config_and_register(ced, timer_of_rate(to), 0xf,
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0xffffffff);
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return 0;
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}
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static int __init ostm_init(struct device_node *np)
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{
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struct timer_of *to;
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int ret;
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to = kzalloc(sizeof(*to), GFP_KERNEL);
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if (!to)
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return -ENOMEM;
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to->flags = TIMER_OF_BASE | TIMER_OF_CLOCK;
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if (system_clock) {
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/*
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* clock sources don't use interrupts, clock events do
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*/
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to->flags |= TIMER_OF_IRQ;
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to->of_irq.flags = IRQF_TIMER | IRQF_IRQPOLL;
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to->of_irq.handler = ostm_timer_interrupt;
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}
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ret = timer_of_init(np, to);
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if (ret)
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goto err_free;
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/*
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* First probed device will be used as system clocksource. Any
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* additional devices will be used as clock events.
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*/
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if (!system_clock) {
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ret = ostm_init_clksrc(to);
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if (ret)
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goto err_cleanup;
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ostm_init_sched_clock(to);
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pr_info("%pOF: used for clocksource\n", np);
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} else {
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ret = ostm_init_clkevt(to);
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if (ret)
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goto err_cleanup;
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pr_info("%pOF: used for clock events\n", np);
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}
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return 0;
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err_cleanup:
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timer_of_cleanup(to);
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err_free:
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kfree(to);
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return ret;
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}
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TIMER_OF_DECLARE(ostm, "renesas,ostm", ostm_init);
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