From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Thu, 11 Apr 2024 10:27:49 +0200 Subject: Adding upstream version 6.6.15. Signed-off-by: Daniel Baumann --- drivers/clocksource/mips-gic-timer.c | 269 +++++++++++++++++++++++++++++++++++ 1 file changed, 269 insertions(+) create mode 100644 drivers/clocksource/mips-gic-timer.c (limited to 'drivers/clocksource/mips-gic-timer.c') diff --git a/drivers/clocksource/mips-gic-timer.c b/drivers/clocksource/mips-gic-timer.c new file mode 100644 index 0000000000..b3ae38f367 --- /dev/null +++ b/drivers/clocksource/mips-gic-timer.c @@ -0,0 +1,269 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (C) 2012 MIPS Technologies, Inc. All rights reserved. + +#define pr_fmt(fmt) "mips-gic-timer: " fmt + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +static DEFINE_PER_CPU(struct clock_event_device, gic_clockevent_device); +static int gic_timer_irq; +static unsigned int gic_frequency; +static bool __read_mostly gic_clock_unstable; + +static void gic_clocksource_unstable(char *reason); + +static u64 notrace gic_read_count_2x32(void) +{ + unsigned int hi, hi2, lo; + + do { + hi = read_gic_counter_32h(); + lo = read_gic_counter_32l(); + hi2 = read_gic_counter_32h(); + } while (hi2 != hi); + + return (((u64) hi) << 32) + lo; +} + +static u64 notrace gic_read_count_64(void) +{ + return read_gic_counter(); +} + +static u64 notrace gic_read_count(void) +{ + if (mips_cm_is64) + return gic_read_count_64(); + + return gic_read_count_2x32(); +} + +static int gic_next_event(unsigned long delta, struct clock_event_device *evt) +{ + int cpu = cpumask_first(evt->cpumask); + u64 cnt; + int res; + + cnt = gic_read_count(); + cnt += (u64)delta; + if (cpu == raw_smp_processor_id()) { + write_gic_vl_compare(cnt); + } else { + write_gic_vl_other(mips_cm_vp_id(cpu)); + write_gic_vo_compare(cnt); + } + res = ((int)(gic_read_count() - cnt) >= 0) ? -ETIME : 0; + return res; +} + +static irqreturn_t gic_compare_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *cd = dev_id; + + write_gic_vl_compare(read_gic_vl_compare()); + cd->event_handler(cd); + return IRQ_HANDLED; +} + +static struct irqaction gic_compare_irqaction = { + .handler = gic_compare_interrupt, + .percpu_dev_id = &gic_clockevent_device, + .flags = IRQF_PERCPU | IRQF_TIMER, + .name = "timer", +}; + +static void gic_clockevent_cpu_init(unsigned int cpu, + struct clock_event_device *cd) +{ + cd->name = "MIPS GIC"; + cd->features = CLOCK_EVT_FEAT_ONESHOT | + CLOCK_EVT_FEAT_C3STOP; + + cd->rating = 350; + cd->irq = gic_timer_irq; + cd->cpumask = cpumask_of(cpu); + cd->set_next_event = gic_next_event; + + clockevents_config_and_register(cd, gic_frequency, 0x300, 0x7fffffff); + + enable_percpu_irq(gic_timer_irq, IRQ_TYPE_NONE); +} + +static void gic_clockevent_cpu_exit(struct clock_event_device *cd) +{ + disable_percpu_irq(gic_timer_irq); +} + +static void gic_update_frequency(void *data) +{ + unsigned long rate = (unsigned long)data; + + clockevents_update_freq(this_cpu_ptr(&gic_clockevent_device), rate); +} + +static int gic_starting_cpu(unsigned int cpu) +{ + gic_clockevent_cpu_init(cpu, this_cpu_ptr(&gic_clockevent_device)); + return 0; +} + +static int gic_clk_notifier(struct notifier_block *nb, unsigned long action, + void *data) +{ + struct clk_notifier_data *cnd = data; + + if (action == POST_RATE_CHANGE) { + gic_clocksource_unstable("ref clock rate change"); + on_each_cpu(gic_update_frequency, (void *)cnd->new_rate, 1); + } + + return NOTIFY_OK; +} + +static int gic_dying_cpu(unsigned int cpu) +{ + gic_clockevent_cpu_exit(this_cpu_ptr(&gic_clockevent_device)); + return 0; +} + +static struct notifier_block gic_clk_nb = { + .notifier_call = gic_clk_notifier, +}; + +static int gic_clockevent_init(void) +{ + int ret; + + if (!gic_frequency) + return -ENXIO; + + ret = setup_percpu_irq(gic_timer_irq, &gic_compare_irqaction); + if (ret < 0) { + pr_err("IRQ %d setup failed (%d)\n", gic_timer_irq, ret); + return ret; + } + + cpuhp_setup_state(CPUHP_AP_MIPS_GIC_TIMER_STARTING, + "clockevents/mips/gic/timer:starting", + gic_starting_cpu, gic_dying_cpu); + return 0; +} + +static u64 gic_hpt_read(struct clocksource *cs) +{ + return gic_read_count(); +} + +static struct clocksource gic_clocksource = { + .name = "GIC", + .read = gic_hpt_read, + .flags = CLOCK_SOURCE_IS_CONTINUOUS, + .vdso_clock_mode = VDSO_CLOCKMODE_GIC, +}; + +static void gic_clocksource_unstable(char *reason) +{ + if (gic_clock_unstable) + return; + + gic_clock_unstable = true; + + pr_info("GIC timer is unstable due to %s\n", reason); + + clocksource_mark_unstable(&gic_clocksource); +} + +static int __init __gic_clocksource_init(void) +{ + unsigned int count_width; + int ret; + + /* Set clocksource mask. */ + count_width = read_gic_config() & GIC_CONFIG_COUNTBITS; + count_width >>= __ffs(GIC_CONFIG_COUNTBITS); + count_width *= 4; + count_width += 32; + gic_clocksource.mask = CLOCKSOURCE_MASK(count_width); + + /* Calculate a somewhat reasonable rating value. */ + gic_clocksource.rating = 200 + gic_frequency / 10000000; + + ret = clocksource_register_hz(&gic_clocksource, gic_frequency); + if (ret < 0) + pr_warn("Unable to register clocksource\n"); + + return ret; +} + +static int __init gic_clocksource_of_init(struct device_node *node) +{ + struct clk *clk; + int ret; + + if (!mips_gic_present() || !node->parent || + !of_device_is_compatible(node->parent, "mti,gic")) { + pr_warn("No DT definition\n"); + return -ENXIO; + } + + clk = of_clk_get(node, 0); + if (!IS_ERR(clk)) { + ret = clk_prepare_enable(clk); + if (ret < 0) { + pr_err("Failed to enable clock\n"); + clk_put(clk); + return ret; + } + + gic_frequency = clk_get_rate(clk); + } else if (of_property_read_u32(node, "clock-frequency", + &gic_frequency)) { + pr_err("Frequency not specified\n"); + return -EINVAL; + } + gic_timer_irq = irq_of_parse_and_map(node, 0); + if (!gic_timer_irq) { + pr_err("IRQ not specified\n"); + return -EINVAL; + } + + ret = __gic_clocksource_init(); + if (ret) + return ret; + + ret = gic_clockevent_init(); + if (!ret && !IS_ERR(clk)) { + if (clk_notifier_register(clk, &gic_clk_nb) < 0) + pr_warn("Unable to register clock notifier\n"); + } + + /* And finally start the counter */ + clear_gic_config(GIC_CONFIG_COUNTSTOP); + + /* + * It's safe to use the MIPS GIC timer as a sched clock source only if + * its ticks are stable, which is true on either the platforms with + * stable CPU frequency or on the platforms with CM3 and CPU frequency + * change performed by the CPC core clocks divider. + */ + if (mips_cm_revision() >= CM_REV_CM3 || !IS_ENABLED(CONFIG_CPU_FREQ)) { + sched_clock_register(mips_cm_is64 ? + gic_read_count_64 : gic_read_count_2x32, + 64, gic_frequency); + } + + return 0; +} +TIMER_OF_DECLARE(mips_gic_timer, "mti,gic-timer", + gic_clocksource_of_init); -- cgit v1.2.3