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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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![Linus Torvalds](/assets/img/avatar_default.png)
Pull timer type cleanups from Thomas Gleixner: "This series does a tree wide cleanup of types related to timers/timekeeping. - Get rid of cycles_t and use a plain u64. The type is not really helpful and caused more confusion than clarity - Get rid of the ktime union. The union has become useless as we use the scalar nanoseconds storage unconditionally now. The 32bit timespec alike storage got removed due to the Y2038 limitations some time ago. That leaves the odd union access around for no reason. Clean it up. Both changes have been done with coccinelle and a small amount of manual mopping up" * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: ktime: Get rid of ktime_equal() ktime: Cleanup ktime_set() usage ktime: Get rid of the union clocksource: Use a plain u64 instead of cycle_t
159 lines
4.5 KiB
C
159 lines
4.5 KiB
C
/*
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* Copyright (C) 2005-2013 Imagination Technologies Ltd.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*
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* Support for Meta per-thread timers.
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*
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* Meta hardware threads have 2 timers. The background timer (TXTIMER) is used
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* as a free-running time base (hz clocksource), and the interrupt timer
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* (TXTIMERI) is used for the timer interrupt (clock event). Both counters
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* traditionally count at approximately 1MHz.
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*/
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#include <clocksource/metag_generic.h>
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#include <linux/cpu.h>
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#include <linux/errno.h>
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/param.h>
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#include <linux/time.h>
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#include <linux/init.h>
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#include <linux/proc_fs.h>
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#include <linux/clocksource.h>
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#include <linux/clockchips.h>
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#include <linux/interrupt.h>
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#include <asm/clock.h>
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#include <asm/hwthread.h>
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#include <asm/core_reg.h>
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#include <asm/metag_mem.h>
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#include <asm/tbx.h>
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#define HARDWARE_FREQ 1000000 /* 1MHz */
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#define HARDWARE_DIV 1 /* divide by 1 = 1MHz clock */
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#define HARDWARE_TO_NS_SHIFT 10 /* convert ticks to ns */
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static unsigned int hwtimer_freq = HARDWARE_FREQ;
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static DEFINE_PER_CPU(struct clock_event_device, local_clockevent);
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static DEFINE_PER_CPU(char [11], local_clockevent_name);
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static int metag_timer_set_next_event(unsigned long delta,
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struct clock_event_device *dev)
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{
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__core_reg_set(TXTIMERI, -delta);
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return 0;
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}
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static u64 metag_clocksource_read(struct clocksource *cs)
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{
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return __core_reg_get(TXTIMER);
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}
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static struct clocksource clocksource_metag = {
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.name = "META",
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.rating = 200,
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.mask = CLOCKSOURCE_MASK(32),
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.read = metag_clocksource_read,
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.flags = CLOCK_SOURCE_IS_CONTINUOUS,
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};
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static irqreturn_t metag_timer_interrupt(int irq, void *dummy)
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{
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struct clock_event_device *evt = this_cpu_ptr(&local_clockevent);
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evt->event_handler(evt);
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return IRQ_HANDLED;
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}
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static struct irqaction metag_timer_irq = {
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.name = "META core timer",
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.handler = metag_timer_interrupt,
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.flags = IRQF_TIMER | IRQF_IRQPOLL | IRQF_PERCPU,
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};
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unsigned long long sched_clock(void)
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{
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unsigned long long ticks = __core_reg_get(TXTIMER);
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return ticks << HARDWARE_TO_NS_SHIFT;
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}
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static int arch_timer_starting_cpu(unsigned int cpu)
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{
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unsigned int txdivtime;
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struct clock_event_device *clk = &per_cpu(local_clockevent, cpu);
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char *name = per_cpu(local_clockevent_name, cpu);
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txdivtime = __core_reg_get(TXDIVTIME);
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txdivtime &= ~TXDIVTIME_DIV_BITS;
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txdivtime |= (HARDWARE_DIV & TXDIVTIME_DIV_BITS);
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__core_reg_set(TXDIVTIME, txdivtime);
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sprintf(name, "META %d", cpu);
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clk->name = name;
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clk->features = CLOCK_EVT_FEAT_ONESHOT,
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clk->rating = 200,
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clk->shift = 12,
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clk->irq = tbisig_map(TBID_SIGNUM_TRT),
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clk->set_next_event = metag_timer_set_next_event,
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clk->mult = div_sc(hwtimer_freq, NSEC_PER_SEC, clk->shift);
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clk->max_delta_ns = clockevent_delta2ns(0x7fffffff, clk);
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clk->min_delta_ns = clockevent_delta2ns(0xf, clk);
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clk->cpumask = cpumask_of(cpu);
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clockevents_register_device(clk);
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/*
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* For all non-boot CPUs we need to synchronize our free
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* running clock (TXTIMER) with the boot CPU's clock.
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*
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* While this won't be accurate, it should be close enough.
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*/
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if (cpu) {
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unsigned int thread0 = cpu_2_hwthread_id[0];
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unsigned long val;
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val = core_reg_read(TXUCT_ID, TXTIMER_REGNUM, thread0);
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__core_reg_set(TXTIMER, val);
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}
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return 0;
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}
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int __init metag_generic_timer_init(void)
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{
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/*
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* On Meta 2 SoCs, the actual frequency of the timer is based on the
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* Meta core clock speed divided by an integer, so it is only
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* approximately 1MHz. Calculating the real frequency here drastically
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* reduces clock skew on these SoCs.
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*/
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#ifdef CONFIG_METAG_META21
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hwtimer_freq = get_coreclock() / (metag_in32(EXPAND_TIMER_DIV) + 1);
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#endif
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pr_info("Timer frequency: %u Hz\n", hwtimer_freq);
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clocksource_register_hz(&clocksource_metag, hwtimer_freq);
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setup_irq(tbisig_map(TBID_SIGNUM_TRT), &metag_timer_irq);
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/* Hook cpu boot to configure the CPU's timers */
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return cpuhp_setup_state(CPUHP_AP_METAG_TIMER_STARTING,
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"clockevents/metag:starting",
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arch_timer_starting_cpu, NULL);
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}
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