| /* |
| * Time related functions for Hexagon architecture |
| * |
| * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved. |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 and |
| * only version 2 as published by the Free Software Foundation. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| * 02110-1301, USA. |
| */ |
| |
| #include <linux/init.h> |
| #include <linux/clockchips.h> |
| #include <linux/clocksource.h> |
| #include <linux/interrupt.h> |
| #include <linux/err.h> |
| #include <linux/platform_device.h> |
| #include <linux/ioport.h> |
| #include <linux/of.h> |
| #include <linux/of_address.h> |
| #include <linux/of_irq.h> |
| #include <linux/module.h> |
| |
| #include <asm/timer-regs.h> |
| #include <asm/hexagon_vm.h> |
| |
| /* |
| * For the clocksource we need: |
| * pcycle frequency (600MHz) |
| * For the loops_per_jiffy we need: |
| * thread/cpu frequency (100MHz) |
| * And for the timer, we need: |
| * sleep clock rate |
| */ |
| |
| cycles_t pcycle_freq_mhz; |
| cycles_t thread_freq_mhz; |
| cycles_t sleep_clk_freq; |
| |
| static struct resource rtos_timer_resources[] = { |
| { |
| .start = RTOS_TIMER_REGS_ADDR, |
| .end = RTOS_TIMER_REGS_ADDR+PAGE_SIZE-1, |
| .flags = IORESOURCE_MEM, |
| }, |
| }; |
| |
| static struct platform_device rtos_timer_device = { |
| .name = "rtos_timer", |
| .id = -1, |
| .num_resources = ARRAY_SIZE(rtos_timer_resources), |
| .resource = rtos_timer_resources, |
| }; |
| |
| /* A lot of this stuff should move into a platform specific section. */ |
| struct adsp_hw_timer_struct { |
| u32 match; /* Match value */ |
| u32 count; |
| u32 enable; /* [1] - CLR_ON_MATCH_EN, [0] - EN */ |
| u32 clear; /* one-shot register that clears the count */ |
| }; |
| |
| /* Look for "TCX0" for related constants. */ |
| static __iomem struct adsp_hw_timer_struct *rtos_timer; |
| |
| static cycle_t timer_get_cycles(struct clocksource *cs) |
| { |
| return (cycle_t) __vmgettime(); |
| } |
| |
| static struct clocksource hexagon_clocksource = { |
| .name = "pcycles", |
| .rating = 250, |
| .read = timer_get_cycles, |
| .mask = CLOCKSOURCE_MASK(64), |
| .flags = CLOCK_SOURCE_IS_CONTINUOUS, |
| }; |
| |
| static int set_next_event(unsigned long delta, struct clock_event_device *evt) |
| { |
| /* Assuming the timer will be disabled when we enter here. */ |
| |
| iowrite32(1, &rtos_timer->clear); |
| iowrite32(0, &rtos_timer->clear); |
| |
| iowrite32(delta, &rtos_timer->match); |
| iowrite32(1 << TIMER_ENABLE, &rtos_timer->enable); |
| return 0; |
| } |
| |
| /* |
| * Sets the mode (periodic, shutdown, oneshot, etc) of a timer. |
| */ |
| static void set_mode(enum clock_event_mode mode, |
| struct clock_event_device *evt) |
| { |
| switch (mode) { |
| case CLOCK_EVT_MODE_SHUTDOWN: |
| /* XXX implement me */ |
| default: |
| break; |
| } |
| } |
| |
| #ifdef CONFIG_SMP |
| /* Broadcast mechanism */ |
| static void broadcast(const struct cpumask *mask) |
| { |
| send_ipi(mask, IPI_TIMER); |
| } |
| #endif |
| |
| static struct clock_event_device hexagon_clockevent_dev = { |
| .name = "clockevent", |
| .features = CLOCK_EVT_FEAT_ONESHOT, |
| .rating = 400, |
| .irq = RTOS_TIMER_INT, |
| .set_next_event = set_next_event, |
| .set_mode = set_mode, |
| #ifdef CONFIG_SMP |
| .broadcast = broadcast, |
| #endif |
| }; |
| |
| #ifdef CONFIG_SMP |
| static DEFINE_PER_CPU(struct clock_event_device, clock_events); |
| |
| void setup_percpu_clockdev(void) |
| { |
| int cpu = smp_processor_id(); |
| struct clock_event_device *ce_dev = &hexagon_clockevent_dev; |
| struct clock_event_device *dummy_clock_dev = |
| &per_cpu(clock_events, cpu); |
| |
| memcpy(dummy_clock_dev, ce_dev, sizeof(*dummy_clock_dev)); |
| INIT_LIST_HEAD(&dummy_clock_dev->list); |
| |
| dummy_clock_dev->features = CLOCK_EVT_FEAT_DUMMY; |
| dummy_clock_dev->cpumask = cpumask_of(cpu); |
| dummy_clock_dev->mode = CLOCK_EVT_MODE_UNUSED; |
| |
| clockevents_register_device(dummy_clock_dev); |
| } |
| |
| /* Called from smp.c for each CPU's timer ipi call */ |
| void ipi_timer(void) |
| { |
| int cpu = smp_processor_id(); |
| struct clock_event_device *ce_dev = &per_cpu(clock_events, cpu); |
| |
| ce_dev->event_handler(ce_dev); |
| } |
| #endif /* CONFIG_SMP */ |
| |
| static irqreturn_t timer_interrupt(int irq, void *devid) |
| { |
| struct clock_event_device *ce_dev = &hexagon_clockevent_dev; |
| |
| iowrite32(0, &rtos_timer->enable); |
| ce_dev->event_handler(ce_dev); |
| |
| return IRQ_HANDLED; |
| } |
| |
| /* This should also be pulled from devtree */ |
| static struct irqaction rtos_timer_intdesc = { |
| .handler = timer_interrupt, |
| .flags = IRQF_TIMER | IRQF_TRIGGER_RISING, |
| .name = "rtos_timer" |
| }; |
| |
| /* |
| * time_init_deferred - called by start_kernel to set up timer/clock source |
| * |
| * Install the IRQ handler for the clock, setup timers. |
| * This is done late, as that way, we can use ioremap(). |
| * |
| * This runs just before the delay loop is calibrated, and |
| * is used for delay calibration. |
| */ |
| void __init time_init_deferred(void) |
| { |
| struct resource *resource = NULL; |
| struct clock_event_device *ce_dev = &hexagon_clockevent_dev; |
| |
| ce_dev->cpumask = cpu_all_mask; |
| |
| if (!resource) |
| resource = rtos_timer_device.resource; |
| |
| /* ioremap here means this has to run later, after paging init */ |
| rtos_timer = ioremap(resource->start, resource_size(resource)); |
| |
| if (!rtos_timer) { |
| release_mem_region(resource->start, resource_size(resource)); |
| } |
| clocksource_register_khz(&hexagon_clocksource, pcycle_freq_mhz * 1000); |
| |
| /* Note: the sim generic RTOS clock is apparently really 18750Hz */ |
| |
| /* |
| * Last arg is some guaranteed seconds for which the conversion will |
| * work without overflow. |
| */ |
| clockevents_calc_mult_shift(ce_dev, sleep_clk_freq, 4); |
| |
| ce_dev->max_delta_ns = clockevent_delta2ns(0x7fffffff, ce_dev); |
| ce_dev->min_delta_ns = clockevent_delta2ns(0xf, ce_dev); |
| |
| #ifdef CONFIG_SMP |
| setup_percpu_clockdev(); |
| #endif |
| |
| clockevents_register_device(ce_dev); |
| setup_irq(ce_dev->irq, &rtos_timer_intdesc); |
| } |
| |
| void __init time_init(void) |
| { |
| late_time_init = time_init_deferred; |
| } |
| |
| void __delay(unsigned long cycles) |
| { |
| unsigned long long start = __vmgettime(); |
| |
| while ((__vmgettime() - start) < cycles) |
| cpu_relax(); |
| } |
| EXPORT_SYMBOL(__delay); |
| |
| /* |
| * This could become parametric or perhaps even computed at run-time, |
| * but for now we take the observed simulator jitter. |
| */ |
| static long long fudgefactor = 350; /* Maybe lower if kernel optimized. */ |
| |
| void __udelay(unsigned long usecs) |
| { |
| unsigned long long start = __vmgettime(); |
| unsigned long long finish = (pcycle_freq_mhz * usecs) - fudgefactor; |
| |
| while ((__vmgettime() - start) < finish) |
| cpu_relax(); /* not sure how this improves readability */ |
| } |
| EXPORT_SYMBOL(__udelay); |