/*
* Time related functions for Hexagon architecture
*
* Copyright (c) 2010-2011, Code Aurora Forum. 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;
struct device_node *dn;
struct resource r;
int err;
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;
}
/*
* 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);
