2012-09-11 04:38:35 +00:00
|
|
|
/*
|
|
|
|
* Copyright 2012 Simon Arlott
|
|
|
|
*
|
|
|
|
* This program is free software; you can redistribute it and/or modify
|
|
|
|
* it under the terms of the GNU General Public License as published by
|
|
|
|
* the Free Software Foundation; either version 2 of the License, or
|
|
|
|
* (at your option) any later version.
|
|
|
|
*
|
|
|
|
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
|
|
|
*/
|
|
|
|
|
|
|
|
#include <linux/bitops.h>
|
|
|
|
#include <linux/clockchips.h>
|
|
|
|
#include <linux/clocksource.h>
|
|
|
|
#include <linux/interrupt.h>
|
|
|
|
#include <linux/irqreturn.h>
|
|
|
|
#include <linux/kernel.h>
|
|
|
|
#include <linux/module.h>
|
|
|
|
#include <linux/of_address.h>
|
|
|
|
#include <linux/of_irq.h>
|
|
|
|
#include <linux/of_platform.h>
|
|
|
|
#include <linux/slab.h>
|
|
|
|
#include <linux/string.h>
|
2013-06-02 06:39:40 +00:00
|
|
|
#include <linux/sched_clock.h>
|
2012-09-11 04:38:35 +00:00
|
|
|
|
|
|
|
#include <asm/irq.h>
|
|
|
|
|
|
|
|
#define REG_CONTROL 0x00
|
|
|
|
#define REG_COUNTER_LO 0x04
|
|
|
|
#define REG_COUNTER_HI 0x08
|
|
|
|
#define REG_COMPARE(n) (0x0c + (n) * 4)
|
|
|
|
#define MAX_TIMER 3
|
|
|
|
#define DEFAULT_TIMER 3
|
|
|
|
|
|
|
|
struct bcm2835_timer {
|
|
|
|
void __iomem *control;
|
|
|
|
void __iomem *compare;
|
|
|
|
int match_mask;
|
|
|
|
struct clock_event_device evt;
|
|
|
|
struct irqaction act;
|
|
|
|
};
|
|
|
|
|
|
|
|
static void __iomem *system_clock __read_mostly;
|
|
|
|
|
2013-07-18 23:21:20 +00:00
|
|
|
static u64 notrace bcm2835_sched_read(void)
|
2012-09-11 04:38:35 +00:00
|
|
|
{
|
|
|
|
return readl_relaxed(system_clock);
|
|
|
|
}
|
|
|
|
|
|
|
|
static int bcm2835_time_set_next_event(unsigned long event,
|
|
|
|
struct clock_event_device *evt_dev)
|
|
|
|
{
|
|
|
|
struct bcm2835_timer *timer = container_of(evt_dev,
|
|
|
|
struct bcm2835_timer, evt);
|
|
|
|
writel_relaxed(readl_relaxed(system_clock) + event,
|
|
|
|
timer->compare);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static irqreturn_t bcm2835_time_interrupt(int irq, void *dev_id)
|
|
|
|
{
|
|
|
|
struct bcm2835_timer *timer = dev_id;
|
|
|
|
void (*event_handler)(struct clock_event_device *);
|
|
|
|
if (readl_relaxed(timer->control) & timer->match_mask) {
|
|
|
|
writel_relaxed(timer->match_mask, timer->control);
|
|
|
|
|
locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns to READ_ONCE()/WRITE_ONCE()
Please do not apply this to mainline directly, instead please re-run the
coccinelle script shown below and apply its output.
For several reasons, it is desirable to use {READ,WRITE}_ONCE() in
preference to ACCESS_ONCE(), and new code is expected to use one of the
former. So far, there's been no reason to change most existing uses of
ACCESS_ONCE(), as these aren't harmful, and changing them results in
churn.
However, for some features, the read/write distinction is critical to
correct operation. To distinguish these cases, separate read/write
accessors must be used. This patch migrates (most) remaining
ACCESS_ONCE() instances to {READ,WRITE}_ONCE(), using the following
coccinelle script:
----
// Convert trivial ACCESS_ONCE() uses to equivalent READ_ONCE() and
// WRITE_ONCE()
// $ make coccicheck COCCI=/home/mark/once.cocci SPFLAGS="--include-headers" MODE=patch
virtual patch
@ depends on patch @
expression E1, E2;
@@
- ACCESS_ONCE(E1) = E2
+ WRITE_ONCE(E1, E2)
@ depends on patch @
expression E;
@@
- ACCESS_ONCE(E)
+ READ_ONCE(E)
----
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: davem@davemloft.net
Cc: linux-arch@vger.kernel.org
Cc: mpe@ellerman.id.au
Cc: shuah@kernel.org
Cc: snitzer@redhat.com
Cc: thor.thayer@linux.intel.com
Cc: tj@kernel.org
Cc: viro@zeniv.linux.org.uk
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/1508792849-3115-19-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-23 21:07:29 +00:00
|
|
|
event_handler = READ_ONCE(timer->evt.event_handler);
|
2012-09-11 04:38:35 +00:00
|
|
|
if (event_handler)
|
|
|
|
event_handler(&timer->evt);
|
|
|
|
return IRQ_HANDLED;
|
|
|
|
} else {
|
|
|
|
return IRQ_NONE;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2016-06-02 16:46:11 +00:00
|
|
|
static int __init bcm2835_timer_init(struct device_node *node)
|
2012-09-11 04:38:35 +00:00
|
|
|
{
|
|
|
|
void __iomem *base;
|
|
|
|
u32 freq;
|
2016-06-02 16:46:11 +00:00
|
|
|
int irq, ret;
|
2012-09-11 04:38:35 +00:00
|
|
|
struct bcm2835_timer *timer;
|
|
|
|
|
|
|
|
base = of_iomap(node, 0);
|
2016-06-02 16:46:11 +00:00
|
|
|
if (!base) {
|
2017-03-09 09:47:10 +00:00
|
|
|
pr_err("Can't remap registers\n");
|
2016-06-02 16:46:11 +00:00
|
|
|
return -ENXIO;
|
|
|
|
}
|
2012-09-11 04:38:35 +00:00
|
|
|
|
2016-06-02 16:46:11 +00:00
|
|
|
ret = of_property_read_u32(node, "clock-frequency", &freq);
|
|
|
|
if (ret) {
|
2017-03-09 09:47:10 +00:00
|
|
|
pr_err("Can't read clock-frequency\n");
|
2016-09-21 17:33:57 +00:00
|
|
|
goto err_iounmap;
|
2016-06-02 16:46:11 +00:00
|
|
|
}
|
2012-09-11 04:38:35 +00:00
|
|
|
|
|
|
|
system_clock = base + REG_COUNTER_LO;
|
2013-07-18 23:21:20 +00:00
|
|
|
sched_clock_register(bcm2835_sched_read, 32, freq);
|
2012-09-11 04:38:35 +00:00
|
|
|
|
|
|
|
clocksource_mmio_init(base + REG_COUNTER_LO, node->name,
|
|
|
|
freq, 300, 32, clocksource_mmio_readl_up);
|
|
|
|
|
|
|
|
irq = irq_of_parse_and_map(node, DEFAULT_TIMER);
|
2016-06-02 16:46:11 +00:00
|
|
|
if (irq <= 0) {
|
2017-03-09 09:47:10 +00:00
|
|
|
pr_err("Can't parse IRQ\n");
|
2016-09-21 17:33:57 +00:00
|
|
|
ret = -EINVAL;
|
|
|
|
goto err_iounmap;
|
2016-06-02 16:46:11 +00:00
|
|
|
}
|
2012-09-11 04:38:35 +00:00
|
|
|
|
|
|
|
timer = kzalloc(sizeof(*timer), GFP_KERNEL);
|
2016-06-02 16:46:11 +00:00
|
|
|
if (!timer) {
|
2016-09-21 17:33:57 +00:00
|
|
|
ret = -ENOMEM;
|
|
|
|
goto err_iounmap;
|
2016-06-02 16:46:11 +00:00
|
|
|
}
|
2012-09-11 04:38:35 +00:00
|
|
|
|
|
|
|
timer->control = base + REG_CONTROL;
|
|
|
|
timer->compare = base + REG_COMPARE(DEFAULT_TIMER);
|
|
|
|
timer->match_mask = BIT(DEFAULT_TIMER);
|
|
|
|
timer->evt.name = node->name;
|
|
|
|
timer->evt.rating = 300;
|
|
|
|
timer->evt.features = CLOCK_EVT_FEAT_ONESHOT;
|
|
|
|
timer->evt.set_next_event = bcm2835_time_set_next_event;
|
|
|
|
timer->evt.cpumask = cpumask_of(0);
|
|
|
|
timer->act.name = node->name;
|
|
|
|
timer->act.flags = IRQF_TIMER | IRQF_SHARED;
|
|
|
|
timer->act.dev_id = timer;
|
|
|
|
timer->act.handler = bcm2835_time_interrupt;
|
|
|
|
|
2016-06-02 16:46:11 +00:00
|
|
|
ret = setup_irq(irq, &timer->act);
|
|
|
|
if (ret) {
|
|
|
|
pr_err("Can't set up timer IRQ\n");
|
2016-09-21 17:33:57 +00:00
|
|
|
goto err_iounmap;
|
2016-06-02 16:46:11 +00:00
|
|
|
}
|
2012-09-11 04:38:35 +00:00
|
|
|
|
|
|
|
clockevents_config_and_register(&timer->evt, freq, 0xf, 0xffffffff);
|
|
|
|
|
|
|
|
pr_info("bcm2835: system timer (irq = %d)\n", irq);
|
2016-06-02 16:46:11 +00:00
|
|
|
|
|
|
|
return 0;
|
2016-09-21 17:33:57 +00:00
|
|
|
|
|
|
|
err_iounmap:
|
|
|
|
iounmap(base);
|
|
|
|
return ret;
|
2012-09-11 04:38:35 +00:00
|
|
|
}
|
2017-05-26 14:56:11 +00:00
|
|
|
TIMER_OF_DECLARE(bcm2835, "brcm,bcm2835-system-timer",
|
2013-01-04 03:23:13 +00:00
|
|
|
bcm2835_timer_init);
|