linux/drivers/clocksource/timer-sp804.c
Viresh Kumar daea72831d clockevents/drivers/timer-sp804: Migrate to new 'set-state' interface
Migrate timer-sp driver to the new 'set-state' interface provided by
clockevents core, the earlier 'set-mode' interface is marked obsolete
now.

This also enables us to implement callbacks for new states of clockevent
devices, for example: ONESHOT_STOPPED.

There are few more changes worth noticing:

- The clockevent device was disabled by writing: 'TIMER_CTRL_32BIT |
  TIMER_CTRL_IE' to ctrl register earlier. i.e. by un-setting the
  TIMER_CTRL_ENABLE bit. Its done by writing zero now and should have
  the same effect.

- For shutdown and resume we were writing the same value twice to the
  register (to disable the timer), which is fixed now.

- Switching to oneshot mode was divided into two parts earlier:
  - Firstly set_mode() was writing:
    'TIMER_CTRL_32BIT | TIMER_CTRL_IE | TIMER_CTRL_ONESHOT'
    to ctrl register (device not enabled yet)
  - Then sp804_set_next_event() was enabling the device by writing
    'readl(ctrl) | TIMER_CTRL_ENABLE' to the ctrl register. This was
    unnecessarily complicated.
  - Change this to: Stop device on set_state_oneshot and configure it in
    sp804_set_next_event().

Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Olof Johansson <olof@lixom.net>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2015-08-10 11:40:55 +02:00

311 lines
7.1 KiB
C

/*
* linux/drivers/clocksource/timer-sp.c
*
* Copyright (C) 1999 - 2003 ARM Limited
* Copyright (C) 2000 Deep Blue Solutions Ltd
*
* 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/clk.h>
#include <linux/clocksource.h>
#include <linux/clockchips.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/sched_clock.h>
#include <clocksource/timer-sp804.h>
#include "timer-sp.h"
static long __init sp804_get_clock_rate(struct clk *clk)
{
long rate;
int err;
err = clk_prepare(clk);
if (err) {
pr_err("sp804: clock failed to prepare: %d\n", err);
clk_put(clk);
return err;
}
err = clk_enable(clk);
if (err) {
pr_err("sp804: clock failed to enable: %d\n", err);
clk_unprepare(clk);
clk_put(clk);
return err;
}
rate = clk_get_rate(clk);
if (rate < 0) {
pr_err("sp804: clock failed to get rate: %ld\n", rate);
clk_disable(clk);
clk_unprepare(clk);
clk_put(clk);
}
return rate;
}
static void __iomem *sched_clock_base;
static u64 notrace sp804_read(void)
{
return ~readl_relaxed(sched_clock_base + TIMER_VALUE);
}
void __init sp804_timer_disable(void __iomem *base)
{
writel(0, base + TIMER_CTRL);
}
void __init __sp804_clocksource_and_sched_clock_init(void __iomem *base,
const char *name,
struct clk *clk,
int use_sched_clock)
{
long rate;
if (!clk) {
clk = clk_get_sys("sp804", name);
if (IS_ERR(clk)) {
pr_err("sp804: clock not found: %d\n",
(int)PTR_ERR(clk));
return;
}
}
rate = sp804_get_clock_rate(clk);
if (rate < 0)
return;
/* setup timer 0 as free-running clocksource */
writel(0, base + TIMER_CTRL);
writel(0xffffffff, base + TIMER_LOAD);
writel(0xffffffff, base + TIMER_VALUE);
writel(TIMER_CTRL_32BIT | TIMER_CTRL_ENABLE | TIMER_CTRL_PERIODIC,
base + TIMER_CTRL);
clocksource_mmio_init(base + TIMER_VALUE, name,
rate, 200, 32, clocksource_mmio_readl_down);
if (use_sched_clock) {
sched_clock_base = base;
sched_clock_register(sp804_read, 32, rate);
}
}
static void __iomem *clkevt_base;
static unsigned long clkevt_reload;
/*
* IRQ handler for the timer
*/
static irqreturn_t sp804_timer_interrupt(int irq, void *dev_id)
{
struct clock_event_device *evt = dev_id;
/* clear the interrupt */
writel(1, clkevt_base + TIMER_INTCLR);
evt->event_handler(evt);
return IRQ_HANDLED;
}
static inline void timer_shutdown(struct clock_event_device *evt)
{
writel(0, clkevt_base + TIMER_CTRL);
}
static int sp804_shutdown(struct clock_event_device *evt)
{
timer_shutdown(evt);
return 0;
}
static int sp804_set_periodic(struct clock_event_device *evt)
{
unsigned long ctrl = TIMER_CTRL_32BIT | TIMER_CTRL_IE |
TIMER_CTRL_PERIODIC | TIMER_CTRL_ENABLE;
timer_shutdown(evt);
writel(clkevt_reload, clkevt_base + TIMER_LOAD);
writel(ctrl, clkevt_base + TIMER_CTRL);
return 0;
}
static int sp804_set_next_event(unsigned long next,
struct clock_event_device *evt)
{
unsigned long ctrl = TIMER_CTRL_32BIT | TIMER_CTRL_IE |
TIMER_CTRL_ONESHOT | TIMER_CTRL_ENABLE;
writel(next, clkevt_base + TIMER_LOAD);
writel(ctrl, clkevt_base + TIMER_CTRL);
return 0;
}
static struct clock_event_device sp804_clockevent = {
.features = CLOCK_EVT_FEAT_PERIODIC |
CLOCK_EVT_FEAT_ONESHOT |
CLOCK_EVT_FEAT_DYNIRQ,
.set_state_shutdown = sp804_shutdown,
.set_state_periodic = sp804_set_periodic,
.set_state_oneshot = sp804_shutdown,
.tick_resume = sp804_shutdown,
.set_next_event = sp804_set_next_event,
.rating = 300,
};
static struct irqaction sp804_timer_irq = {
.name = "timer",
.flags = IRQF_TIMER | IRQF_IRQPOLL,
.handler = sp804_timer_interrupt,
.dev_id = &sp804_clockevent,
};
void __init __sp804_clockevents_init(void __iomem *base, unsigned int irq, struct clk *clk, const char *name)
{
struct clock_event_device *evt = &sp804_clockevent;
long rate;
if (!clk)
clk = clk_get_sys("sp804", name);
if (IS_ERR(clk)) {
pr_err("sp804: %s clock not found: %d\n", name,
(int)PTR_ERR(clk));
return;
}
rate = sp804_get_clock_rate(clk);
if (rate < 0)
return;
clkevt_base = base;
clkevt_reload = DIV_ROUND_CLOSEST(rate, HZ);
evt->name = name;
evt->irq = irq;
evt->cpumask = cpu_possible_mask;
writel(0, base + TIMER_CTRL);
setup_irq(irq, &sp804_timer_irq);
clockevents_config_and_register(evt, rate, 0xf, 0xffffffff);
}
static void __init sp804_of_init(struct device_node *np)
{
static bool initialized = false;
void __iomem *base;
int irq;
u32 irq_num = 0;
struct clk *clk1, *clk2;
const char *name = of_get_property(np, "compatible", NULL);
base = of_iomap(np, 0);
if (WARN_ON(!base))
return;
/* Ensure timers are disabled */
writel(0, base + TIMER_CTRL);
writel(0, base + TIMER_2_BASE + TIMER_CTRL);
if (initialized || !of_device_is_available(np))
goto err;
clk1 = of_clk_get(np, 0);
if (IS_ERR(clk1))
clk1 = NULL;
/* Get the 2nd clock if the timer has 3 timer clocks */
if (of_count_phandle_with_args(np, "clocks", "#clock-cells") == 3) {
clk2 = of_clk_get(np, 1);
if (IS_ERR(clk2)) {
pr_err("sp804: %s clock not found: %d\n", np->name,
(int)PTR_ERR(clk2));
clk2 = NULL;
}
} else
clk2 = clk1;
irq = irq_of_parse_and_map(np, 0);
if (irq <= 0)
goto err;
of_property_read_u32(np, "arm,sp804-has-irq", &irq_num);
if (irq_num == 2) {
__sp804_clockevents_init(base + TIMER_2_BASE, irq, clk2, name);
__sp804_clocksource_and_sched_clock_init(base, name, clk1, 1);
} else {
__sp804_clockevents_init(base, irq, clk1 , name);
__sp804_clocksource_and_sched_clock_init(base + TIMER_2_BASE,
name, clk2, 1);
}
initialized = true;
return;
err:
iounmap(base);
}
CLOCKSOURCE_OF_DECLARE(sp804, "arm,sp804", sp804_of_init);
static void __init integrator_cp_of_init(struct device_node *np)
{
static int init_count = 0;
void __iomem *base;
int irq;
const char *name = of_get_property(np, "compatible", NULL);
struct clk *clk;
base = of_iomap(np, 0);
if (WARN_ON(!base))
return;
clk = of_clk_get(np, 0);
if (WARN_ON(IS_ERR(clk)))
return;
/* Ensure timer is disabled */
writel(0, base + TIMER_CTRL);
if (init_count == 2 || !of_device_is_available(np))
goto err;
if (!init_count)
__sp804_clocksource_and_sched_clock_init(base, name, clk, 0);
else {
irq = irq_of_parse_and_map(np, 0);
if (irq <= 0)
goto err;
__sp804_clockevents_init(base, irq, clk, name);
}
init_count++;
return;
err:
iounmap(base);
}
CLOCKSOURCE_OF_DECLARE(intcp, "arm,integrator-cp-timer", integrator_cp_of_init);