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remarkable-linux/drivers/clocksource/timer-oxnas-rps.c
Daniel Lezcano 1727339590 clocksource/drivers: Rename CLOCKSOURCE_OF_DECLARE to TIMER_OF_DECLARE 
The CLOCKSOURCE_OF_DECLARE macro is used widely for the timers to declare the
clocksource at early stage. However, this macro is also used to initialize
the clockevent if any, or the clockevent only.

It was originally suggested to declare another macro to initialize a
clockevent, so in order to separate the two entities even they belong to the
same IP. This was not accepted because of the impact on the DT where splitting
a clocksource/clockevent definition does not make sense as it is a Linux
concept not a hardware description.

On the other side, the clocksource has not interrupt declared while the
clockevent has, so it is easy from the driver to know if the description is
for a clockevent or a clocksource, IOW it could be implemented at the driver
level.

So instead of dealing with a named clocksource macro, let's use a more generic
one: TIMER_OF_DECLARE.

The patch has not functional changes.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Matthias Brugger <matthias.bgg@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
2017-06-14 11:58:45 +02:00

300 lines
7.2 KiB
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/*
* drivers/clocksource/timer-oxnas-rps.c
*
* Copyright (C) 2009 Oxford Semiconductor Ltd
* Copyright (C) 2013 Ma Haijun <mahaijuns@gmail.com>
* Copyright (C) 2016 Neil Armstrong <narmstrong@baylibre.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope 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, see <http://www.gnu.org/licenses/>.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/init.h>
#include <linux/irq.h>
#include <linux/io.h>
#include <linux/clk.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/of_irq.h>
#include <linux/of_address.h>
#include <linux/clockchips.h>
#include <linux/sched_clock.h>
/* TIMER1 used as tick
* TIMER2 used as clocksource
*/
/* Registers definitions */
#define TIMER_LOAD_REG 0x0
#define TIMER_CURR_REG 0x4
#define TIMER_CTRL_REG 0x8
#define TIMER_CLRINT_REG 0xC
#define TIMER_BITS 24
#define TIMER_MAX_VAL (BIT(TIMER_BITS) - 1)
#define TIMER_PERIODIC BIT(6)
#define TIMER_ENABLE BIT(7)
#define TIMER_DIV1 (0)
#define TIMER_DIV16 (1 << 2)
#define TIMER_DIV256 (2 << 2)
#define TIMER1_REG_OFFSET 0
#define TIMER2_REG_OFFSET 0x20
/* Clockevent & Clocksource data */
struct oxnas_rps_timer {
struct clock_event_device clkevent;
void __iomem *clksrc_base;
void __iomem *clkevt_base;
unsigned long timer_period;
unsigned int timer_prescaler;
struct clk *clk;
int irq;
};
static irqreturn_t oxnas_rps_timer_irq(int irq, void *dev_id)
{
struct oxnas_rps_timer *rps = dev_id;
writel_relaxed(0, rps->clkevt_base + TIMER_CLRINT_REG);
rps->clkevent.event_handler(&rps->clkevent);
return IRQ_HANDLED;
}
static void oxnas_rps_timer_config(struct oxnas_rps_timer *rps,
unsigned long period,
unsigned int periodic)
{
uint32_t cfg = rps->timer_prescaler;
if (period)
cfg |= TIMER_ENABLE;
if (periodic)
cfg |= TIMER_PERIODIC;
writel_relaxed(period, rps->clkevt_base + TIMER_LOAD_REG);
writel_relaxed(cfg, rps->clkevt_base + TIMER_CTRL_REG);
}
static int oxnas_rps_timer_shutdown(struct clock_event_device *evt)
{
struct oxnas_rps_timer *rps =
container_of(evt, struct oxnas_rps_timer, clkevent);
oxnas_rps_timer_config(rps, 0, 0);
return 0;
}
static int oxnas_rps_timer_set_periodic(struct clock_event_device *evt)
{
struct oxnas_rps_timer *rps =
container_of(evt, struct oxnas_rps_timer, clkevent);
oxnas_rps_timer_config(rps, rps->timer_period, 1);
return 0;
}
static int oxnas_rps_timer_set_oneshot(struct clock_event_device *evt)
{
struct oxnas_rps_timer *rps =
container_of(evt, struct oxnas_rps_timer, clkevent);
oxnas_rps_timer_config(rps, rps->timer_period, 0);
return 0;
}
static int oxnas_rps_timer_next_event(unsigned long delta,
struct clock_event_device *evt)
{
struct oxnas_rps_timer *rps =
container_of(evt, struct oxnas_rps_timer, clkevent);
oxnas_rps_timer_config(rps, delta, 0);
return 0;
}
static int __init oxnas_rps_clockevent_init(struct oxnas_rps_timer *rps)
{
ulong clk_rate = clk_get_rate(rps->clk);
ulong timer_rate;
/* Start with prescaler 1 */
rps->timer_prescaler = TIMER_DIV1;
rps->timer_period = DIV_ROUND_UP(clk_rate, HZ);
timer_rate = clk_rate;
if (rps->timer_period > TIMER_MAX_VAL) {
rps->timer_prescaler = TIMER_DIV16;
timer_rate = clk_rate / 16;
rps->timer_period = DIV_ROUND_UP(timer_rate, HZ);
}
if (rps->timer_period > TIMER_MAX_VAL) {
rps->timer_prescaler = TIMER_DIV256;
timer_rate = clk_rate / 256;
rps->timer_period = DIV_ROUND_UP(timer_rate, HZ);
}
rps->clkevent.name = "oxnas-rps";
rps->clkevent.features = CLOCK_EVT_FEAT_PERIODIC |
CLOCK_EVT_FEAT_ONESHOT |
CLOCK_EVT_FEAT_DYNIRQ;
rps->clkevent.tick_resume = oxnas_rps_timer_shutdown;
rps->clkevent.set_state_shutdown = oxnas_rps_timer_shutdown;
rps->clkevent.set_state_periodic = oxnas_rps_timer_set_periodic;
rps->clkevent.set_state_oneshot = oxnas_rps_timer_set_oneshot;
rps->clkevent.set_next_event = oxnas_rps_timer_next_event;
rps->clkevent.rating = 200;
rps->clkevent.cpumask = cpu_possible_mask;
rps->clkevent.irq = rps->irq;
clockevents_config_and_register(&rps->clkevent,
timer_rate,
1,
TIMER_MAX_VAL);
pr_info("Registered clock event rate %luHz prescaler %x period %lu\n",
clk_rate,
rps->timer_prescaler,
rps->timer_period);
return 0;
}
/* Clocksource */
static void __iomem *timer_sched_base;
static u64 notrace oxnas_rps_read_sched_clock(void)
{
return ~readl_relaxed(timer_sched_base);
}
static int __init oxnas_rps_clocksource_init(struct oxnas_rps_timer *rps)
{
ulong clk_rate = clk_get_rate(rps->clk);
int ret;
/* use prescale 16 */
clk_rate = clk_rate / 16;
writel_relaxed(TIMER_MAX_VAL, rps->clksrc_base + TIMER_LOAD_REG);
writel_relaxed(TIMER_PERIODIC | TIMER_ENABLE | TIMER_DIV16,
rps->clksrc_base + TIMER_CTRL_REG);
timer_sched_base = rps->clksrc_base + TIMER_CURR_REG;
sched_clock_register(oxnas_rps_read_sched_clock,
TIMER_BITS, clk_rate);
ret = clocksource_mmio_init(timer_sched_base,
"oxnas_rps_clocksource_timer",
clk_rate, 250, TIMER_BITS,
clocksource_mmio_readl_down);
if (WARN_ON(ret)) {
pr_err("can't register clocksource\n");
return ret;
}
pr_info("Registered clocksource rate %luHz\n", clk_rate);
return 0;
}
static int __init oxnas_rps_timer_init(struct device_node *np)
{
struct oxnas_rps_timer *rps;
void __iomem *base;
int ret;
rps = kzalloc(sizeof(*rps), GFP_KERNEL);
if (!rps)
return -ENOMEM;
rps->clk = of_clk_get(np, 0);
if (IS_ERR(rps->clk)) {
ret = PTR_ERR(rps->clk);
goto err_alloc;
}
ret = clk_prepare_enable(rps->clk);
if (ret)
goto err_clk;
base = of_iomap(np, 0);
if (!base) {
ret = -ENXIO;
goto err_clk_prepare;
}
rps->irq = irq_of_parse_and_map(np, 0);
if (rps->irq < 0) {
ret = -EINVAL;
goto err_iomap;
}
rps->clkevt_base = base + TIMER1_REG_OFFSET;
rps->clksrc_base = base + TIMER2_REG_OFFSET;
/* Disable timers */
writel_relaxed(0, rps->clkevt_base + TIMER_CTRL_REG);
writel_relaxed(0, rps->clksrc_base + TIMER_CTRL_REG);
writel_relaxed(0, rps->clkevt_base + TIMER_LOAD_REG);
writel_relaxed(0, rps->clksrc_base + TIMER_LOAD_REG);
writel_relaxed(0, rps->clkevt_base + TIMER_CLRINT_REG);
writel_relaxed(0, rps->clksrc_base + TIMER_CLRINT_REG);
ret = request_irq(rps->irq, oxnas_rps_timer_irq,
IRQF_TIMER | IRQF_IRQPOLL,
"rps-timer", rps);
if (ret)
goto err_iomap;
ret = oxnas_rps_clocksource_init(rps);
if (ret)
goto err_irqreq;
ret = oxnas_rps_clockevent_init(rps);
if (ret)
goto err_irqreq;
return 0;
err_irqreq:
free_irq(rps->irq, rps);
err_iomap:
iounmap(base);
err_clk_prepare:
clk_disable_unprepare(rps->clk);
err_clk:
clk_put(rps->clk);
err_alloc:
kfree(rps);
return ret;
}
TIMER_OF_DECLARE(ox810se_rps,
"oxsemi,ox810se-rps-timer", oxnas_rps_timer_init);
TIMER_OF_DECLARE(ox820_rps,
"oxsemi,ox820se-rps-timer", oxnas_rps_timer_init);
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