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linux-next/drivers/clocksource/tegra20_timer.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

265 lines
6.6 KiB
C

/*
* Copyright (C) 2010 Google, Inc.
*
* Author:
* Colin Cross <ccross@google.com>
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* 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.
*
*/
#include <linux/init.h>
#include <linux/err.h>
#include <linux/time.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/clockchips.h>
#include <linux/clocksource.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/sched_clock.h>
#include <linux/delay.h>
#include <asm/mach/time.h>
#include <asm/smp_twd.h>
#define RTC_SECONDS 0x08
#define RTC_SHADOW_SECONDS 0x0c
#define RTC_MILLISECONDS 0x10
#define TIMERUS_CNTR_1US 0x10
#define TIMERUS_USEC_CFG 0x14
#define TIMERUS_CNTR_FREEZE 0x4c
#define TIMER1_BASE 0x0
#define TIMER2_BASE 0x8
#define TIMER3_BASE 0x50
#define TIMER4_BASE 0x58
#define TIMER_PTV 0x0
#define TIMER_PCR 0x4
static void __iomem *timer_reg_base;
static void __iomem *rtc_base;
static struct timespec64 persistent_ts;
static u64 persistent_ms, last_persistent_ms;
static struct delay_timer tegra_delay_timer;
#define timer_writel(value, reg) \
writel_relaxed(value, timer_reg_base + (reg))
#define timer_readl(reg) \
readl_relaxed(timer_reg_base + (reg))
static int tegra_timer_set_next_event(unsigned long cycles,
struct clock_event_device *evt)
{
u32 reg;
reg = 0x80000000 | ((cycles > 1) ? (cycles-1) : 0);
timer_writel(reg, TIMER3_BASE + TIMER_PTV);
return 0;
}
static inline void timer_shutdown(struct clock_event_device *evt)
{
timer_writel(0, TIMER3_BASE + TIMER_PTV);
}
static int tegra_timer_shutdown(struct clock_event_device *evt)
{
timer_shutdown(evt);
return 0;
}
static int tegra_timer_set_periodic(struct clock_event_device *evt)
{
u32 reg = 0xC0000000 | ((1000000 / HZ) - 1);
timer_shutdown(evt);
timer_writel(reg, TIMER3_BASE + TIMER_PTV);
return 0;
}
static struct clock_event_device tegra_clockevent = {
.name = "timer0",
.rating = 300,
.features = CLOCK_EVT_FEAT_ONESHOT |
CLOCK_EVT_FEAT_PERIODIC |
CLOCK_EVT_FEAT_DYNIRQ,
.set_next_event = tegra_timer_set_next_event,
.set_state_shutdown = tegra_timer_shutdown,
.set_state_periodic = tegra_timer_set_periodic,
.set_state_oneshot = tegra_timer_shutdown,
.tick_resume = tegra_timer_shutdown,
};
static u64 notrace tegra_read_sched_clock(void)
{
return timer_readl(TIMERUS_CNTR_1US);
}
/*
* tegra_rtc_read - Reads the Tegra RTC registers
* Care must be taken that this funciton is not called while the
* tegra_rtc driver could be executing to avoid race conditions
* on the RTC shadow register
*/
static u64 tegra_rtc_read_ms(void)
{
u32 ms = readl(rtc_base + RTC_MILLISECONDS);
u32 s = readl(rtc_base + RTC_SHADOW_SECONDS);
return (u64)s * MSEC_PER_SEC + ms;
}
/*
* tegra_read_persistent_clock64 - Return time from a persistent clock.
*
* Reads the time from a source which isn't disabled during PM, the
* 32k sync timer. Convert the cycles elapsed since last read into
* nsecs and adds to a monotonically increasing timespec64.
* Care must be taken that this funciton is not called while the
* tegra_rtc driver could be executing to avoid race conditions
* on the RTC shadow register
*/
static void tegra_read_persistent_clock64(struct timespec64 *ts)
{
u64 delta;
last_persistent_ms = persistent_ms;
persistent_ms = tegra_rtc_read_ms();
delta = persistent_ms - last_persistent_ms;
timespec64_add_ns(&persistent_ts, delta * NSEC_PER_MSEC);
*ts = persistent_ts;
}
static unsigned long tegra_delay_timer_read_counter_long(void)
{
return readl(timer_reg_base + TIMERUS_CNTR_1US);
}
static irqreturn_t tegra_timer_interrupt(int irq, void *dev_id)
{
struct clock_event_device *evt = (struct clock_event_device *)dev_id;
timer_writel(1<<30, TIMER3_BASE + TIMER_PCR);
evt->event_handler(evt);
return IRQ_HANDLED;
}
static struct irqaction tegra_timer_irq = {
.name = "timer0",
.flags = IRQF_TIMER | IRQF_TRIGGER_HIGH,
.handler = tegra_timer_interrupt,
.dev_id = &tegra_clockevent,
};
static int __init tegra20_init_timer(struct device_node *np)
{
struct clk *clk;
unsigned long rate;
int ret;
timer_reg_base = of_iomap(np, 0);
if (!timer_reg_base) {
pr_err("Can't map timer registers\n");
return -ENXIO;
}
tegra_timer_irq.irq = irq_of_parse_and_map(np, 2);
if (tegra_timer_irq.irq <= 0) {
pr_err("Failed to map timer IRQ\n");
return -EINVAL;
}
clk = of_clk_get(np, 0);
if (IS_ERR(clk)) {
pr_warn("Unable to get timer clock. Assuming 12Mhz input clock.\n");
rate = 12000000;
} else {
clk_prepare_enable(clk);
rate = clk_get_rate(clk);
}
switch (rate) {
case 12000000:
timer_writel(0x000b, TIMERUS_USEC_CFG);
break;
case 13000000:
timer_writel(0x000c, TIMERUS_USEC_CFG);
break;
case 19200000:
timer_writel(0x045f, TIMERUS_USEC_CFG);
break;
case 26000000:
timer_writel(0x0019, TIMERUS_USEC_CFG);
break;
default:
WARN(1, "Unknown clock rate");
}
sched_clock_register(tegra_read_sched_clock, 32, 1000000);
ret = clocksource_mmio_init(timer_reg_base + TIMERUS_CNTR_1US,
"timer_us", 1000000, 300, 32,
clocksource_mmio_readl_up);
if (ret) {
pr_err("Failed to register clocksource\n");
return ret;
}
tegra_delay_timer.read_current_timer =
tegra_delay_timer_read_counter_long;
tegra_delay_timer.freq = 1000000;
register_current_timer_delay(&tegra_delay_timer);
ret = setup_irq(tegra_timer_irq.irq, &tegra_timer_irq);
if (ret) {
pr_err("Failed to register timer IRQ: %d\n", ret);
return ret;
}
tegra_clockevent.cpumask = cpu_all_mask;
tegra_clockevent.irq = tegra_timer_irq.irq;
clockevents_config_and_register(&tegra_clockevent, 1000000,
0x1, 0x1fffffff);
return 0;
}
TIMER_OF_DECLARE(tegra20_timer, "nvidia,tegra20-timer", tegra20_init_timer);
static int __init tegra20_init_rtc(struct device_node *np)
{
struct clk *clk;
rtc_base = of_iomap(np, 0);
if (!rtc_base) {
pr_err("Can't map RTC registers\n");
return -ENXIO;
}
/*
* rtc registers are used by read_persistent_clock, keep the rtc clock
* enabled
*/
clk = of_clk_get(np, 0);
if (IS_ERR(clk))
pr_warn("Unable to get rtc-tegra clock\n");
else
clk_prepare_enable(clk);
return register_persistent_clock(NULL, tegra_read_persistent_clock64);
}
TIMER_OF_DECLARE(tegra20_rtc, "nvidia,tegra20-rtc", tegra20_init_rtc);