linux/drivers/clocksource/bcm_kona_timer.c
afzal mohammed cc2550b421 clocksource: Replace setup_irq() by request_irq()
request_irq() is preferred over setup_irq(). The early boot setup_irq()
invocations happen either via 'init_IRQ()' or 'time_init()', while
memory allocators are ready by 'mm_init()'.

Per tglx[1], setup_irq() existed in olden days when allocators were not
ready by the time early interrupts were initialized.

Hence replace setup_irq() by request_irq().

Seldom remove_irq() usage has been observed coupled with setup_irq(),
wherever that has been found, it too has been replaced by free_irq().

A build error that was reported by kbuild test robot <lkp@intel.com>
in the previous version of the patch also has been fixed.

[1] https://lkml.kernel.org/r/alpine.DEB.2.20.1710191609480.1971@nanos

Signed-off-by: afzal mohammed <afzal.mohd.ma@gmail.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/91961c77c1cf93d41523f5e1ac52043f32f97077.1582799709.git.afzal.mohd.ma@gmail.com
2020-02-27 12:15:24 +01:00

203 lines
5.2 KiB
C

/*
* Copyright (C) 2012 Broadcom Corporation
*
* 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 version 2.
*
* This program is distributed "as is" WITHOUT ANY WARRANTY of any
* kind, whether express or implied; 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/irq.h>
#include <linux/interrupt.h>
#include <linux/jiffies.h>
#include <linux/clockchips.h>
#include <linux/types.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#define KONA_GPTIMER_STCS_OFFSET 0x00000000
#define KONA_GPTIMER_STCLO_OFFSET 0x00000004
#define KONA_GPTIMER_STCHI_OFFSET 0x00000008
#define KONA_GPTIMER_STCM0_OFFSET 0x0000000C
#define KONA_GPTIMER_STCS_TIMER_MATCH_SHIFT 0
#define KONA_GPTIMER_STCS_COMPARE_ENABLE_SHIFT 4
struct kona_bcm_timers {
int tmr_irq;
void __iomem *tmr_regs;
};
static struct kona_bcm_timers timers;
static u32 arch_timer_rate;
/*
* We use the peripheral timers for system tick, the cpu global timer for
* profile tick
*/
static void kona_timer_disable_and_clear(void __iomem *base)
{
uint32_t reg;
/*
* clear and disable interrupts
* We are using compare/match register 0 for our system interrupts
*/
reg = readl(base + KONA_GPTIMER_STCS_OFFSET);
/* Clear compare (0) interrupt */
reg |= 1 << KONA_GPTIMER_STCS_TIMER_MATCH_SHIFT;
/* disable compare */
reg &= ~(1 << KONA_GPTIMER_STCS_COMPARE_ENABLE_SHIFT);
writel(reg, base + KONA_GPTIMER_STCS_OFFSET);
}
static int
kona_timer_get_counter(void __iomem *timer_base, uint32_t *msw, uint32_t *lsw)
{
int loop_limit = 3;
/*
* Read 64-bit free running counter
* 1. Read hi-word
* 2. Read low-word
* 3. Read hi-word again
* 4.1
* if new hi-word is not equal to previously read hi-word, then
* start from #1
* 4.2
* if new hi-word is equal to previously read hi-word then stop.
*/
do {
*msw = readl(timer_base + KONA_GPTIMER_STCHI_OFFSET);
*lsw = readl(timer_base + KONA_GPTIMER_STCLO_OFFSET);
if (*msw == readl(timer_base + KONA_GPTIMER_STCHI_OFFSET))
break;
} while (--loop_limit);
if (!loop_limit) {
pr_err("bcm_kona_timer: getting counter failed.\n");
pr_err(" Timer will be impacted\n");
return -ETIMEDOUT;
}
return 0;
}
static int kona_timer_set_next_event(unsigned long clc,
struct clock_event_device *unused)
{
/*
* timer (0) is disabled by the timer interrupt already
* so, here we reload the next event value and re-enable
* the timer.
*
* This way, we are potentially losing the time between
* timer-interrupt->set_next_event. CPU local timers, when
* they come in should get rid of skew.
*/
uint32_t lsw, msw;
uint32_t reg;
int ret;
ret = kona_timer_get_counter(timers.tmr_regs, &msw, &lsw);
if (ret)
return ret;
/* Load the "next" event tick value */
writel(lsw + clc, timers.tmr_regs + KONA_GPTIMER_STCM0_OFFSET);
/* Enable compare */
reg = readl(timers.tmr_regs + KONA_GPTIMER_STCS_OFFSET);
reg |= (1 << KONA_GPTIMER_STCS_COMPARE_ENABLE_SHIFT);
writel(reg, timers.tmr_regs + KONA_GPTIMER_STCS_OFFSET);
return 0;
}
static int kona_timer_shutdown(struct clock_event_device *evt)
{
kona_timer_disable_and_clear(timers.tmr_regs);
return 0;
}
static struct clock_event_device kona_clockevent_timer = {
.name = "timer 1",
.features = CLOCK_EVT_FEAT_ONESHOT,
.set_next_event = kona_timer_set_next_event,
.set_state_shutdown = kona_timer_shutdown,
.tick_resume = kona_timer_shutdown,
};
static void __init kona_timer_clockevents_init(void)
{
kona_clockevent_timer.cpumask = cpumask_of(0);
clockevents_config_and_register(&kona_clockevent_timer,
arch_timer_rate, 6, 0xffffffff);
}
static irqreturn_t kona_timer_interrupt(int irq, void *dev_id)
{
struct clock_event_device *evt = &kona_clockevent_timer;
kona_timer_disable_and_clear(timers.tmr_regs);
evt->event_handler(evt);
return IRQ_HANDLED;
}
static int __init kona_timer_init(struct device_node *node)
{
u32 freq;
struct clk *external_clk;
external_clk = of_clk_get_by_name(node, NULL);
if (!IS_ERR(external_clk)) {
arch_timer_rate = clk_get_rate(external_clk);
clk_prepare_enable(external_clk);
} else if (!of_property_read_u32(node, "clock-frequency", &freq)) {
arch_timer_rate = freq;
} else {
pr_err("Kona Timer v1 unable to determine clock-frequency\n");
return -EINVAL;
}
/* Setup IRQ numbers */
timers.tmr_irq = irq_of_parse_and_map(node, 0);
/* Setup IO addresses */
timers.tmr_regs = of_iomap(node, 0);
kona_timer_disable_and_clear(timers.tmr_regs);
kona_timer_clockevents_init();
if (request_irq(timers.tmr_irq, kona_timer_interrupt, IRQF_TIMER,
"Kona Timer Tick", NULL))
pr_err("%s: request_irq() failed\n", "Kona Timer Tick");
kona_timer_set_next_event((arch_timer_rate / HZ), NULL);
return 0;
}
TIMER_OF_DECLARE(brcm_kona, "brcm,kona-timer", kona_timer_init);
/*
* bcm,kona-timer is deprecated by brcm,kona-timer
* being kept here for driver compatibility
*/
TIMER_OF_DECLARE(bcm_kona, "bcm,kona-timer", kona_timer_init);