mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 19:00:25 +00:00
![Thomas Gleixner](/assets/img/avatar_default.png)
The license information clearly states GPL version 2 only. The extra text which excludes warranties is a transcript of the corresponding GPLv2 clause 11, which is explicitely referenced for details. So the SPDX identifier covers it completely. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Florian Fainelli <f.fainelli@gmail.com> Cc: Ray Jui <rjui@broadcom.com> Cc: Scott Branden <sbranden@broadcom.com> Cc: Broadcom Kernel Team <bcm-kernel-feedback-list@broadcom.com> Cc: linux-spdx@vger.kernel.org Acked-by: Florian Fainelli <f.fainelli@gmail.com> Link: https://lore.kernel.org/r/20220510171254.404209482@linutronix.de Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
192 lines
4.8 KiB
C
192 lines
4.8 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
// Copyright (C) 2012 Broadcom Corporation
|
|
|
|
#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);
|