// 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 intkona_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);