// SPDX-License-Identifier: GPL-2.0/* * Ralink System Tick Counter driver present on RT3352 and MT7620 SoCs. * * Copyright (C) 2013 by John Crispin <john@phrozen.org> */ #include <linux/clockchips.h>#include <linux/clocksource.h>#include <linux/interrupt.h>#include <linux/reset.h>#include <linux/init.h>#include <linux/time.h>#include <linux/of.h>#include <linux/of_irq.h>#include <linux/of_address.h> #define SYSTICK_FREQ		(50 * 1000) #define SYSTICK_CONFIG		0x00#define SYSTICK_COMPARE		0x04#define SYSTICK_COUNT		0x08 /* route systick irq to mips irq 7 instead of the r4k-timer */#define CFG_EXT_STK_EN		0x2/* enable the counter */#define CFG_CNT_EN		0x1 struct systick_device {	void __iomem *membase;	struct clock_event_device dev;	int irq_requested;	int freq_scale;}; static int systick_set_oneshot(struct clock_event_device *evt);static int systick_shutdown(struct clock_event_device *evt); static int systick_next_event(unsigned long delta,			      struct clock_event_device *evt){	struct systick_device *sdev;	u32 count; 	sdev = container_of(evt, struct systick_device, dev);	count = ioread32(sdev->membase + SYSTICK_COUNT);	count = (count + delta) % SYSTICK_FREQ;	iowrite32(count, sdev->membase + SYSTICK_COMPARE); 	return 0;} static void systick_event_handler(struct clock_event_device *dev){	/* noting to do here */} static irqreturn_t systick_interrupt(int irq, void *dev_id){	struct clock_event_device *dev = (struct clock_event_device *)dev_id; 	dev->event_handler(dev); 	return IRQ_HANDLED;} static struct systick_device systick = {	.dev = {		/*		 * cevt-r4k uses 300, make sure systick		 * gets used if available		 */		.rating			= 310,		.features		= CLOCK_EVT_FEAT_ONESHOT,		.set_next_event		= systick_next_event,		.set_state_shutdown	= systick_shutdown,		.set_state_oneshot	= systick_set_oneshot,		.event_handler		= systick_event_handler,	},}; static int systick_shutdown(struct clock_event_device *evt){	struct systick_device *sdev; 	sdev = container_of(evt, struct systick_device, dev); 	if (sdev->irq_requested)		free_irq(systick.dev.irq, &systick.dev);	sdev->irq_requested = 0;	iowrite32(0, systick.membase + SYSTICK_CONFIG); 	return 0;} static int systick_set_oneshot(struct clock_event_device *evt){	const char *name = systick.dev.name;	struct systick_device *sdev;	int irq = systick.dev.irq; 	sdev = container_of(evt, struct systick_device, dev); 	if (!sdev->irq_requested) {		if (request_irq(irq, systick_interrupt,				IRQF_PERCPU | IRQF_TIMER, name, &systick.dev))			pr_err("Failed to request irq %d (%s)\n", irq, name);	}	sdev->irq_requested = 1;	iowrite32(CFG_EXT_STK_EN | CFG_CNT_EN,		  systick.membase + SYSTICK_CONFIG); 	return 0;} static int __init ralink_systick_init(struct device_node *np){	int ret; 	systick.membase = of_iomap(np, 0);	if (!systick.membase)		return -ENXIO; 	systick.dev.name = np->name;	clockevents_calc_mult_shift(&systick.dev, SYSTICK_FREQ, 60);	systick.dev.max_delta_ns = clockevent_delta2ns(0x7fff, &systick.dev);	systick.dev.max_delta_ticks = 0x7fff;	systick.dev.min_delta_ns = clockevent_delta2ns(0x3, &systick.dev);	systick.dev.min_delta_ticks = 0x3;	systick.dev.irq = irq_of_parse_and_map(np, 0);	if (!systick.dev.irq) {		pr_err("%pOFn: request_irq failed", np);		ret = -EINVAL;		goto err_iounmap;	} 	ret = clocksource_mmio_init(systick.membase + SYSTICK_COUNT, np->name,				    SYSTICK_FREQ, 301, 16,				    clocksource_mmio_readl_up);	if (ret)		goto err_free_irq; 	clockevents_register_device(&systick.dev); 	pr_info("%pOFn: running - mult: %d, shift: %d\n",			np, systick.dev.mult, systick.dev.shift); 	return 0; err_free_irq:	irq_dispose_mapping(systick.dev.irq);err_iounmap:	iounmap(systick.membase);	return ret;} TIMER_OF_DECLARE(systick, "ralink,cevt-systick", ralink_systick_init);