/* * (C) Copyright 2009 Intel Corporation * Author: Jacob Pan (jacob.jun.pan@intel.com) * * Shared with ARM platforms, Jamie Iles, Picochip 2011 * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * Support for the Synopsys DesignWare APB Timers. */#include <linux/dw_apb_timer.h>#include <linux/delay.h>#include <linux/kernel.h>#include <linux/interrupt.h>#include <linux/irq.h>#include <linux/io.h>#include <linux/slab.h> #define APBT_MIN_PERIOD			4#define APBT_MIN_DELTA_USEC		200 #define APBTMR_N_LOAD_COUNT		0x00#define APBTMR_N_CURRENT_VALUE		0x04#define APBTMR_N_CONTROL		0x08#define APBTMR_N_EOI			0x0c#define APBTMR_N_INT_STATUS		0x10 #define APBTMRS_INT_STATUS		0xa0#define APBTMRS_EOI			0xa4#define APBTMRS_RAW_INT_STATUS		0xa8#define APBTMRS_COMP_VERSION		0xac #define APBTMR_CONTROL_ENABLE		(1 << 0)/* 1: periodic, 0:free running. */#define APBTMR_CONTROL_MODE_PERIODIC	(1 << 1)#define APBTMR_CONTROL_INT		(1 << 2) static inline struct dw_apb_clock_event_device *ced_to_dw_apb_ced(struct clock_event_device *evt){	return container_of(evt, struct dw_apb_clock_event_device, ced);} static inline struct dw_apb_clocksource *clocksource_to_dw_apb_clocksource(struct clocksource *cs){	return container_of(cs, struct dw_apb_clocksource, cs);} static unsigned long apbt_readl(struct dw_apb_timer *timer, unsigned long offs){	return readl(timer->base + offs);} static void apbt_writel(struct dw_apb_timer *timer, unsigned long val,		 unsigned long offs){	writel(val, timer->base + offs);} static void apbt_disable_int(struct dw_apb_timer *timer){	unsigned long ctrl = apbt_readl(timer, APBTMR_N_CONTROL); 	ctrl |= APBTMR_CONTROL_INT;	apbt_writel(timer, ctrl, APBTMR_N_CONTROL);} /** * dw_apb_clockevent_pause() - stop the clock_event_device from running * * @dw_ced:	The APB clock to stop generating events. */void dw_apb_clockevent_pause(struct dw_apb_clock_event_device *dw_ced){	disable_irq(dw_ced->timer.irq);	apbt_disable_int(&dw_ced->timer);} static void apbt_eoi(struct dw_apb_timer *timer){	apbt_readl(timer, APBTMR_N_EOI);} static irqreturn_t dw_apb_clockevent_irq(int irq, void *data){	struct clock_event_device *evt = data;	struct dw_apb_clock_event_device *dw_ced = ced_to_dw_apb_ced(evt); 	if (!evt->event_handler) {		pr_info("Spurious APBT timer interrupt %d", irq);		return IRQ_NONE;	} 	if (dw_ced->eoi)		dw_ced->eoi(&dw_ced->timer); 	evt->event_handler(evt);	return IRQ_HANDLED;} static void apbt_enable_int(struct dw_apb_timer *timer){	unsigned long ctrl = apbt_readl(timer, APBTMR_N_CONTROL);	/* clear pending intr */	apbt_readl(timer, APBTMR_N_EOI);	ctrl &= ~APBTMR_CONTROL_INT;	apbt_writel(timer, ctrl, APBTMR_N_CONTROL);} static void apbt_set_mode(enum clock_event_mode mode,			  struct clock_event_device *evt){	unsigned long ctrl;	unsigned long period;	struct dw_apb_clock_event_device *dw_ced = ced_to_dw_apb_ced(evt); 	pr_debug("%s CPU %d mode=%d\n", __func__, first_cpu(*evt->cpumask),		 mode); 	switch (mode) {	case CLOCK_EVT_MODE_PERIODIC:		period = DIV_ROUND_UP(dw_ced->timer.freq, HZ);		ctrl = apbt_readl(&dw_ced->timer, APBTMR_N_CONTROL);		ctrl |= APBTMR_CONTROL_MODE_PERIODIC;		apbt_writel(&dw_ced->timer, ctrl, APBTMR_N_CONTROL);		/*		 * DW APB p. 46, have to disable timer before load counter,		 * may cause sync problem.		 */		ctrl &= ~APBTMR_CONTROL_ENABLE;		apbt_writel(&dw_ced->timer, ctrl, APBTMR_N_CONTROL);		udelay(1);		pr_debug("Setting clock period %lu for HZ %d\n", period, HZ);		apbt_writel(&dw_ced->timer, period, APBTMR_N_LOAD_COUNT);		ctrl |= APBTMR_CONTROL_ENABLE;		apbt_writel(&dw_ced->timer, ctrl, APBTMR_N_CONTROL);		break; 	case CLOCK_EVT_MODE_ONESHOT:		ctrl = apbt_readl(&dw_ced->timer, APBTMR_N_CONTROL);		/*		 * set free running mode, this mode will let timer reload max		 * timeout which will give time (3min on 25MHz clock) to rearm		 * the next event, therefore emulate the one-shot mode.		 */		ctrl &= ~APBTMR_CONTROL_ENABLE;		ctrl &= ~APBTMR_CONTROL_MODE_PERIODIC; 		apbt_writel(&dw_ced->timer, ctrl, APBTMR_N_CONTROL);		/* write again to set free running mode */		apbt_writel(&dw_ced->timer, ctrl, APBTMR_N_CONTROL); 		/*		 * DW APB p. 46, load counter with all 1s before starting free		 * running mode.		 */		apbt_writel(&dw_ced->timer, ~0, APBTMR_N_LOAD_COUNT);		ctrl &= ~APBTMR_CONTROL_INT;		ctrl |= APBTMR_CONTROL_ENABLE;		apbt_writel(&dw_ced->timer, ctrl, APBTMR_N_CONTROL);		break; 	case CLOCK_EVT_MODE_UNUSED:	case CLOCK_EVT_MODE_SHUTDOWN:		ctrl = apbt_readl(&dw_ced->timer, APBTMR_N_CONTROL);		ctrl &= ~APBTMR_CONTROL_ENABLE;		apbt_writel(&dw_ced->timer, ctrl, APBTMR_N_CONTROL);		break; 	case CLOCK_EVT_MODE_RESUME:		apbt_enable_int(&dw_ced->timer);		break;	}} static int apbt_next_event(unsigned long delta,			   struct clock_event_device *evt){	unsigned long ctrl;	struct dw_apb_clock_event_device *dw_ced = ced_to_dw_apb_ced(evt); 	/* Disable timer */	ctrl = apbt_readl(&dw_ced->timer, APBTMR_N_CONTROL);	ctrl &= ~APBTMR_CONTROL_ENABLE;	apbt_writel(&dw_ced->timer, ctrl, APBTMR_N_CONTROL);	/* write new count */	apbt_writel(&dw_ced->timer, delta, APBTMR_N_LOAD_COUNT);	ctrl |= APBTMR_CONTROL_ENABLE;	apbt_writel(&dw_ced->timer, ctrl, APBTMR_N_CONTROL); 	return 0;} /** * dw_apb_clockevent_init() - use an APB timer as a clock_event_device * * @cpu:	The CPU the events will be targeted at. * @name:	The name used for the timer and the IRQ for it. * @rating:	The rating to give the timer. * @base:	I/O base for the timer registers. * @irq:	The interrupt number to use for the timer. * @freq:	The frequency that the timer counts at. * * This creates a clock_event_device for using with the generic clock layer * but does not start and register it.  This should be done with * dw_apb_clockevent_register() as the next step.  If this is the first time * it has been called for a timer then the IRQ will be requested, if not it * just be enabled to allow CPU hotplug to avoid repeatedly requesting and * releasing the IRQ. */struct dw_apb_clock_event_device *dw_apb_clockevent_init(int cpu, const char *name, unsigned rating,		       void __iomem *base, int irq, unsigned long freq){	struct dw_apb_clock_event_device *dw_ced =		kzalloc(sizeof(*dw_ced), GFP_KERNEL);	int err; 	if (!dw_ced)		return NULL; 	dw_ced->timer.base = base;	dw_ced->timer.irq = irq;	dw_ced->timer.freq = freq; 	clockevents_calc_mult_shift(&dw_ced->ced, freq, APBT_MIN_PERIOD);	dw_ced->ced.max_delta_ns = clockevent_delta2ns(0x7fffffff,						       &dw_ced->ced);	dw_ced->ced.min_delta_ns = clockevent_delta2ns(5000, &dw_ced->ced);	dw_ced->ced.cpumask = cpumask_of(cpu);	dw_ced->ced.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;	dw_ced->ced.set_mode = apbt_set_mode;	dw_ced->ced.set_next_event = apbt_next_event;	dw_ced->ced.irq = dw_ced->timer.irq;	dw_ced->ced.rating = rating;	dw_ced->ced.name = name; 	dw_ced->irqaction.name		= dw_ced->ced.name;	dw_ced->irqaction.handler	= dw_apb_clockevent_irq;	dw_ced->irqaction.dev_id	= &dw_ced->ced;	dw_ced->irqaction.irq		= irq;	dw_ced->irqaction.flags		= IRQF_TIMER | IRQF_IRQPOLL |					  IRQF_NOBALANCING |					  IRQF_DISABLED; 	dw_ced->eoi = apbt_eoi;	err = setup_irq(irq, &dw_ced->irqaction);	if (err) {		pr_err("failed to request timer irq\n");		kfree(dw_ced);		dw_ced = NULL;	} 	return dw_ced;} /** * dw_apb_clockevent_resume() - resume a clock that has been paused. * * @dw_ced:	The APB clock to resume. */void dw_apb_clockevent_resume(struct dw_apb_clock_event_device *dw_ced){	enable_irq(dw_ced->timer.irq);} /** * dw_apb_clockevent_stop() - stop the clock_event_device and release the IRQ. * * @dw_ced:	The APB clock to stop generating the events. */void dw_apb_clockevent_stop(struct dw_apb_clock_event_device *dw_ced){	free_irq(dw_ced->timer.irq, &dw_ced->ced);} /** * dw_apb_clockevent_register() - register the clock with the generic layer * * @dw_ced:	The APB clock to register as a clock_event_device. */void dw_apb_clockevent_register(struct dw_apb_clock_event_device *dw_ced){	apbt_writel(&dw_ced->timer, 0, APBTMR_N_CONTROL);	clockevents_register_device(&dw_ced->ced);	apbt_enable_int(&dw_ced->timer);} /** * dw_apb_clocksource_start() - start the clocksource counting. * * @dw_cs:	The clocksource to start. * * This is used to start the clocksource before registration and can be used * to enable calibration of timers. */void dw_apb_clocksource_start(struct dw_apb_clocksource *dw_cs){	/*	 * start count down from 0xffff_ffff. this is done by toggling the	 * enable bit then load initial load count to ~0.	 */	unsigned long ctrl = apbt_readl(&dw_cs->timer, APBTMR_N_CONTROL); 	ctrl &= ~APBTMR_CONTROL_ENABLE;	apbt_writel(&dw_cs->timer, ctrl, APBTMR_N_CONTROL);	apbt_writel(&dw_cs->timer, ~0, APBTMR_N_LOAD_COUNT);	/* enable, mask interrupt */	ctrl &= ~APBTMR_CONTROL_MODE_PERIODIC;	ctrl |= (APBTMR_CONTROL_ENABLE | APBTMR_CONTROL_INT);	apbt_writel(&dw_cs->timer, ctrl, APBTMR_N_CONTROL);	/* read it once to get cached counter value initialized */	dw_apb_clocksource_read(dw_cs);} static cycle_t __apbt_read_clocksource(struct clocksource *cs){	unsigned long current_count;	struct dw_apb_clocksource *dw_cs =		clocksource_to_dw_apb_clocksource(cs); 	current_count = apbt_readl(&dw_cs->timer, APBTMR_N_CURRENT_VALUE); 	return (cycle_t)~current_count;} static void apbt_restart_clocksource(struct clocksource *cs){	struct dw_apb_clocksource *dw_cs =		clocksource_to_dw_apb_clocksource(cs); 	dw_apb_clocksource_start(dw_cs);} /** * dw_apb_clocksource_init() - use an APB timer as a clocksource. * * @rating:	The rating to give the clocksource. * @name:	The name for the clocksource. * @base:	The I/O base for the timer registers. * @freq:	The frequency that the timer counts at. * * This creates a clocksource using an APB timer but does not yet register it * with the clocksource system.  This should be done with * dw_apb_clocksource_register() as the next step. */struct dw_apb_clocksource *dw_apb_clocksource_init(unsigned rating, const char *name, void __iomem *base,			unsigned long freq){	struct dw_apb_clocksource *dw_cs = kzalloc(sizeof(*dw_cs), GFP_KERNEL); 	if (!dw_cs)		return NULL; 	dw_cs->timer.base = base;	dw_cs->timer.freq = freq;	dw_cs->cs.name = name;	dw_cs->cs.rating = rating;	dw_cs->cs.read = __apbt_read_clocksource;	dw_cs->cs.mask = CLOCKSOURCE_MASK(32);	dw_cs->cs.flags = CLOCK_SOURCE_IS_CONTINUOUS;	dw_cs->cs.resume = apbt_restart_clocksource; 	return dw_cs;} /** * dw_apb_clocksource_register() - register the APB clocksource. * * @dw_cs:	The clocksource to register. */void dw_apb_clocksource_register(struct dw_apb_clocksource *dw_cs){	clocksource_register_hz(&dw_cs->cs, dw_cs->timer.freq);} /** * dw_apb_clocksource_read() - read the current value of a clocksource. * * @dw_cs:	The clocksource to read. */cycle_t dw_apb_clocksource_read(struct dw_apb_clocksource *dw_cs){	return (cycle_t)~apbt_readl(&dw_cs->timer, APBTMR_N_CURRENT_VALUE);}