/* * Allwinner A1X SoCs timer handling. * * Copyright (C) 2012 Maxime Ripard * * Maxime Ripard <maxime.ripard@free-electrons.com> * * Based on code from * Allwinner Technology Co., Ltd. <www.allwinnertech.com> * Benn Huang <benn@allwinnertech.com> * * This file is licensed under the terms of the GNU General Public * License version 2.  This program is licensed "as is" without any * warranty of any kind, whether express or implied. */ #include <linux/clk.h>#include <linux/clockchips.h>#include <linux/interrupt.h>#include <linux/irq.h>#include <linux/irqreturn.h>#include <linux/sched_clock.h>#include <linux/of.h>#include <linux/of_address.h>#include <linux/of_irq.h> #include "timer-of.h" #define TIMER_IRQ_EN_REG	0x00#define TIMER_IRQ_EN(val)		BIT(val)#define TIMER_IRQ_ST_REG	0x04#define TIMER_CTL_REG(val)	(0x10 * val + 0x10)#define TIMER_CTL_ENABLE		BIT(0)#define TIMER_CTL_RELOAD		BIT(1)#define TIMER_CTL_CLK_SRC(val)		(((val) & 0x3) << 2)#define TIMER_CTL_CLK_SRC_OSC24M		(1)#define TIMER_CTL_CLK_PRES(val)		(((val) & 0x7) << 4)#define TIMER_CTL_ONESHOT		BIT(7)#define TIMER_INTVAL_REG(val)	(0x10 * (val) + 0x14)#define TIMER_CNTVAL_REG(val)	(0x10 * (val) + 0x18) #define TIMER_SYNC_TICKS	3 /* * When we disable a timer, we need to wait at least for 2 cycles of * the timer source clock. We will use for that the clocksource timer * that is already setup and runs at the same frequency than the other * timers, and we never will be disabled. */static void sun4i_clkevt_sync(void __iomem *base){	u32 old = readl(base + TIMER_CNTVAL_REG(1)); 	while ((old - readl(base + TIMER_CNTVAL_REG(1))) < TIMER_SYNC_TICKS)		cpu_relax();} static void sun4i_clkevt_time_stop(void __iomem *base, u8 timer){	u32 val = readl(base + TIMER_CTL_REG(timer));	writel(val & ~TIMER_CTL_ENABLE, base + TIMER_CTL_REG(timer));	sun4i_clkevt_sync(base);} static void sun4i_clkevt_time_setup(void __iomem *base, u8 timer,				    unsigned long delay){	writel(delay, base + TIMER_INTVAL_REG(timer));} static void sun4i_clkevt_time_start(void __iomem *base, u8 timer,				    bool periodic){	u32 val = readl(base + TIMER_CTL_REG(timer)); 	if (periodic)		val &= ~TIMER_CTL_ONESHOT;	else		val |= TIMER_CTL_ONESHOT; 	writel(val | TIMER_CTL_ENABLE | TIMER_CTL_RELOAD,	       base + TIMER_CTL_REG(timer));} static int sun4i_clkevt_shutdown(struct clock_event_device *evt){	struct timer_of *to = to_timer_of(evt); 	sun4i_clkevt_time_stop(timer_of_base(to), 0); 	return 0;} static int sun4i_clkevt_set_oneshot(struct clock_event_device *evt){	struct timer_of *to = to_timer_of(evt); 	sun4i_clkevt_time_stop(timer_of_base(to), 0);	sun4i_clkevt_time_start(timer_of_base(to), 0, false); 	return 0;} static int sun4i_clkevt_set_periodic(struct clock_event_device *evt){	struct timer_of *to = to_timer_of(evt); 	sun4i_clkevt_time_stop(timer_of_base(to), 0);	sun4i_clkevt_time_setup(timer_of_base(to), 0, timer_of_period(to));	sun4i_clkevt_time_start(timer_of_base(to), 0, true); 	return 0;} static int sun4i_clkevt_next_event(unsigned long evt,				   struct clock_event_device *clkevt){	struct timer_of *to = to_timer_of(clkevt); 	sun4i_clkevt_time_stop(timer_of_base(to), 0);	sun4i_clkevt_time_setup(timer_of_base(to), 0, evt - TIMER_SYNC_TICKS);	sun4i_clkevt_time_start(timer_of_base(to), 0, false); 	return 0;} static void sun4i_timer_clear_interrupt(void __iomem *base){	writel(TIMER_IRQ_EN(0), base + TIMER_IRQ_ST_REG);} static irqreturn_t sun4i_timer_interrupt(int irq, void *dev_id){	struct clock_event_device *evt = (struct clock_event_device *)dev_id;	struct timer_of *to = to_timer_of(evt); 	sun4i_timer_clear_interrupt(timer_of_base(to));	evt->event_handler(evt); 	return IRQ_HANDLED;} static struct timer_of to = {	.flags = TIMER_OF_IRQ | TIMER_OF_CLOCK | TIMER_OF_BASE, 	.clkevt = {		.name = "sun4i_tick",		.rating = 350,		.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,		.set_state_shutdown = sun4i_clkevt_shutdown,		.set_state_periodic = sun4i_clkevt_set_periodic,		.set_state_oneshot = sun4i_clkevt_set_oneshot,		.tick_resume = sun4i_clkevt_shutdown,		.set_next_event = sun4i_clkevt_next_event,		.cpumask = cpu_possible_mask,	}, 	.of_irq = {		.handler = sun4i_timer_interrupt,		.flags = IRQF_TIMER | IRQF_IRQPOLL,	},}; static u64 notrace sun4i_timer_sched_read(void){	return ~readl(timer_of_base(&to) + TIMER_CNTVAL_REG(1));} static int __init sun4i_timer_init(struct device_node *node){	int ret;	u32 val; 	ret = timer_of_init(node, &to);	if (ret)		return ret; 	writel(~0, timer_of_base(&to) + TIMER_INTVAL_REG(1));	writel(TIMER_CTL_ENABLE | TIMER_CTL_RELOAD |	       TIMER_CTL_CLK_SRC(TIMER_CTL_CLK_SRC_OSC24M),	       timer_of_base(&to) + TIMER_CTL_REG(1)); 	/*	 * sched_clock_register does not have priorities, and on sun6i and	 * later there is a better sched_clock registered by arm_arch_timer.c	 */	if (of_machine_is_compatible("allwinner,sun4i-a10") ||	    of_machine_is_compatible("allwinner,sun5i-a13") ||	    of_machine_is_compatible("allwinner,sun5i-a10s"))		sched_clock_register(sun4i_timer_sched_read, 32,				     timer_of_rate(&to)); 	ret = clocksource_mmio_init(timer_of_base(&to) + TIMER_CNTVAL_REG(1),				    node->name, timer_of_rate(&to), 350, 32,				    clocksource_mmio_readl_down);	if (ret) {		pr_err("Failed to register clocksource\n");		return ret;	} 	writel(TIMER_CTL_CLK_SRC(TIMER_CTL_CLK_SRC_OSC24M),	       timer_of_base(&to) + TIMER_CTL_REG(0)); 	/* Make sure timer is stopped before playing with interrupts */	sun4i_clkevt_time_stop(timer_of_base(&to), 0); 	/* clear timer0 interrupt */	sun4i_timer_clear_interrupt(timer_of_base(&to)); 	clockevents_config_and_register(&to.clkevt, timer_of_rate(&to),					TIMER_SYNC_TICKS, 0xffffffff); 	/* Enable timer0 interrupt */	val = readl(timer_of_base(&to) + TIMER_IRQ_EN_REG);	writel(val | TIMER_IRQ_EN(0), timer_of_base(&to) + TIMER_IRQ_EN_REG); 	return ret;}TIMER_OF_DECLARE(sun4i, "allwinner,sun4i-a10-timer",		       sun4i_timer_init);