// SPDX-License-Identifier: GPL-2.0-only /* * This file contains driver for the Cadence Triple Timer Counter Rev 06 * * Copyright (C) 2011-2013 Xilinx * * based on arch/mips/kernel/time.c timer driver */ #include <linux/clk.h> #include <linux/interrupt.h> #include <linux/clockchips.h> #include <linux/clocksource.h> #include <linux/of_address.h> #include <linux/of_irq.h> #include <linux/platform_device.h> #include <linux/slab.h> #include <linux/sched_clock.h> #include <linux/module.h> #include <linux/of_platform.h> /* * This driver configures the 2 16/32-bit count-up timers as follows: * * T1: Timer 1, clocksource for generic timekeeping * T2: Timer 2, clockevent source for hrtimers * T3: Timer 3, <unused> * * The input frequency to the timer module for emulation is 2.5MHz which is * common to all the timer channels (T1, T2, and T3). With a pre-scaler of 32, * the timers are clocked at 78.125KHz (12.8 us resolution). * The input frequency to the timer module in silicon is configurable and * obtained from device tree. The pre-scaler of 32 is used. */ /* * Timer Register Offset Definitions of Timer 1, Increment base address by 4 * and use same offsets for Timer 2 */ #define TTC_CLK_CNTRL_OFFSET … #define TTC_CNT_CNTRL_OFFSET … #define TTC_COUNT_VAL_OFFSET … #define TTC_INTR_VAL_OFFSET … #define TTC_ISR_OFFSET … #define TTC_IER_OFFSET … #define TTC_CNT_CNTRL_DISABLE_MASK … #define TTC_CLK_CNTRL_CSRC_MASK … #define TTC_CLK_CNTRL_PSV_MASK … #define TTC_CLK_CNTRL_PSV_SHIFT … /* * Setup the timers to use pre-scaling, using a fixed value for now that will * work across most input frequency, but it may need to be more dynamic */ #define PRESCALE_EXPONENT … #define PRESCALE … #define CLK_CNTRL_PRESCALE … #define CLK_CNTRL_PRESCALE_EN … #define CNT_CNTRL_RESET … #define MAX_F_ERR … /** * struct ttc_timer - This definition defines local timer structure * * @base_addr: Base address of timer * @freq: Timer input clock frequency * @clk: Associated clock source * @clk_rate_change_nb: Notifier block for clock rate changes */ struct ttc_timer { … }; #define to_ttc_timer(x) … struct ttc_timer_clocksource { … }; #define to_ttc_timer_clksrc(x) … struct ttc_timer_clockevent { … }; #define to_ttc_timer_clkevent(x) … static void __iomem *ttc_sched_clock_val_reg; /** * ttc_set_interval - Set the timer interval value * * @timer: Pointer to the timer instance * @cycles: Timer interval ticks **/ static void ttc_set_interval(struct ttc_timer *timer, unsigned long cycles) { … } /** * ttc_clock_event_interrupt - Clock event timer interrupt handler * * @irq: IRQ number of the Timer * @dev_id: void pointer to the ttc_timer instance * * Returns: Always IRQ_HANDLED - success **/ static irqreturn_t ttc_clock_event_interrupt(int irq, void *dev_id) { … } /** * __ttc_clocksource_read - Reads the timer counter register * @cs: &clocksource to read from * * Returns: Current timer counter register value **/ static u64 __ttc_clocksource_read(struct clocksource *cs) { … } static u64 notrace ttc_sched_clock_read(void) { … } /** * ttc_set_next_event - Sets the time interval for next event * * @cycles: Timer interval ticks * @evt: Address of clock event instance * * Returns: Always %0 - success **/ static int ttc_set_next_event(unsigned long cycles, struct clock_event_device *evt) { … } /** * ttc_shutdown - Sets the state of timer * @evt: Address of clock event instance * * Used for shutdown or oneshot. * * Returns: Always %0 - success **/ static int ttc_shutdown(struct clock_event_device *evt) { … } /** * ttc_set_periodic - Sets the state of timer * @evt: Address of clock event instance * * Returns: Always %0 - success */ static int ttc_set_periodic(struct clock_event_device *evt) { … } static int ttc_resume(struct clock_event_device *evt) { … } static int ttc_rate_change_clocksource_cb(struct notifier_block *nb, unsigned long event, void *data) { … } static int __init ttc_setup_clocksource(struct clk *clk, void __iomem *base, u32 timer_width) { … } static int ttc_rate_change_clockevent_cb(struct notifier_block *nb, unsigned long event, void *data) { … } static int __init ttc_setup_clockevent(struct clk *clk, void __iomem *base, u32 irq) { … } static int __init ttc_timer_probe(struct platform_device *pdev) { … } static const struct of_device_id ttc_timer_of_match[] = …; MODULE_DEVICE_TABLE(of, ttc_timer_of_match); static struct platform_driver ttc_timer_driver = …; builtin_platform_driver_probe(…);
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