/* * drivers/clocksource/timer-oxnas-rps.c * * Copyright (C) 2009 Oxford Semiconductor Ltd * Copyright (C) 2013 Ma Haijun * Copyright (C) 2016 Neil Armstrong * * This program is free software; you can redistribute it and/or modify it * under the terms and conditions of the GNU General Public License, * version 2, as published by the Free Software Foundation. * * This program is distributed in the hope it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for * more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see . */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include #include #include #include #include #include #include #include /* TIMER1 used as tick * TIMER2 used as clocksource */ /* Registers definitions */ #define TIMER_LOAD_REG 0x0 #define TIMER_CURR_REG 0x4 #define TIMER_CTRL_REG 0x8 #define TIMER_CLRINT_REG 0xC #define TIMER_BITS 24 #define TIMER_MAX_VAL (BIT(TIMER_BITS) - 1) #define TIMER_PERIODIC BIT(6) #define TIMER_ENABLE BIT(7) #define TIMER_DIV1 (0) #define TIMER_DIV16 (1 << 2) #define TIMER_DIV256 (2 << 2) #define TIMER1_REG_OFFSET 0 #define TIMER2_REG_OFFSET 0x20 /* Clockevent & Clocksource data */ struct oxnas_rps_timer { struct clock_event_device clkevent; void __iomem *clksrc_base; void __iomem *clkevt_base; unsigned long timer_period; unsigned int timer_prescaler; struct clk *clk; int irq; }; static irqreturn_t oxnas_rps_timer_irq(int irq, void *dev_id) { struct oxnas_rps_timer *rps = dev_id; writel_relaxed(0, rps->clkevt_base + TIMER_CLRINT_REG); rps->clkevent.event_handler(&rps->clkevent); return IRQ_HANDLED; } static void oxnas_rps_timer_config(struct oxnas_rps_timer *rps, unsigned long period, unsigned int periodic) { uint32_t cfg = rps->timer_prescaler; if (period) cfg |= TIMER_ENABLE; if (periodic) cfg |= TIMER_PERIODIC; writel_relaxed(period, rps->clkevt_base + TIMER_LOAD_REG); writel_relaxed(cfg, rps->clkevt_base + TIMER_CTRL_REG); } static int oxnas_rps_timer_shutdown(struct clock_event_device *evt) { struct oxnas_rps_timer *rps = container_of(evt, struct oxnas_rps_timer, clkevent); oxnas_rps_timer_config(rps, 0, 0); return 0; } static int oxnas_rps_timer_set_periodic(struct clock_event_device *evt) { struct oxnas_rps_timer *rps = container_of(evt, struct oxnas_rps_timer, clkevent); oxnas_rps_timer_config(rps, rps->timer_period, 1); return 0; } static int oxnas_rps_timer_set_oneshot(struct clock_event_device *evt) { struct oxnas_rps_timer *rps = container_of(evt, struct oxnas_rps_timer, clkevent); oxnas_rps_timer_config(rps, rps->timer_period, 0); return 0; } static int oxnas_rps_timer_next_event(unsigned long delta, struct clock_event_device *evt) { struct oxnas_rps_timer *rps = container_of(evt, struct oxnas_rps_timer, clkevent); oxnas_rps_timer_config(rps, delta, 0); return 0; } static int __init oxnas_rps_clockevent_init(struct oxnas_rps_timer *rps) { ulong clk_rate = clk_get_rate(rps->clk); ulong timer_rate; /* Start with prescaler 1 */ rps->timer_prescaler = TIMER_DIV1; rps->timer_period = DIV_ROUND_UP(clk_rate, HZ); timer_rate = clk_rate; if (rps->timer_period > TIMER_MAX_VAL) { rps->timer_prescaler = TIMER_DIV16; timer_rate = clk_rate / 16; rps->timer_period = DIV_ROUND_UP(timer_rate, HZ); } if (rps->timer_period > TIMER_MAX_VAL) { rps->timer_prescaler = TIMER_DIV256; timer_rate = clk_rate / 256; rps->timer_period = DIV_ROUND_UP(timer_rate, HZ); } rps->clkevent.name = "oxnas-rps"; rps->clkevent.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_DYNIRQ; rps->clkevent.tick_resume = oxnas_rps_timer_shutdown; rps->clkevent.set_state_shutdown = oxnas_rps_timer_shutdown; rps->clkevent.set_state_periodic = oxnas_rps_timer_set_periodic; rps->clkevent.set_state_oneshot = oxnas_rps_timer_set_oneshot; rps->clkevent.set_next_event = oxnas_rps_timer_next_event; rps->clkevent.rating = 200; rps->clkevent.cpumask = cpu_possible_mask; rps->clkevent.irq = rps->irq; clockevents_config_and_register(&rps->clkevent, timer_rate, 1, TIMER_MAX_VAL); pr_info("Registered clock event rate %luHz prescaler %x period %lu\n", clk_rate, rps->timer_prescaler, rps->timer_period); return 0; } /* Clocksource */ static void __iomem *timer_sched_base; static u64 notrace oxnas_rps_read_sched_clock(void) { return ~readl_relaxed(timer_sched_base); } static int __init oxnas_rps_clocksource_init(struct oxnas_rps_timer *rps) { ulong clk_rate = clk_get_rate(rps->clk); int ret; /* use prescale 16 */ clk_rate = clk_rate / 16; writel_relaxed(TIMER_MAX_VAL, rps->clksrc_base + TIMER_LOAD_REG); writel_relaxed(TIMER_PERIODIC | TIMER_ENABLE | TIMER_DIV16, rps->clksrc_base + TIMER_CTRL_REG); timer_sched_base = rps->clksrc_base + TIMER_CURR_REG; sched_clock_register(oxnas_rps_read_sched_clock, TIMER_BITS, clk_rate); ret = clocksource_mmio_init(timer_sched_base, "oxnas_rps_clocksource_timer", clk_rate, 250, TIMER_BITS, clocksource_mmio_readl_down); if (WARN_ON(ret)) { pr_err("can't register clocksource\n"); return ret; } pr_info("Registered clocksource rate %luHz\n", clk_rate); return 0; } static int __init oxnas_rps_timer_init(struct device_node *np) { struct oxnas_rps_timer *rps; void __iomem *base; int ret; rps = kzalloc(sizeof(*rps), GFP_KERNEL); if (!rps) return -ENOMEM; rps->clk = of_clk_get(np, 0); if (IS_ERR(rps->clk)) { ret = PTR_ERR(rps->clk); goto err_alloc; } ret = clk_prepare_enable(rps->clk); if (ret) goto err_clk; base = of_iomap(np, 0); if (!base) { ret = -ENXIO; goto err_clk_prepare; } rps->irq = irq_of_parse_and_map(np, 0); if (!rps->irq) { ret = -EINVAL; goto err_iomap; } rps->clkevt_base = base + TIMER1_REG_OFFSET; rps->clksrc_base = base + TIMER2_REG_OFFSET; /* Disable timers */ writel_relaxed(0, rps->clkevt_base + TIMER_CTRL_REG); writel_relaxed(0, rps->clksrc_base + TIMER_CTRL_REG); writel_relaxed(0, rps->clkevt_base + TIMER_LOAD_REG); writel_relaxed(0, rps->clksrc_base + TIMER_LOAD_REG); writel_relaxed(0, rps->clkevt_base + TIMER_CLRINT_REG); writel_relaxed(0, rps->clksrc_base + TIMER_CLRINT_REG); ret = request_irq(rps->irq, oxnas_rps_timer_irq, IRQF_TIMER | IRQF_IRQPOLL, "rps-timer", rps); if (ret) goto err_iomap; ret = oxnas_rps_clocksource_init(rps); if (ret) goto err_irqreq; ret = oxnas_rps_clockevent_init(rps); if (ret) goto err_irqreq; return 0; err_irqreq: free_irq(rps->irq, rps); err_iomap: iounmap(base); err_clk_prepare: clk_disable_unprepare(rps->clk); err_clk: clk_put(rps->clk); err_alloc: kfree(rps); return ret; } CLOCKSOURCE_OF_DECLARE(ox810se_rps, "oxsemi,ox810se-rps-timer", oxnas_rps_timer_init); CLOCKSOURCE_OF_DECLARE(ox820_rps, "oxsemi,ox820se-rps-timer", oxnas_rps_timer_init);