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192 lines
4.7 KiB
192 lines
4.7 KiB
/* |
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* Marvell Orion SoC timer handling. |
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* |
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* Sebastian Hesselbarth <[email protected]> |
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* |
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* This file is licensed under the terms of the GNU General Public |
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* License version 2. This program is licensed "as is" without any |
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* warranty of any kind, whether express or implied. |
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* |
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* Timer 0 is used as free-running clocksource, while timer 1 is |
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* used as clock_event_device. |
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*/ |
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#include <linux/kernel.h> |
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#include <linux/bitops.h> |
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#include <linux/clk.h> |
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#include <linux/clockchips.h> |
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#include <linux/delay.h> |
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#include <linux/interrupt.h> |
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#include <linux/of_address.h> |
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#include <linux/of_irq.h> |
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#include <linux/spinlock.h> |
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#include <linux/sched_clock.h> |
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#define TIMER_CTRL 0x00 |
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#define TIMER0_EN BIT(0) |
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#define TIMER0_RELOAD_EN BIT(1) |
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#define TIMER1_EN BIT(2) |
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#define TIMER1_RELOAD_EN BIT(3) |
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#define TIMER0_RELOAD 0x10 |
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#define TIMER0_VAL 0x14 |
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#define TIMER1_RELOAD 0x18 |
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#define TIMER1_VAL 0x1c |
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#define ORION_ONESHOT_MIN 1 |
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#define ORION_ONESHOT_MAX 0xfffffffe |
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static void __iomem *timer_base; |
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static unsigned long notrace orion_read_timer(void) |
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{ |
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return ~readl(timer_base + TIMER0_VAL); |
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} |
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static struct delay_timer orion_delay_timer = { |
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.read_current_timer = orion_read_timer, |
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}; |
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static void orion_delay_timer_init(unsigned long rate) |
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{ |
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orion_delay_timer.freq = rate; |
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register_current_timer_delay(&orion_delay_timer); |
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} |
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/* |
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* Free-running clocksource handling. |
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*/ |
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static u64 notrace orion_read_sched_clock(void) |
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{ |
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return ~readl(timer_base + TIMER0_VAL); |
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} |
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/* |
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* Clockevent handling. |
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*/ |
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static u32 ticks_per_jiffy; |
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static int orion_clkevt_next_event(unsigned long delta, |
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struct clock_event_device *dev) |
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{ |
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/* setup and enable one-shot timer */ |
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writel(delta, timer_base + TIMER1_VAL); |
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atomic_io_modify(timer_base + TIMER_CTRL, |
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TIMER1_RELOAD_EN | TIMER1_EN, TIMER1_EN); |
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return 0; |
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} |
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static int orion_clkevt_shutdown(struct clock_event_device *dev) |
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{ |
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/* disable timer */ |
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atomic_io_modify(timer_base + TIMER_CTRL, |
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TIMER1_RELOAD_EN | TIMER1_EN, 0); |
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return 0; |
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} |
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static int orion_clkevt_set_periodic(struct clock_event_device *dev) |
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{ |
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/* setup and enable periodic timer at 1/HZ intervals */ |
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writel(ticks_per_jiffy - 1, timer_base + TIMER1_RELOAD); |
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writel(ticks_per_jiffy - 1, timer_base + TIMER1_VAL); |
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atomic_io_modify(timer_base + TIMER_CTRL, |
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TIMER1_RELOAD_EN | TIMER1_EN, |
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TIMER1_RELOAD_EN | TIMER1_EN); |
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return 0; |
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} |
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static struct clock_event_device orion_clkevt = { |
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.name = "orion_event", |
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.features = CLOCK_EVT_FEAT_ONESHOT | |
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CLOCK_EVT_FEAT_PERIODIC, |
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.shift = 32, |
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.rating = 300, |
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.set_next_event = orion_clkevt_next_event, |
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.set_state_shutdown = orion_clkevt_shutdown, |
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.set_state_periodic = orion_clkevt_set_periodic, |
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.set_state_oneshot = orion_clkevt_shutdown, |
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.tick_resume = orion_clkevt_shutdown, |
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}; |
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static irqreturn_t orion_clkevt_irq_handler(int irq, void *dev_id) |
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{ |
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orion_clkevt.event_handler(&orion_clkevt); |
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return IRQ_HANDLED; |
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} |
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static int __init orion_timer_init(struct device_node *np) |
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{ |
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unsigned long rate; |
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struct clk *clk; |
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int irq, ret; |
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/* timer registers are shared with watchdog timer */ |
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timer_base = of_iomap(np, 0); |
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if (!timer_base) { |
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pr_err("%pOFn: unable to map resource\n", np); |
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return -ENXIO; |
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} |
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clk = of_clk_get(np, 0); |
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if (IS_ERR(clk)) { |
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pr_err("%pOFn: unable to get clk\n", np); |
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return PTR_ERR(clk); |
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} |
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ret = clk_prepare_enable(clk); |
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if (ret) { |
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pr_err("Failed to prepare clock\n"); |
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return ret; |
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} |
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/* we are only interested in timer1 irq */ |
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irq = irq_of_parse_and_map(np, 1); |
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if (irq <= 0) { |
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pr_err("%pOFn: unable to parse timer1 irq\n", np); |
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ret = -EINVAL; |
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goto out_unprep_clk; |
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} |
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rate = clk_get_rate(clk); |
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/* setup timer0 as free-running clocksource */ |
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writel(~0, timer_base + TIMER0_VAL); |
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writel(~0, timer_base + TIMER0_RELOAD); |
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atomic_io_modify(timer_base + TIMER_CTRL, |
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TIMER0_RELOAD_EN | TIMER0_EN, |
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TIMER0_RELOAD_EN | TIMER0_EN); |
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ret = clocksource_mmio_init(timer_base + TIMER0_VAL, |
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"orion_clocksource", rate, 300, 32, |
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clocksource_mmio_readl_down); |
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if (ret) { |
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pr_err("Failed to initialize mmio timer\n"); |
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goto out_unprep_clk; |
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} |
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sched_clock_register(orion_read_sched_clock, 32, rate); |
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/* setup timer1 as clockevent timer */ |
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ret = request_irq(irq, orion_clkevt_irq_handler, IRQF_TIMER, |
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"orion_event", NULL); |
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if (ret) { |
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pr_err("%pOFn: unable to setup irq\n", np); |
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goto out_unprep_clk; |
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} |
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ticks_per_jiffy = (clk_get_rate(clk) + HZ/2) / HZ; |
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orion_clkevt.cpumask = cpumask_of(0); |
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orion_clkevt.irq = irq; |
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clockevents_config_and_register(&orion_clkevt, rate, |
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ORION_ONESHOT_MIN, ORION_ONESHOT_MAX); |
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orion_delay_timer_init(rate); |
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return 0; |
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out_unprep_clk: |
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clk_disable_unprepare(clk); |
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return ret; |
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} |
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TIMER_OF_DECLARE(orion_timer, "marvell,orion-timer", orion_timer_init);
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