diff options
Diffstat (limited to 'drivers/clocksource/timer-orion.c')
| -rw-r--r-- | drivers/clocksource/timer-orion.c | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/drivers/clocksource/timer-orion.c b/drivers/clocksource/timer-orion.c new file mode 100644 index 000000000..5101e834d --- /dev/null +++ b/drivers/clocksource/timer-orion.c @@ -0,0 +1,192 @@ +/* + * Marvell Orion SoC timer handling. + * + * Sebastian Hesselbarth <sebastian.hesselbarth@gmail.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. + * + * Timer 0 is used as free-running clocksource, while timer 1 is + * used as clock_event_device. + */ + +#include <linux/kernel.h> +#include <linux/bitops.h> +#include <linux/clk.h> +#include <linux/clockchips.h> +#include <linux/delay.h> +#include <linux/interrupt.h> +#include <linux/of_address.h> +#include <linux/of_irq.h> +#include <linux/spinlock.h> +#include <linux/sched_clock.h> + +#define TIMER_CTRL 0x00 +#define TIMER0_EN BIT(0) +#define TIMER0_RELOAD_EN BIT(1) +#define TIMER1_EN BIT(2) +#define TIMER1_RELOAD_EN BIT(3) +#define TIMER0_RELOAD 0x10 +#define TIMER0_VAL 0x14 +#define TIMER1_RELOAD 0x18 +#define TIMER1_VAL 0x1c + +#define ORION_ONESHOT_MIN 1 +#define ORION_ONESHOT_MAX 0xfffffffe + +static void __iomem *timer_base; + +static unsigned long notrace orion_read_timer(void) +{ + return ~readl(timer_base + TIMER0_VAL); +} + +static struct delay_timer orion_delay_timer = { + .read_current_timer = orion_read_timer, +}; + +static void orion_delay_timer_init(unsigned long rate) +{ + orion_delay_timer.freq = rate; + register_current_timer_delay(&orion_delay_timer); +} + +/* + * Free-running clocksource handling. + */ +static u64 notrace orion_read_sched_clock(void) +{ + return ~readl(timer_base + TIMER0_VAL); +} + +/* + * Clockevent handling. + */ +static u32 ticks_per_jiffy; + +static int orion_clkevt_next_event(unsigned long delta, + struct clock_event_device *dev) +{ + /* setup and enable one-shot timer */ + writel(delta, timer_base + TIMER1_VAL); + atomic_io_modify(timer_base + TIMER_CTRL, + TIMER1_RELOAD_EN | TIMER1_EN, TIMER1_EN); + + return 0; +} + +static int orion_clkevt_shutdown(struct clock_event_device *dev) +{ + /* disable timer */ + atomic_io_modify(timer_base + TIMER_CTRL, + TIMER1_RELOAD_EN | TIMER1_EN, 0); + return 0; +} + +static int orion_clkevt_set_periodic(struct clock_event_device *dev) +{ + /* setup and enable periodic timer at 1/HZ intervals */ + writel(ticks_per_jiffy - 1, timer_base + TIMER1_RELOAD); + writel(ticks_per_jiffy - 1, timer_base + TIMER1_VAL); + atomic_io_modify(timer_base + TIMER_CTRL, + TIMER1_RELOAD_EN | TIMER1_EN, + TIMER1_RELOAD_EN | TIMER1_EN); + return 0; +} + +static struct clock_event_device orion_clkevt = { + .name = "orion_event", + .features = CLOCK_EVT_FEAT_ONESHOT | + CLOCK_EVT_FEAT_PERIODIC, + .shift = 32, + .rating = 300, + .set_next_event = orion_clkevt_next_event, + .set_state_shutdown = orion_clkevt_shutdown, + .set_state_periodic = orion_clkevt_set_periodic, + .set_state_oneshot = orion_clkevt_shutdown, + .tick_resume = orion_clkevt_shutdown, +}; + +static irqreturn_t orion_clkevt_irq_handler(int irq, void *dev_id) +{ + orion_clkevt.event_handler(&orion_clkevt); + return IRQ_HANDLED; +} + +static int __init orion_timer_init(struct device_node *np) +{ + unsigned long rate; + struct clk *clk; + int irq, ret; + + /* timer registers are shared with watchdog timer */ + timer_base = of_iomap(np, 0); + if (!timer_base) { + pr_err("%pOFn: unable to map resource\n", np); + return -ENXIO; + } + + clk = of_clk_get(np, 0); + if (IS_ERR(clk)) { + pr_err("%pOFn: unable to get clk\n", np); + return PTR_ERR(clk); + } + + ret = clk_prepare_enable(clk); + if (ret) { + pr_err("Failed to prepare clock\n"); + return ret; + } + + /* we are only interested in timer1 irq */ + irq = irq_of_parse_and_map(np, 1); + if (irq <= 0) { + pr_err("%pOFn: unable to parse timer1 irq\n", np); + ret = -EINVAL; + goto out_unprep_clk; + } + + rate = clk_get_rate(clk); + + /* setup timer0 as free-running clocksource */ + writel(~0, timer_base + TIMER0_VAL); + writel(~0, timer_base + TIMER0_RELOAD); + atomic_io_modify(timer_base + TIMER_CTRL, + TIMER0_RELOAD_EN | TIMER0_EN, + TIMER0_RELOAD_EN | TIMER0_EN); + + ret = clocksource_mmio_init(timer_base + TIMER0_VAL, + "orion_clocksource", rate, 300, 32, + clocksource_mmio_readl_down); + if (ret) { + pr_err("Failed to initialize mmio timer\n"); + goto out_unprep_clk; + } + + sched_clock_register(orion_read_sched_clock, 32, rate); + + /* setup timer1 as clockevent timer */ + ret = request_irq(irq, orion_clkevt_irq_handler, IRQF_TIMER, + "orion_event", NULL); + if (ret) { + pr_err("%pOFn: unable to setup irq\n", np); + goto out_unprep_clk; + } + + ticks_per_jiffy = (clk_get_rate(clk) + HZ/2) / HZ; + orion_clkevt.cpumask = cpumask_of(0); + orion_clkevt.irq = irq; + clockevents_config_and_register(&orion_clkevt, rate, + ORION_ONESHOT_MIN, ORION_ONESHOT_MAX); + + + orion_delay_timer_init(rate); + + return 0; + +out_unprep_clk: + clk_disable_unprepare(clk); + return ret; +} +TIMER_OF_DECLARE(orion_timer, "marvell,orion-timer", orion_timer_init); |