diff options
Diffstat (limited to 'drivers/clocksource/meson6_timer.c')
| -rw-r--r-- | drivers/clocksource/meson6_timer.c | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/drivers/clocksource/meson6_timer.c b/drivers/clocksource/meson6_timer.c new file mode 100644 index 000000000..5c15cba41 --- /dev/null +++ b/drivers/clocksource/meson6_timer.c @@ -0,0 +1,167 @@ +/* + * Amlogic Meson6 SoCs timer handling. + * + * Copyright (C) 2014 Carlo Caione <carlo@caione.org> + * + * Based on code from Amlogic, Inc + * + * 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> + +#define CED_ID 0 +#define CSD_ID 4 + +#define TIMER_ISA_MUX 0 +#define TIMER_ISA_VAL(t) (((t) + 1) << 2) + +#define TIMER_INPUT_BIT(t) (2 * (t)) +#define TIMER_ENABLE_BIT(t) (16 + (t)) +#define TIMER_PERIODIC_BIT(t) (12 + (t)) + +#define TIMER_CED_INPUT_MASK (3UL << TIMER_INPUT_BIT(CED_ID)) +#define TIMER_CSD_INPUT_MASK (7UL << TIMER_INPUT_BIT(CSD_ID)) + +#define TIMER_CED_UNIT_1US 0 +#define TIMER_CSD_UNIT_1US 1 + +static void __iomem *timer_base; + +static u64 notrace meson6_timer_sched_read(void) +{ + return (u64)readl(timer_base + TIMER_ISA_VAL(CSD_ID)); +} + +static void meson6_clkevt_time_stop(unsigned char timer) +{ + u32 val = readl(timer_base + TIMER_ISA_MUX); + + writel(val & ~TIMER_ENABLE_BIT(timer), timer_base + TIMER_ISA_MUX); +} + +static void meson6_clkevt_time_setup(unsigned char timer, unsigned long delay) +{ + writel(delay, timer_base + TIMER_ISA_VAL(timer)); +} + +static void meson6_clkevt_time_start(unsigned char timer, bool periodic) +{ + u32 val = readl(timer_base + TIMER_ISA_MUX); + + if (periodic) + val |= TIMER_PERIODIC_BIT(timer); + else + val &= ~TIMER_PERIODIC_BIT(timer); + + writel(val | TIMER_ENABLE_BIT(timer), timer_base + TIMER_ISA_MUX); +} + +static void meson6_clkevt_mode(enum clock_event_mode mode, + struct clock_event_device *clk) +{ + switch (mode) { + case CLOCK_EVT_MODE_PERIODIC: + meson6_clkevt_time_stop(CED_ID); + meson6_clkevt_time_setup(CED_ID, USEC_PER_SEC/HZ - 1); + meson6_clkevt_time_start(CED_ID, true); + break; + case CLOCK_EVT_MODE_ONESHOT: + meson6_clkevt_time_stop(CED_ID); + meson6_clkevt_time_start(CED_ID, false); + break; + case CLOCK_EVT_MODE_UNUSED: + case CLOCK_EVT_MODE_SHUTDOWN: + default: + meson6_clkevt_time_stop(CED_ID); + break; + } +} + +static int meson6_clkevt_next_event(unsigned long evt, + struct clock_event_device *unused) +{ + meson6_clkevt_time_stop(CED_ID); + meson6_clkevt_time_setup(CED_ID, evt); + meson6_clkevt_time_start(CED_ID, false); + + return 0; +} + +static struct clock_event_device meson6_clockevent = { + .name = "meson6_tick", + .rating = 400, + .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, + .set_mode = meson6_clkevt_mode, + .set_next_event = meson6_clkevt_next_event, +}; + +static irqreturn_t meson6_timer_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *evt = (struct clock_event_device *)dev_id; + + evt->event_handler(evt); + + return IRQ_HANDLED; +} + +static struct irqaction meson6_timer_irq = { + .name = "meson6_timer", + .flags = IRQF_TIMER | IRQF_IRQPOLL, + .handler = meson6_timer_interrupt, + .dev_id = &meson6_clockevent, +}; + +static void __init meson6_timer_init(struct device_node *node) +{ + u32 val; + int ret, irq; + + timer_base = of_io_request_and_map(node, 0, "meson6-timer"); + if (IS_ERR(timer_base)) + panic("Can't map registers"); + + irq = irq_of_parse_and_map(node, 0); + if (irq <= 0) + panic("Can't parse IRQ"); + + /* Set 1us for timer E */ + val = readl(timer_base + TIMER_ISA_MUX); + val &= ~TIMER_CSD_INPUT_MASK; + val |= TIMER_CSD_UNIT_1US << TIMER_INPUT_BIT(CSD_ID); + writel(val, timer_base + TIMER_ISA_MUX); + + sched_clock_register(meson6_timer_sched_read, 32, USEC_PER_SEC); + clocksource_mmio_init(timer_base + TIMER_ISA_VAL(CSD_ID), node->name, + 1000 * 1000, 300, 32, clocksource_mmio_readl_up); + + /* Timer A base 1us */ + val &= ~TIMER_CED_INPUT_MASK; + val |= TIMER_CED_UNIT_1US << TIMER_INPUT_BIT(CED_ID); + writel(val, timer_base + TIMER_ISA_MUX); + + /* Stop the timer A */ + meson6_clkevt_time_stop(CED_ID); + + ret = setup_irq(irq, &meson6_timer_irq); + if (ret) + pr_warn("failed to setup irq %d\n", irq); + + meson6_clockevent.cpumask = cpu_possible_mask; + meson6_clockevent.irq = irq; + + clockevents_config_and_register(&meson6_clockevent, USEC_PER_SEC, + 1, 0xfffe); +} +CLOCKSOURCE_OF_DECLARE(meson6, "amlogic,meson6-timer", + meson6_timer_init); |