diff options
Diffstat (limited to 'drivers/clocksource/timer-sun4i.c')
| -rw-r--r-- | drivers/clocksource/timer-sun4i.c | 227 |
1 files changed, 227 insertions, 0 deletions
diff --git a/drivers/clocksource/timer-sun4i.c b/drivers/clocksource/timer-sun4i.c new file mode 100644 index 000000000..0ba8155b8 --- /dev/null +++ b/drivers/clocksource/timer-sun4i.c @@ -0,0 +1,227 @@ +/* + * Allwinner A1X SoCs timer handling. + * + * Copyright (C) 2012 Maxime Ripard + * + * Maxime Ripard <maxime.ripard@free-electrons.com> + * + * Based on code from + * Allwinner Technology Co., Ltd. <www.allwinnertech.com> + * Benn Huang <benn@allwinnertech.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. + */ + +#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> + +#include "timer-of.h" + +#define TIMER_IRQ_EN_REG 0x00 +#define TIMER_IRQ_EN(val) BIT(val) +#define TIMER_IRQ_ST_REG 0x04 +#define TIMER_CTL_REG(val) (0x10 * val + 0x10) +#define TIMER_CTL_ENABLE BIT(0) +#define TIMER_CTL_RELOAD BIT(1) +#define TIMER_CTL_CLK_SRC(val) (((val) & 0x3) << 2) +#define TIMER_CTL_CLK_SRC_OSC24M (1) +#define TIMER_CTL_CLK_PRES(val) (((val) & 0x7) << 4) +#define TIMER_CTL_ONESHOT BIT(7) +#define TIMER_INTVAL_REG(val) (0x10 * (val) + 0x14) +#define TIMER_CNTVAL_REG(val) (0x10 * (val) + 0x18) + +#define TIMER_SYNC_TICKS 3 + +/* + * When we disable a timer, we need to wait at least for 2 cycles of + * the timer source clock. We will use for that the clocksource timer + * that is already setup and runs at the same frequency than the other + * timers, and we never will be disabled. + */ +static void sun4i_clkevt_sync(void __iomem *base) +{ + u32 old = readl(base + TIMER_CNTVAL_REG(1)); + + while ((old - readl(base + TIMER_CNTVAL_REG(1))) < TIMER_SYNC_TICKS) + cpu_relax(); +} + +static void sun4i_clkevt_time_stop(void __iomem *base, u8 timer) +{ + u32 val = readl(base + TIMER_CTL_REG(timer)); + writel(val & ~TIMER_CTL_ENABLE, base + TIMER_CTL_REG(timer)); + sun4i_clkevt_sync(base); +} + +static void sun4i_clkevt_time_setup(void __iomem *base, u8 timer, + unsigned long delay) +{ + writel(delay, base + TIMER_INTVAL_REG(timer)); +} + +static void sun4i_clkevt_time_start(void __iomem *base, u8 timer, + bool periodic) +{ + u32 val = readl(base + TIMER_CTL_REG(timer)); + + if (periodic) + val &= ~TIMER_CTL_ONESHOT; + else + val |= TIMER_CTL_ONESHOT; + + writel(val | TIMER_CTL_ENABLE | TIMER_CTL_RELOAD, + base + TIMER_CTL_REG(timer)); +} + +static int sun4i_clkevt_shutdown(struct clock_event_device *evt) +{ + struct timer_of *to = to_timer_of(evt); + + sun4i_clkevt_time_stop(timer_of_base(to), 0); + + return 0; +} + +static int sun4i_clkevt_set_oneshot(struct clock_event_device *evt) +{ + struct timer_of *to = to_timer_of(evt); + + sun4i_clkevt_time_stop(timer_of_base(to), 0); + sun4i_clkevt_time_start(timer_of_base(to), 0, false); + + return 0; +} + +static int sun4i_clkevt_set_periodic(struct clock_event_device *evt) +{ + struct timer_of *to = to_timer_of(evt); + + sun4i_clkevt_time_stop(timer_of_base(to), 0); + sun4i_clkevt_time_setup(timer_of_base(to), 0, timer_of_period(to)); + sun4i_clkevt_time_start(timer_of_base(to), 0, true); + + return 0; +} + +static int sun4i_clkevt_next_event(unsigned long evt, + struct clock_event_device *clkevt) +{ + struct timer_of *to = to_timer_of(clkevt); + + sun4i_clkevt_time_stop(timer_of_base(to), 0); + sun4i_clkevt_time_setup(timer_of_base(to), 0, evt - TIMER_SYNC_TICKS); + sun4i_clkevt_time_start(timer_of_base(to), 0, false); + + return 0; +} + +static void sun4i_timer_clear_interrupt(void __iomem *base) +{ + writel(TIMER_IRQ_EN(0), base + TIMER_IRQ_ST_REG); +} + +static irqreturn_t sun4i_timer_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *evt = (struct clock_event_device *)dev_id; + struct timer_of *to = to_timer_of(evt); + + sun4i_timer_clear_interrupt(timer_of_base(to)); + evt->event_handler(evt); + + return IRQ_HANDLED; +} + +static struct timer_of to = { + .flags = TIMER_OF_IRQ | TIMER_OF_CLOCK | TIMER_OF_BASE, + + .clkevt = { + .name = "sun4i_tick", + .rating = 350, + .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, + .set_state_shutdown = sun4i_clkevt_shutdown, + .set_state_periodic = sun4i_clkevt_set_periodic, + .set_state_oneshot = sun4i_clkevt_set_oneshot, + .tick_resume = sun4i_clkevt_shutdown, + .set_next_event = sun4i_clkevt_next_event, + .cpumask = cpu_possible_mask, + }, + + .of_irq = { + .handler = sun4i_timer_interrupt, + .flags = IRQF_TIMER | IRQF_IRQPOLL, + }, +}; + +static u64 notrace sun4i_timer_sched_read(void) +{ + return ~readl(timer_of_base(&to) + TIMER_CNTVAL_REG(1)); +} + +static int __init sun4i_timer_init(struct device_node *node) +{ + int ret; + u32 val; + + ret = timer_of_init(node, &to); + if (ret) + return ret; + + writel(~0, timer_of_base(&to) + TIMER_INTVAL_REG(1)); + writel(TIMER_CTL_ENABLE | TIMER_CTL_RELOAD | + TIMER_CTL_CLK_SRC(TIMER_CTL_CLK_SRC_OSC24M), + timer_of_base(&to) + TIMER_CTL_REG(1)); + + /* + * sched_clock_register does not have priorities, and on sun6i and + * later there is a better sched_clock registered by arm_arch_timer.c + */ + if (of_machine_is_compatible("allwinner,sun4i-a10") || + of_machine_is_compatible("allwinner,sun5i-a13") || + of_machine_is_compatible("allwinner,sun5i-a10s") || + of_machine_is_compatible("allwinner,suniv-f1c100s")) + sched_clock_register(sun4i_timer_sched_read, 32, + timer_of_rate(&to)); + + ret = clocksource_mmio_init(timer_of_base(&to) + TIMER_CNTVAL_REG(1), + node->name, timer_of_rate(&to), 350, 32, + clocksource_mmio_readl_down); + if (ret) { + pr_err("Failed to register clocksource\n"); + return ret; + } + + writel(TIMER_CTL_CLK_SRC(TIMER_CTL_CLK_SRC_OSC24M), + timer_of_base(&to) + TIMER_CTL_REG(0)); + + /* Make sure timer is stopped before playing with interrupts */ + sun4i_clkevt_time_stop(timer_of_base(&to), 0); + + /* clear timer0 interrupt */ + sun4i_timer_clear_interrupt(timer_of_base(&to)); + + clockevents_config_and_register(&to.clkevt, timer_of_rate(&to), + TIMER_SYNC_TICKS, 0xffffffff); + + /* Enable timer0 interrupt */ + val = readl(timer_of_base(&to) + TIMER_IRQ_EN_REG); + writel(val | TIMER_IRQ_EN(0), timer_of_base(&to) + TIMER_IRQ_EN_REG); + + return ret; +} +TIMER_OF_DECLARE(sun4i, "allwinner,sun4i-a10-timer", + sun4i_timer_init); +TIMER_OF_DECLARE(sun8i_a23, "allwinner,sun8i-a23-timer", + sun4i_timer_init); +TIMER_OF_DECLARE(sun8i_v3s, "allwinner,sun8i-v3s-timer", + sun4i_timer_init); +TIMER_OF_DECLARE(suniv, "allwinner,suniv-f1c100s-timer", + sun4i_timer_init); |