diff options
Diffstat (limited to 'drivers/clocksource/sunxi_timer.c')
| -rw-r--r-- | drivers/clocksource/sunxi_timer.c | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/drivers/clocksource/sunxi_timer.c b/drivers/clocksource/sunxi_timer.c new file mode 100644 index 00000000000..3c46434b64c --- /dev/null +++ b/drivers/clocksource/sunxi_timer.c @@ -0,0 +1,170 @@ +/* + * 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/of.h> +#include <linux/of_address.h> +#include <linux/of_irq.h> +#include <linux/sunxi_timer.h> +#include <linux/clk/sunxi.h> + +#define TIMER_CTL_REG 0x00 +#define TIMER_CTL_ENABLE (1 << 0) +#define TIMER_IRQ_ST_REG 0x04 +#define TIMER0_CTL_REG 0x10 +#define TIMER0_CTL_ENABLE (1 << 0) +#define TIMER0_CTL_AUTORELOAD (1 << 1) +#define TIMER0_CTL_ONESHOT (1 << 7) +#define TIMER0_INTVAL_REG 0x14 +#define TIMER0_CNTVAL_REG 0x18 + +#define TIMER_SCAL 16 + +static void __iomem *timer_base; + +static void sunxi_clkevt_mode(enum clock_event_mode mode, + struct clock_event_device *clk) +{ + u32 u = readl(timer_base + TIMER0_CTL_REG); + + switch (mode) { + case CLOCK_EVT_MODE_PERIODIC: + u &= ~(TIMER0_CTL_ONESHOT); + writel(u | TIMER0_CTL_ENABLE, timer_base + TIMER0_CTL_REG); + break; + + case CLOCK_EVT_MODE_ONESHOT: + writel(u | TIMER0_CTL_ONESHOT, timer_base + TIMER0_CTL_REG); + break; + case CLOCK_EVT_MODE_UNUSED: + case CLOCK_EVT_MODE_SHUTDOWN: + default: + writel(u & ~(TIMER0_CTL_ENABLE), timer_base + TIMER0_CTL_REG); + break; + } +} + +static int sunxi_clkevt_next_event(unsigned long evt, + struct clock_event_device *unused) +{ + u32 u = readl(timer_base + TIMER0_CTL_REG); + writel(evt, timer_base + TIMER0_CNTVAL_REG); + writel(u | TIMER0_CTL_ENABLE | TIMER0_CTL_AUTORELOAD, + timer_base + TIMER0_CTL_REG); + + return 0; +} + +static struct clock_event_device sunxi_clockevent = { + .name = "sunxi_tick", + .shift = 32, + .rating = 300, + .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, + .set_mode = sunxi_clkevt_mode, + .set_next_event = sunxi_clkevt_next_event, +}; + + +static irqreturn_t sunxi_timer_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *evt = (struct clock_event_device *)dev_id; + + writel(0x1, timer_base + TIMER_IRQ_ST_REG); + evt->event_handler(evt); + + return IRQ_HANDLED; +} + +static struct irqaction sunxi_timer_irq = { + .name = "sunxi_timer0", + .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL, + .handler = sunxi_timer_interrupt, + .dev_id = &sunxi_clockevent, +}; + +static struct of_device_id sunxi_timer_dt_ids[] = { + { .compatible = "allwinner,sunxi-timer" }, +}; + +static void __init sunxi_timer_init(void) +{ + struct device_node *node; + unsigned long rate = 0; + struct clk *clk; + int ret, irq; + u32 val; + + node = of_find_matching_node(NULL, sunxi_timer_dt_ids); + if (!node) + panic("No sunxi timer node"); + + timer_base = of_iomap(node, 0); + if (!timer_base) + panic("Can't map registers"); + + irq = irq_of_parse_and_map(node, 0); + if (irq <= 0) + panic("Can't parse IRQ"); + + sunxi_init_clocks(); + + clk = of_clk_get(node, 0); + if (IS_ERR(clk)) + panic("Can't get timer clock"); + + rate = clk_get_rate(clk); + + writel(rate / (TIMER_SCAL * HZ), + timer_base + TIMER0_INTVAL_REG); + + /* set clock source to HOSC, 16 pre-division */ + val = readl(timer_base + TIMER0_CTL_REG); + val &= ~(0x07 << 4); + val &= ~(0x03 << 2); + val |= (4 << 4) | (1 << 2); + writel(val, timer_base + TIMER0_CTL_REG); + + /* set mode to auto reload */ + val = readl(timer_base + TIMER0_CTL_REG); + writel(val | TIMER0_CTL_AUTORELOAD, timer_base + TIMER0_CTL_REG); + + ret = setup_irq(irq, &sunxi_timer_irq); + if (ret) + pr_warn("failed to setup irq %d\n", irq); + + /* Enable timer0 interrupt */ + val = readl(timer_base + TIMER_CTL_REG); + writel(val | TIMER_CTL_ENABLE, timer_base + TIMER_CTL_REG); + + sunxi_clockevent.mult = div_sc(rate / TIMER_SCAL, + NSEC_PER_SEC, + sunxi_clockevent.shift); + sunxi_clockevent.max_delta_ns = clockevent_delta2ns(0xff, + &sunxi_clockevent); + sunxi_clockevent.min_delta_ns = clockevent_delta2ns(0x1, + &sunxi_clockevent); + sunxi_clockevent.cpumask = cpumask_of(0); + + clockevents_register_device(&sunxi_clockevent); +} + +struct sys_timer sunxi_timer = { + .init = sunxi_timer_init, +}; |