diff options
Diffstat (limited to 'drivers/clocksource/zevio-timer.c')
| -rw-r--r-- | drivers/clocksource/zevio-timer.c | 220 |
1 files changed, 220 insertions, 0 deletions
diff --git a/drivers/clocksource/zevio-timer.c b/drivers/clocksource/zevio-timer.c new file mode 100644 index 000000000..7ce442148 --- /dev/null +++ b/drivers/clocksource/zevio-timer.c @@ -0,0 +1,220 @@ +/* + * linux/drivers/clocksource/zevio-timer.c + * + * Copyright (C) 2013 Daniel Tang <tangrs@tangrs.id.au> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2, as + * published by the Free Software Foundation. + * + */ + +#include <linux/io.h> +#include <linux/irq.h> +#include <linux/of.h> +#include <linux/of_address.h> +#include <linux/of_irq.h> +#include <linux/clk.h> +#include <linux/clockchips.h> +#include <linux/cpumask.h> +#include <linux/interrupt.h> +#include <linux/slab.h> + +#define IO_CURRENT_VAL 0x00 +#define IO_DIVIDER 0x04 +#define IO_CONTROL 0x08 + +#define IO_TIMER1 0x00 +#define IO_TIMER2 0x0C + +#define IO_MATCH_BEGIN 0x18 +#define IO_MATCH(x) (IO_MATCH_BEGIN + ((x) << 2)) + +#define IO_INTR_STS 0x00 +#define IO_INTR_ACK 0x00 +#define IO_INTR_MSK 0x04 + +#define CNTL_STOP_TIMER (1 << 4) +#define CNTL_RUN_TIMER (0 << 4) + +#define CNTL_INC (1 << 3) +#define CNTL_DEC (0 << 3) + +#define CNTL_TOZERO 0 +#define CNTL_MATCH(x) ((x) + 1) +#define CNTL_FOREVER 7 + +/* There are 6 match registers but we only use one. */ +#define TIMER_MATCH 0 + +#define TIMER_INTR_MSK (1 << (TIMER_MATCH)) +#define TIMER_INTR_ALL 0x3F + +struct zevio_timer { + void __iomem *base; + void __iomem *timer1, *timer2; + void __iomem *interrupt_regs; + + struct clk *clk; + struct clock_event_device clkevt; + struct irqaction clkevt_irq; + + char clocksource_name[64]; + char clockevent_name[64]; +}; + +static int zevio_timer_set_event(unsigned long delta, + struct clock_event_device *dev) +{ + struct zevio_timer *timer = container_of(dev, struct zevio_timer, + clkevt); + + writel(delta, timer->timer1 + IO_CURRENT_VAL); + writel(CNTL_RUN_TIMER | CNTL_DEC | CNTL_MATCH(TIMER_MATCH), + timer->timer1 + IO_CONTROL); + + return 0; +} + +static void zevio_timer_set_mode(enum clock_event_mode mode, + struct clock_event_device *dev) +{ + struct zevio_timer *timer = container_of(dev, struct zevio_timer, + clkevt); + + switch (mode) { + case CLOCK_EVT_MODE_RESUME: + case CLOCK_EVT_MODE_ONESHOT: + /* Enable timer interrupts */ + writel(TIMER_INTR_MSK, timer->interrupt_regs + IO_INTR_MSK); + writel(TIMER_INTR_ALL, timer->interrupt_regs + IO_INTR_ACK); + break; + case CLOCK_EVT_MODE_SHUTDOWN: + case CLOCK_EVT_MODE_UNUSED: + /* Disable timer interrupts */ + writel(0, timer->interrupt_regs + IO_INTR_MSK); + writel(TIMER_INTR_ALL, timer->interrupt_regs + IO_INTR_ACK); + /* Stop timer */ + writel(CNTL_STOP_TIMER, timer->timer1 + IO_CONTROL); + break; + case CLOCK_EVT_MODE_PERIODIC: + default: + /* Unsupported */ + break; + } +} + +static irqreturn_t zevio_timer_interrupt(int irq, void *dev_id) +{ + struct zevio_timer *timer = dev_id; + u32 intr; + + intr = readl(timer->interrupt_regs + IO_INTR_ACK); + if (!(intr & TIMER_INTR_MSK)) + return IRQ_NONE; + + writel(TIMER_INTR_MSK, timer->interrupt_regs + IO_INTR_ACK); + writel(CNTL_STOP_TIMER, timer->timer1 + IO_CONTROL); + + if (timer->clkevt.event_handler) + timer->clkevt.event_handler(&timer->clkevt); + + return IRQ_HANDLED; +} + +static int __init zevio_timer_add(struct device_node *node) +{ + struct zevio_timer *timer; + struct resource res; + int irqnr, ret; + + timer = kzalloc(sizeof(*timer), GFP_KERNEL); + if (!timer) + return -ENOMEM; + + timer->base = of_iomap(node, 0); + if (!timer->base) { + ret = -EINVAL; + goto error_free; + } + timer->timer1 = timer->base + IO_TIMER1; + timer->timer2 = timer->base + IO_TIMER2; + + timer->clk = of_clk_get(node, 0); + if (IS_ERR(timer->clk)) { + ret = PTR_ERR(timer->clk); + pr_err("Timer clock not found! (error %d)\n", ret); + goto error_unmap; + } + + timer->interrupt_regs = of_iomap(node, 1); + irqnr = irq_of_parse_and_map(node, 0); + + of_address_to_resource(node, 0, &res); + scnprintf(timer->clocksource_name, sizeof(timer->clocksource_name), + "%llx.%s_clocksource", + (unsigned long long)res.start, node->name); + + scnprintf(timer->clockevent_name, sizeof(timer->clockevent_name), + "%llx.%s_clockevent", + (unsigned long long)res.start, node->name); + + if (timer->interrupt_regs && irqnr) { + timer->clkevt.name = timer->clockevent_name; + timer->clkevt.set_next_event = zevio_timer_set_event; + timer->clkevt.set_mode = zevio_timer_set_mode; + timer->clkevt.rating = 200; + timer->clkevt.cpumask = cpu_all_mask; + timer->clkevt.features = CLOCK_EVT_FEAT_ONESHOT; + timer->clkevt.irq = irqnr; + + writel(CNTL_STOP_TIMER, timer->timer1 + IO_CONTROL); + writel(0, timer->timer1 + IO_DIVIDER); + + /* Start with timer interrupts disabled */ + writel(0, timer->interrupt_regs + IO_INTR_MSK); + writel(TIMER_INTR_ALL, timer->interrupt_regs + IO_INTR_ACK); + + /* Interrupt to occur when timer value matches 0 */ + writel(0, timer->base + IO_MATCH(TIMER_MATCH)); + + timer->clkevt_irq.name = timer->clockevent_name; + timer->clkevt_irq.handler = zevio_timer_interrupt; + timer->clkevt_irq.dev_id = timer; + timer->clkevt_irq.flags = IRQF_TIMER | IRQF_IRQPOLL; + + setup_irq(irqnr, &timer->clkevt_irq); + + clockevents_config_and_register(&timer->clkevt, + clk_get_rate(timer->clk), 0x0001, 0xffff); + pr_info("Added %s as clockevent\n", timer->clockevent_name); + } + + writel(CNTL_STOP_TIMER, timer->timer2 + IO_CONTROL); + writel(0, timer->timer2 + IO_CURRENT_VAL); + writel(0, timer->timer2 + IO_DIVIDER); + writel(CNTL_RUN_TIMER | CNTL_FOREVER | CNTL_INC, + timer->timer2 + IO_CONTROL); + + clocksource_mmio_init(timer->timer2 + IO_CURRENT_VAL, + timer->clocksource_name, + clk_get_rate(timer->clk), + 200, 16, + clocksource_mmio_readw_up); + + pr_info("Added %s as clocksource\n", timer->clocksource_name); + + return 0; +error_unmap: + iounmap(timer->base); +error_free: + kfree(timer); + return ret; +} + +static void __init zevio_timer_init(struct device_node *node) +{ + BUG_ON(zevio_timer_add(node)); +} + +CLOCKSOURCE_OF_DECLARE(zevio_timer, "lsi,zevio-timer", zevio_timer_init); |