diff options
Diffstat (limited to 'kernel/arch/arm/mach-gemini/time.c')
| -rw-r--r-- | kernel/arch/arm/mach-gemini/time.c | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/kernel/arch/arm/mach-gemini/time.c b/kernel/arch/arm/mach-gemini/time.c new file mode 100644 index 000000000..0a63c4d25 --- /dev/null +++ b/kernel/arch/arm/mach-gemini/time.c @@ -0,0 +1,170 @@ +/* + * Copyright (C) 2001-2006 Storlink, Corp. + * Copyright (C) 2008-2009 Paulius Zaleckas <paulius.zaleckas@teltonika.lt> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + */ +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <linux/io.h> +#include <mach/hardware.h> +#include <mach/global_reg.h> +#include <asm/mach/time.h> +#include <linux/clockchips.h> +#include <linux/clocksource.h> + +/* + * Register definitions for the timers + */ +#define TIMER_COUNT(BASE_ADDR) (BASE_ADDR + 0x00) +#define TIMER_LOAD(BASE_ADDR) (BASE_ADDR + 0x04) +#define TIMER_MATCH1(BASE_ADDR) (BASE_ADDR + 0x08) +#define TIMER_MATCH2(BASE_ADDR) (BASE_ADDR + 0x0C) +#define TIMER_CR(BASE_ADDR) (BASE_ADDR + 0x30) + +#define TIMER_1_CR_ENABLE (1 << 0) +#define TIMER_1_CR_CLOCK (1 << 1) +#define TIMER_1_CR_INT (1 << 2) +#define TIMER_2_CR_ENABLE (1 << 3) +#define TIMER_2_CR_CLOCK (1 << 4) +#define TIMER_2_CR_INT (1 << 5) +#define TIMER_3_CR_ENABLE (1 << 6) +#define TIMER_3_CR_CLOCK (1 << 7) +#define TIMER_3_CR_INT (1 << 8) + +static unsigned int tick_rate; + +static int gemini_timer_set_next_event(unsigned long cycles, + struct clock_event_device *evt) +{ + u32 cr; + + cr = readl(TIMER_CR(IO_ADDRESS(GEMINI_TIMER_BASE))); + + /* This may be overdoing it, feel free to test without this */ + cr &= ~TIMER_2_CR_ENABLE; + cr &= ~TIMER_2_CR_INT; + writel(cr, TIMER_CR(IO_ADDRESS(GEMINI_TIMER_BASE))); + + /* Set next event */ + writel(cycles, TIMER_COUNT(IO_ADDRESS(GEMINI_TIMER2_BASE))); + writel(cycles, TIMER_LOAD(IO_ADDRESS(GEMINI_TIMER2_BASE))); + cr |= TIMER_2_CR_ENABLE; + cr |= TIMER_2_CR_INT; + writel(cr, TIMER_CR(IO_ADDRESS(GEMINI_TIMER_BASE))); + + return 0; +} + +static void gemini_timer_set_mode(enum clock_event_mode mode, + struct clock_event_device *evt) +{ + u32 period = DIV_ROUND_CLOSEST(tick_rate, HZ); + u32 cr; + + switch (mode) { + case CLOCK_EVT_MODE_PERIODIC: + /* Start the timer */ + writel(period, + TIMER_COUNT(IO_ADDRESS(GEMINI_TIMER2_BASE))); + writel(period, + TIMER_LOAD(IO_ADDRESS(GEMINI_TIMER2_BASE))); + cr = readl(TIMER_CR(IO_ADDRESS(GEMINI_TIMER_BASE))); + cr |= TIMER_2_CR_ENABLE; + cr |= TIMER_2_CR_INT; + writel(cr, TIMER_CR(IO_ADDRESS(GEMINI_TIMER_BASE))); + break; + case CLOCK_EVT_MODE_ONESHOT: + case CLOCK_EVT_MODE_UNUSED: + case CLOCK_EVT_MODE_SHUTDOWN: + case CLOCK_EVT_MODE_RESUME: + /* + * Disable also for oneshot: the set_next() call will + * arm the timer instead. + */ + cr = readl(TIMER_CR(IO_ADDRESS(GEMINI_TIMER_BASE))); + cr &= ~TIMER_2_CR_ENABLE; + cr &= ~TIMER_2_CR_INT; + writel(cr, TIMER_CR(IO_ADDRESS(GEMINI_TIMER_BASE))); + break; + default: + break; + } +} + +/* Use TIMER2 as clock event */ +static struct clock_event_device gemini_clockevent = { + .name = "TIMER2", + .rating = 300, /* Reasonably fast and accurate clock event */ + .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, + .set_next_event = gemini_timer_set_next_event, + .set_mode = gemini_timer_set_mode, +}; + +/* + * IRQ handler for the timer + */ +static irqreturn_t gemini_timer_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *evt = &gemini_clockevent; + + evt->event_handler(evt); + return IRQ_HANDLED; +} + +static struct irqaction gemini_timer_irq = { + .name = "Gemini Timer Tick", + .flags = IRQF_TIMER, + .handler = gemini_timer_interrupt, +}; + +/* + * Set up timer interrupt, and return the current time in seconds. + */ +void __init gemini_timer_init(void) +{ + u32 reg_v; + + reg_v = readl(IO_ADDRESS(GEMINI_GLOBAL_BASE + GLOBAL_STATUS)); + tick_rate = REG_TO_AHB_SPEED(reg_v) * 1000000; + + printk(KERN_INFO "Bus: %dMHz", tick_rate / 1000000); + + tick_rate /= 6; /* APB bus run AHB*(1/6) */ + + switch(reg_v & CPU_AHB_RATIO_MASK) { + case CPU_AHB_1_1: + printk(KERN_CONT "(1/1)\n"); + break; + case CPU_AHB_3_2: + printk(KERN_CONT "(3/2)\n"); + break; + case CPU_AHB_24_13: + printk(KERN_CONT "(24/13)\n"); + break; + case CPU_AHB_2_1: + printk(KERN_CONT "(2/1)\n"); + break; + } + + /* + * Make irqs happen for the system timer + */ + setup_irq(IRQ_TIMER2, &gemini_timer_irq); + + /* Enable and use TIMER1 as clock source */ + writel(0xffffffff, TIMER_COUNT(IO_ADDRESS(GEMINI_TIMER1_BASE))); + writel(0xffffffff, TIMER_LOAD(IO_ADDRESS(GEMINI_TIMER1_BASE))); + writel(TIMER_1_CR_ENABLE, TIMER_CR(IO_ADDRESS(GEMINI_TIMER_BASE))); + if (clocksource_mmio_init(TIMER_COUNT(IO_ADDRESS(GEMINI_TIMER1_BASE)), + "TIMER1", tick_rate, 300, 32, + clocksource_mmio_readl_up)) + pr_err("timer: failed to initialize gemini clock source\n"); + + /* Configure and register the clockevent */ + clockevents_config_and_register(&gemini_clockevent, tick_rate, + 1, 0xffffffff); +} |