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Diffstat (limited to 'arch/arm/mach-ks8695/time.c')
| -rw-r--r-- | arch/arm/mach-ks8695/time.c | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/arch/arm/mach-ks8695/time.c b/arch/arm/mach-ks8695/time.c new file mode 100644 index 000000000..18eb0fbd8 --- /dev/null +++ b/arch/arm/mach-ks8695/time.c @@ -0,0 +1,172 @@ +/* + * arch/arm/mach-ks8695/time.c + * + * Copyright (C) 2006 Ben Dooks <ben@simtec.co.uk> + * Copyright (C) 2006 Simtec Electronics + * + * 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. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <linux/kernel.h> +#include <linux/sched.h> +#include <linux/io.h> +#include <linux/clockchips.h> + +#include <asm/mach/time.h> +#include <asm/system_misc.h> + +#include <mach/regs-irq.h> + +#include "generic.h" + +#define KS8695_TMR_OFFSET (0xF0000 + 0xE400) +#define KS8695_TMR_VA (KS8695_IO_VA + KS8695_TMR_OFFSET) +#define KS8695_TMR_PA (KS8695_IO_PA + KS8695_TMR_OFFSET) + +/* + * Timer registers + */ +#define KS8695_TMCON (0x00) /* Timer Control Register */ +#define KS8695_T1TC (0x04) /* Timer 1 Timeout Count Register */ +#define KS8695_T0TC (0x08) /* Timer 0 Timeout Count Register */ +#define KS8695_T1PD (0x0C) /* Timer 1 Pulse Count Register */ +#define KS8695_T0PD (0x10) /* Timer 0 Pulse Count Register */ + +/* Timer Control Register */ +#define TMCON_T1EN (1 << 1) /* Timer 1 Enable */ +#define TMCON_T0EN (1 << 0) /* Timer 0 Enable */ + +/* Timer0 Timeout Counter Register */ +#define T0TC_WATCHDOG (0xff) /* Enable watchdog mode */ + +static int ks8695_set_periodic(struct clock_event_device *evt) +{ + u32 rate = DIV_ROUND_CLOSEST(KS8695_CLOCK_RATE, HZ); + u32 half = DIV_ROUND_CLOSEST(rate, 2); + u32 tmcon; + + /* Disable timer 1 */ + tmcon = readl_relaxed(KS8695_TMR_VA + KS8695_TMCON); + tmcon &= ~TMCON_T1EN; + writel_relaxed(tmcon, KS8695_TMR_VA + KS8695_TMCON); + + /* Both registers need to count down */ + writel_relaxed(half, KS8695_TMR_VA + KS8695_T1TC); + writel_relaxed(half, KS8695_TMR_VA + KS8695_T1PD); + + /* Re-enable timer1 */ + tmcon |= TMCON_T1EN; + writel_relaxed(tmcon, KS8695_TMR_VA + KS8695_TMCON); + return 0; +} + +static int ks8695_set_next_event(unsigned long cycles, + struct clock_event_device *evt) + +{ + u32 half = DIV_ROUND_CLOSEST(cycles, 2); + u32 tmcon; + + /* Disable timer 1 */ + tmcon = readl_relaxed(KS8695_TMR_VA + KS8695_TMCON); + tmcon &= ~TMCON_T1EN; + writel_relaxed(tmcon, KS8695_TMR_VA + KS8695_TMCON); + + /* Both registers need to count down */ + writel_relaxed(half, KS8695_TMR_VA + KS8695_T1TC); + writel_relaxed(half, KS8695_TMR_VA + KS8695_T1PD); + + /* Re-enable timer1 */ + tmcon |= TMCON_T1EN; + writel_relaxed(tmcon, KS8695_TMR_VA + KS8695_TMCON); + + return 0; +} + +static struct clock_event_device clockevent_ks8695 = { + .name = "ks8695_t1tc", + /* Reasonably fast and accurate clock event */ + .rating = 300, + .features = CLOCK_EVT_FEAT_ONESHOT | + CLOCK_EVT_FEAT_PERIODIC, + .set_next_event = ks8695_set_next_event, + .set_state_periodic = ks8695_set_periodic, +}; + +/* + * IRQ handler for the timer. + */ +static irqreturn_t ks8695_timer_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *evt = &clockevent_ks8695; + + evt->event_handler(evt); + return IRQ_HANDLED; +} + +static struct irqaction ks8695_timer_irq = { + .name = "ks8695_tick", + .flags = IRQF_TIMER, + .handler = ks8695_timer_interrupt, +}; + +static void ks8695_timer_setup(void) +{ + unsigned long tmcon; + + /* Disable timer 0 and 1 */ + tmcon = readl_relaxed(KS8695_TMR_VA + KS8695_TMCON); + tmcon &= ~TMCON_T0EN; + tmcon &= ~TMCON_T1EN; + writel_relaxed(tmcon, KS8695_TMR_VA + KS8695_TMCON); + + /* + * Use timer 1 to fire IRQs on the timeline, minimum 2 cycles + * (one on each counter) maximum 2*2^32, but the API will only + * accept up to a 32bit full word (0xFFFFFFFFU). + */ + clockevents_config_and_register(&clockevent_ks8695, + KS8695_CLOCK_RATE, 2, + 0xFFFFFFFFU); +} + +void __init ks8695_timer_init(void) +{ + ks8695_timer_setup(); + + /* Enable timer interrupts */ + setup_irq(KS8695_IRQ_TIMER1, &ks8695_timer_irq); +} + +void ks8695_restart(enum reboot_mode reboot_mode, const char *cmd) +{ + unsigned int reg; + + if (reboot_mode == REBOOT_SOFT) + soft_restart(0); + + /* disable timer0 */ + reg = readl_relaxed(KS8695_TMR_VA + KS8695_TMCON); + writel_relaxed(reg & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON); + + /* enable watchdog mode */ + writel_relaxed((10 << 8) | T0TC_WATCHDOG, KS8695_TMR_VA + KS8695_T0TC); + + /* re-enable timer0 */ + writel_relaxed(reg | TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON); +} |