diff options
Diffstat (limited to 'arch/arm/mach-omap1/timer32k.c')
| -rw-r--r-- | arch/arm/mach-omap1/timer32k.c | 209 |
1 files changed, 209 insertions, 0 deletions
diff --git a/arch/arm/mach-omap1/timer32k.c b/arch/arm/mach-omap1/timer32k.c new file mode 100644 index 00000000000..fbbdb806c95 --- /dev/null +++ b/arch/arm/mach-omap1/timer32k.c @@ -0,0 +1,209 @@ +/* + * linux/arch/arm/mach-omap1/timer32k.c + * + * OMAP 32K Timer + * + * Copyright (C) 2004 - 2005 Nokia Corporation + * Partial timer rewrite and additional dynamic tick timer support by + * Tony Lindgen <tony@atomide.com> and + * Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com> + * OMAP Dual-mode timer framework support by Timo Teras + * + * MPU timer code based on the older MPU timer code for OMAP + * Copyright (C) 2000 RidgeRun, Inc. + * Author: Greg Lonnon <glonnon@ridgerun.com> + * + * 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 SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED + * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN + * NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF + * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON + * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + * 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., + * 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/delay.h> +#include <linux/interrupt.h> +#include <linux/sched.h> +#include <linux/spinlock.h> +#include <linux/err.h> +#include <linux/clk.h> +#include <linux/clocksource.h> +#include <linux/clockchips.h> + +#include <asm/system.h> +#include <asm/hardware.h> +#include <asm/io.h> +#include <asm/leds.h> +#include <asm/irq.h> +#include <asm/mach/irq.h> +#include <asm/mach/time.h> +#include <asm/arch/dmtimer.h> + +struct sys_timer omap_timer; + +/* + * --------------------------------------------------------------------------- + * 32KHz OS timer + * + * This currently works only on 16xx, as 1510 does not have the continuous + * 32KHz synchronous timer. The 32KHz synchronous timer is used to keep track + * of time in addition to the 32KHz OS timer. Using only the 32KHz OS timer + * on 1510 would be possible, but the timer would not be as accurate as + * with the 32KHz synchronized timer. + * --------------------------------------------------------------------------- + */ + +#if defined(CONFIG_ARCH_OMAP16XX) +#define TIMER_32K_SYNCHRONIZED 0xfffbc410 +#else +#error OMAP 32KHz timer does not currently work on 15XX! +#endif + +/* 16xx specific defines */ +#define OMAP1_32K_TIMER_BASE 0xfffb9000 +#define OMAP1_32K_TIMER_CR 0x08 +#define OMAP1_32K_TIMER_TVR 0x00 +#define OMAP1_32K_TIMER_TCR 0x04 + +#define OMAP_32K_TICKS_PER_SEC (32768) + +/* + * TRM says 1 / HZ = ( TVR + 1) / 32768, so TRV = (32768 / HZ) - 1 + * so with HZ = 128, TVR = 255. + */ +#define OMAP_32K_TIMER_TICK_PERIOD ((OMAP_32K_TICKS_PER_SEC / HZ) - 1) + +#define JIFFIES_TO_HW_TICKS(nr_jiffies, clock_rate) \ + (((nr_jiffies) * (clock_rate)) / HZ) + +static inline void omap_32k_timer_write(int val, int reg) +{ + omap_writew(val, OMAP1_32K_TIMER_BASE + reg); +} + +static inline unsigned long omap_32k_timer_read(int reg) +{ + return omap_readl(OMAP1_32K_TIMER_BASE + reg) & 0xffffff; +} + +static inline void omap_32k_timer_start(unsigned long load_val) +{ + if (!load_val) + load_val = 1; + omap_32k_timer_write(load_val, OMAP1_32K_TIMER_TVR); + omap_32k_timer_write(0x0f, OMAP1_32K_TIMER_CR); +} + +static inline void omap_32k_timer_stop(void) +{ + omap_32k_timer_write(0x0, OMAP1_32K_TIMER_CR); +} + +#define omap_32k_timer_ack_irq() + +static int omap_32k_timer_set_next_event(unsigned long delta, + struct clock_event_device *dev) +{ + omap_32k_timer_start(delta); + + return 0; +} + +static void omap_32k_timer_set_mode(enum clock_event_mode mode, + struct clock_event_device *evt) +{ + omap_32k_timer_stop(); + + switch (mode) { + case CLOCK_EVT_MODE_PERIODIC: + omap_32k_timer_start(OMAP_32K_TIMER_TICK_PERIOD); + break; + case CLOCK_EVT_MODE_ONESHOT: + case CLOCK_EVT_MODE_UNUSED: + case CLOCK_EVT_MODE_SHUTDOWN: + break; + case CLOCK_EVT_MODE_RESUME: + break; + } +} + +static struct clock_event_device clockevent_32k_timer = { + .name = "32k-timer", + .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, + .shift = 32, + .set_next_event = omap_32k_timer_set_next_event, + .set_mode = omap_32k_timer_set_mode, +}; + +/* + * The 32KHz synchronized timer is an additional timer on 16xx. + * It is always running. + */ +static inline unsigned long omap_32k_sync_timer_read(void) +{ + return omap_readl(TIMER_32K_SYNCHRONIZED); +} + +static irqreturn_t omap_32k_timer_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *evt = &clockevent_32k_timer; + omap_32k_timer_ack_irq(); + + evt->event_handler(evt); + + return IRQ_HANDLED; +} + +static struct irqaction omap_32k_timer_irq = { + .name = "32KHz timer", + .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL, + .handler = omap_32k_timer_interrupt, +}; + +static __init void omap_init_32k_timer(void) +{ + setup_irq(INT_OS_TIMER, &omap_32k_timer_irq); + + clockevent_32k_timer.mult = div_sc(OMAP_32K_TICKS_PER_SEC, + NSEC_PER_SEC, + clockevent_32k_timer.shift); + clockevent_32k_timer.max_delta_ns = + clockevent_delta2ns(0xfffffffe, &clockevent_32k_timer); + clockevent_32k_timer.min_delta_ns = + clockevent_delta2ns(1, &clockevent_32k_timer); + + clockevent_32k_timer.cpumask = cpumask_of_cpu(0); + clockevents_register_device(&clockevent_32k_timer); +} + +/* + * --------------------------------------------------------------------------- + * Timer initialization + * --------------------------------------------------------------------------- + */ +static void __init omap_timer_init(void) +{ +#ifdef CONFIG_OMAP_DM_TIMER + omap_dm_timer_init(); +#endif + omap_init_32k_timer(); +} + +struct sys_timer omap_timer = { + .init = omap_timer_init, +}; |