diff options
Diffstat (limited to 'arch/arm/plat-omap/timer32k.c')
| -rw-r--r-- | arch/arm/plat-omap/timer32k.c | 325 |
1 files changed, 325 insertions, 0 deletions
diff --git a/arch/arm/plat-omap/timer32k.c b/arch/arm/plat-omap/timer32k.c new file mode 100644 index 00000000000..b2a943bf11e --- /dev/null +++ b/arch/arm/plat-omap/timer32k.c @@ -0,0 +1,325 @@ +/* + * linux/arch/arm/plat-omap/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> + * + * 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/config.h> +#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 <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> + +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 +#elif defined(CONFIG_ARCH_OMAP24XX) +#define TIMER_32K_SYNCHRONIZED 0x48004010 +#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 + +/* 24xx specific defines */ +#define OMAP2_GP_TIMER_BASE 0x48028000 +#define CM_CLKSEL_WKUP 0x48008440 +#define GP_TIMER_TIDR 0x00 +#define GP_TIMER_TISR 0x18 +#define GP_TIMER_TIER 0x1c +#define GP_TIMER_TCLR 0x24 +#define GP_TIMER_TCRR 0x28 +#define GP_TIMER_TLDR 0x2c +#define GP_TIMER_TTGR 0x30 +#define GP_TIMER_TSICR 0x40 + +#define OMAP_32K_TICKS_PER_HZ (32768 / HZ) + +/* + * TRM says 1 / HZ = ( TVR + 1) / 32768, so TRV = (32768 / HZ) - 1 + * so with HZ = 128, TVR = 255. + */ +#define OMAP_32K_TIMER_TICK_PERIOD ((32768 / 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) +{ + if (cpu_class_is_omap1()) + omap_writew(val, OMAP1_32K_TIMER_BASE + reg); + + if (cpu_is_omap24xx()) + omap_writel(val, OMAP2_GP_TIMER_BASE + reg); +} + +static inline unsigned long omap_32k_timer_read(int reg) +{ + if (cpu_class_is_omap1()) + return omap_readl(OMAP1_32K_TIMER_BASE + reg) & 0xffffff; + + if (cpu_is_omap24xx()) + return omap_readl(OMAP2_GP_TIMER_BASE + reg); +} + +/* + * 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 inline void omap_32k_timer_start(unsigned long load_val) +{ + if (cpu_class_is_omap1()) { + omap_32k_timer_write(load_val, OMAP1_32K_TIMER_TVR); + omap_32k_timer_write(0x0f, OMAP1_32K_TIMER_CR); + } + + if (cpu_is_omap24xx()) { + omap_32k_timer_write(0xffffffff - load_val, GP_TIMER_TCRR); + omap_32k_timer_write((1 << 1), GP_TIMER_TIER); + omap_32k_timer_write((1 << 1) | 1, GP_TIMER_TCLR); + } +} + +static inline void omap_32k_timer_stop(void) +{ + if (cpu_class_is_omap1()) + omap_32k_timer_write(0x0, OMAP1_32K_TIMER_CR); + + if (cpu_is_omap24xx()) + omap_32k_timer_write(0x0, GP_TIMER_TCLR); +} + +/* + * Rounds down to nearest usec. Note that this will overflow for larger values. + */ +static inline unsigned long omap_32k_ticks_to_usecs(unsigned long ticks_32k) +{ + return (ticks_32k * 5*5*5*5*5*5) >> 9; +} + +/* + * Rounds down to nearest nsec. + */ +static inline unsigned long long +omap_32k_ticks_to_nsecs(unsigned long ticks_32k) +{ + return (unsigned long long) ticks_32k * 1000 * 5*5*5*5*5*5 >> 9; +} + +static unsigned long omap_32k_last_tick = 0; + +/* + * Returns elapsed usecs since last 32k timer interrupt + */ +static unsigned long omap_32k_timer_gettimeoffset(void) +{ + unsigned long now = omap_32k_sync_timer_read(); + return omap_32k_ticks_to_usecs(now - omap_32k_last_tick); +} + +/* + * Returns current time from boot in nsecs. It's OK for this to wrap + * around for now, as it's just a relative time stamp. + */ +unsigned long long sched_clock(void) +{ + return omap_32k_ticks_to_nsecs(omap_32k_sync_timer_read()); +} + +/* + * Timer interrupt for 32KHz timer. When dynamic tick is enabled, this + * function is also called from other interrupts to remove latency + * issues with dynamic tick. In the dynamic tick case, we need to lock + * with irqsave. + */ +static irqreturn_t omap_32k_timer_interrupt(int irq, void *dev_id, + struct pt_regs *regs) +{ + unsigned long flags; + unsigned long now; + + write_seqlock_irqsave(&xtime_lock, flags); + + if (cpu_is_omap24xx()) { + u32 status = omap_32k_timer_read(GP_TIMER_TISR); + omap_32k_timer_write(status, GP_TIMER_TISR); + } + + now = omap_32k_sync_timer_read(); + + while (now - omap_32k_last_tick >= OMAP_32K_TICKS_PER_HZ) { + omap_32k_last_tick += OMAP_32K_TICKS_PER_HZ; + timer_tick(regs); + } + + /* Restart timer so we don't drift off due to modulo or dynamic tick. + * By default we program the next timer to be continuous to avoid + * latencies during high system load. During dynamic tick operation the + * continuous timer can be overridden from pm_idle to be longer. + */ + omap_32k_timer_start(omap_32k_last_tick + OMAP_32K_TICKS_PER_HZ - now); + write_sequnlock_irqrestore(&xtime_lock, flags); + + return IRQ_HANDLED; +} + +#ifdef CONFIG_NO_IDLE_HZ +/* + * Programs the next timer interrupt needed. Called when dynamic tick is + * enabled, and to reprogram the ticks to skip from pm_idle. Note that + * we can keep the timer continuous, and don't need to set it to run in + * one-shot mode. This is because the timer will get reprogrammed again + * after next interrupt. + */ +void omap_32k_timer_reprogram(unsigned long next_tick) +{ + omap_32k_timer_start(JIFFIES_TO_HW_TICKS(next_tick, 32768) + 1); +} + +static struct irqaction omap_32k_timer_irq; +extern struct timer_update_handler timer_update; + +static int omap_32k_timer_enable_dyn_tick(void) +{ + /* No need to reprogram timer, just use the next interrupt */ + return 0; +} + +static int omap_32k_timer_disable_dyn_tick(void) +{ + omap_32k_timer_start(OMAP_32K_TIMER_TICK_PERIOD); + return 0; +} + +static struct dyn_tick_timer omap_dyn_tick_timer = { + .enable = omap_32k_timer_enable_dyn_tick, + .disable = omap_32k_timer_disable_dyn_tick, + .reprogram = omap_32k_timer_reprogram, + .handler = omap_32k_timer_interrupt, +}; +#endif /* CONFIG_NO_IDLE_HZ */ + +static struct irqaction omap_32k_timer_irq = { + .name = "32KHz timer", + .flags = SA_INTERRUPT | SA_TIMER, + .handler = omap_32k_timer_interrupt, +}; + +static struct clk * gpt1_ick; +static struct clk * gpt1_fck; + +static __init void omap_init_32k_timer(void) +{ +#ifdef CONFIG_NO_IDLE_HZ + omap_timer.dyn_tick = &omap_dyn_tick_timer; +#endif + + if (cpu_class_is_omap1()) + setup_irq(INT_OS_TIMER, &omap_32k_timer_irq); + if (cpu_is_omap24xx()) + setup_irq(37, &omap_32k_timer_irq); + omap_timer.offset = omap_32k_timer_gettimeoffset; + omap_32k_last_tick = omap_32k_sync_timer_read(); + + /* REVISIT: Check 24xx TIOCP_CFG settings after idle works */ + if (cpu_is_omap24xx()) { + omap_32k_timer_write(0, GP_TIMER_TCLR); + omap_writel(0, CM_CLKSEL_WKUP); /* 32KHz clock source */ + + gpt1_ick = clk_get(NULL, "gpt1_ick"); + if (IS_ERR(gpt1_ick)) + printk(KERN_ERR "Could not get gpt1_ick\n"); + else + clk_enable(gpt1_ick); + + gpt1_fck = clk_get(NULL, "gpt1_fck"); + if (IS_ERR(gpt1_fck)) + printk(KERN_ERR "Could not get gpt1_fck\n"); + else + clk_enable(gpt1_fck); + + mdelay(100); /* Wait for clocks to stabilize */ + + omap_32k_timer_write(0x7, GP_TIMER_TISR); + } + + omap_32k_timer_start(OMAP_32K_TIMER_TICK_PERIOD); +} + +/* + * --------------------------------------------------------------------------- + * Timer initialization + * --------------------------------------------------------------------------- + */ +static void __init omap_timer_init(void) +{ + omap_init_32k_timer(); +} + +struct sys_timer omap_timer = { + .init = omap_timer_init, + .offset = NULL, /* Initialized later */ +}; |