/* * 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 and * Tuukka Tikkanen * 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 * * 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "hardware.h" #include "common.h" /* * --------------------------------------------------------------------------- * 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. * --------------------------------------------------------------------------- */ /* 16xx specific defines */ #define OMAP1_32K_TIMER_BASE 0xfffb9000 #define OMAP1_32KSYNC_TIMER_BASE 0xfffbc400 #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 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 int omap_32k_timer_shutdown(struct clock_event_device *evt) { omap_32k_timer_stop(); return 0; } static int omap_32k_timer_set_periodic(struct clock_event_device *evt) { omap_32k_timer_stop(); omap_32k_timer_start(OMAP_32K_TIMER_TICK_PERIOD); return 0; } static struct clock_event_device clockevent_32k_timer = { .name = "32k-timer", .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, .set_next_event = omap_32k_timer_set_next_event, .set_state_shutdown = omap_32k_timer_shutdown, .set_state_periodic = omap_32k_timer_set_periodic, .set_state_oneshot = omap_32k_timer_shutdown, .tick_resume = omap_32k_timer_shutdown, }; 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 __init void omap_init_32k_timer(void) { if (request_irq(INT_OS_TIMER, omap_32k_timer_interrupt, IRQF_TIMER | IRQF_IRQPOLL, "32KHz timer", NULL)) pr_err("Failed to request irq %d(32KHz timer)\n", INT_OS_TIMER); clockevent_32k_timer.cpumask = cpumask_of(0); clockevents_config_and_register(&clockevent_32k_timer, OMAP_32K_TICKS_PER_SEC, 1, 0xfffffffe); } /* OMAP2_32KSYNCNT_CR_OFF: offset of 32ksync counter register */ #define OMAP2_32KSYNCNT_REV_OFF 0x0 #define OMAP2_32KSYNCNT_REV_SCHEME (0x3 << 30) #define OMAP2_32KSYNCNT_CR_OFF_LOW 0x10 #define OMAP2_32KSYNCNT_CR_OFF_HIGH 0x30 /* * 32KHz clocksource ... always available, on pretty most chips except * OMAP 730 and 1510. Other timers could be used as clocksources, with * higher resolution in free-running counter modes (e.g. 12 MHz xtal), * but systems won't necessarily want to spend resources that way. */ static void __iomem *sync32k_cnt_reg; static u64 notrace omap_32k_read_sched_clock(void) { return sync32k_cnt_reg ? readl_relaxed(sync32k_cnt_reg) : 0; } /** * omap_read_persistent_clock64 - Return time from a persistent clock. * * Reads the time from a source which isn't disabled during PM, the * 32k sync timer. Convert the cycles elapsed since last read into * nsecs and adds to a monotonically increasing timespec64. */ static struct timespec64 persistent_ts; static cycles_t cycles; static unsigned int persistent_mult, persistent_shift; static void omap_read_persistent_clock64(struct timespec64 *ts) { unsigned long long nsecs; cycles_t last_cycles; last_cycles = cycles; cycles = sync32k_cnt_reg ? readl_relaxed(sync32k_cnt_reg) : 0; nsecs = clocksource_cyc2ns(cycles - last_cycles, persistent_mult, persistent_shift); timespec64_add_ns(&persistent_ts, nsecs); *ts = persistent_ts; } /** * omap_init_clocksource_32k - setup and register counter 32k as a * kernel clocksource * @pbase: base addr of counter_32k module * @size: size of counter_32k to map * * Returns 0 upon success or negative error code upon failure. * */ int __init omap_init_clocksource_32k(void __iomem *vbase) { int ret; /* * 32k sync Counter IP register offsets vary between the * highlander version and the legacy ones. * The 'SCHEME' bits(30-31) of the revision register is used * to identify the version. */ if (readl_relaxed(vbase + OMAP2_32KSYNCNT_REV_OFF) & OMAP2_32KSYNCNT_REV_SCHEME) sync32k_cnt_reg = vbase + OMAP2_32KSYNCNT_CR_OFF_HIGH; else sync32k_cnt_reg = vbase + OMAP2_32KSYNCNT_CR_OFF_LOW; /* * 120000 rough estimate from the calculations in * __clocksource_update_freq_scale. */ clocks_calc_mult_shift(&persistent_mult, &persistent_shift, 32768, NSEC_PER_SEC, 120000); ret = clocksource_mmio_init(sync32k_cnt_reg, "32k_counter", 32768, 250, 32, clocksource_mmio_readl_up); if (ret) { pr_err("32k_counter: can't register clocksource\n"); return ret; } sched_clock_register(omap_32k_read_sched_clock, 32, 32768); register_persistent_clock(omap_read_persistent_clock64); pr_info("OMAP clocksource: 32k_counter at 32768 Hz\n"); return 0; } /* * --------------------------------------------------------------------------- * Timer initialization * --------------------------------------------------------------------------- */ int __init omap_32k_timer_init(void) { int ret = -ENODEV; if (cpu_is_omap16xx()) { void __iomem *base; struct clk *sync32k_ick; base = ioremap(OMAP1_32KSYNC_TIMER_BASE, SZ_1K); if (!base) { pr_err("32k_counter: failed to map base addr\n"); return -ENODEV; } sync32k_ick = clk_get(NULL, "omap_32ksync_ick"); if (!IS_ERR(sync32k_ick)) clk_enable(sync32k_ick); ret = omap_init_clocksource_32k(base); } if (!ret) omap_init_32k_timer(); return ret; }