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Diffstat (limited to 'arch/arm/mach-omap1/timer32k.c')
| -rw-r--r-- | arch/arm/mach-omap1/timer32k.c | 282 |
1 files changed, 282 insertions, 0 deletions
diff --git a/arch/arm/mach-omap1/timer32k.c b/arch/arm/mach-omap1/timer32k.c new file mode 100644 index 000000000..f618a6df2 --- /dev/null +++ b/arch/arm/mach-omap1/timer32k.c @@ -0,0 +1,282 @@ +/* + * 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 <linux/io.h> +#include <linux/sched_clock.h> + +#include <asm/irq.h> +#include <asm/mach/irq.h> +#include <asm/mach/time.h> + +#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; +} + +static struct timespec64 persistent_ts; +static cycles_t cycles; +static unsigned int persistent_mult, persistent_shift; + +/** + * omap_read_persistent_clock64 - Return time from a persistent clock. + * @ts: &struct timespec64 for the returned time + * + * 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 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 + * @vbase: base addr of counter_32k module + * + * Returns: %0 upon success or negative error code upon failure. + * + */ +static 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_prepare_enable(sync32k_ick); + + ret = omap_init_clocksource_32k(base); + } + + if (!ret) + omap_init_32k_timer(); + + return ret; +} |