2006-04-02 18:46:21 +02:00
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/*
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2008-03-13 07:47:21 +01:00
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* linux/arch/arm/mach-omap1/timer32k.c
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2006-04-02 18:46:21 +02:00
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*
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* OMAP 32K Timer
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*
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* Copyright (C) 2004 - 2005 Nokia Corporation
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* Partial timer rewrite and additional dynamic tick timer support by
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* Tony Lindgen <tony@atomide.com> and
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* Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>
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2006-06-27 01:16:12 +02:00
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* OMAP Dual-mode timer framework support by Timo Teras
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2006-04-02 18:46:21 +02:00
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*
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* MPU timer code based on the older MPU timer code for OMAP
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* Copyright (C) 2000 RidgeRun, Inc.
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* Author: Greg Lonnon <glonnon@ridgerun.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
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* NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
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* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/delay.h>
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#include <linux/interrupt.h>
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#include <linux/sched.h>
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#include <linux/spinlock.h>
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#include <linux/err.h>
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#include <linux/clk.h>
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2007-03-08 20:32:19 +01:00
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#include <linux/clocksource.h>
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#include <linux/clockchips.h>
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2008-09-06 13:10:45 +02:00
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#include <linux/io.h>
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2006-04-02 18:46:21 +02:00
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#include <asm/irq.h>
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#include <asm/mach/irq.h>
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#include <asm/mach/time.h>
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2012-02-24 19:34:34 +01:00
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2012-10-30 00:45:47 +01:00
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#include <plat/counter-32k.h>
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2006-04-02 18:46:21 +02:00
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2012-02-24 19:34:34 +01:00
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#include <mach/hardware.h>
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#include "common.h"
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2006-04-02 18:46:21 +02:00
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/*
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* ---------------------------------------------------------------------------
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* 32KHz OS timer
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*
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* This currently works only on 16xx, as 1510 does not have the continuous
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* 32KHz synchronous timer. The 32KHz synchronous timer is used to keep track
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* of time in addition to the 32KHz OS timer. Using only the 32KHz OS timer
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* on 1510 would be possible, but the timer would not be as accurate as
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* with the 32KHz synchronized timer.
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* ---------------------------------------------------------------------------
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*/
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/* 16xx specific defines */
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#define OMAP1_32K_TIMER_BASE 0xfffb9000
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ARM: OMAP: Make OMAP clocksource source selection using kernel param
Current OMAP code supports couple of clocksource options based
on compilation flag (CONFIG_OMAP_32K_TIMER). The 32KHz sync-timer
and a gptimer which can run on 32KHz or system clock (e.g 38.4 MHz).
So there can be 3 options -
1. 32KHz sync-timer
2. Sys_clock based (e.g 13/19.2/26/38.4 MHz) gptimer
3. 32KHz based gptimer.
The optional gptimer based clocksource was added so that it can
give the high precision than sync-timer, so expected usage was 2
and not 3.
Unfortunately option 2, clocksource doesn't meet the requirement of
free-running clock as per clocksource need. It stops in low power states
when sys_clock is cut. That makes gptimer based clocksource option
useless for OMAP2/3/4 devices with sys_clock as a clock input.
So, in order to use option 2, deeper idle state MUST be disabled.
Option 3 will still work but it is no better than 32K sync-timer
based clocksource.
We must support both sync timer and gptimer based clocksource as
some OMAP based derivative SoCs like AM33XX does not have the
sync timer.
Considering above, make sync-timer and gptimer clocksource runtime
selectable so that both OMAP and AMXXXX continue to use the same code.
And, in order to precisely configure/setup sched_clock for given
clocksource, decision has to be made early enough in boot sequence.
So, the solution is,
Use standard kernel parameter ("clocksource=") to override
default 32k_sync-timer, in addition to this, we also use hwmod database
lookup mechanism, through which at run-time we can identify availability
of 32k-sync timer on the device, else fall back to gptimer.
Also, moved low-level SoC specific init code to respective files,
(mach-omap1/timer32k.c and mach-omap2/timer.c)
Signed-off-by: Vaibhav Hiremath <hvaibhav@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Kevin Hilman <khilman@ti.com>
Tested-by: Kevin Hilman <khilman@ti.com>
Cc: Benoit Cousson <b-cousson@ti.com>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Tarun Kanti DebBarma <tarun.kanti@ti.com>
Cc: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
2012-05-09 19:07:05 +02:00
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#define OMAP1_32KSYNC_TIMER_BASE 0xfffbc400
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2006-04-02 18:46:21 +02:00
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#define OMAP1_32K_TIMER_CR 0x08
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#define OMAP1_32K_TIMER_TVR 0x00
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#define OMAP1_32K_TIMER_TCR 0x04
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2007-03-08 20:32:19 +01:00
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#define OMAP_32K_TICKS_PER_SEC (32768)
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2006-04-02 18:46:21 +02:00
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/*
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* TRM says 1 / HZ = ( TVR + 1) / 32768, so TRV = (32768 / HZ) - 1
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* so with HZ = 128, TVR = 255.
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*/
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2007-03-08 20:32:19 +01:00
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#define OMAP_32K_TIMER_TICK_PERIOD ((OMAP_32K_TICKS_PER_SEC / HZ) - 1)
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2006-04-02 18:46:21 +02:00
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#define JIFFIES_TO_HW_TICKS(nr_jiffies, clock_rate) \
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(((nr_jiffies) * (clock_rate)) / HZ)
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static inline void omap_32k_timer_write(int val, int reg)
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{
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2006-06-27 01:16:12 +02:00
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omap_writew(val, OMAP1_32K_TIMER_BASE + reg);
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2006-04-02 18:46:21 +02:00
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}
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2006-06-27 01:16:12 +02:00
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static inline void omap_32k_timer_start(unsigned long load_val)
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{
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2006-09-25 11:41:21 +02:00
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if (!load_val)
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load_val = 1;
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2006-06-27 01:16:12 +02:00
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omap_32k_timer_write(load_val, OMAP1_32K_TIMER_TVR);
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omap_32k_timer_write(0x0f, OMAP1_32K_TIMER_CR);
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2006-04-02 18:46:21 +02:00
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}
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2006-06-27 01:16:12 +02:00
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static inline void omap_32k_timer_stop(void)
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2006-04-02 18:46:21 +02:00
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{
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2006-06-27 01:16:12 +02:00
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omap_32k_timer_write(0x0, OMAP1_32K_TIMER_CR);
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2006-04-02 18:46:21 +02:00
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}
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2006-06-27 01:16:12 +02:00
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#define omap_32k_timer_ack_irq()
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2008-03-13 07:47:21 +01:00
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static int omap_32k_timer_set_next_event(unsigned long delta,
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struct clock_event_device *dev)
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{
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omap_32k_timer_start(delta);
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return 0;
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}
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2015-02-27 09:09:52 +01:00
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static int omap_32k_timer_shutdown(struct clock_event_device *evt)
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2007-03-08 20:32:19 +01:00
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{
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2007-05-16 17:52:05 +02:00
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omap_32k_timer_stop();
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2015-02-27 09:09:52 +01:00
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return 0;
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}
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2007-05-16 17:52:05 +02:00
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2015-02-27 09:09:52 +01:00
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static int omap_32k_timer_set_periodic(struct clock_event_device *evt)
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{
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omap_32k_timer_stop();
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omap_32k_timer_start(OMAP_32K_TIMER_TICK_PERIOD);
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return 0;
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2007-03-08 20:32:19 +01:00
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}
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static struct clock_event_device clockevent_32k_timer = {
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2015-02-27 09:09:52 +01:00
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.name = "32k-timer",
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.features = CLOCK_EVT_FEAT_PERIODIC |
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CLOCK_EVT_FEAT_ONESHOT,
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.set_next_event = omap_32k_timer_set_next_event,
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.set_state_shutdown = omap_32k_timer_shutdown,
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.set_state_periodic = omap_32k_timer_set_periodic,
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.set_state_oneshot = omap_32k_timer_shutdown,
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.tick_resume = omap_32k_timer_shutdown,
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2007-03-08 20:32:19 +01:00
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};
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2006-10-06 19:53:39 +02:00
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static irqreturn_t omap_32k_timer_interrupt(int irq, void *dev_id)
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2006-09-25 11:41:40 +02:00
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{
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2007-03-08 20:32:19 +01:00
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struct clock_event_device *evt = &clockevent_32k_timer;
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omap_32k_timer_ack_irq();
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2006-09-25 11:41:40 +02:00
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2007-03-08 20:32:19 +01:00
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evt->event_handler(evt);
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2006-04-02 18:46:21 +02:00
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return IRQ_HANDLED;
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}
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static struct irqaction omap_32k_timer_irq = {
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.name = "32KHz timer",
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2013-09-07 09:19:25 +02:00
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.flags = IRQF_TIMER | IRQF_IRQPOLL,
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2006-04-02 18:46:21 +02:00
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.handler = omap_32k_timer_interrupt,
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};
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static __init void omap_init_32k_timer(void)
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{
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2008-03-13 07:47:21 +01:00
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setup_irq(INT_OS_TIMER, &omap_32k_timer_irq);
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2008-12-13 11:50:26 +01:00
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clockevent_32k_timer.cpumask = cpumask_of(0);
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2013-01-12 12:50:05 +01:00
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clockevents_config_and_register(&clockevent_32k_timer,
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OMAP_32K_TICKS_PER_SEC, 1, 0xfffffffe);
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2006-04-02 18:46:21 +02:00
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}
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/*
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* ---------------------------------------------------------------------------
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* Timer initialization
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* ---------------------------------------------------------------------------
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*/
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2012-05-09 19:07:05 +02:00
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int __init omap_32k_timer_init(void)
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2006-04-02 18:46:21 +02:00
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{
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2012-05-09 19:07:05 +02:00
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int ret = -ENODEV;
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2006-04-02 18:46:21 +02:00
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ARM: OMAP: Make OMAP clocksource source selection using kernel param
Current OMAP code supports couple of clocksource options based
on compilation flag (CONFIG_OMAP_32K_TIMER). The 32KHz sync-timer
and a gptimer which can run on 32KHz or system clock (e.g 38.4 MHz).
So there can be 3 options -
1. 32KHz sync-timer
2. Sys_clock based (e.g 13/19.2/26/38.4 MHz) gptimer
3. 32KHz based gptimer.
The optional gptimer based clocksource was added so that it can
give the high precision than sync-timer, so expected usage was 2
and not 3.
Unfortunately option 2, clocksource doesn't meet the requirement of
free-running clock as per clocksource need. It stops in low power states
when sys_clock is cut. That makes gptimer based clocksource option
useless for OMAP2/3/4 devices with sys_clock as a clock input.
So, in order to use option 2, deeper idle state MUST be disabled.
Option 3 will still work but it is no better than 32K sync-timer
based clocksource.
We must support both sync timer and gptimer based clocksource as
some OMAP based derivative SoCs like AM33XX does not have the
sync timer.
Considering above, make sync-timer and gptimer clocksource runtime
selectable so that both OMAP and AMXXXX continue to use the same code.
And, in order to precisely configure/setup sched_clock for given
clocksource, decision has to be made early enough in boot sequence.
So, the solution is,
Use standard kernel parameter ("clocksource=") to override
default 32k_sync-timer, in addition to this, we also use hwmod database
lookup mechanism, through which at run-time we can identify availability
of 32k-sync timer on the device, else fall back to gptimer.
Also, moved low-level SoC specific init code to respective files,
(mach-omap1/timer32k.c and mach-omap2/timer.c)
Signed-off-by: Vaibhav Hiremath <hvaibhav@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Kevin Hilman <khilman@ti.com>
Tested-by: Kevin Hilman <khilman@ti.com>
Cc: Benoit Cousson <b-cousson@ti.com>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Tarun Kanti DebBarma <tarun.kanti@ti.com>
Cc: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
2012-05-09 19:07:05 +02:00
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if (cpu_is_omap16xx()) {
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void __iomem *base;
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struct clk *sync32k_ick;
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base = ioremap(OMAP1_32KSYNC_TIMER_BASE, SZ_1K);
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if (!base) {
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pr_err("32k_counter: failed to map base addr\n");
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return -ENODEV;
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}
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sync32k_ick = clk_get(NULL, "omap_32ksync_ick");
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if (!IS_ERR(sync32k_ick))
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clk_enable(sync32k_ick);
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ret = omap_init_clocksource_32k(base);
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}
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2012-05-09 19:07:05 +02:00
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if (!ret)
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omap_init_32k_timer();
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return ret;
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2011-01-18 21:42:23 +01:00
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}
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