ARM: mxs: Add timer support
There are 2 versions of the timrot on Freescale MXS-based SoCs. The v1 on MX23 only gets 16 bits counter, while v2 on MX28 extends the counter to 32 bits. The implementation uses two timers, one for clock_event and another for clocksource. MX28 uses timrot 0 and 1, while MX23 uses 0 and 2. Signed-off-by: Shawn Guo <shawn.guo@freescale.com> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
This commit is contained in:
Shawn Guo
Uwe Kleine-König
parent
41fa75bc09
commit
4e472096fa
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/*
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* Copyright (C) 2000-2001 Deep Blue Solutions
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* Copyright (C) 2002 Shane Nay (shane@minirl.com)
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* Copyright (C) 2006-2007 Pavel Pisa (ppisa@pikron.com)
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* Copyright (C) 2008 Juergen Beisert (kernel@pengutronix.de)
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* Copyright (C) 2010 Freescale Semiconductor, Inc. All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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* MA 02110-1301, USA.
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*/
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#include <linux/interrupt.h>
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#include <linux/irq.h>
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#include <linux/clockchips.h>
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#include <linux/clk.h>
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#include <asm/mach/time.h>
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#include <mach/mxs.h>
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#include <mach/common.h>
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/*
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* There are 2 versions of the timrot on Freescale MXS-based SoCs.
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* The v1 on MX23 only gets 16 bits counter, while v2 on MX28
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* extends the counter to 32 bits.
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*
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* The implementation uses two timers, one for clock_event and
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* another for clocksource. MX28 uses timrot 0 and 1, while MX23
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* uses 0 and 2.
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*/
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#define MX23_TIMROT_VERSION_OFFSET 0x0a0
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#define MX28_TIMROT_VERSION_OFFSET 0x120
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#define BP_TIMROT_MAJOR_VERSION 24
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#define BV_TIMROT_VERSION_1 0x01
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#define BV_TIMROT_VERSION_2 0x02
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#define timrot_is_v1() (timrot_major_version == BV_TIMROT_VERSION_1)
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/*
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* There are 4 registers for each timrotv2 instance, and 2 registers
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* for each timrotv1. So address step 0x40 in macros below strides
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* one instance of timrotv2 while two instances of timrotv1.
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*
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* As the result, HW_TIMROT_XXXn(1) defines the address of timrot1
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* on MX28 while timrot2 on MX23.
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*/
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/* common between v1 and v2 */
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#define HW_TIMROT_ROTCTRL 0x00
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#define HW_TIMROT_TIMCTRLn(n) (0x20 + (n) * 0x40)
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/* v1 only */
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#define HW_TIMROT_TIMCOUNTn(n) (0x30 + (n) * 0x40)
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/* v2 only */
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#define HW_TIMROT_RUNNING_COUNTn(n) (0x30 + (n) * 0x40)
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#define HW_TIMROT_FIXED_COUNTn(n) (0x40 + (n) * 0x40)
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#define BM_TIMROT_TIMCTRLn_RELOAD (1 << 6)
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#define BM_TIMROT_TIMCTRLn_UPDATE (1 << 7)
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#define BM_TIMROT_TIMCTRLn_IRQ_EN (1 << 14)
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#define BM_TIMROT_TIMCTRLn_IRQ (1 << 15)
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#define BP_TIMROT_TIMCTRLn_SELECT 0
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#define BV_TIMROTv1_TIMCTRLn_SELECT__32KHZ_XTAL 0x8
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#define BV_TIMROTv2_TIMCTRLn_SELECT__32KHZ_XTAL 0xb
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static struct clock_event_device mxs_clockevent_device;
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static enum clock_event_mode mxs_clockevent_mode = CLOCK_EVT_MODE_UNUSED;
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static void __iomem *mxs_timrot_base = MXS_IO_ADDRESS(MXS_TIMROT_BASE_ADDR);
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static u32 timrot_major_version;
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static inline void timrot_irq_disable(void)
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{
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__mxs_clrl(BM_TIMROT_TIMCTRLn_IRQ_EN,
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mxs_timrot_base + HW_TIMROT_TIMCTRLn(0));
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}
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static inline void timrot_irq_enable(void)
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{
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__mxs_setl(BM_TIMROT_TIMCTRLn_IRQ_EN,
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mxs_timrot_base + HW_TIMROT_TIMCTRLn(0));
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}
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static void timrot_irq_acknowledge(void)
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{
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__mxs_clrl(BM_TIMROT_TIMCTRLn_IRQ,
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mxs_timrot_base + HW_TIMROT_TIMCTRLn(0));
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}
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static cycle_t timrotv1_get_cycles(struct clocksource *cs)
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{
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return ~((__raw_readl(mxs_timrot_base + HW_TIMROT_TIMCOUNTn(1))
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& 0xffff0000) >> 16);
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}
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static cycle_t timrotv2_get_cycles(struct clocksource *cs)
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{
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return ~__raw_readl(mxs_timrot_base + HW_TIMROT_RUNNING_COUNTn(1));
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}
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static int timrotv1_set_next_event(unsigned long evt,
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struct clock_event_device *dev)
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{
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/* timrot decrements the count */
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__raw_writel(evt, mxs_timrot_base + HW_TIMROT_TIMCOUNTn(0));
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return 0;
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}
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static int timrotv2_set_next_event(unsigned long evt,
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struct clock_event_device *dev)
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{
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/* timrot decrements the count */
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__raw_writel(evt, mxs_timrot_base + HW_TIMROT_FIXED_COUNTn(0));
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return 0;
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}
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static irqreturn_t mxs_timer_interrupt(int irq, void *dev_id)
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{
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struct clock_event_device *evt = dev_id;
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timrot_irq_acknowledge();
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evt->event_handler(evt);
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return IRQ_HANDLED;
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}
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static struct irqaction mxs_timer_irq = {
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.name = "MXS Timer Tick",
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.dev_id = &mxs_clockevent_device,
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.flags = IRQF_TIMER | IRQF_IRQPOLL,
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.handler = mxs_timer_interrupt,
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};
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#ifdef DEBUG
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static const char *clock_event_mode_label[] const = {
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[CLOCK_EVT_MODE_PERIODIC] = "CLOCK_EVT_MODE_PERIODIC",
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[CLOCK_EVT_MODE_ONESHOT] = "CLOCK_EVT_MODE_ONESHOT",
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[CLOCK_EVT_MODE_SHUTDOWN] = "CLOCK_EVT_MODE_SHUTDOWN",
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[CLOCK_EVT_MODE_UNUSED] = "CLOCK_EVT_MODE_UNUSED"
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};
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#endif /* DEBUG */
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static void mxs_set_mode(enum clock_event_mode mode,
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struct clock_event_device *evt)
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{
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/* Disable interrupt in timer module */
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timrot_irq_disable();
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if (mode != mxs_clockevent_mode) {
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/* Set event time into the furthest future */
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if (timrot_is_v1())
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__raw_writel(0xffff,
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mxs_timrot_base + HW_TIMROT_TIMCOUNTn(1));
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else
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__raw_writel(0xffffffff,
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mxs_timrot_base + HW_TIMROT_FIXED_COUNTn(1));
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/* Clear pending interrupt */
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timrot_irq_acknowledge();
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}
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#ifdef DEBUG
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pr_info("%s: changing mode from %s to %s\n", __func__,
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clock_event_mode_label[mxs_clockevent_mode],
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clock_event_mode_label[mode]);
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#endif /* DEBUG */
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/* Remember timer mode */
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mxs_clockevent_mode = mode;
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switch (mode) {
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case CLOCK_EVT_MODE_PERIODIC:
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pr_err("%s: Periodic mode is not implemented\n", __func__);
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break;
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case CLOCK_EVT_MODE_ONESHOT:
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timrot_irq_enable();
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break;
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case CLOCK_EVT_MODE_SHUTDOWN:
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case CLOCK_EVT_MODE_UNUSED:
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case CLOCK_EVT_MODE_RESUME:
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/* Left event sources disabled, no more interrupts appear */
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break;
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}
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}
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static struct clock_event_device mxs_clockevent_device = {
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.name = "mxs_timrot",
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.features = CLOCK_EVT_FEAT_ONESHOT,
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.shift = 32,
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.set_mode = mxs_set_mode,
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.set_next_event = timrotv2_set_next_event,
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.rating = 200,
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};
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static int __init mxs_clockevent_init(struct clk *timer_clk)
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{
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unsigned int c = clk_get_rate(timer_clk);
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mxs_clockevent_device.mult =
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div_sc(c, NSEC_PER_SEC, mxs_clockevent_device.shift);
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mxs_clockevent_device.cpumask = cpumask_of(0);
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if (timrot_is_v1()) {
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mxs_clockevent_device.set_next_event = timrotv1_set_next_event;
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mxs_clockevent_device.max_delta_ns =
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clockevent_delta2ns(0xfffe, &mxs_clockevent_device);
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mxs_clockevent_device.min_delta_ns =
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clockevent_delta2ns(0xf, &mxs_clockevent_device);
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} else {
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mxs_clockevent_device.max_delta_ns =
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clockevent_delta2ns(0xfffffffe, &mxs_clockevent_device);
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mxs_clockevent_device.min_delta_ns =
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clockevent_delta2ns(0xf, &mxs_clockevent_device);
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}
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clockevents_register_device(&mxs_clockevent_device);
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return 0;
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}
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static struct clocksource clocksource_mxs = {
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.name = "mxs_timer",
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.rating = 200,
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.read = timrotv2_get_cycles,
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.mask = CLOCKSOURCE_MASK(32),
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.flags = CLOCK_SOURCE_IS_CONTINUOUS,
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};
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static int __init mxs_clocksource_init(struct clk *timer_clk)
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{
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unsigned int c = clk_get_rate(timer_clk);
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if (timrot_is_v1()) {
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clocksource_mxs.read = timrotv1_get_cycles;
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clocksource_mxs.mask = CLOCKSOURCE_MASK(16);
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}
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clocksource_register_hz(&clocksource_mxs, c);
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return 0;
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}
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void __init mxs_timer_init(struct clk *timer_clk, int irq)
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{
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clk_enable(timer_clk);
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/*
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* Initialize timers to a known state
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*/
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mxs_reset_block(mxs_timrot_base + HW_TIMROT_ROTCTRL);
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/* get timrot version */
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timrot_major_version = __raw_readl(mxs_timrot_base +
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(cpu_is_mx23() ? MX23_TIMROT_VERSION_OFFSET :
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MX28_TIMROT_VERSION_OFFSET));
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timrot_major_version >>= BP_TIMROT_MAJOR_VERSION;
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/* one for clock_event */
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__raw_writel((timrot_is_v1() ?
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BV_TIMROTv1_TIMCTRLn_SELECT__32KHZ_XTAL :
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BV_TIMROTv2_TIMCTRLn_SELECT__32KHZ_XTAL) |
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BM_TIMROT_TIMCTRLn_UPDATE |
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BM_TIMROT_TIMCTRLn_IRQ_EN,
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mxs_timrot_base + HW_TIMROT_TIMCTRLn(0));
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/* another for clocksource */
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__raw_writel((timrot_is_v1() ?
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BV_TIMROTv1_TIMCTRLn_SELECT__32KHZ_XTAL :
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BV_TIMROTv2_TIMCTRLn_SELECT__32KHZ_XTAL) |
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BM_TIMROT_TIMCTRLn_RELOAD,
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mxs_timrot_base + HW_TIMROT_TIMCTRLn(1));
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/* set clocksource timer fixed count to the maximum */
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if (timrot_is_v1())
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__raw_writel(0xffff,
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mxs_timrot_base + HW_TIMROT_TIMCOUNTn(1));
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else
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__raw_writel(0xffffffff,
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mxs_timrot_base + HW_TIMROT_FIXED_COUNTn(1));
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/* init and register the timer to the framework */
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mxs_clocksource_init(timer_clk);
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mxs_clockevent_init(timer_clk);
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/* Make irqs happen */
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setup_irq(irq, &mxs_timer_irq);
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}
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