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linux/drivers/clocksource/mxs_timer.c

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/*
* Copyright (C) 2000-2001 Deep Blue Solutions
* Copyright (C) 2002 Shane Nay (shane@minirl.com)
* Copyright (C) 2006-2007 Pavel Pisa (ppisa@pikron.com)
* Copyright (C) 2008 Juergen Beisert (kernel@pengutronix.de)
* Copyright (C) 2010 Freescale Semiconductor, Inc. All Rights Reserved.
*
* 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 program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* 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., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301, USA.
*/
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/clockchips.h>
#include <linux/clk.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/stmp_device.h>
#include <linux/sched_clock.h>
/*
* 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.
*/
#define MX23_TIMROT_VERSION_OFFSET 0x0a0
#define MX28_TIMROT_VERSION_OFFSET 0x120
#define BP_TIMROT_MAJOR_VERSION 24
#define BV_TIMROT_VERSION_1 0x01
#define BV_TIMROT_VERSION_2 0x02
#define timrot_is_v1() (timrot_major_version == BV_TIMROT_VERSION_1)
/*
* There are 4 registers for each timrotv2 instance, and 2 registers
* for each timrotv1. So address step 0x40 in macros below strides
* one instance of timrotv2 while two instances of timrotv1.
*
* As the result, HW_TIMROT_XXXn(1) defines the address of timrot1
* on MX28 while timrot2 on MX23.
*/
/* common between v1 and v2 */
#define HW_TIMROT_ROTCTRL 0x00
#define HW_TIMROT_TIMCTRLn(n) (0x20 + (n) * 0x40)
/* v1 only */
#define HW_TIMROT_TIMCOUNTn(n) (0x30 + (n) * 0x40)
/* v2 only */
#define HW_TIMROT_RUNNING_COUNTn(n) (0x30 + (n) * 0x40)
#define HW_TIMROT_FIXED_COUNTn(n) (0x40 + (n) * 0x40)
#define BM_TIMROT_TIMCTRLn_RELOAD (1 << 6)
#define BM_TIMROT_TIMCTRLn_UPDATE (1 << 7)
#define BM_TIMROT_TIMCTRLn_IRQ_EN (1 << 14)
#define BM_TIMROT_TIMCTRLn_IRQ (1 << 15)
#define BP_TIMROT_TIMCTRLn_SELECT 0
#define BV_TIMROTv1_TIMCTRLn_SELECT__32KHZ_XTAL 0x8
#define BV_TIMROTv2_TIMCTRLn_SELECT__32KHZ_XTAL 0xb
#define BV_TIMROTv2_TIMCTRLn_SELECT__TICK_ALWAYS 0xf
static struct clock_event_device mxs_clockevent_device;
static void __iomem *mxs_timrot_base;
static u32 timrot_major_version;
static inline void timrot_irq_disable(void)
{
__raw_writel(BM_TIMROT_TIMCTRLn_IRQ_EN, mxs_timrot_base +
HW_TIMROT_TIMCTRLn(0) + STMP_OFFSET_REG_CLR);
}
static inline void timrot_irq_enable(void)
{
__raw_writel(BM_TIMROT_TIMCTRLn_IRQ_EN, mxs_timrot_base +
HW_TIMROT_TIMCTRLn(0) + STMP_OFFSET_REG_SET);
}
static void timrot_irq_acknowledge(void)
{
__raw_writel(BM_TIMROT_TIMCTRLn_IRQ, mxs_timrot_base +
HW_TIMROT_TIMCTRLn(0) + STMP_OFFSET_REG_CLR);
}
static u64 timrotv1_get_cycles(struct clocksource *cs)
{
return ~((__raw_readl(mxs_timrot_base + HW_TIMROT_TIMCOUNTn(1))
& 0xffff0000) >> 16);
}
static int timrotv1_set_next_event(unsigned long evt,
struct clock_event_device *dev)
{
/* timrot decrements the count */
__raw_writel(evt, mxs_timrot_base + HW_TIMROT_TIMCOUNTn(0));
return 0;
}
static int timrotv2_set_next_event(unsigned long evt,
struct clock_event_device *dev)
{
/* timrot decrements the count */
__raw_writel(evt, mxs_timrot_base + HW_TIMROT_FIXED_COUNTn(0));
return 0;
}
static irqreturn_t mxs_timer_interrupt(int irq, void *dev_id)
{
struct clock_event_device *evt = dev_id;
timrot_irq_acknowledge();
evt->event_handler(evt);
return IRQ_HANDLED;
}
static struct irqaction mxs_timer_irq = {
.name = "MXS Timer Tick",
.dev_id = &mxs_clockevent_device,
.flags = IRQF_TIMER | IRQF_IRQPOLL,
.handler = mxs_timer_interrupt,
};
static void mxs_irq_clear(char *state)
{
/* Disable interrupt in timer module */
timrot_irq_disable();
/* Set event time into the furthest future */
if (timrot_is_v1())
__raw_writel(0xffff, mxs_timrot_base + HW_TIMROT_TIMCOUNTn(1));
else
__raw_writel(0xffffffff,
mxs_timrot_base + HW_TIMROT_FIXED_COUNTn(1));
/* Clear pending interrupt */
timrot_irq_acknowledge();
#ifdef DEBUG
pr_info("%s: changing mode to %s\n", __func__, state)
#endif /* DEBUG */
}
static int mxs_shutdown(struct clock_event_device *evt)
{
mxs_irq_clear("shutdown");
return 0;
}
static int mxs_set_oneshot(struct clock_event_device *evt)
{
if (clockevent_state_oneshot(evt))
mxs_irq_clear("oneshot");
timrot_irq_enable();
return 0;
}
static struct clock_event_device mxs_clockevent_device = {
.name = "mxs_timrot",
.features = CLOCK_EVT_FEAT_ONESHOT,
.set_state_shutdown = mxs_shutdown,
.set_state_oneshot = mxs_set_oneshot,
.tick_resume = mxs_shutdown,
.set_next_event = timrotv2_set_next_event,
.rating = 200,
};
static int __init mxs_clockevent_init(struct clk *timer_clk)
{
if (timrot_is_v1())
mxs_clockevent_device.set_next_event = timrotv1_set_next_event;
mxs_clockevent_device.cpumask = cpumask_of(0);
clockevents_config_and_register(&mxs_clockevent_device,
clk_get_rate(timer_clk),
timrot_is_v1() ? 0xf : 0x2,
timrot_is_v1() ? 0xfffe : 0xfffffffe);
return 0;
}
static struct clocksource clocksource_mxs = {
.name = "mxs_timer",
.rating = 200,
.read = timrotv1_get_cycles,
.mask = CLOCKSOURCE_MASK(16),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
static u64 notrace mxs_read_sched_clock_v2(void)
{
return ~readl_relaxed(mxs_timrot_base + HW_TIMROT_RUNNING_COUNTn(1));
}
static int __init mxs_clocksource_init(struct clk *timer_clk)
{
unsigned int c = clk_get_rate(timer_clk);
if (timrot_is_v1())
clocksource_register_hz(&clocksource_mxs, c);
else {
clocksource_mmio_init(mxs_timrot_base + HW_TIMROT_RUNNING_COUNTn(1),
"mxs_timer", c, 200, 32, clocksource_mmio_readl_down);
sched_clock_register(mxs_read_sched_clock_v2, 32, c);
}
return 0;
}
static int __init mxs_timer_init(struct device_node *np)
{
struct clk *timer_clk;
int irq, ret;
mxs_timrot_base = of_iomap(np, 0);
WARN_ON(!mxs_timrot_base);
timer_clk = of_clk_get(np, 0);
if (IS_ERR(timer_clk)) {
pr_err("%s: failed to get clk\n", __func__);
return PTR_ERR(timer_clk);
}
ret = clk_prepare_enable(timer_clk);
if (ret)
return ret;
/*
* Initialize timers to a known state
*/
stmp_reset_block(mxs_timrot_base + HW_TIMROT_ROTCTRL);
/* get timrot version */
timrot_major_version = __raw_readl(mxs_timrot_base +
(of_device_is_compatible(np, "fsl,imx23-timrot") ?
MX23_TIMROT_VERSION_OFFSET :
MX28_TIMROT_VERSION_OFFSET));
timrot_major_version >>= BP_TIMROT_MAJOR_VERSION;
/* one for clock_event */
__raw_writel((timrot_is_v1() ?
BV_TIMROTv1_TIMCTRLn_SELECT__32KHZ_XTAL :
BV_TIMROTv2_TIMCTRLn_SELECT__TICK_ALWAYS) |
BM_TIMROT_TIMCTRLn_UPDATE |
BM_TIMROT_TIMCTRLn_IRQ_EN,
mxs_timrot_base + HW_TIMROT_TIMCTRLn(0));
/* another for clocksource */
__raw_writel((timrot_is_v1() ?
BV_TIMROTv1_TIMCTRLn_SELECT__32KHZ_XTAL :
BV_TIMROTv2_TIMCTRLn_SELECT__TICK_ALWAYS) |
BM_TIMROT_TIMCTRLn_RELOAD,
mxs_timrot_base + HW_TIMROT_TIMCTRLn(1));
/* set clocksource timer fixed count to the maximum */
if (timrot_is_v1())
__raw_writel(0xffff,
mxs_timrot_base + HW_TIMROT_TIMCOUNTn(1));
else
__raw_writel(0xffffffff,
mxs_timrot_base + HW_TIMROT_FIXED_COUNTn(1));
/* init and register the timer to the framework */
ret = mxs_clocksource_init(timer_clk);
if (ret)
return ret;
ret = mxs_clockevent_init(timer_clk);
if (ret)
return ret;
/* Make irqs happen */
irq = irq_of_parse_and_map(np, 0);
if (irq <= 0)
return -EINVAL;
return setup_irq(irq, &mxs_timer_irq);
}
TIMER_OF_DECLARE(mxs, "fsl,timrot", mxs_timer_init);
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