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OpenCloudOS-Kernel/arch/arm/plat-mxc/time.c

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/*
* linux/arch/arm/plat-mxc/time.c
*
* 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)
*
* 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/interrupt.h>
#include <linux/irq.h>
#include <linux/clockchips.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <mach/hardware.h>
#include <asm/sched_clock.h>
#include <asm/mach/time.h>
#include <mach/common.h>
/*
* There are 2 versions of the timer hardware on Freescale MXC hardware.
* Version 1: MX1/MXL, MX21, MX27.
* Version 2: MX25, MX31, MX35, MX37, MX51
*/
/* defines common for all i.MX */
#define MXC_TCTL 0x00
#define MXC_TCTL_TEN (1 << 0) /* Enable module */
#define MXC_TPRER 0x04
/* MX1, MX21, MX27 */
#define MX1_2_TCTL_CLK_PCLK1 (1 << 1)
#define MX1_2_TCTL_IRQEN (1 << 4)
#define MX1_2_TCTL_FRR (1 << 8)
#define MX1_2_TCMP 0x08
#define MX1_2_TCN 0x10
#define MX1_2_TSTAT 0x14
/* MX21, MX27 */
#define MX2_TSTAT_CAPT (1 << 1)
#define MX2_TSTAT_COMP (1 << 0)
/* MX31, MX35, MX25, MX5 */
#define V2_TCTL_WAITEN (1 << 3) /* Wait enable mode */
#define V2_TCTL_CLK_IPG (1 << 6)
#define V2_TCTL_CLK_PER (2 << 6)
#define V2_TCTL_FRR (1 << 9)
#define V2_IR 0x0c
#define V2_TSTAT 0x08
#define V2_TSTAT_OF1 (1 << 0)
#define V2_TCN 0x24
#define V2_TCMP 0x10
#define timer_is_v1() (cpu_is_mx1() || cpu_is_mx21() || cpu_is_mx27())
#define timer_is_v2() (!timer_is_v1())
static struct clock_event_device clockevent_mxc;
static enum clock_event_mode clockevent_mode = CLOCK_EVT_MODE_UNUSED;
static void __iomem *timer_base;
static inline void gpt_irq_disable(void)
{
unsigned int tmp;
if (timer_is_v2())
__raw_writel(0, timer_base + V2_IR);
else {
tmp = __raw_readl(timer_base + MXC_TCTL);
__raw_writel(tmp & ~MX1_2_TCTL_IRQEN, timer_base + MXC_TCTL);
}
}
static inline void gpt_irq_enable(void)
{
if (timer_is_v2())
__raw_writel(1<<0, timer_base + V2_IR);
else {
__raw_writel(__raw_readl(timer_base + MXC_TCTL) | MX1_2_TCTL_IRQEN,
timer_base + MXC_TCTL);
}
}
static void gpt_irq_acknowledge(void)
{
if (timer_is_v1()) {
if (cpu_is_mx1())
__raw_writel(0, timer_base + MX1_2_TSTAT);
else
__raw_writel(MX2_TSTAT_CAPT | MX2_TSTAT_COMP,
timer_base + MX1_2_TSTAT);
} else if (timer_is_v2())
__raw_writel(V2_TSTAT_OF1, timer_base + V2_TSTAT);
}
static void __iomem *sched_clock_reg;
static u32 notrace mxc_read_sched_clock(void)
{
return sched_clock_reg ? __raw_readl(sched_clock_reg) : 0;
}
static int __init mxc_clocksource_init(struct clk *timer_clk)
{
unsigned int c = clk_get_rate(timer_clk);
void __iomem *reg = timer_base + (timer_is_v2() ? V2_TCN : MX1_2_TCN);
sched_clock_reg = reg;
setup_sched_clock(mxc_read_sched_clock, 32, c);
return clocksource_mmio_init(reg, "mxc_timer1", c, 200, 32,
clocksource_mmio_readl_up);
}
/* clock event */
static int mx1_2_set_next_event(unsigned long evt,
struct clock_event_device *unused)
{
unsigned long tcmp;
tcmp = __raw_readl(timer_base + MX1_2_TCN) + evt;
__raw_writel(tcmp, timer_base + MX1_2_TCMP);
return (int)(tcmp - __raw_readl(timer_base + MX1_2_TCN)) < 0 ?
-ETIME : 0;
}
static int v2_set_next_event(unsigned long evt,
struct clock_event_device *unused)
{
unsigned long tcmp;
tcmp = __raw_readl(timer_base + V2_TCN) + evt;
__raw_writel(tcmp, timer_base + V2_TCMP);
return (int)(tcmp - __raw_readl(timer_base + V2_TCN)) < 0 ?
-ETIME : 0;
}
#ifdef DEBUG
static const char *clock_event_mode_label[] = {
[CLOCK_EVT_MODE_PERIODIC] = "CLOCK_EVT_MODE_PERIODIC",
[CLOCK_EVT_MODE_ONESHOT] = "CLOCK_EVT_MODE_ONESHOT",
[CLOCK_EVT_MODE_SHUTDOWN] = "CLOCK_EVT_MODE_SHUTDOWN",
[CLOCK_EVT_MODE_UNUSED] = "CLOCK_EVT_MODE_UNUSED",
[CLOCK_EVT_MODE_RESUME] = "CLOCK_EVT_MODE_RESUME",
};
#endif /* DEBUG */
static void mxc_set_mode(enum clock_event_mode mode,
struct clock_event_device *evt)
{
unsigned long flags;
/*
* The timer interrupt generation is disabled at least
* for enough time to call mxc_set_next_event()
*/
local_irq_save(flags);
/* Disable interrupt in GPT module */
gpt_irq_disable();
if (mode != clockevent_mode) {
/* Set event time into far-far future */
if (timer_is_v2())
__raw_writel(__raw_readl(timer_base + V2_TCN) - 3,
timer_base + V2_TCMP);
else
__raw_writel(__raw_readl(timer_base + MX1_2_TCN) - 3,
timer_base + MX1_2_TCMP);
/* Clear pending interrupt */
gpt_irq_acknowledge();
}
#ifdef DEBUG
printk(KERN_INFO "mxc_set_mode: changing mode from %s to %s\n",
clock_event_mode_label[clockevent_mode],
clock_event_mode_label[mode]);
#endif /* DEBUG */
/* Remember timer mode */
clockevent_mode = mode;
local_irq_restore(flags);
switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
printk(KERN_ERR"mxc_set_mode: Periodic mode is not "
"supported for i.MX\n");
break;
case CLOCK_EVT_MODE_ONESHOT:
/*
* Do not put overhead of interrupt enable/disable into
* mxc_set_next_event(), the core has about 4 minutes
* to call mxc_set_next_event() or shutdown clock after
* mode switching
*/
local_irq_save(flags);
gpt_irq_enable();
local_irq_restore(flags);
break;
case CLOCK_EVT_MODE_SHUTDOWN:
case CLOCK_EVT_MODE_UNUSED:
case CLOCK_EVT_MODE_RESUME:
/* Left event sources disabled, no more interrupts appear */
break;
}
}
/*
* IRQ handler for the timer
*/
static irqreturn_t mxc_timer_interrupt(int irq, void *dev_id)
{
struct clock_event_device *evt = &clockevent_mxc;
uint32_t tstat;
if (timer_is_v2())
tstat = __raw_readl(timer_base + V2_TSTAT);
else
tstat = __raw_readl(timer_base + MX1_2_TSTAT);
gpt_irq_acknowledge();
evt->event_handler(evt);
return IRQ_HANDLED;
}
static struct irqaction mxc_timer_irq = {
.name = "i.MX Timer Tick",
.flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
.handler = mxc_timer_interrupt,
};
static struct clock_event_device clockevent_mxc = {
.name = "mxc_timer1",
.features = CLOCK_EVT_FEAT_ONESHOT,
.shift = 32,
.set_mode = mxc_set_mode,
.set_next_event = mx1_2_set_next_event,
.rating = 200,
};
static int __init mxc_clockevent_init(struct clk *timer_clk)
{
unsigned int c = clk_get_rate(timer_clk);
if (timer_is_v2())
clockevent_mxc.set_next_event = v2_set_next_event;
clockevent_mxc.mult = div_sc(c, NSEC_PER_SEC,
clockevent_mxc.shift);
clockevent_mxc.max_delta_ns =
clockevent_delta2ns(0xfffffffe, &clockevent_mxc);
clockevent_mxc.min_delta_ns =
clockevent_delta2ns(0xff, &clockevent_mxc);
clockevent_mxc.cpumask = cpumask_of(0);
clockevents_register_device(&clockevent_mxc);
return 0;
}
void __init mxc_timer_init(void __iomem *base, int irq)
{
uint32_t tctl_val;
struct clk *timer_clk;
struct clk *timer_ipg_clk;
timer_clk = clk_get_sys("imx-gpt.0", "per");
if (IS_ERR(timer_clk)) {
pr_err("i.MX timer: unable to get clk\n");
return;
}
timer_ipg_clk = clk_get_sys("imx-gpt.0", "ipg");
if (!IS_ERR(timer_ipg_clk))
clk_prepare_enable(timer_ipg_clk);
clk_prepare_enable(timer_clk);
timer_base = base;
/*
* Initialise to a known state (all timers off, and timing reset)
*/
__raw_writel(0, timer_base + MXC_TCTL);
__raw_writel(0, timer_base + MXC_TPRER); /* see datasheet note */
if (timer_is_v2())
tctl_val = V2_TCTL_CLK_PER | V2_TCTL_FRR | V2_TCTL_WAITEN | MXC_TCTL_TEN;
else
tctl_val = MX1_2_TCTL_FRR | MX1_2_TCTL_CLK_PCLK1 | MXC_TCTL_TEN;
__raw_writel(tctl_val, timer_base + MXC_TCTL);
/* init and register the timer to the framework */
mxc_clocksource_init(timer_clk);
mxc_clockevent_init(timer_clk);
/* Make irqs happen */
setup_irq(irq, &mxc_timer_irq);
}
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