linux/arch/arm/plat-nomadik/timer.c
Jonas Aaberg 05387a9fbf ARM: plat-nomadik: timer: Export reset functions
We make the reset function from the driver public, then
we also move of all register defines from the public header
file into driver, where they belong.

Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jonas Aaberg <jonas.aberg@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2011-09-22 15:44:17 +02:00

251 lines
6.6 KiB
C

/*
* linux/arch/arm/plat-nomadik/timer.c
*
* Copyright (C) 2008 STMicroelectronics
* Copyright (C) 2010 Alessandro Rubini
* Copyright (C) 2010 Linus Walleij for ST-Ericsson
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2, as
* published by the Free Software Foundation.
*/
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/io.h>
#include <linux/clockchips.h>
#include <linux/clk.h>
#include <linux/jiffies.h>
#include <linux/err.h>
#include <linux/sched.h>
#include <asm/mach/time.h>
#include <asm/sched_clock.h>
/*
* Guaranteed runtime conversion range in seconds for
* the clocksource and clockevent.
*/
#define MTU_MIN_RANGE 4
/*
* The MTU device hosts four different counters, with 4 set of
* registers. These are register names.
*/
#define MTU_IMSC 0x00 /* Interrupt mask set/clear */
#define MTU_RIS 0x04 /* Raw interrupt status */
#define MTU_MIS 0x08 /* Masked interrupt status */
#define MTU_ICR 0x0C /* Interrupt clear register */
/* per-timer registers take 0..3 as argument */
#define MTU_LR(x) (0x10 + 0x10 * (x) + 0x00) /* Load value */
#define MTU_VAL(x) (0x10 + 0x10 * (x) + 0x04) /* Current value */
#define MTU_CR(x) (0x10 + 0x10 * (x) + 0x08) /* Control reg */
#define MTU_BGLR(x) (0x10 + 0x10 * (x) + 0x0c) /* At next overflow */
/* bits for the control register */
#define MTU_CRn_ENA 0x80
#define MTU_CRn_PERIODIC 0x40 /* if 0 = free-running */
#define MTU_CRn_PRESCALE_MASK 0x0c
#define MTU_CRn_PRESCALE_1 0x00
#define MTU_CRn_PRESCALE_16 0x04
#define MTU_CRn_PRESCALE_256 0x08
#define MTU_CRn_32BITS 0x02
#define MTU_CRn_ONESHOT 0x01 /* if 0 = wraps reloading from BGLR*/
/* Other registers are usual amba/primecell registers, currently not used */
#define MTU_ITCR 0xff0
#define MTU_ITOP 0xff4
#define MTU_PERIPH_ID0 0xfe0
#define MTU_PERIPH_ID1 0xfe4
#define MTU_PERIPH_ID2 0xfe8
#define MTU_PERIPH_ID3 0xfeC
#define MTU_PCELL0 0xff0
#define MTU_PCELL1 0xff4
#define MTU_PCELL2 0xff8
#define MTU_PCELL3 0xffC
static bool clkevt_periodic;
static u32 clk_prescale;
static u32 nmdk_cycle; /* write-once */
void __iomem *mtu_base; /* Assigned by machine code */
#ifdef CONFIG_NOMADIK_MTU_SCHED_CLOCK
/*
* Override the global weak sched_clock symbol with this
* local implementation which uses the clocksource to get some
* better resolution when scheduling the kernel.
*/
static DEFINE_CLOCK_DATA(cd);
unsigned long long notrace sched_clock(void)
{
u32 cyc;
if (unlikely(!mtu_base))
return 0;
cyc = -readl(mtu_base + MTU_VAL(0));
return cyc_to_sched_clock(&cd, cyc, (u32)~0);
}
static void notrace nomadik_update_sched_clock(void)
{
u32 cyc = -readl(mtu_base + MTU_VAL(0));
update_sched_clock(&cd, cyc, (u32)~0);
}
#endif
/* Clockevent device: use one-shot mode */
static int nmdk_clkevt_next(unsigned long evt, struct clock_event_device *ev)
{
writel(1 << 1, mtu_base + MTU_IMSC);
writel(evt, mtu_base + MTU_LR(1));
/* Load highest value, enable device, enable interrupts */
writel(MTU_CRn_ONESHOT | clk_prescale |
MTU_CRn_32BITS | MTU_CRn_ENA,
mtu_base + MTU_CR(1));
return 0;
}
void nmdk_clkevt_reset(void)
{
if (clkevt_periodic) {
/* Timer: configure load and background-load, and fire it up */
writel(nmdk_cycle, mtu_base + MTU_LR(1));
writel(nmdk_cycle, mtu_base + MTU_BGLR(1));
writel(MTU_CRn_PERIODIC | clk_prescale |
MTU_CRn_32BITS | MTU_CRn_ENA,
mtu_base + MTU_CR(1));
writel(1 << 1, mtu_base + MTU_IMSC);
} else {
/* Generate an interrupt to start the clockevent again */
(void) nmdk_clkevt_next(nmdk_cycle, NULL);
}
}
static void nmdk_clkevt_mode(enum clock_event_mode mode,
struct clock_event_device *dev)
{
switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
clkevt_periodic = true;
nmdk_clkevt_reset();
break;
case CLOCK_EVT_MODE_ONESHOT:
clkevt_periodic = false;
break;
case CLOCK_EVT_MODE_SHUTDOWN:
case CLOCK_EVT_MODE_UNUSED:
writel(0, mtu_base + MTU_IMSC);
/* disable timer */
writel(0, mtu_base + MTU_CR(1));
/* load some high default value */
writel(0xffffffff, mtu_base + MTU_LR(1));
break;
case CLOCK_EVT_MODE_RESUME:
break;
}
}
static struct clock_event_device nmdk_clkevt = {
.name = "mtu_1",
.features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC,
.rating = 200,
.set_mode = nmdk_clkevt_mode,
.set_next_event = nmdk_clkevt_next,
};
/*
* IRQ Handler for timer 1 of the MTU block.
*/
static irqreturn_t nmdk_timer_interrupt(int irq, void *dev_id)
{
struct clock_event_device *evdev = dev_id;
writel(1 << 1, mtu_base + MTU_ICR); /* Interrupt clear reg */
evdev->event_handler(evdev);
return IRQ_HANDLED;
}
static struct irqaction nmdk_timer_irq = {
.name = "Nomadik Timer Tick",
.flags = IRQF_DISABLED | IRQF_TIMER,
.handler = nmdk_timer_interrupt,
.dev_id = &nmdk_clkevt,
};
void nmdk_clksrc_reset(void)
{
/* Disable */
writel(0, mtu_base + MTU_CR(0));
/* ClockSource: configure load and background-load, and fire it up */
writel(nmdk_cycle, mtu_base + MTU_LR(0));
writel(nmdk_cycle, mtu_base + MTU_BGLR(0));
writel(clk_prescale | MTU_CRn_32BITS | MTU_CRn_ENA,
mtu_base + MTU_CR(0));
}
void __init nmdk_timer_init(void)
{
unsigned long rate;
struct clk *clk0;
clk0 = clk_get_sys("mtu0", NULL);
BUG_ON(IS_ERR(clk0));
clk_enable(clk0);
/*
* Tick rate is 2.4MHz for Nomadik and 2.4Mhz, 100MHz or 133 MHz
* for ux500.
* Use a divide-by-16 counter if the tick rate is more than 32MHz.
* At 32 MHz, the timer (with 32 bit counter) can be programmed
* to wake-up at a max 127s a head in time. Dividing a 2.4 MHz timer
* with 16 gives too low timer resolution.
*/
rate = clk_get_rate(clk0);
if (rate > 32000000) {
rate /= 16;
clk_prescale = MTU_CRn_PRESCALE_16;
} else {
clk_prescale = MTU_CRn_PRESCALE_1;
}
nmdk_cycle = (rate + HZ/2) / HZ;
/* Timer 0 is the free running clocksource */
nmdk_clksrc_reset();
if (clocksource_mmio_init(mtu_base + MTU_VAL(0), "mtu_0",
rate, 200, 32, clocksource_mmio_readl_down))
pr_err("timer: failed to initialize clock source %s\n",
"mtu_0");
#ifdef CONFIG_NOMADIK_MTU_SCHED_CLOCK
init_sched_clock(&cd, nomadik_update_sched_clock, 32, rate);
#endif
/* Timer 1 is used for events */
clockevents_calc_mult_shift(&nmdk_clkevt, rate, MTU_MIN_RANGE);
nmdk_clkevt.max_delta_ns =
clockevent_delta2ns(0xffffffff, &nmdk_clkevt);
nmdk_clkevt.min_delta_ns =
clockevent_delta2ns(0x00000002, &nmdk_clkevt);
nmdk_clkevt.cpumask = cpumask_of(0);
/* Register irq and clockevents */
setup_irq(IRQ_MTU0, &nmdk_timer_irq);
clockevents_register_device(&nmdk_clkevt);
}