- 根目录:
- drivers
- clocksource
- timer-u300.c
/*
* Copyright (C) 2007-2009 ST-Ericsson AB
* License terms: GNU General Public License (GPL) version 2
* Timer COH 901 328, runs the OS timer interrupt.
* Author: Linus Walleij <linus.walleij@stericsson.com>
*/
#include <linux/interrupt.h>
#include <linux/time.h>
#include <linux/timex.h>
#include <linux/clockchips.h>
#include <linux/clocksource.h>
#include <linux/types.h>
#include <linux/io.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/irq.h>
#include <linux/delay.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/sched_clock.h>
/* Generic stuff */
#include <asm/mach/map.h>
#include <asm/mach/time.h>
/*
* APP side special timer registers
* This timer contains four timers which can fire an interrupt each.
* OS (operating system) timer @ 32768 Hz
* DD (device driver) timer @ 1 kHz
* GP1 (general purpose 1) timer @ 1MHz
* GP2 (general purpose 2) timer @ 1MHz
*/
/* Reset OS Timer 32bit (-/W) */
#define U300_TIMER_APP_ROST (0x0000)
#define U300_TIMER_APP_ROST_TIMER_RESET (0x00000000)
/* Enable OS Timer 32bit (-/W) */
#define U300_TIMER_APP_EOST (0x0004)
#define U300_TIMER_APP_EOST_TIMER_ENABLE (0x00000000)
/* Disable OS Timer 32bit (-/W) */
#define U300_TIMER_APP_DOST (0x0008)
#define U300_TIMER_APP_DOST_TIMER_DISABLE (0x00000000)
/* OS Timer Mode Register 32bit (-/W) */
#define U300_TIMER_APP_SOSTM (0x000c)
#define U300_TIMER_APP_SOSTM_MODE_CONTINUOUS (0x00000000)
#define U300_TIMER_APP_SOSTM_MODE_ONE_SHOT (0x00000001)
/* OS Timer Status Register 32bit (R/-) */
#define U300_TIMER_APP_OSTS (0x0010)
#define U300_TIMER_APP_OSTS_TIMER_STATE_MASK (0x0000000F)
#define U300_TIMER_APP_OSTS_TIMER_STATE_IDLE (0x00000001)
#define U300_TIMER_APP_OSTS_TIMER_STATE_ACTIVE (0x00000002)
#define U300_TIMER_APP_OSTS_ENABLE_IND (0x00000010)
#define U300_TIMER_APP_OSTS_MODE_MASK (0x00000020)
#define U300_TIMER_APP_OSTS_MODE_CONTINUOUS (0x00000000)
#define U300_TIMER_APP_OSTS_MODE_ONE_SHOT (0x00000020)
#define U300_TIMER_APP_OSTS_IRQ_ENABLED_IND (0x00000040)
#define U300_TIMER_APP_OSTS_IRQ_PENDING_IND (0x00000080)
/* OS Timer Current Count Register 32bit (R/-) */
#define U300_TIMER_APP_OSTCC (0x0014)
/* OS Timer Terminal Count Register 32bit (R/W) */
#define U300_TIMER_APP_OSTTC (0x0018)
/* OS Timer Interrupt Enable Register 32bit (-/W) */
#define U300_TIMER_APP_OSTIE (0x001c)
#define U300_TIMER_APP_OSTIE_IRQ_DISABLE (0x00000000)
#define U300_TIMER_APP_OSTIE_IRQ_ENABLE (0x00000001)
/* OS Timer Interrupt Acknowledge Register 32bit (-/W) */
#define U300_TIMER_APP_OSTIA (0x0020)
#define U300_TIMER_APP_OSTIA_IRQ_ACK (0x00000080)
/* Reset DD Timer 32bit (-/W) */
#define U300_TIMER_APP_RDDT (0x0040)
#define U300_TIMER_APP_RDDT_TIMER_RESET (0x00000000)
/* Enable DD Timer 32bit (-/W) */
#define U300_TIMER_APP_EDDT (0x0044)
#define U300_TIMER_APP_EDDT_TIMER_ENABLE (0x00000000)
/* Disable DD Timer 32bit (-/W) */
#define U300_TIMER_APP_DDDT (0x0048)
#define U300_TIMER_APP_DDDT_TIMER_DISABLE (0x00000000)
/* DD Timer Mode Register 32bit (-/W) */
#define U300_TIMER_APP_SDDTM (0x004c)
#define U300_TIMER_APP_SDDTM_MODE_CONTINUOUS (0x00000000)
#define U300_TIMER_APP_SDDTM_MODE_ONE_SHOT (0x00000001)
/* DD Timer Status Register 32bit (R/-) */
#define U300_TIMER_APP_DDTS (0x0050)
#define U300_TIMER_APP_DDTS_TIMER_STATE_MASK (0x0000000F)
#define U300_TIMER_APP_DDTS_TIMER_STATE_IDLE (0x00000001)
#define U300_TIMER_APP_DDTS_TIMER_STATE_ACTIVE (0x00000002)
#define U300_TIMER_APP_DDTS_ENABLE_IND (0x00000010)
#define U300_TIMER_APP_DDTS_MODE_MASK (0x00000020)
#define U300_TIMER_APP_DDTS_MODE_CONTINUOUS (0x00000000)
#define U300_TIMER_APP_DDTS_MODE_ONE_SHOT (0x00000020)
#define U300_TIMER_APP_DDTS_IRQ_ENABLED_IND (0x00000040)
#define U300_TIMER_APP_DDTS_IRQ_PENDING_IND (0x00000080)
/* DD Timer Current Count Register 32bit (R/-) */
#define U300_TIMER_APP_DDTCC (0x0054)
/* DD Timer Terminal Count Register 32bit (R/W) */
#define U300_TIMER_APP_DDTTC (0x0058)
/* DD Timer Interrupt Enable Register 32bit (-/W) */
#define U300_TIMER_APP_DDTIE (0x005c)
#define U300_TIMER_APP_DDTIE_IRQ_DISABLE (0x00000000)
#define U300_TIMER_APP_DDTIE_IRQ_ENABLE (0x00000001)
/* DD Timer Interrupt Acknowledge Register 32bit (-/W) */
#define U300_TIMER_APP_DDTIA (0x0060)
#define U300_TIMER_APP_DDTIA_IRQ_ACK (0x00000080)
/* Reset GP1 Timer 32bit (-/W) */
#define U300_TIMER_APP_RGPT1 (0x0080)
#define U300_TIMER_APP_RGPT1_TIMER_RESET (0x00000000)
/* Enable GP1 Timer 32bit (-/W) */
#define U300_TIMER_APP_EGPT1 (0x0084)
#define U300_TIMER_APP_EGPT1_TIMER_ENABLE (0x00000000)
/* Disable GP1 Timer 32bit (-/W) */
#define U300_TIMER_APP_DGPT1 (0x0088)
#define U300_TIMER_APP_DGPT1_TIMER_DISABLE (0x00000000)
/* GP1 Timer Mode Register 32bit (-/W) */
#define U300_TIMER_APP_SGPT1M (0x008c)
#define U300_TIMER_APP_SGPT1M_MODE_CONTINUOUS (0x00000000)
#define U300_TIMER_APP_SGPT1M_MODE_ONE_SHOT (0x00000001)
/* GP1 Timer Status Register 32bit (R/-) */
#define U300_TIMER_APP_GPT1S (0x0090)
#define U300_TIMER_APP_GPT1S_TIMER_STATE_MASK (0x0000000F)
#define U300_TIMER_APP_GPT1S_TIMER_STATE_IDLE (0x00000001)
#define U300_TIMER_APP_GPT1S_TIMER_STATE_ACTIVE (0x00000002)
#define U300_TIMER_APP_GPT1S_ENABLE_IND (0x00000010)
#define U300_TIMER_APP_GPT1S_MODE_MASK (0x00000020)
#define U300_TIMER_APP_GPT1S_MODE_CONTINUOUS (0x00000000)
#define U300_TIMER_APP_GPT1S_MODE_ONE_SHOT (0x00000020)
#define U300_TIMER_APP_GPT1S_IRQ_ENABLED_IND (0x00000040)
#define U300_TIMER_APP_GPT1S_IRQ_PENDING_IND (0x00000080)
/* GP1 Timer Current Count Register 32bit (R/-) */
#define U300_TIMER_APP_GPT1CC (0x0094)
/* GP1 Timer Terminal Count Register 32bit (R/W) */
#define U300_TIMER_APP_GPT1TC (0x0098)
/* GP1 Timer Interrupt Enable Register 32bit (-/W) */
#define U300_TIMER_APP_GPT1IE (0x009c)
#define U300_TIMER_APP_GPT1IE_IRQ_DISABLE (0x00000000)
#define U300_TIMER_APP_GPT1IE_IRQ_ENABLE (0x00000001)
/* GP1 Timer Interrupt Acknowledge Register 32bit (-/W) */
#define U300_TIMER_APP_GPT1IA (0x00a0)
#define U300_TIMER_APP_GPT1IA_IRQ_ACK (0x00000080)
/* Reset GP2 Timer 32bit (-/W) */
#define U300_TIMER_APP_RGPT2 (0x00c0)
#define U300_TIMER_APP_RGPT2_TIMER_RESET (0x00000000)
/* Enable GP2 Timer 32bit (-/W) */
#define U300_TIMER_APP_EGPT2 (0x00c4)
#define U300_TIMER_APP_EGPT2_TIMER_ENABLE (0x00000000)
/* Disable GP2 Timer 32bit (-/W) */
#define U300_TIMER_APP_DGPT2 (0x00c8)
#define U300_TIMER_APP_DGPT2_TIMER_DISABLE (0x00000000)
/* GP2 Timer Mode Register 32bit (-/W) */
#define U300_TIMER_APP_SGPT2M (0x00cc)
#define U300_TIMER_APP_SGPT2M_MODE_CONTINUOUS (0x00000000)
#define U300_TIMER_APP_SGPT2M_MODE_ONE_SHOT (0x00000001)
/* GP2 Timer Status Register 32bit (R/-) */
#define U300_TIMER_APP_GPT2S (0x00d0)
#define U300_TIMER_APP_GPT2S_TIMER_STATE_MASK (0x0000000F)
#define U300_TIMER_APP_GPT2S_TIMER_STATE_IDLE (0x00000001)
#define U300_TIMER_APP_GPT2S_TIMER_STATE_ACTIVE (0x00000002)
#define U300_TIMER_APP_GPT2S_ENABLE_IND (0x00000010)
#define U300_TIMER_APP_GPT2S_MODE_MASK (0x00000020)
#define U300_TIMER_APP_GPT2S_MODE_CONTINUOUS (0x00000000)
#define U300_TIMER_APP_GPT2S_MODE_ONE_SHOT (0x00000020)
#define U300_TIMER_APP_GPT2S_IRQ_ENABLED_IND (0x00000040)
#define U300_TIMER_APP_GPT2S_IRQ_PENDING_IND (0x00000080)
/* GP2 Timer Current Count Register 32bit (R/-) */
#define U300_TIMER_APP_GPT2CC (0x00d4)
/* GP2 Timer Terminal Count Register 32bit (R/W) */
#define U300_TIMER_APP_GPT2TC (0x00d8)
/* GP2 Timer Interrupt Enable Register 32bit (-/W) */
#define U300_TIMER_APP_GPT2IE (0x00dc)
#define U300_TIMER_APP_GPT2IE_IRQ_DISABLE (0x00000000)
#define U300_TIMER_APP_GPT2IE_IRQ_ENABLE (0x00000001)
/* GP2 Timer Interrupt Acknowledge Register 32bit (-/W) */
#define U300_TIMER_APP_GPT2IA (0x00e0)
#define U300_TIMER_APP_GPT2IA_IRQ_ACK (0x00000080)
/* Clock request control register - all four timers */
#define U300_TIMER_APP_CRC (0x100)
#define U300_TIMER_APP_CRC_CLOCK_REQUEST_ENABLE (0x00000001)
static void __iomem *u300_timer_base;
struct u300_clockevent_data {
struct clock_event_device cevd;
unsigned ticks_per_jiffy;
};
/*
* The u300_set_mode() function is always called first, if we
* have oneshot timer active, the oneshot scheduling function
* u300_set_next_event() is called immediately after.
*/
static void u300_set_mode(enum clock_event_mode mode,
struct clock_event_device *evt)
{
struct u300_clockevent_data *cevdata =
container_of(evt, struct u300_clockevent_data, cevd);
switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
/* Disable interrupts on GPT1 */
writel(U300_TIMER_APP_GPT1IE_IRQ_DISABLE,
u300_timer_base + U300_TIMER_APP_GPT1IE);
/* Disable GP1 while we're reprogramming it. */
writel(U300_TIMER_APP_DGPT1_TIMER_DISABLE,
u300_timer_base + U300_TIMER_APP_DGPT1);
/*
* Set the periodic mode to a certain number of ticks per
* jiffy.
*/
writel(cevdata->ticks_per_jiffy,
u300_timer_base + U300_TIMER_APP_GPT1TC);
/*
* Set continuous mode, so the timer keeps triggering
* interrupts.
*/
writel(U300_TIMER_APP_SGPT1M_MODE_CONTINUOUS,
u300_timer_base + U300_TIMER_APP_SGPT1M);
/* Enable timer interrupts */
writel(U300_TIMER_APP_GPT1IE_IRQ_ENABLE,
u300_timer_base + U300_TIMER_APP_GPT1IE);
/* Then enable the OS timer again */
writel(U300_TIMER_APP_EGPT1_TIMER_ENABLE,
u300_timer_base + U300_TIMER_APP_EGPT1);
break;
case CLOCK_EVT_MODE_ONESHOT:
/* Just break; here? */
/*
* The actual event will be programmed by the next event hook,
* so we just set a dummy value somewhere at the end of the
* universe here.
*/
/* Disable interrupts on GPT1 */
writel(U300_TIMER_APP_GPT1IE_IRQ_DISABLE,
u300_timer_base + U300_TIMER_APP_GPT1IE);
/* Disable GP1 while we're reprogramming it. */
writel(U300_TIMER_APP_DGPT1_TIMER_DISABLE,
u300_timer_base + U300_TIMER_APP_DGPT1);
/*
* Expire far in the future, u300_set_next_event() will be
* called soon...
*/
writel(0xFFFFFFFF, u300_timer_base + U300_TIMER_APP_GPT1TC);
/* We run one shot per tick here! */
writel(U300_TIMER_APP_SGPT1M_MODE_ONE_SHOT,
u300_timer_base + U300_TIMER_APP_SGPT1M);
/* Enable interrupts for this timer */
writel(U300_TIMER_APP_GPT1IE_IRQ_ENABLE,
u300_timer_base + U300_TIMER_APP_GPT1IE);
/* Enable timer */
writel(U300_TIMER_APP_EGPT1_TIMER_ENABLE,
u300_timer_base + U300_TIMER_APP_EGPT1);
break;
case CLOCK_EVT_MODE_UNUSED:
case CLOCK_EVT_MODE_SHUTDOWN:
/* Disable interrupts on GP1 */
writel(U300_TIMER_APP_GPT1IE_IRQ_DISABLE,
u300_timer_base + U300_TIMER_APP_GPT1IE);
/* Disable GP1 */
writel(U300_TIMER_APP_DGPT1_TIMER_DISABLE,
u300_timer_base + U300_TIMER_APP_DGPT1);
break;
case CLOCK_EVT_MODE_RESUME:
/* Ignore this call */
break;
}
}
/*
* The app timer in one shot mode obviously has to be reprogrammed
* in EXACTLY this sequence to work properly. Do NOT try to e.g. replace
* the interrupt disable + timer disable commands with a reset command,
* it will fail miserably. Apparently (and I found this the hard way)
* the timer is very sensitive to the instruction order, though you don't
* get that impression from the data sheet.
*/
static int u300_set_next_event(unsigned long cycles,
struct clock_event_device *evt)
{
/* Disable interrupts on GPT1 */
writel(U300_TIMER_APP_GPT1IE_IRQ_DISABLE,
u300_timer_base + U300_TIMER_APP_GPT1IE);
/* Disable GP1 while we're reprogramming it. */
writel(U300_TIMER_APP_DGPT1_TIMER_DISABLE,
u300_timer_base + U300_TIMER_APP_DGPT1);
/* Reset the General Purpose timer 1. */
writel(U300_TIMER_APP_RGPT1_TIMER_RESET,
u300_timer_base + U300_TIMER_APP_RGPT1);
/* IRQ in n * cycles */
writel(cycles, u300_timer_base + U300_TIMER_APP_GPT1TC);
/*
* We run one shot per tick here! (This is necessary to reconfigure,
* the timer will tilt if you don't!)
*/
writel(U300_TIMER_APP_SGPT1M_MODE_ONE_SHOT,
u300_timer_base + U300_TIMER_APP_SGPT1M);
/* Enable timer interrupts */
writel(U300_TIMER_APP_GPT1IE_IRQ_ENABLE,
u300_timer_base + U300_TIMER_APP_GPT1IE);
/* Then enable the OS timer again */
writel(U300_TIMER_APP_EGPT1_TIMER_ENABLE,
u300_timer_base + U300_TIMER_APP_EGPT1);
return 0;
}
static struct u300_clockevent_data u300_clockevent_data = {
/* Use general purpose timer 1 as clock event */
.cevd = {
.name = "GPT1",
/* Reasonably fast and accurate clock event */
.rating = 300,
.features = CLOCK_EVT_FEAT_PERIODIC |
CLOCK_EVT_FEAT_ONESHOT,
.set_next_event = u300_set_next_event,
.set_mode = u300_set_mode,
},
};
/* Clock event timer interrupt handler */
static irqreturn_t u300_timer_interrupt(int irq, void *dev_id)
{
struct clock_event_device *evt = &u300_clockevent_data.cevd;
/* ACK/Clear timer IRQ for the APP GPT1 Timer */
writel(U300_TIMER_APP_GPT1IA_IRQ_ACK,
u300_timer_base + U300_TIMER_APP_GPT1IA);
evt->event_handler(evt);
return IRQ_HANDLED;
}
static struct irqaction u300_timer_irq = {
.name = "U300 Timer Tick",
.flags = IRQF_TIMER | IRQF_IRQPOLL,
.handler = u300_timer_interrupt,
};
/*
* Override the global weak sched_clock symbol with this
* local implementation which uses the clocksource to get some
* better resolution when scheduling the kernel. We accept that
* this wraps around for now, since it is just a relative time
* stamp. (Inspired by OMAP implementation.)
*/
static u64 notrace u300_read_sched_clock(void)
{
return readl(u300_timer_base + U300_TIMER_APP_GPT2CC);
}
static unsigned long u300_read_current_timer(void)
{
return readl(u300_timer_base + U300_TIMER_APP_GPT2CC);
}
static struct delay_timer u300_delay_timer;
/*
* This sets up the system timers, clock source and clock event.
*/
static void __init u300_timer_init_of(struct device_node *np)
{
unsigned int irq;
struct clk *clk;
unsigned long rate;
u300_timer_base = of_iomap(np, 0);
if (!u300_timer_base)
panic("could not ioremap system timer\n");
/* Get the IRQ for the GP1 timer */
irq = irq_of_parse_and_map(np, 2);
if (!irq)
panic("no IRQ for system timer\n");
pr_info("U300 GP1 timer @ base: %p, IRQ: %u\n", u300_timer_base, irq);
/* Clock the interrupt controller */
clk = of_clk_get(np, 0);
BUG_ON(IS_ERR(clk));
clk_prepare_enable(clk);
rate = clk_get_rate(clk);
u300_clockevent_data.ticks_per_jiffy = DIV_ROUND_CLOSEST(rate, HZ);
sched_clock_register(u300_read_sched_clock, 32, rate);
u300_delay_timer.read_current_timer = &u300_read_current_timer;
u300_delay_timer.freq = rate;
register_current_timer_delay(&u300_delay_timer);
/*
* Disable the "OS" and "DD" timers - these are designed for Symbian!
* Example usage in cnh1601578 cpu subsystem pd_timer_app.c
*/
writel(U300_TIMER_APP_CRC_CLOCK_REQUEST_ENABLE,
u300_timer_base + U300_TIMER_APP_CRC);
writel(U300_TIMER_APP_ROST_TIMER_RESET,
u300_timer_base + U300_TIMER_APP_ROST);
writel(U300_TIMER_APP_DOST_TIMER_DISABLE,
u300_timer_base + U300_TIMER_APP_DOST);
writel(U300_TIMER_APP_RDDT_TIMER_RESET,
u300_timer_base + U300_TIMER_APP_RDDT);
writel(U300_TIMER_APP_DDDT_TIMER_DISABLE,
u300_timer_base + U300_TIMER_APP_DDDT);
/* Reset the General Purpose timer 1. */
writel(U300_TIMER_APP_RGPT1_TIMER_RESET,
u300_timer_base + U300_TIMER_APP_RGPT1);
/* Set up the IRQ handler */
setup_irq(irq, &u300_timer_irq);
/* Reset the General Purpose timer 2 */
writel(U300_TIMER_APP_RGPT2_TIMER_RESET,
u300_timer_base + U300_TIMER_APP_RGPT2);
/* Set this timer to run around forever */
writel(0xFFFFFFFFU, u300_timer_base + U300_TIMER_APP_GPT2TC);
/* Set continuous mode so it wraps around */
writel(U300_TIMER_APP_SGPT2M_MODE_CONTINUOUS,
u300_timer_base + U300_TIMER_APP_SGPT2M);
/* Disable timer interrupts */
writel(U300_TIMER_APP_GPT2IE_IRQ_DISABLE,
u300_timer_base + U300_TIMER_APP_GPT2IE);
/* Then enable the GP2 timer to use as a free running us counter */
writel(U300_TIMER_APP_EGPT2_TIMER_ENABLE,
u300_timer_base + U300_TIMER_APP_EGPT2);
/* Use general purpose timer 2 as clock source */
if (clocksource_mmio_init(u300_timer_base + U300_TIMER_APP_GPT2CC,
"GPT2", rate, 300, 32, clocksource_mmio_readl_up))
pr_err("timer: failed to initialize U300 clock source\n");
/* Configure and register the clockevent */
clockevents_config_and_register(&u300_clockevent_data.cevd, rate,
1, 0xffffffff);
/*
* TODO: init and register the rest of the timers too, they can be
* used by hrtimers!
*/
}
CLOCKSOURCE_OF_DECLARE(u300_timer, "stericsson,u300-apptimer",
u300_timer_init_of);