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Release 4.7 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;
};


static int u300_shutdown(struct clock_event_device *evt) { /* 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); return 0; }

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Total34100.00%3100.00%

/* * If we have oneshot timer active, the oneshot scheduling function * u300_set_next_event() is called immediately after. */
static int u300_set_oneshot(struct clock_event_device *evt) { /* Just return; 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); return 0; }

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static int u300_set_periodic(struct clock_event_device *evt) { struct u300_clockevent_data *cevdata = container_of(evt, struct u300_clockevent_data, cevd); /* 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); return 0; }

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/* * 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; }

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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_state_shutdown = u300_shutdown, .set_state_periodic = u300_set_periodic, .set_state_oneshot = u300_set_oneshot, }, }; /* 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; }

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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); }

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linus walleijlinus walleij15.88%125.00%
Total17100.00%4100.00%


static unsigned long u300_read_current_timer(void) { return readl(u300_timer_base + U300_TIMER_APP_GPT2CC); }

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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! */ }

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thierry redingthierry reding41.34%15.88%
marc zyngiermarc zyngier10.34%15.88%
stephen boydstephen boyd10.34%15.88%
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CLOCKSOURCE_OF_DECLARE(u300_timer, "stericsson,u300-apptimer", u300_timer_init_of);

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uwe kleine-koeniguwe kleine-koenig423.26%14.55%
russell kingrussell king352.72%313.64%
marc zyngiermarc zyngier40.31%14.55%
thierry redingthierry reding40.31%14.55%
stephen boydstephen boyd20.16%14.55%
linus torvaldslinus torvalds10.08%14.55%
Total1288100.00%22100.00%
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