cregit-Linux how code gets into the kernel

Release 4.7 drivers/clocksource/tegra20_timer.c

/*
 * Copyright (C) 2010 Google, Inc.
 *
 * Author:
 *      Colin Cross <ccross@google.com>
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * 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.
 *
 */

#include <linux/init.h>
#include <linux/err.h>
#include <linux/time.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/clockchips.h>
#include <linux/clocksource.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/sched_clock.h>
#include <linux/delay.h>

#include <asm/mach/time.h>
#include <asm/smp_twd.h>


#define RTC_SECONDS            0x08

#define RTC_SHADOW_SECONDS     0x0c

#define RTC_MILLISECONDS       0x10


#define TIMERUS_CNTR_1US 0x10

#define TIMERUS_USEC_CFG 0x14

#define TIMERUS_CNTR_FREEZE 0x4c


#define TIMER1_BASE 0x0

#define TIMER2_BASE 0x8

#define TIMER3_BASE 0x50

#define TIMER4_BASE 0x58


#define TIMER_PTV 0x0

#define TIMER_PCR 0x4


static void __iomem *timer_reg_base;

static void __iomem *rtc_base;


static struct timespec64 persistent_ts;


static u64 persistent_ms, last_persistent_ms;


static struct delay_timer tegra_delay_timer;


#define timer_writel(value, reg) \
	writel_relaxed(value, timer_reg_base + (reg))

#define timer_readl(reg) \
	readl_relaxed(timer_reg_base + (reg))


static int tegra_timer_set_next_event(unsigned long cycles, struct clock_event_device *evt) { u32 reg; reg = 0x80000000 | ((cycles > 1) ? (cycles-1) : 0); timer_writel(reg, TIMER3_BASE + TIMER_PTV); return 0; }

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static inline void timer_shutdown(struct clock_event_device *evt) { timer_writel(0, TIMER3_BASE + TIMER_PTV); }

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static int tegra_timer_shutdown(struct clock_event_device *evt) { timer_shutdown(evt); return 0; }

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static int tegra_timer_set_periodic(struct clock_event_device *evt) { u32 reg = 0xC0000000 | ((1000000 / HZ) - 1); timer_shutdown(evt); timer_writel(reg, TIMER3_BASE + TIMER_PTV); return 0; }

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static struct clock_event_device tegra_clockevent = { .name = "timer0", .rating = 300, .features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_DYNIRQ, .set_next_event = tegra_timer_set_next_event, .set_state_shutdown = tegra_timer_shutdown, .set_state_periodic = tegra_timer_set_periodic, .set_state_oneshot = tegra_timer_shutdown, .tick_resume = tegra_timer_shutdown, };
static u64 notrace tegra_read_sched_clock(void) { return timer_readl(TIMERUS_CNTR_1US); }

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stephen boydstephen boyd16.67%120.00%
Total15100.00%5100.00%

/* * tegra_rtc_read - Reads the Tegra RTC registers * Care must be taken that this funciton is not called while the * tegra_rtc driver could be executing to avoid race conditions * on the RTC shadow register */
static u64 tegra_rtc_read_ms(void) { u32 ms = readl(rtc_base + RTC_MILLISECONDS); u32 s = readl(rtc_base + RTC_SHADOW_SECONDS); return (u64)s * MSEC_PER_SEC + ms; }

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Total38100.00%2100.00%

/* * tegra_read_persistent_clock64 - Return time from a persistent clock. * * Reads the time from a source which isn't disabled during PM, the * 32k sync timer. Convert the cycles elapsed since last read into * nsecs and adds to a monotonically increasing timespec64. * Care must be taken that this funciton is not called while the * tegra_rtc driver could be executing to avoid race conditions * on the RTC shadow register */
static void tegra_read_persistent_clock64(struct timespec64 *ts) { u64 delta; last_persistent_ms = persistent_ms; persistent_ms = tegra_rtc_read_ms(); delta = persistent_ms - last_persistent_ms; timespec64_add_ns(&persistent_ts, delta * NSEC_PER_MSEC); *ts = persistent_ts; }

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marc zyngiermarc zyngier12.27%133.33%
Total44100.00%3100.00%


static unsigned long tegra_delay_timer_read_counter_long(void) { return readl(timer_reg_base + TIMERUS_CNTR_1US); }

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static irqreturn_t tegra_timer_interrupt(int irq, void *dev_id) { struct clock_event_device *evt = (struct clock_event_device *)dev_id; timer_writel(1<<30, TIMER3_BASE + TIMER_PCR); evt->event_handler(evt); return IRQ_HANDLED; }

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static struct irqaction tegra_timer_irq = { .name = "timer0", .flags = IRQF_TIMER | IRQF_TRIGGER_HIGH, .handler = tegra_timer_interrupt, .dev_id = &tegra_clockevent, };
static void __init tegra20_init_timer(struct device_node *np) { struct clk *clk; unsigned long rate; int ret; timer_reg_base = of_iomap(np, 0); if (!timer_reg_base) { pr_err("Can't map timer registers\n"); BUG(); } tegra_timer_irq.irq = irq_of_parse_and_map(np, 2); if (tegra_timer_irq.irq <= 0) { pr_err("Failed to map timer IRQ\n"); BUG(); } clk = of_clk_get(np, 0); if (IS_ERR(clk)) { pr_warn("Unable to get timer clock. Assuming 12Mhz input clock.\n"); rate = 12000000; } else { clk_prepare_enable(clk); rate = clk_get_rate(clk); } switch (rate) { case 12000000: timer_writel(0x000b, TIMERUS_USEC_CFG); break; case 13000000: timer_writel(0x000c, TIMERUS_USEC_CFG); break; case 19200000: timer_writel(0x045f, TIMERUS_USEC_CFG); break; case 26000000: timer_writel(0x0019, TIMERUS_USEC_CFG); break; default: WARN(1, "Unknown clock rate"); } sched_clock_register(tegra_read_sched_clock, 32, 1000000); if (clocksource_mmio_init(timer_reg_base + TIMERUS_CNTR_1US, "timer_us", 1000000, 300, 32, clocksource_mmio_readl_up)) { pr_err("Failed to register clocksource\n"); BUG(); } tegra_delay_timer.read_current_timer = tegra_delay_timer_read_counter_long; tegra_delay_timer.freq = 1000000; register_current_timer_delay(&tegra_delay_timer); ret = setup_irq(tegra_timer_irq.irq, &tegra_timer_irq); if (ret) { pr_err("Failed to register timer IRQ: %d\n", ret); BUG(); } tegra_clockevent.cpumask = cpu_all_mask; tegra_clockevent.irq = tegra_timer_irq.irq; clockevents_config_and_register(&tegra_clockevent, 1000000, 0x1, 0x1fffffff); }

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stephen warrenstephen warren6121.25%421.05%
peter de schrijverpeter de schrijver4214.63%421.05%
russell kingrussell king196.62%210.53%
shawn guoshawn guo72.44%15.26%
rob herringrob herring31.05%210.53%
marc zyngiermarc zyngier10.35%15.26%
hiroshi doyuhiroshi doyu10.35%15.26%
stephen boydstephen boyd10.35%15.26%
prashant gaikwadprashant gaikwad10.35%15.26%
Total287100.00%19100.00%

CLOCKSOURCE_OF_DECLARE(tegra20_timer, "nvidia,tegra20-timer", tegra20_init_timer);
static void __init tegra20_init_rtc(struct device_node *np) { struct clk *clk; rtc_base = of_iomap(np, 0); if (!rtc_base) { pr_err("Can't map RTC registers"); BUG(); } /* * rtc registers are used by read_persistent_clock, keep the rtc clock * enabled */ clk = of_clk_get(np, 0); if (IS_ERR(clk)) pr_warn("Unable to get rtc-tegra clock\n"); else clk_prepare_enable(clk); register_persistent_clock(NULL, tegra_read_persistent_clock64); }

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rob herringrob herring6585.53%120.00%
marc zyngiermarc zyngier67.89%120.00%
arnd bergmannarnd bergmann33.95%120.00%
colin crosscolin cross11.32%120.00%
pang xunleipang xunlei11.32%120.00%
Total76100.00%5100.00%

CLOCKSOURCE_OF_DECLARE(tegra20_rtc, "nvidia,tegra20-rtc", tegra20_init_rtc);

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colin crosscolin cross55161.43%413.33%
rob herringrob herring808.92%26.67%
stephen warrenstephen warren728.03%413.33%
peter de schrijverpeter de schrijver677.47%413.33%
viresh kumarviresh kumar586.47%13.33%
russell kingrussell king252.79%26.67%
marc zyngiermarc zyngier111.23%26.67%
pang xunleipang xunlei111.23%26.67%
shawn guoshawn guo70.78%13.33%
stephen boydstephen boyd50.56%26.67%
arnd bergmannarnd bergmann30.33%13.33%
dmitry osipenkodmitry osipenko20.22%13.33%
lucas stachlucas stach20.22%13.33%
olof johanssonolof johansson10.11%13.33%
prashant gaikwadprashant gaikwad10.11%13.33%
hiroshi doyuhiroshi doyu10.11%13.33%
Total897100.00%30100.00%
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