cregit-Linux how code gets into the kernel

Release 4.7 drivers/clocksource/clksrc-dbx500-prcmu.c

/*
 * Copyright (C) ST-Ericsson SA 2011
 *
 * License Terms: GNU General Public License v2
 * Author: Mattias Wallin <mattias.wallin@stericsson.com> for ST-Ericsson
 * Author: Sundar Iyer for ST-Ericsson
 * sched_clock implementation is based on:
 * plat-nomadik/timer.c Linus Walleij <linus.walleij@stericsson.com>
 *
 * DBx500-PRCMU Timer
 * The PRCMU has 5 timers which are available in a always-on
 * power domain.  We use the Timer 4 for our always-on clock
 * source on DB8500.
 */
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/clockchips.h>
#include <linux/sched_clock.h>


#define RATE_32K		32768


#define TIMER_MODE_CONTINOUS	0x1

#define TIMER_DOWNCOUNT_VAL	0xffffffff


#define PRCMU_TIMER_REF		0

#define PRCMU_TIMER_DOWNCOUNT	0x4

#define PRCMU_TIMER_MODE	0x8


#define SCHED_CLOCK_MIN_WRAP 131072 
/* 2^32 / 32768 */


static void __iomem *clksrc_dbx500_timer_base;


static cycle_t notrace clksrc_dbx500_prcmu_read(struct clocksource *cs) { void __iomem *base = clksrc_dbx500_timer_base; u32 count, count2; do { count = readl_relaxed(base + PRCMU_TIMER_DOWNCOUNT); count2 = readl_relaxed(base + PRCMU_TIMER_DOWNCOUNT); } while (count2 != count); /* Negate because the timer is a decrementing counter */ return ~count; }

Contributors

PersonTokensPropCommitsCommitProp
mattias wallinmattias wallin4578.95%150.00%
rabin vincentrabin vincent1221.05%150.00%
Total57100.00%2100.00%

static struct clocksource clocksource_dbx500_prcmu = { .name = "dbx500-prcmu-timer", .rating = 300, .read = clksrc_dbx500_prcmu_read, .mask = CLOCKSOURCE_MASK(32), .flags = CLOCK_SOURCE_IS_CONTINUOUS, }; #ifdef CONFIG_CLKSRC_DBX500_PRCMU_SCHED_CLOCK
static u64 notrace dbx500_prcmu_sched_clock_read(void) { if (unlikely(!clksrc_dbx500_timer_base)) return 0; return clksrc_dbx500_prcmu_read(&clocksource_dbx500_prcmu); }

Contributors

PersonTokensPropCommitsCommitProp
mattias wallinmattias wallin2385.19%133.33%
linus walleijlinus walleij311.11%133.33%
stephen boydstephen boyd13.70%133.33%
Total27100.00%3100.00%

#endif
static void __init clksrc_dbx500_prcmu_init(struct device_node *node) { clksrc_dbx500_timer_base = of_iomap(node, 0); /* * The A9 sub system expects the timer to be configured as * a continous looping timer. * The PRCMU should configure it but if it for some reason * don't we do it here. */ if (readl(clksrc_dbx500_timer_base + PRCMU_TIMER_MODE) != TIMER_MODE_CONTINOUS) { writel(TIMER_MODE_CONTINOUS, clksrc_dbx500_timer_base + PRCMU_TIMER_MODE); writel(TIMER_DOWNCOUNT_VAL, clksrc_dbx500_timer_base + PRCMU_TIMER_REF); } #ifdef CONFIG_CLKSRC_DBX500_PRCMU_SCHED_CLOCK sched_clock_register(dbx500_prcmu_sched_clock_read, 32, RATE_32K); #endif clocksource_register_hz(&clocksource_dbx500_prcmu, RATE_32K); }

Contributors

PersonTokensPropCommitsCommitProp
mattias wallinmattias wallin5877.33%116.67%
linus walleijlinus walleij1520.00%350.00%
stephen boydstephen boyd11.33%116.67%
yong zhangyong zhang11.33%116.67%
Total75100.00%6100.00%

CLOCKSOURCE_OF_DECLARE(dbx500_prcmu, "stericsson,db8500-prcmu-timer-4", clksrc_dbx500_prcmu_init);

Overall Contributors

PersonTokensPropCommitsCommitProp
mattias wallinmattias wallin20680.47%111.11%
linus walleijlinus walleij3312.89%333.33%
rabin vincentrabin vincent124.69%111.11%
stephen boydstephen boyd31.17%222.22%
fabio baltierifabio baltieri10.39%111.11%
yong zhangyong zhang10.39%111.11%
Total256100.00%9100.00%
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