arch/m68k/coldfire/sltimers.c

Source file repositories/reference/linux-study-clean/arch/m68k/coldfire/sltimers.c

File Facts

System
Linux kernel
Corpus path
arch/m68k/coldfire/sltimers.c
Extension
.c
Size
3891 bytes
Lines
150
Domain
Architecture Layer
Bucket
arch/m68k
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0
/***************************************************************************/

/*
 *	sltimers.c -- generic ColdFire slice timer support.
 *
 *	Copyright (C) 2009-2010, Philippe De Muyter <phdm@macqel.be>
 *	based on
 *	timers.c -- generic ColdFire hardware timer support.
 *	Copyright (C) 1999-2008, Greg Ungerer <gerg@snapgear.com>
 */

/***************************************************************************/

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/profile.h>
#include <linux/clocksource.h>
#include <asm/io.h>
#include <asm/traps.h>
#include <asm/machdep.h>
#include <asm/coldfire.h>
#include <asm/mcfslt.h>
#include <asm/mcfsim.h>

/***************************************************************************/

#ifdef CONFIG_HIGHPROFILE

/*
 *	By default use Slice Timer 1 as the profiler clock timer.
 */
#define	PA(a)	(MCFSLT_TIMER1 + (a))

/*
 *	Choose a reasonably fast profile timer. Make it an odd value to
 *	try and get good coverage of kernel operations.
 */
#define	PROFILEHZ	1013

irqreturn_t mcfslt_profile_tick(int irq, void *dummy)
{
	/* Reset Slice Timer 1 */
	mcf_write32(MCFSLT_SSR_BE | MCFSLT_SSR_TE, PA(MCFSLT_SSR));
	if (current->pid)
		profile_tick(CPU_PROFILING);
	return IRQ_HANDLED;
}

void mcfslt_profile_init(void)
{
	int ret;

	printk(KERN_INFO "PROFILE: lodging TIMER 1 @ %dHz as profile timer\n",
	       PROFILEHZ);

	ret = request_irq(MCF_IRQ_PROFILER, mcfslt_profile_tick, IRQF_TIMER,
			  "profile timer", NULL);
	if (ret) {
		pr_err("Failed to request irq %d (profile timer): %pe\n",
		       MCF_IRQ_PROFILER, ERR_PTR(ret));
	}

	/* Set up TIMER 2 as high speed profile clock */
	mcf_write32(MCF_BUSCLK / PROFILEHZ - 1, PA(MCFSLT_STCNT));
	mcf_write32(MCFSLT_SCR_RUN | MCFSLT_SCR_IEN | MCFSLT_SCR_TEN,
								PA(MCFSLT_SCR));

}

#endif	/* CONFIG_HIGHPROFILE */

/***************************************************************************/

/*
 *	By default use Slice Timer 0 as the system clock timer.
 */
#define	TA(a)	(MCFSLT_TIMER0 + (a))

static u32 mcfslt_cycles_per_jiffy;
static u32 mcfslt_cnt;

static irqreturn_t mcfslt_tick(int irq, void *dummy)
{
	/* Reset Slice Timer 0 */
	mcf_write32(MCFSLT_SSR_BE | MCFSLT_SSR_TE, TA(MCFSLT_SSR));
	mcfslt_cnt += mcfslt_cycles_per_jiffy;

Annotation

Implementation Notes