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Commit a91549a8 authored by Mikael Pettersson's avatar Mikael Pettersson Committed by Dan Williams
Browse files

iop: clocksource support 



This updates the IOP platform to expose the free-running
timer 1 as a clocksource object. This timer is now also
properly initialised, which requires a new write_tcr1()
function from the mach-specific code. Apart from the
explicit initialisation, there is no functional change
in how timer 1 is programmed.

Tested on n2100, compile-tested for all plat-iop machines.

Signed-off-by: default avatarMikael Pettersson <mikpe@it.uu.se>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 012abeea

arch/arm/include/asm/hardware/iop3xx.h

+5 −0
Original line number Diff line number Diff line
@@ -260,6 +260,11 @@ static inline u32 read_tcr1(void) 
	return val;

}



static inline void write_tcr1(u32 val)

{

	asm volatile("mcr p6, 0, %0, c3, c1, 0" : : "r" (val));

}



static inline void write_trr0(u32 val)

{

	asm volatile("mcr p6, 0, %0, c4, c1, 0" : : "r" (val));

arch/arm/mach-iop13xx/include/mach/time.h

+5 −0
Original line number Diff line number Diff line
@@ -90,6 +90,11 @@ static inline u32 read_tcr1(void) 
	return val;

}



static inline void write_tcr1(u32 val)

{

	asm volatile("mcr p6, 0, %0, c3, c9, 0" : : "r" (val));

}



static inline void write_trr0(u32 val)

{

	asm volatile("mcr p6, 0, %0, c4, c9, 0" : : "r" (val));

arch/arm/plat-iop/time.c

+45 −0
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
#include <linux/init.h>

#include <linux/timex.h>

#include <linux/io.h>

#include <linux/clocksource.h>

#include <mach/hardware.h>

#include <asm/irq.h>

#include <asm/uaccess.h>
@@ -26,6 +27,43 @@ 
#include <asm/mach/time.h>

#include <mach/time.h>



/*

 * IOP clocksource (free-running timer 1).

 */

static cycle_t iop_clocksource_read(struct clocksource *unused)

{

	return 0xffffffffu - read_tcr1();

}



static struct clocksource iop_clocksource = {

	.name 		= "iop_timer1",

	.rating		= 300,

	.read		= iop_clocksource_read,

	.mask		= CLOCKSOURCE_MASK(32),

	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,

};



static void __init iop_clocksource_set_hz(struct clocksource *cs, unsigned int hz)

{

	u64 temp;

	u32 shift;



	/* Find shift and mult values for hz. */

	shift = 32;

	do {

		temp = (u64) NSEC_PER_SEC << shift;

		do_div(temp, hz);

		if ((temp >> 32) == 0)

			break;

	} while (--shift != 0);



	cs->shift = shift;

	cs->mult = (u32) temp;



	printk(KERN_INFO "clocksource: %s uses shift %u mult %#x\n",

	       cs->name, cs->shift, cs->mult);

}



static unsigned long ticks_per_jiffy;

static unsigned long ticks_per_usec;

static unsigned long next_jiffy_time;
@@ -99,8 +137,15 @@ void __init iop_init_time(unsigned long tick_rate) 
	 */

	write_trr0(ticks_per_jiffy - 1);

	write_tmr0(timer_ctl);



	/*

	 * Set up free-running clocksource timer 1.

	 */

	write_trr1(0xffffffff);

	write_tcr1(0xffffffff);

	write_tmr1(timer_ctl);

	iop_clocksource_set_hz(&iop_clocksource, tick_rate);

	clocksource_register(&iop_clocksource);



	setup_irq(IRQ_IOP_TIMER0, &iop_timer_irq);

}