[mirror_ubuntu-bionic-kernel.git] / arch / cris / arch-v32 / lib / delay.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Precise Delay Loops for ETRAX FS
 *
 * Copyright (C) 2006 Axis Communications AB.
 *
 */

#include <hwregs/reg_map.h>
#include <hwregs/reg_rdwr.h>
#include <hwregs/timer_defs.h>
#include <linux/types.h>
#include <linux/delay.h>
#include <linux/module.h>

/*
 * On ETRAX FS, we can check the free-running read-only 100MHz timer
 * getting 32-bit 10ns precision, theoretically good for 42.94967295
 * seconds.  Unsigned arithmetic and careful expression handles
 * wrapping.
 */

void cris_delay10ns(u32 n10ns)
{
	u32 t0 = REG_RD(timer, regi_timer0, r_time);
	while (REG_RD(timer, regi_timer0, r_time) - t0 < n10ns)
		;
}
EXPORT_SYMBOL(cris_delay10ns);
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
48c87a44 JN	2	/*
	3	* Precise Delay Loops for ETRAX FS
	4	*
	5	* Copyright (C) 2006 Axis Communications AB.
	6	*
	7	*/
	8
	9	#include <hwregs/reg_map.h>
	10	#include <hwregs/reg_rdwr.h>
	11	#include <hwregs/timer_defs.h>
	12	#include <linux/types.h>
	13	#include <linux/delay.h>
	14	#include <linux/module.h>
	15
	16	/*
	17	* On ETRAX FS, we can check the free-running read-only 100MHz timer
	18	* getting 32-bit 10ns precision, theoretically good for 42.94967295
	19	* seconds. Unsigned arithmetic and careful expression handles
	20	* wrapping.
	21	*/
	22
	23	void cris_delay10ns(u32 n10ns)
	24	{
	25	u32 t0 = REG_RD(timer, regi_timer0, r_time);
	26	while (REG_RD(timer, regi_timer0, r_time) - t0 < n10ns)
	27	;
	28	}
	29	EXPORT_SYMBOL(cris_delay10ns);