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arm11_pmc.c revision 1.2 
      1 /*	$NetBSD: arm11_pmc.c,v 1.2 2008/04/27 18:58:43 matt Exp $	*/
      2 
      3 /* Copyright (c) 2007 Microsoft
      4  * All rights reserved.
      5  *
      6  * Redistribution and use in source and binary forms, with or without
      7  * modification, are permitted provided that the following conditions
      8  * are met:
      9  * 1. Redistributions of source code must retain the above copyright
     10  *    notice, this list of conditions and the following disclaimer.
     11  * 2. Redistributions in binary form must reproduce the above copyright
     12  *    notice, this list of conditions and the following disclaimer in the
     13  *    documentation and/or other materials provided with the distribution.
     14  * 3. All advertising materials mentioning features or use of this software
     15  *    must display the following acknowledgement:
     16  *	This product includes software developed by Microsoft
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
     19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     20  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     21  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL WASABI SYSTEMS, INC
     22  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     23  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     24  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     25  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     26  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     27  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     28  * POSSIBILITY OF SUCH DAMAGE.
     29  */
     30 
     31 
     32 /*
     33  * support for ARM 11 Performance Monitor Counters
     34  */
     35 
     36 #include <sys/cdefs.h>
     37 __KERNEL_RCSID(0, "$NetBSD: arm11_pmc.c,v 1.2 2008/04/27 18:58:43 matt Exp $");
     38 #include "opt_perfctrs.h"
     39 #include <sys/types.h>
     40 #include <sys/param.h>
     41 #include <sys/systm.h>
     42 #include <sys/kernel.h>
     43 #include <sys/time.h>
     44 #include <sys/timetc.h>
     45 #include <dev/clock_subr.h>
     46 #include <arm/armreg.h>
     47 #include <arm/cpufunc.h>
     48 
     49 #ifndef ARM11_PMC_CCNT_HZ
     50 # define ARM11_PMC_CCNT_HZ	400000000	/* 400MHz */
     51 #endif
     52 
     53 void arm11_pmc_ccnt_init(void);
     54 
     55 #define COUNTS_PER_USEC	(ARM11_PMC_CCNT_HZ / 1000000)
     56 
     57 static uint32_t counts_per_wrap = ~0UL;		/* XXX off by 1 */
     58 
     59 static inline uint32_t
     60 arm11_pmc_ctrl_read(void)
     61 {
     62 	uint32_t val;
     63 
     64 	__asm volatile ("mrc p15, 0, %0, c15, c12, 0" : "=r" (val));
     65 
     66 	return val;
     67 }
     68 
     69 static inline void
     70 arm11_pmc_ctrl_write(uint32_t val)
     71 {
     72 	__asm volatile ("mcr p15, 0, %0, c15, c12, 0" :: "r" (val));
     73 }
     74 
     75 static inline uint32_t
     76 arm11_pmc_ccnt_read(void)
     77 {
     78 	uint32_t val;
     79 
     80 	__asm volatile ("mrc p15, 0, %0, c15, c12, 1" : "=r" (val));
     81 
     82 	return val;
     83 }
     84 
     85 static inline void
     86 arm11_pmc_ccnt_write(uint32_t val)
     87 {
     88 	__asm volatile ("mcr p15, 0, %0, c15, c12, 1;" :: "r" (val));
     89 }
     90 
     91 /*
     92  * enable the PMC CCNT for delay()
     93  */
     94 void
     95 arm11_pmc_ccnt_init(void)
     96 {
     97 	uint32_t val;
     98 
     99 	val = ARM11_PMCCTL_E | ARM11_PMCCTL_P | ARM11_PMCCTL_C;
    100 
    101 	arm11_pmc_ctrl_write(val);
    102 }
    103 
    104 /*
    105  * delay - for "at least" arg usec
    106  *
    107  *	NOTE: at 400MHz we are restricted to (uint32_t)~0 "counts"
    108  *	if this is a problem, accumulate counts in LL vars
    109  */
    110 #define DELAY_ARG_LIMIT (((uint32_t)~0) / COUNTS_PER_USEC)	/* about 10 sec */
    111 void
    112 delay(u_int arg)
    113 {
    114 	uint32_t ctrl;
    115 	uint32_t cur;
    116 	uint32_t last;
    117 	uint32_t delta = 0;
    118 	uint32_t usecs = 0;
    119 
    120 	if (arg > DELAY_ARG_LIMIT)
    121 		panic("delay: arg %u overflow, limit is %d usec\n", arg, DELAY_ARG_LIMIT);
    122 
    123 	last = arm11_pmc_ccnt_read();
    124 	delta = usecs = 0;
    125 
    126 	while (arg > usecs) {
    127 		cur  = arm11_pmc_ccnt_read();
    128 		ctrl = arm11_pmc_ctrl_read();
    129 		if (ctrl & ARM11_PMCCTL_CCR) {
    130 			/*
    131 			 * reset CCR, do not reset other write-to-clear flags;
    132 			 * maintain the rest of the PMC Control Reg configuration
    133 			 */
    134 			ctrl &= ~(ARM11_PMCCTL_CR0|ARM11_PMCCTL_CR1);
    135 			arm11_pmc_ctrl_write(ctrl);
    136 			delta += (last + (counts_per_wrap - cur));
    137 		} else {
    138 			delta += (last - cur);
    139 		}
    140 		last = cur;
    141 		if (delta >= COUNTS_PER_USEC) {
    142 			usecs += delta / COUNTS_PER_USEC;
    143 			delta %= COUNTS_PER_USEC;
    144 		}
    145 	}
    146 }
    147