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cortex_pmc.c revision 1.1.4.2 
      1 /* Copyright (c) 2007 Microsoft
      2  * All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  * 1. Redistributions of source code must retain the above copyright
      8  *    notice, this list of conditions and the following disclaimer.
      9  * 2. Redistributions in binary form must reproduce the above copyright
     10  *    notice, this list of conditions and the following disclaimer in the
     11  *    documentation and/or other materials provided with the distribution.
     12  * 3. All advertising materials mentioning features or use of this software
     13  *    must display the following acknowledgement:
     14  *	This product includes software developed by Microsoft
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
     17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     18  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     19  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL WASABI SYSTEMS, INC
     20  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     21  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     22  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     23  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     24  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     25  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     26  * POSSIBILITY OF SUCH DAMAGE.
     27  */
     28 
     29 
     30 /*
     31  * support for ARM cortexa8 Performance Monitor Counters
     32  * based on arm11_pmc.c
     33  */
     34 
     35 #include <sys/cdefs.h>
     36 /* __KERNEL_RCSID(0, "$NetBSD: cortex_pmc.c,v 1.1.4.2 2010/08/11 22:51:39 yamt Exp $"); */
     37 #include "opt_perfctrs.h"
     38 #include <sys/types.h>
     39 #include <sys/param.h>
     40 #include <sys/systm.h>
     41 #include <sys/kernel.h>
     42 #include <sys/time.h>
     43 #include <sys/timetc.h>
     44 #include <dev/clock_subr.h>
     45 #include <arm/armreg.h>
     46 #include <arm/cpufunc.h>
     47 
     48 #ifndef CORTEX_PMC_CCNT_HZ
     49 # define CORTEX_PMC_CCNT_HZ	400000000	/* 400MHz */
     50 #endif
     51 
     52 void cortexa8_pmc_ccnt_init(void);
     53 
     54 #define COUNTS_PER_USEC	(CORTEX_PMC_CCNT_HZ / 1000000)
     55 
     56 static uint32_t counts_per_wrap = ~0UL;		/* XXX off by 1 */
     57 
     58 #define PMNC "c9, c12, 0"
     59 #define CCNT "c9, c13, 0"
     60 
     61 static inline uint32_t
     62 cortexa8_pmc_ctrl_read(void)
     63 {
     64 	uint32_t val;
     65 
     66 	__asm volatile ("mrc p15, 0, %0, " PMNC : "=r" (val));
     67 
     68 	return val;
     69 }
     70 
     71 static inline void
     72 cortexa8_pmc_ctrl_write(uint32_t val)
     73 {
     74 	__asm volatile ("mcr p15, 0, %0, " PMNC :: "r" (val));
     75 }
     76 
     77 static inline uint32_t
     78 cortexa8_pmc_ccnt_read(void)
     79 {
     80 	uint32_t val;
     81 
     82 	__asm volatile ("mrc p15, 0, %0, " CCNT : "=r" (val));
     83 
     84 	return val;
     85 }
     86 
     87 static inline void
     88 cortexa8_pmc_ccnt_write(uint32_t val)
     89 {
     90   __asm volatile ("mcr p15, 0, %0, c9, c12, 2"  :: "r" (CORTEX_CNTENC_C));
     91   __asm volatile ("mcr p15, 0, %0, " CCNT :: "r" (val));
     92   __asm volatile ("mcr p15, 0, %0, c9, c12, 1" :: "r" (CORTEX_CNTENS_C));
     93 }
     94 
     95 /*
     96  * enable the PMC CCNT for delay()
     97  */
     98 void
     99 cortexa8_pmc_ccnt_init(void)
    100 {
    101   uint32_t val;
    102 
    103   val = ARM11_PMCCTL_E | ARM11_PMCCTL_P | ARM11_PMCCTL_C;
    104 
    105   cortexa8_pmc_ctrl_write(val);
    106   __asm volatile ("mcr p15, 0, %0, c9, c12, 1" :: "r" (CORTEX_CNTENS_C));
    107 }
    108 
    109 /*
    110  * delay - for "at least" arg usec
    111  *
    112  *	NOTE: at 400MHz we are restricted to (uint32_t)~0 "counts"
    113  *	if this is a problem, accumulate counts in LL vars
    114  */
    115 #define DELAY_ARG_LIMIT (((uint32_t)~0) / COUNTS_PER_USEC)	/* about 10 sec */
    116 void
    117 delay(u_int arg)
    118 {
    119 	uint32_t ctrl;
    120 	uint32_t cur;
    121 	uint32_t last;
    122 	uint32_t delta = 0;
    123 	uint32_t usecs = 0;
    124 
    125 	if (arg > DELAY_ARG_LIMIT)
    126 		panic("delay: arg %u overflow, limit is %d usec\n", arg, DELAY_ARG_LIMIT);
    127 
    128 	last = cortexa8_pmc_ccnt_read();
    129 	delta = usecs = 0;
    130 	while (arg > usecs) {
    131 		cur  = cortexa8_pmc_ccnt_read();
    132 
    133 		/* overflow flag is moved to a separate register
    134 		   and is not read from PMC Control Register */
    135 		__asm volatile ("mrc p15, 0, %0, c9, c12, 3" : "=r" (ctrl));
    136 		if(ctrl & CORTEX_CNTOFL_C){
    137 		  /* Reset overflow flag for cycle counter in overflow register */
    138 		  __asm volatile ("mcr p15, 0, %0, c9, c12, 3" :: "r" (CORTEX_CNTOFL_C));
    139 		  delta += (last + (counts_per_wrap - cur));
    140 		} else {
    141 			delta += (cur - last);
    142 		}
    143 		last = cur;
    144 		if (delta >= COUNTS_PER_USEC) {
    145 			usecs += delta / COUNTS_PER_USEC;
    146 			delta %= COUNTS_PER_USEC;
    147 		}
    148 	}
    149 }
    150