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cortex_pmc.c revision 1.1.14.1 
      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 cortex 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 1.1.14.1 2012/10/30 17:18:56 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 
     45 #include <dev/clock_subr.h>
     46 
     47 #include <uvm/uvm_extern.h>
     48 
     49 #include <arm/armreg.h>
     50 #include <arm/cpufunc.h>
     51 #include <arm/arm32/machdep.h>
     52 
     53 #ifndef CORTEX_PMC_CCNT_HZ
     54 # define CORTEX_PMC_CCNT_HZ	400000000	/* 400MHz */
     55 #endif
     56 
     57 #define COUNTS_PER_USEC	(curcpu()->ci_data.cpu_cc_freq / (1000*1000))
     58 
     59 static const uint32_t counts_per_wrap = ~0UL - 1;
     60 
     61 /*
     62  * enable the PMC CCNT for delay()
     63  */
     64 void
     65 cortex_pmc_ccnt_init(void)
     66 {
     67 	if (curcpu()->ci_data.cpu_cc_freq == 0) {
     68 		curcpu()->ci_data.cpu_cc_freq = CORTEX_PMC_CCNT_HZ;
     69 	}
     70 }
     71 
     72 /*
     73  * delay - for "at least" arg usec
     74  *
     75  *	NOTE: at 400MHz we are restricted to (uint32_t)~0 "counts"
     76  *	if this is a problem, accumulate counts in LL vars
     77  */
     78 void
     79 delay(u_int arg)
     80 {
     81 	uint32_t ctrl;
     82 	uint32_t cur;
     83 	uint32_t last;
     84 	uint32_t delta = 0;
     85 	uint32_t usecs = 0;
     86 	const uint32_t counts_per_usec = COUNTS_PER_USEC;
     87 	const uint32_t delay_arg_limit = ~0UL / counts_per_usec; /* about 10 sec */
     88 
     89 	if (arg > delay_arg_limit)
     90 		panic("%s: arg %u overflow, limit is %u usec\n",
     91 		    __func__, arg, delay_arg_limit);
     92 
     93 	last = armreg_pmccntr_read();
     94 	delta = usecs = 0;
     95 	while (arg > usecs) {
     96 		cur = armreg_pmccntr_read();
     97 
     98 		/* overflow flag is moved to a separate register
     99 		   and is not read from PMC Control Register */
    100 		ctrl = armreg_pmovsr_read();
    101 		if (ctrl & CORTEX_CNTOFL_C) {
    102 		  /* Reset overflow flag for cycle counter in overflow register */
    103 			armreg_pmovsr_write(CORTEX_CNTOFL_C);
    104 			delta += (last + (counts_per_wrap - cur));
    105 		} else {
    106 			delta += (cur - last);
    107 		}
    108 		last = cur;
    109 		if (delta >= counts_per_usec) {
    110 			usecs += delta / counts_per_usec;
    111 			delta %= counts_per_usec;
    112 		}
    113 	}
    114 }
    115