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      1 /*	$NetBSD: cortex_pmc.c,v 1.8 2020/06/20 07:10:36 skrll 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 cortex Performance Monitor Counters
     34  * based on arm11_pmc.c
     35  */
     36 
     37 #include <sys/cdefs.h>
     38 /* __KERNEL_RCSID(0, "$NetBSD: cortex_pmc.c,v 1.8 2020/06/20 07:10:36 skrll Exp $"); */
     39 
     40 #include <sys/param.h>
     41 #include <sys/types.h>
     42 
     43 #include <sys/kernel.h>
     44 #include <sys/systm.h>
     45 #include <sys/time.h>
     46 #include <sys/timetc.h>
     47 
     48 #include <dev/clock_subr.h>
     49 
     50 #include <uvm/uvm_extern.h>
     51 
     52 #include <arm/armreg.h>
     53 #include <arm/cpufunc.h>
     54 #include <arm/arm32/machdep.h>
     55 
     56 #ifndef CORTEX_PMC_CCNT_HZ
     57 # define CORTEX_PMC_CCNT_HZ	400000000	/* 400MHz */
     58 #endif
     59 
     60 #define COUNTS_PER_USEC	(curcpu()->ci_data.cpu_cc_freq / (1000*1000))
     61 
     62 static const uint32_t counts_per_wrap = ~0UL - 1;
     63 
     64 /*
     65  * enable the PMC CCNT for delay()
     66  */
     67 void
     68 cortex_pmc_ccnt_init(void)
     69 {
     70 	if (curcpu()->ci_data.cpu_cc_freq == 0) {
     71 		curcpu()->ci_data.cpu_cc_freq = CORTEX_PMC_CCNT_HZ;
     72 	}
     73 }
     74 
     75 /*
     76  * delay - for "at least" arg usec
     77  *
     78  *	NOTE: at 400MHz we are restricted to (uint32_t)~0 "counts"
     79  *	if this is a problem, accumulate counts in LL vars
     80  */
     81 void
     82 delay(u_int arg)
     83 {
     84 	uint32_t ctrl;
     85 	uint32_t cur;
     86 	uint32_t last;
     87 	uint32_t delta = 0;
     88 	uint32_t usecs = 0;
     89 	const uint32_t counts_per_usec = COUNTS_PER_USEC;
     90 	const uint32_t delay_arg_limit = ~0UL / counts_per_usec; /* about 10 sec */
     91 
     92 	if (arg > delay_arg_limit)
     93 		panic("%s: arg %u overflow, limit is %u usec\n",
     94 		    __func__, arg, delay_arg_limit);
     95 
     96 	last = armreg_pmccntr_read();
     97 	delta = usecs = 0;
     98 	while (arg > usecs) {
     99 		cur = armreg_pmccntr_read();
    100 
    101 		/*
    102 		 * overflow flag is moved to a separate register
    103 		 * and is not read from PMC Control Register
    104 		 */
    105 		ctrl = armreg_pmovsr_read();
    106 		if (ctrl & CORTEX_CNTOFL_C) {
    107 			/*
    108 			 * Reset overflow flag for cycle counter in overflow
    109 			 * register
    110 			 */
    111 			armreg_pmovsr_write(CORTEX_CNTOFL_C);
    112 			delta += (cur + (counts_per_wrap - last));
    113 		} else {
    114 			delta += (cur - last);
    115 		}
    116 		last = cur;
    117 		if (delta >= counts_per_usec) {
    118 			usecs += delta / counts_per_usec;
    119 			delta %= counts_per_usec;
    120 		}
    121 	}
    122 }
    123