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      1 /*	$NetBSD: clock.c,v 1.33 2022/10/05 08:18:00 rin Exp $	*/
      2 /*      $OpenBSD: clock.c,v 1.3 1997/10/13 13:42:53 pefo Exp $  */
      3 
      4 /*
      5  * Copyright (C) 1995, 1996 Wolfgang Solfrank.
      6  * Copyright (C) 1995, 1996 TooLs GmbH.
      7  * All rights reserved.
      8  *
      9  * Redistribution and use in source and binary forms, with or without
     10  * modification, are permitted provided that the following conditions
     11  * are met:
     12  * 1. Redistributions of source code must retain the above copyright
     13  *    notice, this list of conditions and the following disclaimer.
     14  * 2. Redistributions in binary form must reproduce the above copyright
     15  *    notice, this list of conditions and the following disclaimer in the
     16  *    documentation and/or other materials provided with the distribution.
     17  * 3. All advertising materials mentioning features or use of this software
     18  *    must display the following acknowledgement:
     19  *	This product includes software developed by TooLs GmbH.
     20  * 4. The name of TooLs GmbH may not be used to endorse or promote products
     21  *    derived from this software without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
     24  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     25  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     26  * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     27  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     28  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
     29  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
     30  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
     31  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
     32  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     33  */
     34 
     35 #include <sys/cdefs.h>
     36 __KERNEL_RCSID(0, "$NetBSD: clock.c,v 1.33 2022/10/05 08:18:00 rin Exp $");
     37 
     38 #ifdef _KERNEL_OPT
     39 #include "opt_ppcarch.h"
     40 #include "opt_ppcparam.h"
     41 #endif
     42 
     43 #include <sys/param.h>
     44 #include <sys/kernel.h>
     45 #include <sys/systm.h>
     46 #include <sys/timetc.h>
     47 #include <sys/cpu.h>
     48 
     49 #include <uvm/uvm_extern.h>
     50 
     51 #include <prop/proplib.h>
     52 
     53 #include <powerpc/spr.h>
     54 #include <powerpc/ibm4xx/spr.h>
     55 #include <powerpc/ibm4xx/cpu.h>
     56 
     57 /*
     58  * Initially we assume a processor with a bus frequency of 12.5 MHz.
     59  */
     60 static u_long ticks_per_sec;
     61 static u_long ns_per_tick;
     62 static long ticks_per_intr;
     63 static volatile u_long lasttb, lasttb2;
     64 static u_long ticksmissed;
     65 static volatile int tickspending;
     66 
     67 static void init_ppc4xx_tc(void);
     68 static u_int get_ppc4xx_timecount(struct timecounter *);
     69 
     70 static struct timecounter ppc4xx_timecounter = {
     71 	.tc_get_timecount = get_ppc4xx_timecount,
     72 	.tc_counter_mask = ~0u,
     73 	.tc_name = "ppc_timebase",
     74 	.tc_quality = 100,
     75 };
     76 
     77 void decr_intr(struct clockframe *);	/* called from trap_subr.S */
     78 void stat_intr(struct clockframe *);	/* called from trap_subr.S */
     79 
     80 #ifdef FAST_STAT_CLOCK
     81 /* Stat clock runs at ~ 1.5 kHz */
     82 #define PERIOD_POWER	17
     83 #define TCR_PERIOD	TCR_FP_2_17
     84 #else
     85 /* Stat clock runs at ~ 95Hz */
     86 #define PERIOD_POWER	21
     87 #define TCR_PERIOD	TCR_FP_2_21
     88 #endif
     89 
     90 
     91 void
     92 stat_intr(struct clockframe *frame)
     93 {
     94 	struct cpu_info * const ci = curcpu();
     95 
     96 	mtspr(SPR_TSR, TSR_FIS);	/* Clear TSR[FIS] */
     97 	ci->ci_data.cpu_nintr++;
     98 	ci->ci_ev_statclock.ev_count++;
     99 
    100 	/* Nobody can interrupt us, but see if we're allowed to run. */
    101 	int s = splclock();
    102 
    103 	/*
    104 	 * Reenable interrupts
    105 	 */
    106 	__asm volatile ("wrteei 1");
    107 
    108 	if (IPL_CLOCK > s) {
    109 		ci->ci_idepth++;
    110   		statclock(frame);
    111 		ci->ci_idepth--;
    112 	}
    113 	splx(s);
    114 }
    115 
    116 void
    117 decr_intr(struct clockframe *frame)
    118 {
    119 	struct cpu_info * const ci = curcpu();
    120 	int pcpl;
    121 	long tbtick, xticks;
    122 	int nticks;
    123 
    124 	/*
    125 	 * Check whether we are initialized.
    126 	 */
    127 	if (!ticks_per_intr)
    128 		return;
    129 
    130 	tbtick = mftbl();
    131 	mtspr(SPR_TSR, TSR_PIS);	/* Clear TSR[PIS] */
    132 
    133 	xticks = tbtick - lasttb2;	/* Number of TLB cycles since last exception */
    134 	for (nticks = 0; xticks > ticks_per_intr; nticks++)
    135 		xticks -= ticks_per_intr;
    136 	lasttb2 = tbtick - xticks;
    137 
    138 	ci->ci_data.cpu_nintr++;
    139 	ci->ci_ev_clock.ev_count++;
    140 	pcpl = splclock();
    141 
    142 	/*
    143 	 * Reenable interrupts
    144 	 */
    145 	__asm volatile ("wrteei 1");
    146 
    147 	if (pcpl >= IPL_CLOCK) {
    148 		tickspending += nticks;
    149 		ticksmissed += nticks;
    150 	} else {
    151 		nticks += tickspending;
    152 		tickspending = 0;
    153 
    154 		/*
    155 		 * lasttb is used during microtime. Set it to the virtual
    156 		 * start of this tick interval.
    157 		 */
    158 		lasttb = lasttb2;
    159 
    160 		/*
    161 		 * Do standard timer interrupt stuff.
    162 		 */
    163 		ci->ci_idepth++;
    164 		while (nticks-- > 0)
    165 			hardclock(frame);
    166 		ci->ci_idepth--;
    167 	}
    168 	splx(pcpl);
    169 }
    170 
    171 void
    172 cpu_initclocks(void)
    173 {
    174 	struct cpu_info * const ci = curcpu();
    175 
    176 	/* Initialized in powerpc/ibm4xx/cpu.c */
    177 	evcnt_attach_static(&ci->ci_ev_clock);
    178 	evcnt_attach_static(&ci->ci_ev_statclock);
    179 
    180 	ticks_per_intr = ticks_per_sec / hz;
    181 	stathz = profhz = ticks_per_sec / (1 << PERIOD_POWER);
    182 
    183 	printf("Setting PIT to %ld/%d = %ld\n", ticks_per_sec, hz,
    184 	    ticks_per_intr);
    185 
    186 	lasttb2 = lasttb = mftbl();
    187 	mtspr(SPR_PIT, ticks_per_intr);
    188 
    189 	/* Enable PIT & FIT(2^17c = 0.655ms) interrupts and auto-reload */
    190 	mtspr(SPR_TCR, TCR_PIE | TCR_ARE | TCR_FIE | TCR_PERIOD);
    191 
    192 	init_ppc4xx_tc();
    193 }
    194 
    195 void
    196 calc_delayconst(void)
    197 {
    198 	prop_number_t freq;
    199 
    200 	freq = prop_dictionary_get(board_properties, "processor-frequency");
    201 
    202 #ifndef PPC_CPU_FREQ
    203 	KASSERT(freq != NULL);
    204 #else
    205 	/* XXX hack for pckbc_cnattach() for Explora */
    206 	if (freq == NULL)
    207 		ticks_per_sec = (u_long) PPC_CPU_FREQ;
    208 	else
    209 #endif
    210 		ticks_per_sec = (u_long) prop_number_integer_value(freq);
    211 
    212 	ns_per_tick = 1000000000 / ticks_per_sec;
    213 }
    214 
    215 static u_int
    216 get_ppc4xx_timecount(struct timecounter *tc)
    217 {
    218 	u_long tb;
    219 	int msr;
    220 
    221 	__asm volatile ("mfmsr %0; wrteei 0" : "=r" (msr));
    222 	tb = mftbl();
    223 	__asm volatile ("mtmsr %0" :: "r" (msr));
    224 
    225 	return tb;
    226 }
    227 
    228 /*
    229  * Wait for about n microseconds (at least!).
    230  */
    231 void
    232 delay(unsigned int n)
    233 {
    234 	u_quad_t tb;
    235 	u_long tbh, tbl, scratch;
    236 
    237 	tb = mftb();
    238 	/* use 1000ULL to force 64 bit math to avoid 32 bit overflows */
    239 	tb += (n * 1000ULL + ns_per_tick - 1) / ns_per_tick;
    240 	tbh = tb >> 32;
    241 	tbl = tb;
    242 	__asm volatile (
    243 	"1:"
    244 #ifdef PPC_IBM403
    245 		"mftbhi	%0;"
    246 #else
    247 		"mftbu	%0;"
    248 #endif
    249 		"cmplw	%0,%1;"
    250 		"blt	1b;"
    251 		"bgt	2f;"
    252 #ifdef PPC_IBM403
    253 		"mftblo	%0;"
    254 #else
    255 		"mftb	%0;"
    256 #endif
    257 		"cmplw	%0,%2;"
    258 		"blt	1b;"
    259 	"2:"
    260 	    : "=&r" (scratch)
    261 	    : "r" (tbh), "r" (tbl)
    262 	    : "cr0");
    263 }
    264 
    265 /*
    266  * Nothing to do.
    267  */
    268 void
    269 setstatclockrate(int arg)
    270 {
    271 
    272 	/* Do nothing */
    273 }
    274 
    275 static void
    276 init_ppc4xx_tc(void)
    277 {
    278 	/* from machdep initialization */
    279 	ppc4xx_timecounter.tc_frequency = ticks_per_sec;
    280 	tc_init(&ppc4xx_timecounter);
    281 }
    282