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      1 /*	$NetBSD: clock.c,v 1.34 2026/06/13 20:16:23 rkujawa 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 1.34 2026/06/13 20:16:23 rkujawa 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 long ticks_per_intr;
     62 static volatile u_long lasttb, lasttb2;
     63 static u_long ticksmissed;
     64 static volatile int tickspending;
     65 
     66 static void init_ppc4xx_tc(void);
     67 static u_int get_ppc4xx_timecount(struct timecounter *);
     68 
     69 static struct timecounter ppc4xx_timecounter = {
     70 	.tc_get_timecount = get_ppc4xx_timecount,
     71 	.tc_counter_mask = ~0u,
     72 	.tc_name = "ppc_timebase",
     73 	.tc_quality = 100,
     74 };
     75 
     76 void decr_intr(struct clockframe *);	/* called from trap_subr.S */
     77 void stat_intr(struct clockframe *);	/* called from trap_subr.S */
     78 
     79 #ifdef FAST_STAT_CLOCK
     80 /* Stat clock runs at ~ 1.5 kHz */
     81 #define PERIOD_POWER	17
     82 #define TCR_PERIOD	TCR_FP_2_17
     83 #else
     84 /* Stat clock runs at ~ 550Hz (440) / ~95Hz (405) */
     85 #define PERIOD_POWER	21
     86 #define TCR_PERIOD	TCR_FP_2_21
     87 #endif
     88 
     89 #ifdef PPC_IBM440
     90 /*
     91  * tprof sampling shares the FIT
     92  */
     93 void (*ibm4xx_tprof_samplefn)(struct clockframe *);
     94 u_int ibm4xx_tprof_div;
     95 #endif
     96 
     97 
     98 void
     99 stat_intr(struct clockframe *frame)
    100 {
    101 	struct cpu_info * const ci = curcpu();
    102 
    103 	mtspr(SPR_TSR, TSR_FIS);	/* Clear TSR[FIS] */
    104 	ci->ci_data.cpu_nintr++;
    105 	ci->ci_ev_statclock.ev_count++;
    106 
    107 #ifdef PPC_IBM440
    108 	if (ibm4xx_tprof_div != 0) {
    109 		static u_int statdiv;
    110 
    111 		/* take a PC sample every (fast) FIT tick. */
    112 		(*ibm4xx_tprof_samplefn)(frame);
    113 
    114 		/* statclock only every ibm4xx_tprof_div ticks. */
    115 		if (++statdiv < ibm4xx_tprof_div)
    116 			return;
    117 		statdiv = 0;
    118 	}
    119 #endif
    120 
    121 	/* Nobody can interrupt us, but see if we're allowed to run. */
    122 	int s = splclock();
    123 
    124 	/*
    125 	 * Reenable interrupts
    126 	 */
    127 	__asm volatile ("wrteei 1");
    128 
    129 	if (IPL_CLOCK > s) {
    130 		ci->ci_idepth++;
    131   		statclock(frame);
    132 		ci->ci_idepth--;
    133 	}
    134 	splx(s);
    135 }
    136 
    137 void
    138 decr_intr(struct clockframe *frame)
    139 {
    140 	struct cpu_info * const ci = curcpu();
    141 	int pcpl;
    142 	long tbtick, xticks;
    143 	int nticks;
    144 
    145 	/*
    146 	 * Check whether we are initialized.
    147 	 */
    148 	if (!ticks_per_intr)
    149 		return;
    150 
    151 	tbtick = mftbl();
    152 	mtspr(SPR_TSR, TSR_PIS);	/* Clear TSR[PIS] */
    153 
    154 	xticks = tbtick - lasttb2;	/* Number of TLB cycles since last exception */
    155 	for (nticks = 0; xticks > ticks_per_intr; nticks++)
    156 		xticks -= ticks_per_intr;
    157 	lasttb2 = tbtick - xticks;
    158 
    159 	ci->ci_data.cpu_nintr++;
    160 	ci->ci_ev_clock.ev_count++;
    161 	pcpl = splclock();
    162 
    163 	/*
    164 	 * Reenable interrupts
    165 	 */
    166 	__asm volatile ("wrteei 1");
    167 
    168 	if (pcpl >= IPL_CLOCK) {
    169 		tickspending += nticks;
    170 		ticksmissed += nticks;
    171 	} else {
    172 		nticks += tickspending;
    173 		tickspending = 0;
    174 
    175 		/*
    176 		 * lasttb is used during microtime. Set it to the virtual
    177 		 * start of this tick interval.
    178 		 */
    179 		lasttb = lasttb2;
    180 
    181 		/*
    182 		 * Do standard timer interrupt stuff.
    183 		 */
    184 		ci->ci_idepth++;
    185 		while (nticks-- > 0)
    186 			hardclock(frame);
    187 		ci->ci_idepth--;
    188 	}
    189 	splx(pcpl);
    190 }
    191 
    192 void
    193 cpu_initclocks(void)
    194 {
    195 	struct cpu_info * const ci = curcpu();
    196 
    197 	/* Initialized in powerpc/ibm4xx/cpu.c */
    198 	evcnt_attach_static(&ci->ci_ev_clock);
    199 	evcnt_attach_static(&ci->ci_ev_statclock);
    200 
    201 	ticks_per_intr = ticks_per_sec / hz;
    202 	stathz = profhz = ticks_per_sec / (1 << PERIOD_POWER);
    203 
    204 	printf("Setting PIT to %ld/%d = %ld\n", ticks_per_sec, hz,
    205 	    ticks_per_intr);
    206 
    207 	lasttb2 = lasttb = mftbl();
    208 #ifdef PPC_IBM440
    209 	/*
    210 	 * PIT is replaced by the decrementer!
    211 	 * TCR/TSR bit positions match.
    212 	 */
    213 	mtspr(SPR_DECAR, ticks_per_intr);
    214 	mtspr(SPR_DEC, ticks_per_intr);
    215 
    216 	/* Enable DEC & FIT interrupts and auto-reload */
    217 	mtspr(SPR_TCR, TCR_DIE | TCR_ARE | TCR_FIE | TCR_PERIOD);
    218 #else
    219 	mtspr(SPR_PIT, ticks_per_intr);
    220 
    221 	/* Enable PIT & FIT(2^17c = 0.655ms) interrupts and auto-reload */
    222 	mtspr(SPR_TCR, TCR_PIE | TCR_ARE | TCR_FIE | TCR_PERIOD);
    223 #endif
    224 
    225 	init_ppc4xx_tc();
    226 }
    227 
    228 void
    229 calc_delayconst(void)
    230 {
    231 	prop_number_t freq;
    232 
    233 	freq = prop_dictionary_get(board_properties, "processor-frequency");
    234 
    235 #ifndef PPC_CPU_FREQ
    236 	KASSERT(freq != NULL);
    237 #else
    238 	/* XXX hack for pckbc_cnattach() for Explora */
    239 	if (freq == NULL)
    240 		ticks_per_sec = (u_long) PPC_CPU_FREQ;
    241 	else
    242 #endif
    243 		ticks_per_sec = (u_long) prop_number_integer_value(freq);
    244 }
    245 
    246 static u_int
    247 get_ppc4xx_timecount(struct timecounter *tc)
    248 {
    249 	u_long tb;
    250 	int msr;
    251 
    252 	__asm volatile ("mfmsr %0; wrteei 0" : "=r" (msr));
    253 	tb = mftbl();
    254 	__asm volatile ("mtmsr %0" :: "r" (msr));
    255 
    256 	return tb;
    257 }
    258 
    259 /*
    260  * Wait for about n microseconds (at least!).
    261  */
    262 void
    263 delay(unsigned int n)
    264 {
    265 	u_quad_t tb;
    266 	u_long tbh, tbl, scratch;
    267 
    268 	tb = mftb();
    269 	/* Math must handle clock speed above 1GHz. */
    270 	tb += ((u_quad_t)n * ticks_per_sec + 999999) / 1000000;
    271 	tbh = tb >> 32;
    272 	tbl = tb;
    273 	__asm volatile (
    274 	"1:"
    275 #ifdef PPC_IBM403
    276 		"mftbhi	%0;"
    277 #else
    278 		"mftbu	%0;"
    279 #endif
    280 		"cmplw	%0,%1;"
    281 		"blt	1b;"
    282 		"bgt	2f;"
    283 #ifdef PPC_IBM403
    284 		"mftblo	%0;"
    285 #else
    286 		"mftb	%0;"
    287 #endif
    288 		"cmplw	%0,%2;"
    289 		"blt	1b;"
    290 	"2:"
    291 	    : "=&r" (scratch)
    292 	    : "r" (tbh), "r" (tbl)
    293 	    : "cr0");
    294 }
    295 
    296 /*
    297  * Nothing to do.
    298  */
    299 void
    300 setstatclockrate(int arg)
    301 {
    302 
    303 	/* Do nothing */
    304 }
    305 
    306 static void
    307 init_ppc4xx_tc(void)
    308 {
    309 	/* from machdep initialization */
    310 	ppc4xx_timecounter.tc_frequency = ticks_per_sec;
    311 	tc_init(&ppc4xx_timecounter);
    312 }
    313