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      1 /*	$NetBSD: nouveau_nvkm_subdev_timer_nv41.c,v 1.3 2021/12/18 23:45:42 riastradh Exp $	*/
      2 
      3 /*
      4  * Copyright 2012 Red Hat Inc.
      5  *
      6  * Permission is hereby granted, free of charge, to any person obtaining a
      7  * copy of this software and associated documentation files (the "Software"),
      8  * to deal in the Software without restriction, including without limitation
      9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
     10  * and/or sell copies of the Software, and to permit persons to whom the
     11  * Software is furnished to do so, subject to the following conditions:
     12  *
     13  * The above copyright notice and this permission notice shall be included in
     14  * all copies or substantial portions of the Software.
     15  *
     16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
     19  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
     20  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
     21  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
     22  * OTHER DEALINGS IN THE SOFTWARE.
     23  *
     24  * Authors: Ben Skeggs
     25  */
     26 #include <sys/cdefs.h>
     27 __KERNEL_RCSID(0, "$NetBSD: nouveau_nvkm_subdev_timer_nv41.c,v 1.3 2021/12/18 23:45:42 riastradh Exp $");
     28 
     29 #include "priv.h"
     30 #include "regsnv04.h"
     31 
     32 static void
     33 nv41_timer_init(struct nvkm_timer *tmr)
     34 {
     35 	struct nvkm_subdev *subdev = &tmr->subdev;
     36 	struct nvkm_device *device = subdev->device;
     37 	u32 f = device->crystal;
     38 	u32 m = 1, n, d;
     39 
     40 	/* aim for 31.25MHz, which gives us nanosecond timestamps */
     41 	d = 1000000 / 32;
     42 	n = f;
     43 
     44 	while (n < (d * 2)) {
     45 		n += (n / m);
     46 		m++;
     47 	}
     48 
     49 	/* reduce ratio to acceptable values */
     50 	while (((n % 5) == 0) && ((d % 5) == 0)) {
     51 		n /= 5;
     52 		d /= 5;
     53 	}
     54 
     55 	while (((n % 2) == 0) && ((d % 2) == 0)) {
     56 		n /= 2;
     57 		d /= 2;
     58 	}
     59 
     60 	while (n > 0xffff || d > 0xffff) {
     61 		n >>= 1;
     62 		d >>= 1;
     63 	}
     64 
     65 	nvkm_debug(subdev, "input frequency : %dHz\n", f);
     66 	nvkm_debug(subdev, "input multiplier: %d\n", m);
     67 	nvkm_debug(subdev, "numerator       : %08x\n", n);
     68 	nvkm_debug(subdev, "denominator     : %08x\n", d);
     69 	nvkm_debug(subdev, "timer frequency : %dHz\n", (f * m) * d / n);
     70 
     71 	nvkm_wr32(device, 0x009220, m - 1);
     72 	nvkm_wr32(device, NV04_PTIMER_NUMERATOR, n);
     73 	nvkm_wr32(device, NV04_PTIMER_DENOMINATOR, d);
     74 }
     75 
     76 static const struct nvkm_timer_func
     77 nv41_timer = {
     78 	.init = nv41_timer_init,
     79 	.intr = nv04_timer_intr,
     80 	.read = nv04_timer_read,
     81 	.time = nv04_timer_time,
     82 	.alarm_init = nv04_timer_alarm_init,
     83 	.alarm_fini = nv04_timer_alarm_fini,
     84 };
     85 
     86 int
     87 nv41_timer_new(struct nvkm_device *device, int index, struct nvkm_timer **ptmr)
     88 {
     89 	return nvkm_timer_new_(&nv41_timer, device, index, ptmr);
     90 }
     91