1 | /* $NetBSD: nouveau_subdev_clock_pllnva3.c,v 1.1.1.1 2014/08/06 12:36:29 riastradh Exp $ */ |
2 | |
3 | /* |
4 | * Copyright 2010 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 | |
27 | #include <sys/cdefs.h> |
28 | __KERNEL_RCSID(0, "$NetBSD: nouveau_subdev_clock_pllnva3.c,v 1.1.1.1 2014/08/06 12:36:29 riastradh Exp $" ); |
29 | |
30 | #include <subdev/clock.h> |
31 | #include <subdev/bios.h> |
32 | #include <subdev/bios/pll.h> |
33 | |
34 | #include "pll.h" |
35 | |
36 | int |
37 | nva3_pll_calc(struct nouveau_subdev *subdev, struct nvbios_pll *info, |
38 | u32 freq, int *pN, int *pfN, int *pM, int *P) |
39 | { |
40 | u32 best_err = ~0, err; |
41 | int M, lM, hM, N, fN; |
42 | |
43 | *P = info->vco1.max_freq / freq; |
44 | if (*P > info->max_p) |
45 | *P = info->max_p; |
46 | if (*P < info->min_p) |
47 | *P = info->min_p; |
48 | |
49 | lM = (info->refclk + info->vco1.max_inputfreq) / info->vco1.max_inputfreq; |
50 | lM = max(lM, (int)info->vco1.min_m); |
51 | hM = (info->refclk + info->vco1.min_inputfreq) / info->vco1.min_inputfreq; |
52 | hM = min(hM, (int)info->vco1.max_m); |
53 | lM = min(lM, hM); |
54 | |
55 | for (M = lM; M <= hM; M++) { |
56 | u32 tmp = freq * *P * M; |
57 | N = tmp / info->refclk; |
58 | fN = tmp % info->refclk; |
59 | |
60 | if (!pfN) { |
61 | if (fN >= info->refclk / 2) |
62 | N++; |
63 | } else { |
64 | if (fN < info->refclk / 2) |
65 | N--; |
66 | fN = tmp - (N * info->refclk); |
67 | } |
68 | |
69 | if (N < info->vco1.min_n) |
70 | continue; |
71 | if (N > info->vco1.max_n) |
72 | break; |
73 | |
74 | err = abs(freq - (info->refclk * N / M / *P)); |
75 | if (err < best_err) { |
76 | best_err = err; |
77 | *pN = N; |
78 | *pM = M; |
79 | } |
80 | |
81 | if (pfN) { |
82 | *pfN = ((fN << 13) + info->refclk / 2) / info->refclk; |
83 | *pfN = (*pfN - 4096) & 0xffff; |
84 | return freq; |
85 | } |
86 | } |
87 | |
88 | if (unlikely(best_err == ~0)) { |
89 | nv_error(subdev, "unable to find matching pll values\n" ); |
90 | return -EINVAL; |
91 | } |
92 | |
93 | return info->refclk * *pN / *pM / *P; |
94 | } |
95 | |