Linux Kernel  3.7.1
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pq2.c
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1 /*
2  * PowerQUICC II support functions
3  *
4  * Author: Scott Wood <[email protected]>
5  *
6  * Copyright (c) 2007 Freescale Semiconductor, Inc.
7  *
8  * This program is free software; you can redistribute it and/or modify it
9  * under the terms of the GNU General Public License version 2 as published
10  * by the Free Software Foundation.
11  */
12 
13 #include "ops.h"
14 #include "types.h"
15 #include "fsl-soc.h"
16 #include "pq2.h"
17 #include "stdio.h"
18 #include "io.h"
19 
20 #define PQ2_SCCR (0x10c80/4) /* System Clock Configuration Register */
21 #define PQ2_SCMR (0x10c88/4) /* System Clock Mode Register */
22 
23 static int pq2_corecnf_map[] = {
24  3, 2, 2, 2, 4, 4, 5, 9, 6, 11, 8, 10, 3, 12, 7, -1,
25  6, 5, 13, 2, 14, 4, 15, 9, 0, 11, 8, 10, 16, 12, 7, -1
26 };
27 
28 /* Get various clocks from crystal frequency.
29  * Returns zero on failure and non-zero on success.
30  */
31 int pq2_get_clocks(u32 crystal, u32 *sysfreq, u32 *corefreq,
32  u32 *timebase, u32 *brgfreq)
33 {
34  u32 *immr;
35  u32 sccr, scmr, mainclk, busclk;
36  int corecnf, busdf, plldf, pllmf, dfbrg;
37 
38  immr = fsl_get_immr();
39  if (!immr) {
40  printf("pq2_get_clocks: Couldn't get IMMR base.\r\n");
41  return 0;
42  }
43 
44  sccr = in_be32(&immr[PQ2_SCCR]);
45  scmr = in_be32(&immr[PQ2_SCMR]);
46 
47  dfbrg = sccr & 3;
48  corecnf = (scmr >> 24) & 0x1f;
49  busdf = (scmr >> 20) & 0xf;
50  plldf = (scmr >> 12) & 1;
51  pllmf = scmr & 0xfff;
52 
53  mainclk = crystal * (pllmf + 1) / (plldf + 1);
54  busclk = mainclk / (busdf + 1);
55 
56  if (sysfreq)
57  *sysfreq = mainclk / 2;
58  if (timebase)
59  *timebase = busclk / 4;
60  if (brgfreq)
61  *brgfreq = mainclk / (1 << ((dfbrg + 1) * 2));
62 
63  if (corefreq) {
64  int coremult = pq2_corecnf_map[corecnf];
65 
66  if (coremult < 0)
67  *corefreq = mainclk / 2;
68  else if (coremult == 0)
69  return 0;
70  else
71  *corefreq = busclk * coremult / 2;
72  }
73 
74  return 1;
75 }
76 
77 /* Set common device tree fields based on the given clock frequencies. */
78 void pq2_set_clocks(u32 sysfreq, u32 corefreq, u32 timebase, u32 brgfreq)
79 {
80  void *node;
81 
82  dt_fixup_cpu_clocks(corefreq, timebase, sysfreq);
83 
84  node = finddevice("/soc/cpm");
85  if (node)
86  setprop(node, "clock-frequency", &sysfreq, 4);
87 
88  node = finddevice("/soc/cpm/brg");
89  if (node)
90  setprop(node, "clock-frequency", &brgfreq, 4);
91 }
92 
93 int pq2_fixup_clocks(u32 crystal)
94 {
95  u32 sysfreq, corefreq, timebase, brgfreq;
96 
97  if (!pq2_get_clocks(crystal, &sysfreq, &corefreq, &timebase, &brgfreq))
98  return 0;
99 
100  pq2_set_clocks(sysfreq, corefreq, timebase, brgfreq);
101  return 1;
102 }