tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * MPC8xx support functions
3 *
4 * Author: Scott Wood <scottwood@freescale.com>
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 "mpc8xx.h"
17#include "stdio.h"
18#include "io.h"
19
20#define MPC8XX_PLPRCR (0x284/4) /* PLL and Reset Control Register */
21
22/* Return system clock from crystal frequency */
23u32 mpc885_get_clock(u32 crystal)
24{
25 u32 *immr;
26 u32 plprcr;
27 int mfi, mfn, mfd, pdf;
28 u32 ret;
29
30 immr = fsl_get_immr();
31 if (!immr) {
32 printf("mpc885_get_clock: Couldn't get IMMR base.\r\n");
33 return 0;
34 }
35
36 plprcr = in_be32(&immr[MPC8XX_PLPRCR]);
37
38 mfi = (plprcr >> 16) & 15;
39 if (mfi < 5) {
40 printf("Warning: PLPRCR[MFI] value of %d out-of-bounds\r\n",
41 mfi);
42 mfi = 5;
43 }
44
45 pdf = (plprcr >> 1) & 0xf;
46 mfd = (plprcr >> 22) & 0x1f;
47 mfn = (plprcr >> 27) & 0x1f;
48
49 ret = crystal * mfi;
50
51 if (mfn != 0)
52 ret += crystal * mfn / (mfd + 1);
53
54 return ret / (pdf + 1);
55}
56
57/* Set common device tree fields based on the given clock frequencies. */
58void mpc8xx_set_clocks(u32 sysclk)
59{
60 void *node;
61
62 dt_fixup_cpu_clocks(sysclk, sysclk / 16, sysclk);
63
64 node = finddevice("/soc/cpm");
65 if (node)
66 setprop(node, "clock-frequency", &sysclk, 4);
67
68 node = finddevice("/soc/cpm/brg");
69 if (node)
70 setprop(node, "clock-frequency", &sysclk, 4);
71}
72
73int mpc885_fixup_clocks(u32 crystal)
74{
75 u32 sysclk = mpc885_get_clock(crystal);
76 if (!sysclk)
77 return 0;
78
79 mpc8xx_set_clocks(sysclk);
80 return 1;
81}