Scott Wood | bbc6fac | 2007-08-27 13:46:38 -0500 | [diff] [blame^] | 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 */ |
| 23 | u32 mpc885_get_clock(u32 crystal) |
| 24 | { |
| 25 | u32 *immr; |
| 26 | u32 plprcr; |
| 27 | int mfi, mfn, mfd, pdf, div; |
| 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 | div = (plprcr >> 20) & 3; |
| 47 | mfd = (plprcr >> 22) & 0x1f; |
| 48 | mfn = (plprcr >> 27) & 0x1f; |
| 49 | |
| 50 | ret = crystal * mfi; |
| 51 | |
| 52 | if (mfn != 0) |
| 53 | ret += crystal * mfn / (mfd + 1); |
| 54 | |
| 55 | return ret / (pdf + 1); |
| 56 | } |
| 57 | |
| 58 | /* Set common device tree fields based on the given clock frequencies. */ |
| 59 | void mpc8xx_set_clocks(u32 sysclk) |
| 60 | { |
| 61 | void *node; |
| 62 | |
| 63 | dt_fixup_cpu_clocks(sysclk, sysclk / 16, sysclk); |
| 64 | |
| 65 | node = finddevice("/soc/cpm"); |
| 66 | if (node) |
| 67 | setprop(node, "clock-frequency", &sysclk, 4); |
| 68 | |
| 69 | node = finddevice("/soc/cpm/brg"); |
| 70 | if (node) |
| 71 | setprop(node, "clock-frequency", &sysclk, 4); |
| 72 | } |
| 73 | |
| 74 | int mpc885_fixup_clocks(u32 crystal) |
| 75 | { |
| 76 | u32 sysclk = mpc885_get_clock(crystal); |
| 77 | if (!sysclk) |
| 78 | return 0; |
| 79 | |
| 80 | mpc8xx_set_clocks(sysclk); |
| 81 | return 1; |
| 82 | } |