arch/powerpc/boot/pq2.c

   1 /*
   2  * PowerQUICC II 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 "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 }