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pq2.c

/*
 * PowerQUICC II support functions
 *
 * Author: Scott Wood <scottwood@freescale.com>
 *
 * Copyright (c) 2007 Freescale Semiconductor, Inc.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published
 * by the Free Software Foundation.
 */

#include "ops.h"
#include "types.h"
#include "fsl-soc.h"
#include "pq2.h"
#include "stdio.h"
#include "io.h"

#define PQ2_SCCR (0x10c80/4) /* System Clock Configuration Register */
#define PQ2_SCMR (0x10c88/4) /* System Clock Mode Register */

static int pq2_corecnf_map[] = {
      3, 2, 2, 2, 4, 4, 5, 9, 6, 11, 8, 10, 3, 12, 7, -1,
      6, 5, 13, 2, 14, 4, 15, 9, 0, 11, 8, 10, 16, 12, 7, -1
};

/* Get various clocks from crystal frequency.
 * Returns zero on failure and non-zero on success.
 */
int pq2_get_clocks(u32 crystal, u32 *sysfreq, u32 *corefreq,
                   u32 *timebase, u32 *brgfreq)
{
      u32 *immr;
      u32 sccr, scmr, mainclk, busclk;
      int corecnf, busdf, plldf, pllmf, dfbrg;

      immr = fsl_get_immr();
      if (!immr) {
            printf("pq2_get_clocks: Couldn't get IMMR base.\r\n");
            return 0;
      }

      sccr = in_be32(&immr[PQ2_SCCR]);
      scmr = in_be32(&immr[PQ2_SCMR]);

      dfbrg = sccr & 3;
      corecnf = (scmr >> 24) & 0x1f;
      busdf = (scmr >> 20) & 0xf;
      plldf = (scmr >> 12) & 1;
      pllmf = scmr & 0xfff;

      mainclk = crystal * (pllmf + 1) / (plldf + 1);
      busclk = mainclk / (busdf + 1);

      if (sysfreq)
            *sysfreq = mainclk / 2;
      if (timebase)
            *timebase = busclk / 4;
      if (brgfreq)
            *brgfreq = mainclk / (1 << ((dfbrg + 1) * 2));

      if (corefreq) {
            int coremult = pq2_corecnf_map[corecnf];

            if (coremult < 0)
                  *corefreq = mainclk / 2;
            else if (coremult == 0)
                  return 0;
            else
                  *corefreq = busclk * coremult / 2;
      }

      return 1;
}

/* Set common device tree fields based on the given clock frequencies. */
void pq2_set_clocks(u32 sysfreq, u32 corefreq, u32 timebase, u32 brgfreq)
{
      void *node;

      dt_fixup_cpu_clocks(corefreq, timebase, sysfreq);

      node = finddevice("/soc/cpm");
      if (node)
            setprop(node, "clock-frequency", &sysfreq, 4);

      node = finddevice("/soc/cpm/brg");
      if (node)
            setprop(node, "clock-frequency", &brgfreq, 4);
}

int pq2_fixup_clocks(u32 crystal)
{
      u32 sysfreq, corefreq, timebase, brgfreq;

      if (!pq2_get_clocks(crystal, &sysfreq, &corefreq, &timebase, &brgfreq))
            return 0;

      pq2_set_clocks(sysfreq, corefreq, timebase, brgfreq);
      return 1;
}

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