cpu/mcf5227x/speed.c

   1 /*
   2  *
   3  * Copyright (C) 2004-2007 Freescale Semiconductor, Inc.
   4  * TsiChung Liew (Tsi-Chung.Liew@freescale.com)
   5  *
   6  * See file CREDITS for list of people who contributed to this
   7  * project.
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License as
  11  * published by the Free Software Foundation; either version 2 of
  12  * the License, or (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  22  * MA 02111-1307 USA
  23  */
  24
  25 #include <common.h>
  26 #include <asm/processor.h>
  27
  28 #include <asm/immap.h>
  29
  30 DECLARE_GLOBAL_DATA_PTR;
  31
  32 /*
  33  * Low Power Divider specifications
  34  */
  35 #define CLOCK_LPD_MIN           (1 << 0)        /* Divider (decoded) */
  36 #define CLOCK_LPD_MAX           (1 << 15)       /* Divider (decoded) */
  37
  38 #define CLOCK_PLL_FVCO_MAX      540000000
  39 #define CLOCK_PLL_FVCO_MIN      300000000
  40
  41 #define CLOCK_PLL_FSYS_MAX      266666666
  42 #define CLOCK_PLL_FSYS_MIN      100000000
  43 #define MHZ                     1000000
  44
  45 void clock_enter_limp(int lpdiv)
  46 {
  47         volatile ccm_t *ccm = (volatile ccm_t *)MMAP_CCM;
  48         int i, j;
  49
  50         /* Check bounds of divider */
  51         if (lpdiv < CLOCK_LPD_MIN)
  52                 lpdiv = CLOCK_LPD_MIN;
  53         if (lpdiv > CLOCK_LPD_MAX)
  54                 lpdiv = CLOCK_LPD_MAX;
  55
  56         /* Round divider down to nearest power of two */
  57         for (i = 0, j = lpdiv; j != 1; j >>= 1, i++) ;
  58
  59         /* Apply the divider to the system clock */
  60         ccm->cdr = (ccm->cdr & 0xF0FF) | CCM_CDR_LPDIV(i);
  61
  62         /* Enable Limp Mode */
  63         ccm->misccr |= CCM_MISCCR_LIMP;
  64 }
  65
  66 /*
  67  * brief   Exit Limp mode
  68  * warning The PLL should be set and locked prior to exiting Limp mode
  69  */
  70 void clock_exit_limp(void)
  71 {
  72         volatile ccm_t *ccm = (volatile ccm_t *)MMAP_CCM;
  73         volatile pll_t *pll = (volatile pll_t *)MMAP_PLL;
  74
  75         /* Exit Limp mode */
  76         ccm->misccr &= ~CCM_MISCCR_LIMP;
  77
  78         /* Wait for the PLL to lock */
  79         while (!(pll->psr & PLL_PSR_LOCK)) ;
  80 }
  81
  82 /*
  83  * get_clocks() fills in gd->cpu_clock and gd->bus_clk
  84  */
  85 int get_clocks(void)
  86 {
  87
  88         volatile ccm_t *ccm = (volatile ccm_t *)MMAP_CCM;
  89         volatile pll_t *pll = (volatile pll_t *)MMAP_PLL;
  90         int vco, temp, pcrvalue, pfdr;
  91         u8 bootmode;
  92
  93         bootmode = (ccm->ccr & 0x000C) >> 2;
  94
  95         pcrvalue = pll->pcr & 0xFF0F0FFF;
  96         pfdr = pcrvalue >> 24;
  97
  98         if (pfdr != 0x1E) {
  99                 /* serial mode */
 100         } else {
 101                 /* Normal Mode */
 102                 vco = pfdr * CFG_INPUT_CLKSRC;
 103                 gd->vco_clk = vco;
 104         }
 105
 106         if ((ccm->ccr & CCM_MISCCR_LIMP) == CCM_MISCCR_LIMP) {
 107                 /* Limp mode */
 108         } else {
 109                 gd->inp_clk = CFG_INPUT_CLKSRC; /* Input clock */
 110
 111                 temp = (pll->pcr & PLL_PCR_OUTDIV1_MASK) + 1;
 112                 gd->cpu_clk = vco / temp;       /* cpu clock */
 113
 114                 temp = ((pll->pcr & PLL_PCR_OUTDIV2_MASK) >> 4) + 1;
 115                 gd->flb_clk = vco / temp;       /* flexbus clock */
 116                 gd->bus_clk = gd->flb_clk;
 117         }
 118
 119         return (0);
 120 }