hw/misc/imx_ccm.c

   1 /*
   2  * IMX31 Clock Control Module
   3  *
   4  * Copyright (C) 2012 NICTA
   5  * Updated by Jean-Christophe Dubois <jcd@tribudubois.net>
   6  *
   7  * This work is licensed under the terms of the GNU GPL, version 2 or later.
   8  * See the COPYING file in the top-level directory.
   9  *
  10  * This is an abstract base class used to get a common interface to
  11  * retrieve the CCM frequencies from the various i.MX SOC.
  12  */
  13
  14 #include "hw/misc/imx_ccm.h"
  15
  16 #ifndef DEBUG_IMX_CCM
  17 #define DEBUG_IMX_CCM 0
  18 #endif
  19
  20 #define DPRINTF(fmt, args...) \
  21     do { \
  22         if (DEBUG_IMX_CCM) { \
  23             fprintf(stderr, "[%s]%s: " fmt , TYPE_IMX_CCM, \
  24                                              __func__, ##args); \
  25         } \
  26     } while (0)
  27
  28
  29 uint32_t imx_ccm_get_clock_frequency(IMXCCMState *dev, IMXClk clock)
  30 {
  31     uint32_t freq = 0;
  32     IMXCCMClass *klass = IMX_GET_CLASS(dev);
  33
  34     if (klass->get_clock_frequency) {
  35         freq = klass->get_clock_frequency(dev, clock);
  36     }
  37
  38     DPRINTF("(clock = %d) = %d\n", clock, freq);
  39
  40     return freq;
  41 }
  42
  43 /*
  44  * Calculate PLL output frequency
  45  */
  46 uint32_t imx_ccm_calc_pll(uint32_t pllreg, uint32_t base_freq)
  47 {
  48     int32_t freq;
  49     int32_t mfn = MFN(pllreg);  /* Numerator */
  50     uint32_t mfi = MFI(pllreg); /* Integer part */
  51     uint32_t mfd = 1 + MFD(pllreg); /* Denominator */
  52     uint32_t pd = 1 + PD(pllreg);   /* Pre-divider */
  53
  54     if (mfi < 5) {
  55         mfi = 5;
  56     }
  57
  58     /* mfn is 10-bit signed twos-complement */
  59     mfn <<= 32 - 10;
  60     mfn >>= 32 - 10;
  61
  62     freq = ((2 * (base_freq >> 10) * (mfi * mfd + mfn)) /
  63             (mfd * pd)) << 10;
  64
  65     DPRINTF("(pllreg = 0x%08x, base_freq = %d) = %d\n", pllreg, base_freq,
  66             freq);
  67
  68     return freq;
  69 }
  70
  71 static const TypeInfo imx_ccm_info = {
  72     .name          = TYPE_IMX_CCM,
  73     .parent        = TYPE_SYS_BUS_DEVICE,
  74     .instance_size = sizeof(IMXCCMState),
  75     .class_size    = sizeof(IMXCCMClass),
  76     .abstract      = true,
  77 };
  78
  79 static void imx_ccm_register_types(void)
  80 {
  81     type_register_static(&imx_ccm_info);
  82 }
  83
  84 type_init(imx_ccm_register_types)