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 "qemu/osdep.h"
  15 #include "hw/misc/imx_ccm.h"
  16
  17 #ifndef DEBUG_IMX_CCM
  18 #define DEBUG_IMX_CCM 0
  19 #endif
  20
  21 #define DPRINTF(fmt, args...) \
  22     do { \
  23         if (DEBUG_IMX_CCM) { \
  24             fprintf(stderr, "[%s]%s: " fmt , TYPE_IMX_CCM, \
  25                                              __func__, ##args); \
  26         } \
  27     } while (0)
  28
  29
  30 uint32_t imx_ccm_get_clock_frequency(IMXCCMState *dev, IMXClk clock)
  31 {
  32     uint32_t freq = 0;
  33     IMXCCMClass *klass = IMX_GET_CLASS(dev);
  34
  35     if (klass->get_clock_frequency) {
  36         freq = klass->get_clock_frequency(dev, clock);
  37     }
  38
  39     DPRINTF("(clock = %d) = %d\n", clock, freq);
  40
  41     return freq;
  42 }
  43
  44 /*
  45  * Calculate PLL output frequency
  46  */
  47 uint32_t imx_ccm_calc_pll(uint32_t pllreg, uint32_t base_freq)
  48 {
  49     int32_t freq;
  50     int32_t mfn = MFN(pllreg);  /* Numerator */
  51     uint32_t mfi = MFI(pllreg); /* Integer part */
  52     uint32_t mfd = 1 + MFD(pllreg); /* Denominator */
  53     uint32_t pd = 1 + PD(pllreg);   /* Pre-divider */
  54
  55     if (mfi < 5) {
  56         mfi = 5;
  57     }
  58
  59     /* mfn is 10-bit signed twos-complement */
  60     mfn <<= 32 - 10;
  61     mfn >>= 32 - 10;
  62
  63     freq = ((2 * (base_freq >> 10) * (mfi * mfd + mfn)) /
  64             (mfd * pd)) << 10;
  65
  66     DPRINTF("(pllreg = 0x%08x, base_freq = %d) = %d\n", pllreg, base_freq,
  67             freq);
  68
  69     return freq;
  70 }
  71
  72 static const TypeInfo imx_ccm_info = {
  73     .name          = TYPE_IMX_CCM,
  74     .parent        = TYPE_SYS_BUS_DEVICE,
  75     .instance_size = sizeof(IMXCCMState),
  76     .class_size    = sizeof(IMXCCMClass),
  77     .abstract      = true,
  78 };
  79
  80 static void imx_ccm_register_types(void)
  81 {
  82     type_register_static(&imx_ccm_info);
  83 }
  84
  85 type_init(imx_ccm_register_types)