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