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