hw/timer/omap_synctimer.c

   1 /*
   2  * TI OMAP2 32kHz sync timer emulation.
   3  *
   4  * Copyright (C) 2007-2008 Nokia Corporation
   5  * Written by Andrzej Zaborowski <andrew@openedhand.com>
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License as
   9  * published by the Free Software Foundation; either version 2 or
  10  * (at your option) any later version of the License.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; if not, see <http://www.gnu.org/licenses/>.
  19  */
  20 #include "hw/hw.h"
  21 #include "qemu/timer.h"
  22 #include "hw/arm/omap.h"
  23 struct omap_synctimer_s {
  24     MemoryRegion iomem;
  25     uint32_t val;
  26     uint16_t readh;
  27 };
  28
  29 /* 32-kHz Sync Timer of the OMAP2 */
  30 static uint32_t omap_synctimer_read(struct omap_synctimer_s *s) {
  31     return muldiv64(qemu_get_clock_ns(vm_clock), 0x8000, get_ticks_per_sec());
  32 }
  33
  34 void omap_synctimer_reset(struct omap_synctimer_s *s)
  35 {
  36     s->val = omap_synctimer_read(s);
  37 }
  38
  39 static uint32_t omap_synctimer_readw(void *opaque, hwaddr addr)
  40 {
  41     struct omap_synctimer_s *s = (struct omap_synctimer_s *) opaque;
  42
  43     switch (addr) {
  44     case 0x00:  /* 32KSYNCNT_REV */
  45         return 0x21;
  46
  47     case 0x10:  /* CR */
  48         return omap_synctimer_read(s) - s->val;
  49     }
  50
  51     OMAP_BAD_REG(addr);
  52     return 0;
  53 }
  54
  55 static uint32_t omap_synctimer_readh(void *opaque, hwaddr addr)
  56 {
  57     struct omap_synctimer_s *s = (struct omap_synctimer_s *) opaque;
  58     uint32_t ret;
  59
  60     if (addr & 2)
  61         return s->readh;
  62     else {
  63         ret = omap_synctimer_readw(opaque, addr);
  64         s->readh = ret >> 16;
  65         return ret & 0xffff;
  66     }
  67 }
  68
  69 static void omap_synctimer_write(void *opaque, hwaddr addr,
  70                 uint32_t value)
  71 {
  72     OMAP_BAD_REG(addr);
  73 }
  74
  75 static const MemoryRegionOps omap_synctimer_ops = {
  76     .old_mmio = {
  77         .read = {
  78             omap_badwidth_read32,
  79             omap_synctimer_readh,
  80             omap_synctimer_readw,
  81         },
  82         .write = {
  83             omap_badwidth_write32,
  84             omap_synctimer_write,
  85             omap_synctimer_write,
  86         },
  87     },
  88     .endianness = DEVICE_NATIVE_ENDIAN,
  89 };
  90
  91 struct omap_synctimer_s *omap_synctimer_init(struct omap_target_agent_s *ta,
  92                 struct omap_mpu_state_s *mpu, omap_clk fclk, omap_clk iclk)
  93 {
  94     struct omap_synctimer_s *s = g_malloc0(sizeof(*s));
  95
  96     omap_synctimer_reset(s);
  97     memory_region_init_io(&s->iomem, &omap_synctimer_ops, s, "omap.synctimer",
  98                           omap_l4_region_size(ta, 0));
  99     omap_l4_attach(ta, 0, &s->iomem);
 100
 101     return s;
 102 }