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 "qemu/osdep.h"
  21 #include "hw/hw.h"
  22 #include "qemu/timer.h"
  23 #include "hw/arm/omap.h"
  24 struct omap_synctimer_s {
  25     MemoryRegion iomem;
  26     uint32_t val;
  27     uint16_t readh;
  28 };
  29
  30 /* 32-kHz Sync Timer of the OMAP2 */
  31 static uint32_t omap_synctimer_read(struct omap_synctimer_s *s) {
  32     return muldiv64(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL), 0x8000,
  33                     NANOSECONDS_PER_SECOND);
  34 }
  35
  36 void omap_synctimer_reset(struct omap_synctimer_s *s)
  37 {
  38     s->val = omap_synctimer_read(s);
  39 }
  40
  41 static uint32_t omap_synctimer_readw(void *opaque, hwaddr addr)
  42 {
  43     struct omap_synctimer_s *s = (struct omap_synctimer_s *) opaque;
  44
  45     switch (addr) {
  46     case 0x00:  /* 32KSYNCNT_REV */
  47         return 0x21;
  48
  49     case 0x10:  /* CR */
  50         return omap_synctimer_read(s) - s->val;
  51     }
  52
  53     OMAP_BAD_REG(addr);
  54     return 0;
  55 }
  56
  57 static uint32_t omap_synctimer_readh(void *opaque, hwaddr addr)
  58 {
  59     struct omap_synctimer_s *s = (struct omap_synctimer_s *) opaque;
  60     uint32_t ret;
  61
  62     if (addr & 2)
  63         return s->readh;
  64     else {
  65         ret = omap_synctimer_readw(opaque, addr);
  66         s->readh = ret >> 16;
  67         return ret & 0xffff;
  68     }
  69 }
  70
  71 static void omap_synctimer_write(void *opaque, hwaddr addr,
  72                 uint32_t value)
  73 {
  74     OMAP_BAD_REG(addr);
  75 }
  76
  77 static const MemoryRegionOps omap_synctimer_ops = {
  78     .old_mmio = {
  79         .read = {
  80             omap_badwidth_read32,
  81             omap_synctimer_readh,
  82             omap_synctimer_readw,
  83         },
  84         .write = {
  85             omap_badwidth_write32,
  86             omap_synctimer_write,
  87             omap_synctimer_write,
  88         },
  89     },
  90     .endianness = DEVICE_NATIVE_ENDIAN,
  91 };
  92
  93 struct omap_synctimer_s *omap_synctimer_init(struct omap_target_agent_s *ta,
  94                 struct omap_mpu_state_s *mpu, omap_clk fclk, omap_clk iclk)
  95 {
  96     struct omap_synctimer_s *s = g_malloc0(sizeof(*s));
  97
  98     omap_synctimer_reset(s);
  99     memory_region_init_io(&s->iomem, NULL, &omap_synctimer_ops, s, "omap.synctimer",
 100                           omap_l4_region_size(ta, 0));
 101     omap_l4_attach(ta, 0, &s->iomem);
 102
 103     return s;
 104 }