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 "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_clock_get_ns(QEMU_CLOCK_VIRTUAL), 0x8000,
  32                     NANOSECONDS_PER_SECOND);
  33 }
  34
  35 void omap_synctimer_reset(struct omap_synctimer_s *s)
  36 {
  37     s->val = omap_synctimer_read(s);
  38 }
  39
  40 static uint32_t omap_synctimer_readw(void *opaque, hwaddr addr)
  41 {
  42     struct omap_synctimer_s *s = opaque;
  43
  44     switch (addr) {
  45     case 0x00:  /* 32KSYNCNT_REV */
  46         return 0x21;
  47
  48     case 0x10:  /* CR */
  49         return omap_synctimer_read(s) - s->val;
  50     }
  51
  52     OMAP_BAD_REG(addr);
  53     return 0;
  54 }
  55
  56 static uint32_t omap_synctimer_readh(void *opaque, hwaddr addr)
  57 {
  58     struct omap_synctimer_s *s = opaque;
  59     uint32_t ret;
  60
  61     if (addr & 2)
  62         return s->readh;
  63     else {
  64         ret = omap_synctimer_readw(opaque, addr);
  65         s->readh = ret >> 16;
  66         return ret & 0xffff;
  67     }
  68 }
  69
  70 static uint64_t omap_synctimer_readfn(void *opaque, hwaddr addr,
  71                                       unsigned size)
  72 {
  73     switch (size) {
  74     case 1:
  75         return omap_badwidth_read32(opaque, addr);
  76     case 2:
  77         return omap_synctimer_readh(opaque, addr);
  78     case 4:
  79         return omap_synctimer_readw(opaque, addr);
  80     default:
  81         g_assert_not_reached();
  82     }
  83 }
  84
  85 static void omap_synctimer_writefn(void *opaque, hwaddr addr,
  86                                    uint64_t value, unsigned size)
  87 {
  88     OMAP_BAD_REG(addr);
  89 }
  90
  91 static const MemoryRegionOps omap_synctimer_ops = {
  92     .read = omap_synctimer_readfn,
  93     .write = omap_synctimer_writefn,
  94     .valid.min_access_size = 1,
  95     .valid.max_access_size = 4,
  96     .endianness = DEVICE_NATIVE_ENDIAN,
  97 };
  98
  99 struct omap_synctimer_s *omap_synctimer_init(struct omap_target_agent_s *ta,
 100                 struct omap_mpu_state_s *mpu, omap_clk fclk, omap_clk iclk)
 101 {
 102     struct omap_synctimer_s *s = g_malloc0(sizeof(*s));
 103
 104     omap_synctimer_reset(s);
 105     memory_region_init_io(&s->iomem, NULL, &omap_synctimer_ops, s, "omap.synctimer",
 106                           omap_l4_region_size(ta, 0));
 107     omap_l4_attach(ta, 0, &s->iomem);
 108
 109     return s;
 110 }