hw/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.h"
  21 #include "qemu-timer.h"
  22 #include "omap.h"
  23 struct omap_synctimer_s {
  24     uint32_t val;
  25     uint16_t readh;
  26 };
  27
  28 /* 32-kHz Sync Timer of the OMAP2 */
  29 static uint32_t omap_synctimer_read(struct omap_synctimer_s *s) {
  30     return muldiv64(qemu_get_clock_ns(vm_clock), 0x8000, get_ticks_per_sec());
  31 }
  32
  33 void omap_synctimer_reset(struct omap_synctimer_s *s)
  34 {
  35     s->val = omap_synctimer_read(s);
  36 }
  37
  38 static uint32_t omap_synctimer_readw(void *opaque, target_phys_addr_t addr)
  39 {
  40     struct omap_synctimer_s *s = (struct omap_synctimer_s *) opaque;
  41
  42     switch (addr) {
  43     case 0x00:  /* 32KSYNCNT_REV */
  44         return 0x21;
  45
  46     case 0x10:  /* CR */
  47         return omap_synctimer_read(s) - s->val;
  48     }
  49
  50     OMAP_BAD_REG(addr);
  51     return 0;
  52 }
  53
  54 static uint32_t omap_synctimer_readh(void *opaque, target_phys_addr_t addr)
  55 {
  56     struct omap_synctimer_s *s = (struct omap_synctimer_s *) opaque;
  57     uint32_t ret;
  58
  59     if (addr & 2)
  60         return s->readh;
  61     else {
  62         ret = omap_synctimer_readw(opaque, addr);
  63         s->readh = ret >> 16;
  64         return ret & 0xffff;
  65     }
  66 }
  67
  68 static CPUReadMemoryFunc * const omap_synctimer_readfn[] = {
  69     omap_badwidth_read32,
  70     omap_synctimer_readh,
  71     omap_synctimer_readw,
  72 };
  73
  74 static void omap_synctimer_write(void *opaque, target_phys_addr_t addr,
  75                 uint32_t value)
  76 {
  77     OMAP_BAD_REG(addr);
  78 }
  79
  80 static CPUWriteMemoryFunc * const omap_synctimer_writefn[] = {
  81     omap_badwidth_write32,
  82     omap_synctimer_write,
  83     omap_synctimer_write,
  84 };
  85
  86 struct omap_synctimer_s *omap_synctimer_init(struct omap_target_agent_s *ta,
  87                 struct omap_mpu_state_s *mpu, omap_clk fclk, omap_clk iclk)
  88 {
  89     struct omap_synctimer_s *s = qemu_mallocz(sizeof(*s));
  90
  91     omap_synctimer_reset(s);
  92     omap_l4_attach(ta, 0, l4_register_io_memory(
  93                       omap_synctimer_readfn, omap_synctimer_writefn, s));
  94
  95     return s;
  96 }