xref: /openbmc/qemu/hw/timer/omap_synctimer.c (revision a75ed3c4)
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 */
omap_synctimer_read(struct omap_synctimer_s * s)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 
omap_synctimer_reset(struct omap_synctimer_s * s)35 void omap_synctimer_reset(struct omap_synctimer_s *s)
36 {
37     s->val = omap_synctimer_read(s);
38 }
39 
omap_synctimer_readw(void * opaque,hwaddr addr)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 
omap_synctimer_readh(void * opaque,hwaddr addr)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 
omap_synctimer_readfn(void * opaque,hwaddr addr,unsigned size)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 
omap_synctimer_writefn(void * opaque,hwaddr addr,uint64_t value,unsigned size)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 
omap_synctimer_init(struct omap_target_agent_s * ta,struct omap_mpu_state_s * mpu,omap_clk fclk,omap_clk iclk)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 }
111