xref: /openbmc/qemu/hw/misc/allwinner-sid.c (revision 4921d0a7)
1 /*
2  * Allwinner Security ID emulation
3  *
4  * Copyright (C) 2019 Niek Linnenbank <nieklinnenbank@gmail.com>
5  *
6  * This program is free software: you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation, either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
18  */
19 
20 #include "qemu/osdep.h"
21 #include "qemu/units.h"
22 #include "hw/sysbus.h"
23 #include "migration/vmstate.h"
24 #include "qemu/log.h"
25 #include "qemu/module.h"
26 #include "qemu/guest-random.h"
27 #include "qapi/error.h"
28 #include "hw/qdev-properties.h"
29 #include "hw/qdev-properties-system.h"
30 #include "hw/misc/allwinner-sid.h"
31 #include "trace.h"
32 
33 /* SID register offsets */
34 enum {
35     REG_PRCTL = 0x40,   /* Control */
36     REG_RDKEY = 0x60,   /* Read Key */
37 };
38 
39 /* SID register flags */
40 enum {
41     REG_PRCTL_WRITE   = 0x0002, /* Unknown write flag */
42     REG_PRCTL_OP_LOCK = 0xAC00, /* Lock operation */
43 };
44 
45 static uint64_t allwinner_sid_read(void *opaque, hwaddr offset,
46                                    unsigned size)
47 {
48     const AwSidState *s = AW_SID(opaque);
49     uint64_t val = 0;
50 
51     switch (offset) {
52     case REG_PRCTL:    /* Control */
53         val = s->control;
54         break;
55     case REG_RDKEY:    /* Read Key */
56         val = s->rdkey;
57         break;
58     default:
59         qemu_log_mask(LOG_GUEST_ERROR, "%s: out-of-bounds offset 0x%04x\n",
60                       __func__, (uint32_t)offset);
61         return 0;
62     }
63 
64     trace_allwinner_sid_read(offset, val, size);
65 
66     return val;
67 }
68 
69 static void allwinner_sid_write(void *opaque, hwaddr offset,
70                                 uint64_t val, unsigned size)
71 {
72     AwSidState *s = AW_SID(opaque);
73 
74     trace_allwinner_sid_write(offset, val, size);
75 
76     switch (offset) {
77     case REG_PRCTL:    /* Control */
78         s->control = val;
79 
80         if ((s->control & REG_PRCTL_OP_LOCK) &&
81             (s->control & REG_PRCTL_WRITE)) {
82             uint32_t id = s->control >> 16;
83 
84             if (id <= sizeof(QemuUUID) - sizeof(s->rdkey)) {
85                 s->rdkey = ldl_be_p(&s->identifier.data[id]);
86             }
87         }
88         s->control &= ~REG_PRCTL_WRITE;
89         break;
90     case REG_RDKEY:    /* Read Key */
91         break;
92     default:
93         qemu_log_mask(LOG_GUEST_ERROR, "%s: out-of-bounds offset 0x%04x\n",
94                       __func__, (uint32_t)offset);
95         break;
96     }
97 }
98 
99 static const MemoryRegionOps allwinner_sid_ops = {
100     .read = allwinner_sid_read,
101     .write = allwinner_sid_write,
102     .endianness = DEVICE_NATIVE_ENDIAN,
103     .valid = {
104         .min_access_size = 4,
105         .max_access_size = 4,
106     },
107     .impl.min_access_size = 4,
108 };
109 
110 static void allwinner_sid_reset(DeviceState *dev)
111 {
112     AwSidState *s = AW_SID(dev);
113 
114     /* Set default values for registers */
115     s->control = 0;
116     s->rdkey = 0;
117 }
118 
119 static void allwinner_sid_init(Object *obj)
120 {
121     SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
122     AwSidState *s = AW_SID(obj);
123 
124     /* Memory mapping */
125     memory_region_init_io(&s->iomem, OBJECT(s), &allwinner_sid_ops, s,
126                            TYPE_AW_SID, 1 * KiB);
127     sysbus_init_mmio(sbd, &s->iomem);
128 }
129 
130 static Property allwinner_sid_properties[] = {
131     DEFINE_PROP_UUID_NODEFAULT("identifier", AwSidState, identifier),
132     DEFINE_PROP_END_OF_LIST()
133 };
134 
135 static const VMStateDescription allwinner_sid_vmstate = {
136     .name = "allwinner-sid",
137     .version_id = 1,
138     .minimum_version_id = 1,
139     .fields = (const VMStateField[]) {
140         VMSTATE_UINT32(control, AwSidState),
141         VMSTATE_UINT32(rdkey, AwSidState),
142         VMSTATE_UINT8_ARRAY_V(identifier.data, AwSidState, sizeof(QemuUUID), 1),
143         VMSTATE_END_OF_LIST()
144     }
145 };
146 
147 static void allwinner_sid_class_init(ObjectClass *klass, void *data)
148 {
149     DeviceClass *dc = DEVICE_CLASS(klass);
150 
151     dc->reset = allwinner_sid_reset;
152     dc->vmsd = &allwinner_sid_vmstate;
153     device_class_set_props(dc, allwinner_sid_properties);
154 }
155 
156 static const TypeInfo allwinner_sid_info = {
157     .name          = TYPE_AW_SID,
158     .parent        = TYPE_SYS_BUS_DEVICE,
159     .instance_init = allwinner_sid_init,
160     .instance_size = sizeof(AwSidState),
161     .class_init    = allwinner_sid_class_init,
162 };
163 
164 static void allwinner_sid_register(void)
165 {
166     type_register_static(&allwinner_sid_info);
167 }
168 
169 type_init(allwinner_sid_register)
170