xref: /qemu/hw/misc/imx7_snvs.c (revision abff1abf) 
1 /*
2  * IMX7 Secure Non-Volatile Storage
3  *
4  * Copyright (c) 2018, Impinj, Inc.
5  *
6  * Author: Andrey Smirnov <andrew.smirnov@gmail.com>
7  *
8  * This work is licensed under the terms of the GNU GPL, version 2 or later.
9  * See the COPYING file in the top-level directory.
10  *
11  * Bare minimum emulation code needed to support being able to shut
12  * down linux guest gracefully.
13  */
14 
15 #include "qemu/osdep.h"
16 #include "hw/misc/imx7_snvs.h"
17 #include "qemu/log.h"
18 #include "qemu/module.h"
19 #include "sysemu/runstate.h"
20 
21 static uint64_t imx7_snvs_read(void *opaque, hwaddr offset, unsigned size)
22 {
23     return 0;
24 }
25 
26 static void imx7_snvs_write(void *opaque, hwaddr offset,
27                             uint64_t v, unsigned size)
28 {
29     const uint32_t value = v;
30     const uint32_t mask  = SNVS_LPCR_TOP | SNVS_LPCR_DP_EN;
31 
32     if (offset == SNVS_LPCR && ((value & mask) == mask)) {
33         qemu_system_shutdown_request(SHUTDOWN_CAUSE_GUEST_SHUTDOWN);
34     }
35 }
36 
37 static const struct MemoryRegionOps imx7_snvs_ops = {
38     .read = imx7_snvs_read,
39     .write = imx7_snvs_write,
40     .endianness = DEVICE_NATIVE_ENDIAN,
41     .impl = {
42         /*
43          * Our device would not work correctly if the guest was doing
44          * unaligned access. This might not be a limitation on the real
45          * device but in practice there is no reason for a guest to access
46          * this device unaligned.
47          */
48         .min_access_size = 4,
49         .max_access_size = 4,
50         .unaligned = false,
51     },
52 };
53 
54 static void imx7_snvs_init(Object *obj)
55 {
56     SysBusDevice *sd = SYS_BUS_DEVICE(obj);
57     IMX7SNVSState *s = IMX7_SNVS(obj);
58 
59     memory_region_init_io(&s->mmio, obj, &imx7_snvs_ops, s,
60                           TYPE_IMX7_SNVS, 0x1000);
61 
62     sysbus_init_mmio(sd, &s->mmio);
63 }
64 
65 static void imx7_snvs_class_init(ObjectClass *klass, void *data)
66 {
67     DeviceClass *dc = DEVICE_CLASS(klass);
68 
69     dc->desc  = "i.MX7 Secure Non-Volatile Storage Module";
70 }
71 
72 static const TypeInfo imx7_snvs_info = {
73     .name          = TYPE_IMX7_SNVS,
74     .parent        = TYPE_SYS_BUS_DEVICE,
75     .instance_size = sizeof(IMX7SNVSState),
76     .instance_init = imx7_snvs_init,
77     .class_init    = imx7_snvs_class_init,
78 };
79 
80 static void imx7_snvs_register_type(void)
81 {
82     type_register_static(&imx7_snvs_info);
83 }
84 type_init(imx7_snvs_register_type)
85