xref: /openbmc/qemu/hw/char/debugcon.c (revision b3c818a4)
1 /*
2  * QEMU Bochs-style debug console ("port E9") emulation
3  *
4  * Copyright (c) 2003-2004 Fabrice Bellard
5  * Copyright (c) 2008 Citrix Systems, Inc.
6  * Copyright (c) Intel Corporation; author: H. Peter Anvin
7  *
8  * Permission is hereby granted, free of charge, to any person obtaining a copy
9  * of this software and associated documentation files (the "Software"), to deal
10  * in the Software without restriction, including without limitation the rights
11  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
12  * copies of the Software, and to permit persons to whom the Software is
13  * furnished to do so, subject to the following conditions:
14  *
15  * The above copyright notice and this permission notice shall be included in
16  * all copies or substantial portions of the Software.
17  *
18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
21  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
22  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
23  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
24  * THE SOFTWARE.
25  */
26 
27 #include "qemu/osdep.h"
28 #include "qapi/error.h"
29 #include "qemu/module.h"
30 #include "chardev/char-fe.h"
31 #include "hw/isa/isa.h"
32 #include "hw/qdev-properties.h"
33 #include "hw/qdev-properties-system.h"
34 #include "qom/object.h"
35 
36 #define TYPE_ISA_DEBUGCON_DEVICE "isa-debugcon"
37 OBJECT_DECLARE_SIMPLE_TYPE(ISADebugconState, ISA_DEBUGCON_DEVICE)
38 
39 //#define DEBUG_DEBUGCON
40 
41 typedef struct DebugconState {
42     MemoryRegion io;
43     CharBackend chr;
44     uint32_t readback;
45 } DebugconState;
46 
47 struct ISADebugconState {
48     ISADevice parent_obj;
49 
50     uint32_t iobase;
51     DebugconState state;
52 };
53 
54 static void debugcon_ioport_write(void *opaque, hwaddr addr, uint64_t val,
55                                   unsigned width)
56 {
57     DebugconState *s = opaque;
58     unsigned char ch = val;
59 
60 #ifdef DEBUG_DEBUGCON
61     printf(" [debugcon: write addr=0x%04" HWADDR_PRIx " val=0x%02" PRIx64 "]\n", addr, val);
62 #endif
63 
64     /* XXX this blocks entire thread. Rewrite to use
65      * qemu_chr_fe_write and background I/O callbacks */
66     qemu_chr_fe_write_all(&s->chr, &ch, 1);
67 }
68 
69 
70 static uint64_t debugcon_ioport_read(void *opaque, hwaddr addr, unsigned width)
71 {
72     DebugconState *s = opaque;
73 
74 #ifdef DEBUG_DEBUGCON
75     printf("debugcon: read addr=0x%04" HWADDR_PRIx "\n", addr);
76 #endif
77 
78     return s->readback;
79 }
80 
81 static const MemoryRegionOps debugcon_ops = {
82     .read = debugcon_ioport_read,
83     .write = debugcon_ioport_write,
84     .valid.min_access_size = 1,
85     .valid.max_access_size = 1,
86     .endianness = DEVICE_LITTLE_ENDIAN,
87 };
88 
89 static void debugcon_realize_core(DebugconState *s, Error **errp)
90 {
91     if (!qemu_chr_fe_backend_connected(&s->chr)) {
92         error_setg(errp, "Can't create debugcon device, empty char device");
93         return;
94     }
95 
96     qemu_chr_fe_set_handlers(&s->chr, NULL, NULL, NULL, NULL, s, NULL, true);
97 }
98 
99 static void debugcon_isa_realizefn(DeviceState *dev, Error **errp)
100 {
101     ISADevice *d = ISA_DEVICE(dev);
102     ISADebugconState *isa = ISA_DEBUGCON_DEVICE(dev);
103     DebugconState *s = &isa->state;
104     Error *err = NULL;
105 
106     debugcon_realize_core(s, &err);
107     if (err != NULL) {
108         error_propagate(errp, err);
109         return;
110     }
111     memory_region_init_io(&s->io, OBJECT(dev), &debugcon_ops, s,
112                           TYPE_ISA_DEBUGCON_DEVICE, 1);
113     memory_region_add_subregion(isa_address_space_io(d),
114                                 isa->iobase, &s->io);
115 }
116 
117 static Property debugcon_isa_properties[] = {
118     DEFINE_PROP_UINT32("iobase", ISADebugconState, iobase, 0xe9),
119     DEFINE_PROP_CHR("chardev",  ISADebugconState, state.chr),
120     DEFINE_PROP_UINT32("readback", ISADebugconState, state.readback, 0xe9),
121     DEFINE_PROP_END_OF_LIST(),
122 };
123 
124 static void debugcon_isa_class_initfn(ObjectClass *klass, void *data)
125 {
126     DeviceClass *dc = DEVICE_CLASS(klass);
127 
128     dc->realize = debugcon_isa_realizefn;
129     device_class_set_props(dc, debugcon_isa_properties);
130     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
131 }
132 
133 static const TypeInfo debugcon_isa_info = {
134     .name          = TYPE_ISA_DEBUGCON_DEVICE,
135     .parent        = TYPE_ISA_DEVICE,
136     .instance_size = sizeof(ISADebugconState),
137     .class_init    = debugcon_isa_class_initfn,
138 };
139 
140 static void debugcon_register_types(void)
141 {
142     type_register_static(&debugcon_isa_info);
143 }
144 
145 type_init(debugcon_register_types)
146