xref: /openbmc/qemu/hw/char/debugcon.c (revision 979a8902)
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 
34 #define TYPE_ISA_DEBUGCON_DEVICE "isa-debugcon"
35 #define ISA_DEBUGCON_DEVICE(obj) \
36      OBJECT_CHECK(ISADebugconState, (obj), TYPE_ISA_DEBUGCON_DEVICE)
37 
38 //#define DEBUG_DEBUGCON
39 
40 typedef struct DebugconState {
41     MemoryRegion io;
42     CharBackend chr;
43     uint32_t readback;
44 } DebugconState;
45 
46 typedef struct ISADebugconState {
47     ISADevice parent_obj;
48 
49     uint32_t iobase;
50     DebugconState state;
51 } ISADebugconState;
52 
53 static void debugcon_ioport_write(void *opaque, hwaddr addr, uint64_t val,
54                                   unsigned width)
55 {
56     DebugconState *s = opaque;
57     unsigned char ch = val;
58 
59 #ifdef DEBUG_DEBUGCON
60     printf(" [debugcon: write addr=0x%04" HWADDR_PRIx " val=0x%02" PRIx64 "]\n", addr, val);
61 #endif
62 
63     /* XXX this blocks entire thread. Rewrite to use
64      * qemu_chr_fe_write and background I/O callbacks */
65     qemu_chr_fe_write_all(&s->chr, &ch, 1);
66 }
67 
68 
69 static uint64_t debugcon_ioport_read(void *opaque, hwaddr addr, unsigned width)
70 {
71     DebugconState *s = opaque;
72 
73 #ifdef DEBUG_DEBUGCON
74     printf("debugcon: read addr=0x%04" HWADDR_PRIx "\n", addr);
75 #endif
76 
77     return s->readback;
78 }
79 
80 static const MemoryRegionOps debugcon_ops = {
81     .read = debugcon_ioport_read,
82     .write = debugcon_ioport_write,
83     .valid.min_access_size = 1,
84     .valid.max_access_size = 1,
85     .endianness = DEVICE_LITTLE_ENDIAN,
86 };
87 
88 static void debugcon_realize_core(DebugconState *s, Error **errp)
89 {
90     if (!qemu_chr_fe_backend_connected(&s->chr)) {
91         error_setg(errp, "Can't create debugcon device, empty char device");
92         return;
93     }
94 
95     qemu_chr_fe_set_handlers(&s->chr, NULL, NULL, NULL, NULL, s, NULL, true);
96 }
97 
98 static void debugcon_isa_realizefn(DeviceState *dev, Error **errp)
99 {
100     ISADevice *d = ISA_DEVICE(dev);
101     ISADebugconState *isa = ISA_DEBUGCON_DEVICE(dev);
102     DebugconState *s = &isa->state;
103     Error *err = NULL;
104 
105     debugcon_realize_core(s, &err);
106     if (err != NULL) {
107         error_propagate(errp, err);
108         return;
109     }
110     memory_region_init_io(&s->io, OBJECT(dev), &debugcon_ops, s,
111                           TYPE_ISA_DEBUGCON_DEVICE, 1);
112     memory_region_add_subregion(isa_address_space_io(d),
113                                 isa->iobase, &s->io);
114 }
115 
116 static Property debugcon_isa_properties[] = {
117     DEFINE_PROP_UINT32("iobase", ISADebugconState, iobase, 0xe9),
118     DEFINE_PROP_CHR("chardev",  ISADebugconState, state.chr),
119     DEFINE_PROP_UINT32("readback", ISADebugconState, state.readback, 0xe9),
120     DEFINE_PROP_END_OF_LIST(),
121 };
122 
123 static void debugcon_isa_class_initfn(ObjectClass *klass, void *data)
124 {
125     DeviceClass *dc = DEVICE_CLASS(klass);
126 
127     dc->realize = debugcon_isa_realizefn;
128     device_class_set_props(dc, debugcon_isa_properties);
129     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
130 }
131 
132 static const TypeInfo debugcon_isa_info = {
133     .name          = TYPE_ISA_DEBUGCON_DEVICE,
134     .parent        = TYPE_ISA_DEVICE,
135     .instance_size = sizeof(ISADebugconState),
136     .class_init    = debugcon_isa_class_initfn,
137 };
138 
139 static void debugcon_register_types(void)
140 {
141     type_register_static(&debugcon_isa_info);
142 }
143 
144 type_init(debugcon_register_types)
145