xref: /openbmc/qemu/hw/char/spapr_vty.c (revision 0b1183e3)
1 #include "qemu/osdep.h"
2 #include "qemu/error-report.h"
3 #include "qapi/error.h"
4 #include "qemu-common.h"
5 #include "cpu.h"
6 #include "hw/qdev.h"
7 #include "chardev/char-fe.h"
8 #include "hw/ppc/spapr.h"
9 #include "hw/ppc/spapr_vio.h"
10 
11 #define VTERM_BUFSIZE   16
12 
13 typedef struct VIOsPAPRVTYDevice {
14     VIOsPAPRDevice sdev;
15     CharBackend chardev;
16     uint32_t in, out;
17     uint8_t buf[VTERM_BUFSIZE];
18 } VIOsPAPRVTYDevice;
19 
20 #define TYPE_VIO_SPAPR_VTY_DEVICE "spapr-vty"
21 #define VIO_SPAPR_VTY_DEVICE(obj) \
22      OBJECT_CHECK(VIOsPAPRVTYDevice, (obj), TYPE_VIO_SPAPR_VTY_DEVICE)
23 
24 static int vty_can_receive(void *opaque)
25 {
26     VIOsPAPRVTYDevice *dev = VIO_SPAPR_VTY_DEVICE(opaque);
27 
28     return VTERM_BUFSIZE - (dev->in - dev->out);
29 }
30 
31 static void vty_receive(void *opaque, const uint8_t *buf, int size)
32 {
33     VIOsPAPRVTYDevice *dev = VIO_SPAPR_VTY_DEVICE(opaque);
34     int i;
35 
36     if ((dev->in == dev->out) && size) {
37         /* toggle line to simulate edge interrupt */
38         qemu_irq_pulse(spapr_vio_qirq(&dev->sdev));
39     }
40     for (i = 0; i < size; i++) {
41         if (dev->in - dev->out >= VTERM_BUFSIZE) {
42             static bool reported;
43             if (!reported) {
44                 error_report("VTY input buffer exhausted - characters dropped."
45                              " (input size = %i)", size);
46                 reported = true;
47             }
48             break;
49         }
50         dev->buf[dev->in++ % VTERM_BUFSIZE] = buf[i];
51     }
52 }
53 
54 static int vty_getchars(VIOsPAPRDevice *sdev, uint8_t *buf, int max)
55 {
56     VIOsPAPRVTYDevice *dev = VIO_SPAPR_VTY_DEVICE(sdev);
57     int n = 0;
58 
59     while ((n < max) && (dev->out != dev->in)) {
60         buf[n++] = dev->buf[dev->out++ % VTERM_BUFSIZE];
61     }
62 
63     qemu_chr_fe_accept_input(&dev->chardev);
64 
65     return n;
66 }
67 
68 void vty_putchars(VIOsPAPRDevice *sdev, uint8_t *buf, int len)
69 {
70     VIOsPAPRVTYDevice *dev = VIO_SPAPR_VTY_DEVICE(sdev);
71 
72     /* XXX this blocks entire thread. Rewrite to use
73      * qemu_chr_fe_write and background I/O callbacks */
74     qemu_chr_fe_write_all(&dev->chardev, buf, len);
75 }
76 
77 static void spapr_vty_realize(VIOsPAPRDevice *sdev, Error **errp)
78 {
79     VIOsPAPRVTYDevice *dev = VIO_SPAPR_VTY_DEVICE(sdev);
80 
81     if (!qemu_chr_fe_backend_connected(&dev->chardev)) {
82         error_setg(errp, "chardev property not set");
83         return;
84     }
85 
86     qemu_chr_fe_set_handlers(&dev->chardev, vty_can_receive,
87                              vty_receive, NULL, NULL, dev, NULL, true);
88 }
89 
90 /* Forward declaration */
91 static target_ulong h_put_term_char(PowerPCCPU *cpu, sPAPRMachineState *spapr,
92                                     target_ulong opcode, target_ulong *args)
93 {
94     target_ulong reg = args[0];
95     target_ulong len = args[1];
96     target_ulong char0_7 = args[2];
97     target_ulong char8_15 = args[3];
98     VIOsPAPRDevice *sdev;
99     uint8_t buf[16];
100 
101     sdev = vty_lookup(spapr, reg);
102     if (!sdev) {
103         return H_PARAMETER;
104     }
105 
106     if (len > 16) {
107         return H_PARAMETER;
108     }
109 
110     *((uint64_t *)buf) = cpu_to_be64(char0_7);
111     *((uint64_t *)buf + 1) = cpu_to_be64(char8_15);
112 
113     vty_putchars(sdev, buf, len);
114 
115     return H_SUCCESS;
116 }
117 
118 static target_ulong h_get_term_char(PowerPCCPU *cpu, sPAPRMachineState *spapr,
119                                     target_ulong opcode, target_ulong *args)
120 {
121     target_ulong reg = args[0];
122     target_ulong *len = args + 0;
123     target_ulong *char0_7 = args + 1;
124     target_ulong *char8_15 = args + 2;
125     VIOsPAPRDevice *sdev;
126     uint8_t buf[16];
127 
128     sdev = vty_lookup(spapr, reg);
129     if (!sdev) {
130         return H_PARAMETER;
131     }
132 
133     *len = vty_getchars(sdev, buf, sizeof(buf));
134     if (*len < 16) {
135         memset(buf + *len, 0, 16 - *len);
136     }
137 
138     *char0_7 = be64_to_cpu(*((uint64_t *)buf));
139     *char8_15 = be64_to_cpu(*((uint64_t *)buf + 1));
140 
141     return H_SUCCESS;
142 }
143 
144 void spapr_vty_create(VIOsPAPRBus *bus, Chardev *chardev)
145 {
146     DeviceState *dev;
147 
148     dev = qdev_create(&bus->bus, "spapr-vty");
149     qdev_prop_set_chr(dev, "chardev", chardev);
150     qdev_init_nofail(dev);
151 }
152 
153 static Property spapr_vty_properties[] = {
154     DEFINE_SPAPR_PROPERTIES(VIOsPAPRVTYDevice, sdev),
155     DEFINE_PROP_CHR("chardev", VIOsPAPRVTYDevice, chardev),
156     DEFINE_PROP_END_OF_LIST(),
157 };
158 
159 static const VMStateDescription vmstate_spapr_vty = {
160     .name = "spapr_vty",
161     .version_id = 1,
162     .minimum_version_id = 1,
163     .fields = (VMStateField[]) {
164         VMSTATE_SPAPR_VIO(sdev, VIOsPAPRVTYDevice),
165 
166         VMSTATE_UINT32(in, VIOsPAPRVTYDevice),
167         VMSTATE_UINT32(out, VIOsPAPRVTYDevice),
168         VMSTATE_BUFFER(buf, VIOsPAPRVTYDevice),
169         VMSTATE_END_OF_LIST()
170     },
171 };
172 
173 static void spapr_vty_class_init(ObjectClass *klass, void *data)
174 {
175     DeviceClass *dc = DEVICE_CLASS(klass);
176     VIOsPAPRDeviceClass *k = VIO_SPAPR_DEVICE_CLASS(klass);
177 
178     k->realize = spapr_vty_realize;
179     k->dt_name = "vty";
180     k->dt_type = "serial";
181     k->dt_compatible = "hvterm1";
182     set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
183     dc->props = spapr_vty_properties;
184     dc->vmsd = &vmstate_spapr_vty;
185 }
186 
187 static const TypeInfo spapr_vty_info = {
188     .name          = TYPE_VIO_SPAPR_VTY_DEVICE,
189     .parent        = TYPE_VIO_SPAPR_DEVICE,
190     .instance_size = sizeof(VIOsPAPRVTYDevice),
191     .class_init    = spapr_vty_class_init,
192 };
193 
194 VIOsPAPRDevice *spapr_vty_get_default(VIOsPAPRBus *bus)
195 {
196     VIOsPAPRDevice *sdev, *selected;
197     BusChild *kid;
198 
199     /*
200      * To avoid the console bouncing around we want one VTY to be
201      * the "default". We haven't really got anything to go on, so
202      * arbitrarily choose the one with the lowest reg value.
203      */
204 
205     selected = NULL;
206     QTAILQ_FOREACH(kid, &bus->bus.children, sibling) {
207         DeviceState *iter = kid->child;
208 
209         /* Only look at VTY devices */
210         if (!object_dynamic_cast(OBJECT(iter), TYPE_VIO_SPAPR_VTY_DEVICE)) {
211             continue;
212         }
213 
214         sdev = VIO_SPAPR_DEVICE(iter);
215 
216         /* First VTY we've found, so it is selected for now */
217         if (!selected) {
218             selected = sdev;
219             continue;
220         }
221 
222         /* Choose VTY with lowest reg value */
223         if (sdev->reg < selected->reg) {
224             selected = sdev;
225         }
226     }
227 
228     return selected;
229 }
230 
231 VIOsPAPRDevice *vty_lookup(sPAPRMachineState *spapr, target_ulong reg)
232 {
233     VIOsPAPRDevice *sdev;
234 
235     sdev = spapr_vio_find_by_reg(spapr->vio_bus, reg);
236     if (!sdev && reg == 0) {
237         /* Hack for kernel early debug, which always specifies reg==0.
238          * We search all VIO devices, and grab the vty with the lowest
239          * reg.  This attempts to mimic existing PowerVM behaviour
240          * (early debug does work there, despite having no vty with
241          * reg==0. */
242         return spapr_vty_get_default(spapr->vio_bus);
243     }
244 
245     if (!object_dynamic_cast(OBJECT(sdev), TYPE_VIO_SPAPR_VTY_DEVICE)) {
246         return NULL;
247     }
248 
249     return sdev;
250 }
251 
252 static void spapr_vty_register_types(void)
253 {
254     spapr_register_hypercall(H_PUT_TERM_CHAR, h_put_term_char);
255     spapr_register_hypercall(H_GET_TERM_CHAR, h_get_term_char);
256     type_register_static(&spapr_vty_info);
257 }
258 
259 type_init(spapr_vty_register_types)
260