xref: /openbmc/qemu/hw/char/spapr_vty.c (revision ca693d1c)
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 SpaprVioVty {
14     SpaprVioDevice sdev;
15     CharBackend chardev;
16     uint32_t in, out;
17     uint8_t buf[VTERM_BUFSIZE];
18 } SpaprVioVty;
19 
20 #define TYPE_VIO_SPAPR_VTY_DEVICE "spapr-vty"
21 #define VIO_SPAPR_VTY_DEVICE(obj) \
22      OBJECT_CHECK(SpaprVioVty, (obj), TYPE_VIO_SPAPR_VTY_DEVICE)
23 
24 static int vty_can_receive(void *opaque)
25 {
26     SpaprVioVty *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     SpaprVioVty *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(SpaprVioDevice *sdev, uint8_t *buf, int max)
55 {
56     SpaprVioVty *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         /* PowerVM's vty implementation has a bug where it inserts a
63          * \0 after every \r going to the guest.  Existing guests have
64          * a workaround for this which removes every \0 immediately
65          * following a \r, so here we make ourselves bug-for-bug
66          * compatible, so that the guest won't drop a real \0-after-\r
67          * that happens to occur in a binary stream. */
68         if (buf[n - 1] == '\r') {
69             if (n < max) {
70                 buf[n++] = '\0';
71             } else {
72                 /* No room for the extra \0, roll back and try again
73                  * next time */
74                 dev->out--;
75                 n--;
76                 break;
77             }
78         }
79     }
80 
81     qemu_chr_fe_accept_input(&dev->chardev);
82 
83     return n;
84 }
85 
86 void vty_putchars(SpaprVioDevice *sdev, uint8_t *buf, int len)
87 {
88     SpaprVioVty *dev = VIO_SPAPR_VTY_DEVICE(sdev);
89 
90     /* XXX this blocks entire thread. Rewrite to use
91      * qemu_chr_fe_write and background I/O callbacks */
92     qemu_chr_fe_write_all(&dev->chardev, buf, len);
93 }
94 
95 static void spapr_vty_realize(SpaprVioDevice *sdev, Error **errp)
96 {
97     SpaprVioVty *dev = VIO_SPAPR_VTY_DEVICE(sdev);
98 
99     if (!qemu_chr_fe_backend_connected(&dev->chardev)) {
100         error_setg(errp, "chardev property not set");
101         return;
102     }
103 
104     qemu_chr_fe_set_handlers(&dev->chardev, vty_can_receive,
105                              vty_receive, NULL, NULL, dev, NULL, true);
106 }
107 
108 /* Forward declaration */
109 static target_ulong h_put_term_char(PowerPCCPU *cpu, SpaprMachineState *spapr,
110                                     target_ulong opcode, target_ulong *args)
111 {
112     target_ulong reg = args[0];
113     target_ulong len = args[1];
114     target_ulong char0_7 = args[2];
115     target_ulong char8_15 = args[3];
116     SpaprVioDevice *sdev;
117     uint8_t buf[16];
118 
119     sdev = vty_lookup(spapr, reg);
120     if (!sdev) {
121         return H_PARAMETER;
122     }
123 
124     if (len > 16) {
125         return H_PARAMETER;
126     }
127 
128     *((uint64_t *)buf) = cpu_to_be64(char0_7);
129     *((uint64_t *)buf + 1) = cpu_to_be64(char8_15);
130 
131     vty_putchars(sdev, buf, len);
132 
133     return H_SUCCESS;
134 }
135 
136 static target_ulong h_get_term_char(PowerPCCPU *cpu, SpaprMachineState *spapr,
137                                     target_ulong opcode, target_ulong *args)
138 {
139     target_ulong reg = args[0];
140     target_ulong *len = args + 0;
141     target_ulong *char0_7 = args + 1;
142     target_ulong *char8_15 = args + 2;
143     SpaprVioDevice *sdev;
144     uint8_t buf[16];
145 
146     sdev = vty_lookup(spapr, reg);
147     if (!sdev) {
148         return H_PARAMETER;
149     }
150 
151     *len = vty_getchars(sdev, buf, sizeof(buf));
152     if (*len < 16) {
153         memset(buf + *len, 0, 16 - *len);
154     }
155 
156     *char0_7 = be64_to_cpu(*((uint64_t *)buf));
157     *char8_15 = be64_to_cpu(*((uint64_t *)buf + 1));
158 
159     return H_SUCCESS;
160 }
161 
162 void spapr_vty_create(SpaprVioBus *bus, Chardev *chardev)
163 {
164     DeviceState *dev;
165 
166     dev = qdev_create(&bus->bus, "spapr-vty");
167     qdev_prop_set_chr(dev, "chardev", chardev);
168     qdev_init_nofail(dev);
169 }
170 
171 static Property spapr_vty_properties[] = {
172     DEFINE_SPAPR_PROPERTIES(SpaprVioVty, sdev),
173     DEFINE_PROP_CHR("chardev", SpaprVioVty, chardev),
174     DEFINE_PROP_END_OF_LIST(),
175 };
176 
177 static const VMStateDescription vmstate_spapr_vty = {
178     .name = "spapr_vty",
179     .version_id = 1,
180     .minimum_version_id = 1,
181     .fields = (VMStateField[]) {
182         VMSTATE_SPAPR_VIO(sdev, SpaprVioVty),
183 
184         VMSTATE_UINT32(in, SpaprVioVty),
185         VMSTATE_UINT32(out, SpaprVioVty),
186         VMSTATE_BUFFER(buf, SpaprVioVty),
187         VMSTATE_END_OF_LIST()
188     },
189 };
190 
191 static void spapr_vty_class_init(ObjectClass *klass, void *data)
192 {
193     DeviceClass *dc = DEVICE_CLASS(klass);
194     SpaprVioDeviceClass *k = VIO_SPAPR_DEVICE_CLASS(klass);
195 
196     k->realize = spapr_vty_realize;
197     k->dt_name = "vty";
198     k->dt_type = "serial";
199     k->dt_compatible = "hvterm1";
200     set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
201     dc->props = spapr_vty_properties;
202     dc->vmsd = &vmstate_spapr_vty;
203 }
204 
205 static const TypeInfo spapr_vty_info = {
206     .name          = TYPE_VIO_SPAPR_VTY_DEVICE,
207     .parent        = TYPE_VIO_SPAPR_DEVICE,
208     .instance_size = sizeof(SpaprVioVty),
209     .class_init    = spapr_vty_class_init,
210 };
211 
212 SpaprVioDevice *spapr_vty_get_default(SpaprVioBus *bus)
213 {
214     SpaprVioDevice *sdev, *selected;
215     BusChild *kid;
216 
217     /*
218      * To avoid the console bouncing around we want one VTY to be
219      * the "default". We haven't really got anything to go on, so
220      * arbitrarily choose the one with the lowest reg value.
221      */
222 
223     selected = NULL;
224     QTAILQ_FOREACH(kid, &bus->bus.children, sibling) {
225         DeviceState *iter = kid->child;
226 
227         /* Only look at VTY devices */
228         if (!object_dynamic_cast(OBJECT(iter), TYPE_VIO_SPAPR_VTY_DEVICE)) {
229             continue;
230         }
231 
232         sdev = VIO_SPAPR_DEVICE(iter);
233 
234         /* First VTY we've found, so it is selected for now */
235         if (!selected) {
236             selected = sdev;
237             continue;
238         }
239 
240         /* Choose VTY with lowest reg value */
241         if (sdev->reg < selected->reg) {
242             selected = sdev;
243         }
244     }
245 
246     return selected;
247 }
248 
249 SpaprVioDevice *vty_lookup(SpaprMachineState *spapr, target_ulong reg)
250 {
251     SpaprVioDevice *sdev;
252 
253     sdev = spapr_vio_find_by_reg(spapr->vio_bus, reg);
254     if (!sdev && reg == 0) {
255         /* Hack for kernel early debug, which always specifies reg==0.
256          * We search all VIO devices, and grab the vty with the lowest
257          * reg.  This attempts to mimic existing PowerVM behaviour
258          * (early debug does work there, despite having no vty with
259          * reg==0. */
260         return spapr_vty_get_default(spapr->vio_bus);
261     }
262 
263     if (!object_dynamic_cast(OBJECT(sdev), TYPE_VIO_SPAPR_VTY_DEVICE)) {
264         return NULL;
265     }
266 
267     return sdev;
268 }
269 
270 static void spapr_vty_register_types(void)
271 {
272     spapr_register_hypercall(H_PUT_TERM_CHAR, h_put_term_char);
273     spapr_register_hypercall(H_GET_TERM_CHAR, h_get_term_char);
274     type_register_static(&spapr_vty_info);
275 }
276 
277 type_init(spapr_vty_register_types)
278