xref: /openbmc/qemu/hw/char/spapr_vty.c (revision 6a0acfff)
1 #include "qemu/osdep.h"
2 #include "qemu/error-report.h"
3 #include "qemu/module.h"
4 #include "qapi/error.h"
5 #include "cpu.h"
6 #include "hw/qdev.h"
7 #include "chardev/char-fe.h"
8 #include "hw/irq.h"
9 #include "hw/ppc/spapr.h"
10 #include "hw/ppc/spapr_vio.h"
11 
12 #define VTERM_BUFSIZE   16
13 
14 typedef struct SpaprVioVty {
15     SpaprVioDevice sdev;
16     CharBackend chardev;
17     uint32_t in, out;
18     uint8_t buf[VTERM_BUFSIZE];
19 } SpaprVioVty;
20 
21 #define TYPE_VIO_SPAPR_VTY_DEVICE "spapr-vty"
22 #define VIO_SPAPR_VTY_DEVICE(obj) \
23      OBJECT_CHECK(SpaprVioVty, (obj), TYPE_VIO_SPAPR_VTY_DEVICE)
24 
25 static int vty_can_receive(void *opaque)
26 {
27     SpaprVioVty *dev = VIO_SPAPR_VTY_DEVICE(opaque);
28 
29     return VTERM_BUFSIZE - (dev->in - dev->out);
30 }
31 
32 static void vty_receive(void *opaque, const uint8_t *buf, int size)
33 {
34     SpaprVioVty *dev = VIO_SPAPR_VTY_DEVICE(opaque);
35     int i;
36 
37     if ((dev->in == dev->out) && size) {
38         /* toggle line to simulate edge interrupt */
39         qemu_irq_pulse(spapr_vio_qirq(&dev->sdev));
40     }
41     for (i = 0; i < size; i++) {
42         if (dev->in - dev->out >= VTERM_BUFSIZE) {
43             static bool reported;
44             if (!reported) {
45                 error_report("VTY input buffer exhausted - characters dropped."
46                              " (input size = %i)", size);
47                 reported = true;
48             }
49             break;
50         }
51         dev->buf[dev->in++ % VTERM_BUFSIZE] = buf[i];
52     }
53 }
54 
55 static int vty_getchars(SpaprVioDevice *sdev, uint8_t *buf, int max)
56 {
57     SpaprVioVty *dev = VIO_SPAPR_VTY_DEVICE(sdev);
58     int n = 0;
59 
60     while ((n < max) && (dev->out != dev->in)) {
61         buf[n++] = dev->buf[dev->out++ % VTERM_BUFSIZE];
62 
63         /* PowerVM's vty implementation has a bug where it inserts a
64          * \0 after every \r going to the guest.  Existing guests have
65          * a workaround for this which removes every \0 immediately
66          * following a \r, so here we make ourselves bug-for-bug
67          * compatible, so that the guest won't drop a real \0-after-\r
68          * that happens to occur in a binary stream. */
69         if (buf[n - 1] == '\r') {
70             if (n < max) {
71                 buf[n++] = '\0';
72             } else {
73                 /* No room for the extra \0, roll back and try again
74                  * next time */
75                 dev->out--;
76                 n--;
77                 break;
78             }
79         }
80     }
81 
82     qemu_chr_fe_accept_input(&dev->chardev);
83 
84     return n;
85 }
86 
87 void vty_putchars(SpaprVioDevice *sdev, uint8_t *buf, int len)
88 {
89     SpaprVioVty *dev = VIO_SPAPR_VTY_DEVICE(sdev);
90 
91     /* XXX this blocks entire thread. Rewrite to use
92      * qemu_chr_fe_write and background I/O callbacks */
93     qemu_chr_fe_write_all(&dev->chardev, buf, len);
94 }
95 
96 static void spapr_vty_realize(SpaprVioDevice *sdev, Error **errp)
97 {
98     SpaprVioVty *dev = VIO_SPAPR_VTY_DEVICE(sdev);
99 
100     if (!qemu_chr_fe_backend_connected(&dev->chardev)) {
101         error_setg(errp, "chardev property not set");
102         return;
103     }
104 
105     qemu_chr_fe_set_handlers(&dev->chardev, vty_can_receive,
106                              vty_receive, NULL, NULL, dev, NULL, true);
107 }
108 
109 /* Forward declaration */
110 static target_ulong h_put_term_char(PowerPCCPU *cpu, SpaprMachineState *spapr,
111                                     target_ulong opcode, target_ulong *args)
112 {
113     target_ulong reg = args[0];
114     target_ulong len = args[1];
115     target_ulong char0_7 = args[2];
116     target_ulong char8_15 = args[3];
117     SpaprVioDevice *sdev;
118     uint8_t buf[16];
119 
120     sdev = vty_lookup(spapr, reg);
121     if (!sdev) {
122         return H_PARAMETER;
123     }
124 
125     if (len > 16) {
126         return H_PARAMETER;
127     }
128 
129     *((uint64_t *)buf) = cpu_to_be64(char0_7);
130     *((uint64_t *)buf + 1) = cpu_to_be64(char8_15);
131 
132     vty_putchars(sdev, buf, len);
133 
134     return H_SUCCESS;
135 }
136 
137 static target_ulong h_get_term_char(PowerPCCPU *cpu, SpaprMachineState *spapr,
138                                     target_ulong opcode, target_ulong *args)
139 {
140     target_ulong reg = args[0];
141     target_ulong *len = args + 0;
142     target_ulong *char0_7 = args + 1;
143     target_ulong *char8_15 = args + 2;
144     SpaprVioDevice *sdev;
145     uint8_t buf[16];
146 
147     sdev = vty_lookup(spapr, reg);
148     if (!sdev) {
149         return H_PARAMETER;
150     }
151 
152     *len = vty_getchars(sdev, buf, sizeof(buf));
153     if (*len < 16) {
154         memset(buf + *len, 0, 16 - *len);
155     }
156 
157     *char0_7 = be64_to_cpu(*((uint64_t *)buf));
158     *char8_15 = be64_to_cpu(*((uint64_t *)buf + 1));
159 
160     return H_SUCCESS;
161 }
162 
163 void spapr_vty_create(SpaprVioBus *bus, Chardev *chardev)
164 {
165     DeviceState *dev;
166 
167     dev = qdev_create(&bus->bus, "spapr-vty");
168     qdev_prop_set_chr(dev, "chardev", chardev);
169     qdev_init_nofail(dev);
170 }
171 
172 static Property spapr_vty_properties[] = {
173     DEFINE_SPAPR_PROPERTIES(SpaprVioVty, sdev),
174     DEFINE_PROP_CHR("chardev", SpaprVioVty, chardev),
175     DEFINE_PROP_END_OF_LIST(),
176 };
177 
178 static const VMStateDescription vmstate_spapr_vty = {
179     .name = "spapr_vty",
180     .version_id = 1,
181     .minimum_version_id = 1,
182     .fields = (VMStateField[]) {
183         VMSTATE_SPAPR_VIO(sdev, SpaprVioVty),
184 
185         VMSTATE_UINT32(in, SpaprVioVty),
186         VMSTATE_UINT32(out, SpaprVioVty),
187         VMSTATE_BUFFER(buf, SpaprVioVty),
188         VMSTATE_END_OF_LIST()
189     },
190 };
191 
192 static void spapr_vty_class_init(ObjectClass *klass, void *data)
193 {
194     DeviceClass *dc = DEVICE_CLASS(klass);
195     SpaprVioDeviceClass *k = VIO_SPAPR_DEVICE_CLASS(klass);
196 
197     k->realize = spapr_vty_realize;
198     k->dt_name = "vty";
199     k->dt_type = "serial";
200     k->dt_compatible = "hvterm1";
201     set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
202     dc->props = spapr_vty_properties;
203     dc->vmsd = &vmstate_spapr_vty;
204 }
205 
206 static const TypeInfo spapr_vty_info = {
207     .name          = TYPE_VIO_SPAPR_VTY_DEVICE,
208     .parent        = TYPE_VIO_SPAPR_DEVICE,
209     .instance_size = sizeof(SpaprVioVty),
210     .class_init    = spapr_vty_class_init,
211 };
212 
213 SpaprVioDevice *spapr_vty_get_default(SpaprVioBus *bus)
214 {
215     SpaprVioDevice *sdev, *selected;
216     BusChild *kid;
217 
218     /*
219      * To avoid the console bouncing around we want one VTY to be
220      * the "default". We haven't really got anything to go on, so
221      * arbitrarily choose the one with the lowest reg value.
222      */
223 
224     selected = NULL;
225     QTAILQ_FOREACH(kid, &bus->bus.children, sibling) {
226         DeviceState *iter = kid->child;
227 
228         /* Only look at VTY devices */
229         if (!object_dynamic_cast(OBJECT(iter), TYPE_VIO_SPAPR_VTY_DEVICE)) {
230             continue;
231         }
232 
233         sdev = VIO_SPAPR_DEVICE(iter);
234 
235         /* First VTY we've found, so it is selected for now */
236         if (!selected) {
237             selected = sdev;
238             continue;
239         }
240 
241         /* Choose VTY with lowest reg value */
242         if (sdev->reg < selected->reg) {
243             selected = sdev;
244         }
245     }
246 
247     return selected;
248 }
249 
250 SpaprVioDevice *vty_lookup(SpaprMachineState *spapr, target_ulong reg)
251 {
252     SpaprVioDevice *sdev;
253 
254     sdev = spapr_vio_find_by_reg(spapr->vio_bus, reg);
255     if (!sdev && reg == 0) {
256         /* Hack for kernel early debug, which always specifies reg==0.
257          * We search all VIO devices, and grab the vty with the lowest
258          * reg.  This attempts to mimic existing PowerVM behaviour
259          * (early debug does work there, despite having no vty with
260          * reg==0. */
261         return spapr_vty_get_default(spapr->vio_bus);
262     }
263 
264     if (!object_dynamic_cast(OBJECT(sdev), TYPE_VIO_SPAPR_VTY_DEVICE)) {
265         return NULL;
266     }
267 
268     return sdev;
269 }
270 
271 static void spapr_vty_register_types(void)
272 {
273     spapr_register_hypercall(H_PUT_TERM_CHAR, h_put_term_char);
274     spapr_register_hypercall(H_GET_TERM_CHAR, h_get_term_char);
275     type_register_static(&spapr_vty_info);
276 }
277 
278 type_init(spapr_vty_register_types)
279