1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * vio driver interface to hvc_console.c
4 *
5 * This code was moved here to allow the remaining code to be reused as a
6 * generic polling mode with semi-reliable transport driver core to the
7 * console and tty subsystems.
8 *
9 *
10 * Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM
11 * Copyright (C) 2001 Paul Mackerras <paulus@au.ibm.com>, IBM
12 * Copyright (C) 2004 Benjamin Herrenschmidt <benh@kernel.crashing.org>, IBM Corp.
13 * Copyright (C) 2004 IBM Corporation
14 *
15 * Additional Author(s):
16 * Ryan S. Arnold <rsa@us.ibm.com>
17 *
18 * TODO:
19 *
20 * - handle error in sending hvsi protocol packets
21 * - retry nego on subsequent sends ?
22 */
23
24 #undef DEBUG
25
26 #include <linux/types.h>
27 #include <linux/init.h>
28 #include <linux/delay.h>
29 #include <linux/slab.h>
30 #include <linux/console.h>
31 #include <linux/of.h>
32
33 #include <asm/hvconsole.h>
34 #include <asm/vio.h>
35 #include <asm/hvsi.h>
36 #include <asm/udbg.h>
37 #include <asm/machdep.h>
38
39 #include "hvc_console.h"
40
41 static const char hvc_driver_name[] = "hvc_console";
42
43 static const struct vio_device_id hvc_driver_table[] = {
44 {"serial", "hvterm1"},
45 #ifndef HVC_OLD_HVSI
46 {"serial", "hvterm-protocol"},
47 #endif
48 { "", "" }
49 };
50
51 typedef enum hv_protocol {
52 HV_PROTOCOL_RAW,
53 HV_PROTOCOL_HVSI
54 } hv_protocol_t;
55
56 struct hvterm_priv {
57 u32 termno; /* HV term number */
58 hv_protocol_t proto; /* Raw data or HVSI packets */
59 struct hvsi_priv hvsi; /* HVSI specific data */
60 spinlock_t buf_lock;
61 u8 buf[SIZE_VIO_GET_CHARS];
62 size_t left;
63 size_t offset;
64 };
65 static struct hvterm_priv *hvterm_privs[MAX_NR_HVC_CONSOLES];
66 /* For early boot console */
67 static struct hvterm_priv hvterm_priv0;
68
hvterm_raw_get_chars(uint32_t vtermno,u8 * buf,size_t count)69 static ssize_t hvterm_raw_get_chars(uint32_t vtermno, u8 *buf, size_t count)
70 {
71 struct hvterm_priv *pv = hvterm_privs[vtermno];
72 unsigned long i;
73 unsigned long flags;
74 size_t got;
75
76 if (WARN_ON(!pv))
77 return 0;
78
79 spin_lock_irqsave(&pv->buf_lock, flags);
80
81 if (pv->left == 0) {
82 pv->offset = 0;
83 pv->left = hvc_get_chars(pv->termno, pv->buf, count);
84
85 /*
86 * Work around a HV bug where it gives us a null
87 * after every \r. -- paulus
88 */
89 for (i = 1; i < pv->left; ++i) {
90 if (pv->buf[i] == 0 && pv->buf[i-1] == '\r') {
91 --pv->left;
92 if (i < pv->left) {
93 memmove(&pv->buf[i], &pv->buf[i+1],
94 pv->left - i);
95 }
96 }
97 }
98 }
99
100 got = min(count, pv->left);
101 memcpy(buf, &pv->buf[pv->offset], got);
102 pv->offset += got;
103 pv->left -= got;
104
105 spin_unlock_irqrestore(&pv->buf_lock, flags);
106
107 return got;
108 }
109
110 /**
111 * hvterm_raw_put_chars: send characters to firmware for given vterm adapter
112 * @vtermno: The virtual terminal number.
113 * @buf: The characters to send. Because of the underlying hypercall in
114 * hvc_put_chars(), this buffer must be at least 16 bytes long, even if
115 * you are sending fewer chars.
116 * @count: number of chars to send.
117 */
hvterm_raw_put_chars(uint32_t vtermno,const u8 * buf,size_t count)118 static ssize_t hvterm_raw_put_chars(uint32_t vtermno, const u8 *buf,
119 size_t count)
120 {
121 struct hvterm_priv *pv = hvterm_privs[vtermno];
122
123 if (WARN_ON(!pv))
124 return 0;
125
126 return hvc_put_chars(pv->termno, buf, count);
127 }
128
129 static const struct hv_ops hvterm_raw_ops = {
130 .get_chars = hvterm_raw_get_chars,
131 .put_chars = hvterm_raw_put_chars,
132 .notifier_add = notifier_add_irq,
133 .notifier_del = notifier_del_irq,
134 .notifier_hangup = notifier_hangup_irq,
135 };
136
hvterm_hvsi_get_chars(uint32_t vtermno,u8 * buf,size_t count)137 static ssize_t hvterm_hvsi_get_chars(uint32_t vtermno, u8 *buf, size_t count)
138 {
139 struct hvterm_priv *pv = hvterm_privs[vtermno];
140
141 if (WARN_ON(!pv))
142 return 0;
143
144 return hvsilib_get_chars(&pv->hvsi, buf, count);
145 }
146
hvterm_hvsi_put_chars(uint32_t vtermno,const u8 * buf,size_t count)147 static ssize_t hvterm_hvsi_put_chars(uint32_t vtermno, const u8 *buf,
148 size_t count)
149 {
150 struct hvterm_priv *pv = hvterm_privs[vtermno];
151
152 if (WARN_ON(!pv))
153 return 0;
154
155 return hvsilib_put_chars(&pv->hvsi, buf, count);
156 }
157
hvterm_hvsi_open(struct hvc_struct * hp,int data)158 static int hvterm_hvsi_open(struct hvc_struct *hp, int data)
159 {
160 struct hvterm_priv *pv = hvterm_privs[hp->vtermno];
161 int rc;
162
163 pr_devel("HVSI@%x: open !\n", pv->termno);
164
165 rc = notifier_add_irq(hp, data);
166 if (rc)
167 return rc;
168
169 return hvsilib_open(&pv->hvsi, hp);
170 }
171
hvterm_hvsi_close(struct hvc_struct * hp,int data)172 static void hvterm_hvsi_close(struct hvc_struct *hp, int data)
173 {
174 struct hvterm_priv *pv = hvterm_privs[hp->vtermno];
175
176 pr_devel("HVSI@%x: do close !\n", pv->termno);
177
178 hvsilib_close(&pv->hvsi, hp);
179
180 notifier_del_irq(hp, data);
181 }
182
hvterm_hvsi_hangup(struct hvc_struct * hp,int data)183 static void hvterm_hvsi_hangup(struct hvc_struct *hp, int data)
184 {
185 struct hvterm_priv *pv = hvterm_privs[hp->vtermno];
186
187 pr_devel("HVSI@%x: do hangup !\n", pv->termno);
188
189 hvsilib_close(&pv->hvsi, hp);
190
191 notifier_hangup_irq(hp, data);
192 }
193
hvterm_hvsi_tiocmget(struct hvc_struct * hp)194 static int hvterm_hvsi_tiocmget(struct hvc_struct *hp)
195 {
196 struct hvterm_priv *pv = hvterm_privs[hp->vtermno];
197
198 if (!pv)
199 return -EINVAL;
200 return pv->hvsi.mctrl;
201 }
202
hvterm_hvsi_tiocmset(struct hvc_struct * hp,unsigned int set,unsigned int clear)203 static int hvterm_hvsi_tiocmset(struct hvc_struct *hp, unsigned int set,
204 unsigned int clear)
205 {
206 struct hvterm_priv *pv = hvterm_privs[hp->vtermno];
207
208 pr_devel("HVSI@%x: Set modem control, set=%x,clr=%x\n",
209 pv->termno, set, clear);
210
211 if (set & TIOCM_DTR)
212 hvsilib_write_mctrl(&pv->hvsi, 1);
213 else if (clear & TIOCM_DTR)
214 hvsilib_write_mctrl(&pv->hvsi, 0);
215
216 return 0;
217 }
218
219 static const struct hv_ops hvterm_hvsi_ops = {
220 .get_chars = hvterm_hvsi_get_chars,
221 .put_chars = hvterm_hvsi_put_chars,
222 .notifier_add = hvterm_hvsi_open,
223 .notifier_del = hvterm_hvsi_close,
224 .notifier_hangup = hvterm_hvsi_hangup,
225 .tiocmget = hvterm_hvsi_tiocmget,
226 .tiocmset = hvterm_hvsi_tiocmset,
227 };
228
udbg_hvc_putc(char c)229 static void udbg_hvc_putc(char c)
230 {
231 int count = -1;
232 unsigned char bounce_buffer[16];
233
234 if (!hvterm_privs[0])
235 return;
236
237 if (c == '\n')
238 udbg_hvc_putc('\r');
239
240 do {
241 switch(hvterm_privs[0]->proto) {
242 case HV_PROTOCOL_RAW:
243 /*
244 * hvterm_raw_put_chars requires at least a 16-byte
245 * buffer, so go via the bounce buffer
246 */
247 bounce_buffer[0] = c;
248 count = hvterm_raw_put_chars(0, bounce_buffer, 1);
249 break;
250 case HV_PROTOCOL_HVSI:
251 count = hvterm_hvsi_put_chars(0, &c, 1);
252 break;
253 }
254 } while (count == 0 || count == -EAGAIN);
255 }
256
udbg_hvc_getc_poll(void)257 static int udbg_hvc_getc_poll(void)
258 {
259 int rc = 0;
260 char c;
261
262 if (!hvterm_privs[0])
263 return -1;
264
265 switch(hvterm_privs[0]->proto) {
266 case HV_PROTOCOL_RAW:
267 rc = hvterm_raw_get_chars(0, &c, 1);
268 break;
269 case HV_PROTOCOL_HVSI:
270 rc = hvterm_hvsi_get_chars(0, &c, 1);
271 break;
272 }
273 if (!rc)
274 return -1;
275 return c;
276 }
277
udbg_hvc_getc(void)278 static int udbg_hvc_getc(void)
279 {
280 int ch;
281
282 if (!hvterm_privs[0])
283 return -1;
284
285 for (;;) {
286 ch = udbg_hvc_getc_poll();
287 if (ch == -1) {
288 /* This shouldn't be needed...but... */
289 volatile unsigned long delay;
290 for (delay=0; delay < 2000000; delay++)
291 ;
292 } else {
293 return ch;
294 }
295 }
296 }
297
hvc_vio_probe(struct vio_dev * vdev,const struct vio_device_id * id)298 static int hvc_vio_probe(struct vio_dev *vdev,
299 const struct vio_device_id *id)
300 {
301 const struct hv_ops *ops;
302 struct hvc_struct *hp;
303 struct hvterm_priv *pv;
304 hv_protocol_t proto;
305 int i, termno = -1;
306
307 /* probed with invalid parameters. */
308 if (!vdev || !id)
309 return -EPERM;
310
311 if (of_device_is_compatible(vdev->dev.of_node, "hvterm1")) {
312 proto = HV_PROTOCOL_RAW;
313 ops = &hvterm_raw_ops;
314 } else if (of_device_is_compatible(vdev->dev.of_node, "hvterm-protocol")) {
315 proto = HV_PROTOCOL_HVSI;
316 ops = &hvterm_hvsi_ops;
317 } else {
318 pr_err("hvc_vio: Unknown protocol for %pOF\n", vdev->dev.of_node);
319 return -ENXIO;
320 }
321
322 pr_devel("hvc_vio_probe() device %pOF, using %s protocol\n",
323 vdev->dev.of_node,
324 proto == HV_PROTOCOL_RAW ? "raw" : "hvsi");
325
326 /* Is it our boot one ? */
327 if (hvterm_privs[0] == &hvterm_priv0 &&
328 vdev->unit_address == hvterm_priv0.termno) {
329 pv = hvterm_privs[0];
330 termno = 0;
331 pr_devel("->boot console, using termno 0\n");
332 }
333 /* nope, allocate a new one */
334 else {
335 for (i = 0; i < MAX_NR_HVC_CONSOLES && termno < 0; i++)
336 if (!hvterm_privs[i])
337 termno = i;
338 pr_devel("->non-boot console, using termno %d\n", termno);
339 if (termno < 0)
340 return -ENODEV;
341 pv = kzalloc(sizeof(struct hvterm_priv), GFP_KERNEL);
342 if (!pv)
343 return -ENOMEM;
344 pv->termno = vdev->unit_address;
345 pv->proto = proto;
346 spin_lock_init(&pv->buf_lock);
347 hvterm_privs[termno] = pv;
348 hvsilib_init(&pv->hvsi, hvc_get_chars, hvc_put_chars,
349 pv->termno, 0);
350 }
351
352 hp = hvc_alloc(termno, vdev->irq, ops, MAX_VIO_PUT_CHARS);
353 if (IS_ERR(hp))
354 return PTR_ERR(hp);
355 dev_set_drvdata(&vdev->dev, hp);
356
357 /* register udbg if it's not there already for console 0 */
358 if (hp->index == 0 && !udbg_putc) {
359 udbg_putc = udbg_hvc_putc;
360 udbg_getc = udbg_hvc_getc;
361 udbg_getc_poll = udbg_hvc_getc_poll;
362 }
363
364 return 0;
365 }
366
367 static struct vio_driver hvc_vio_driver = {
368 .id_table = hvc_driver_table,
369 .probe = hvc_vio_probe,
370 .name = hvc_driver_name,
371 .driver = {
372 .suppress_bind_attrs = true,
373 },
374 };
375
hvc_vio_init(void)376 static int __init hvc_vio_init(void)
377 {
378 int rc;
379
380 /* Register as a vio device to receive callbacks */
381 rc = vio_register_driver(&hvc_vio_driver);
382
383 return rc;
384 }
385 device_initcall(hvc_vio_init); /* after drivers/tty/hvc/hvc_console.c */
386
hvc_vio_init_early(void)387 void __init hvc_vio_init_early(void)
388 {
389 const __be32 *termno;
390 const struct hv_ops *ops;
391
392 /* find the boot console from /chosen/stdout */
393 /* Check if it's a virtual terminal */
394 if (!of_node_name_prefix(of_stdout, "vty"))
395 return;
396 termno = of_get_property(of_stdout, "reg", NULL);
397 if (termno == NULL)
398 return;
399 hvterm_priv0.termno = of_read_number(termno, 1);
400 spin_lock_init(&hvterm_priv0.buf_lock);
401 hvterm_privs[0] = &hvterm_priv0;
402
403 /* Check the protocol */
404 if (of_device_is_compatible(of_stdout, "hvterm1")) {
405 hvterm_priv0.proto = HV_PROTOCOL_RAW;
406 ops = &hvterm_raw_ops;
407 }
408 else if (of_device_is_compatible(of_stdout, "hvterm-protocol")) {
409 hvterm_priv0.proto = HV_PROTOCOL_HVSI;
410 ops = &hvterm_hvsi_ops;
411 hvsilib_init(&hvterm_priv0.hvsi, hvc_get_chars, hvc_put_chars,
412 hvterm_priv0.termno, 1);
413 /* HVSI, perform the handshake now */
414 hvsilib_establish(&hvterm_priv0.hvsi);
415 } else
416 return;
417 udbg_putc = udbg_hvc_putc;
418 udbg_getc = udbg_hvc_getc;
419 udbg_getc_poll = udbg_hvc_getc_poll;
420 #ifdef HVC_OLD_HVSI
421 /* When using the old HVSI driver don't register the HVC
422 * backend for HVSI, only do udbg
423 */
424 if (hvterm_priv0.proto == HV_PROTOCOL_HVSI)
425 return;
426 #endif
427 /* Check whether the user has requested a different console. */
428 if (!strstr(boot_command_line, "console="))
429 add_preferred_console("hvc", 0, NULL);
430 hvc_instantiate(0, 0, ops);
431 }
432
433 /* call this from early_init() for a working debug console on
434 * vterm capable LPAR machines
435 */
436 #ifdef CONFIG_PPC_EARLY_DEBUG_LPAR
udbg_init_debug_lpar(void)437 void __init udbg_init_debug_lpar(void)
438 {
439 /*
440 * If we're running as a hypervisor then we definitely can't call the
441 * hypervisor to print debug output (we *are* the hypervisor), so don't
442 * register if we detect that MSR_HV=1.
443 */
444 if (mfmsr() & MSR_HV)
445 return;
446
447 hvterm_privs[0] = &hvterm_priv0;
448 hvterm_priv0.termno = 0;
449 hvterm_priv0.proto = HV_PROTOCOL_RAW;
450 spin_lock_init(&hvterm_priv0.buf_lock);
451 udbg_putc = udbg_hvc_putc;
452 udbg_getc = udbg_hvc_getc;
453 udbg_getc_poll = udbg_hvc_getc_poll;
454 }
455 #endif /* CONFIG_PPC_EARLY_DEBUG_LPAR */
456
457 #ifdef CONFIG_PPC_EARLY_DEBUG_LPAR_HVSI
udbg_init_debug_lpar_hvsi(void)458 void __init udbg_init_debug_lpar_hvsi(void)
459 {
460 /* See comment above in udbg_init_debug_lpar() */
461 if (mfmsr() & MSR_HV)
462 return;
463
464 hvterm_privs[0] = &hvterm_priv0;
465 hvterm_priv0.termno = CONFIG_PPC_EARLY_DEBUG_HVSI_VTERMNO;
466 hvterm_priv0.proto = HV_PROTOCOL_HVSI;
467 spin_lock_init(&hvterm_priv0.buf_lock);
468 udbg_putc = udbg_hvc_putc;
469 udbg_getc = udbg_hvc_getc;
470 udbg_getc_poll = udbg_hvc_getc_poll;
471 hvsilib_init(&hvterm_priv0.hvsi, hvc_get_chars, hvc_put_chars,
472 hvterm_priv0.termno, 1);
473 hvsilib_establish(&hvterm_priv0.hvsi);
474 }
475 #endif /* CONFIG_PPC_EARLY_DEBUG_LPAR_HVSI */
476