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 	char			buf[SIZE_VIO_GET_CHARS];
62 	int			left;
63 	int			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,char * buf,int count)69 static int hvterm_raw_get_chars(uint32_t vtermno, char *buf, int count)
70 {
71 	struct hvterm_priv *pv = hvterm_privs[vtermno];
72 	unsigned long i;
73 	unsigned long flags;
74 	int 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 char * buf,int count)118 static int hvterm_raw_put_chars(uint32_t vtermno, const char *buf, int count)
119 {
120 	struct hvterm_priv *pv = hvterm_privs[vtermno];
121 
122 	if (WARN_ON(!pv))
123 		return 0;
124 
125 	return hvc_put_chars(pv->termno, buf, count);
126 }
127 
128 static const struct hv_ops hvterm_raw_ops = {
129 	.get_chars = hvterm_raw_get_chars,
130 	.put_chars = hvterm_raw_put_chars,
131 	.notifier_add = notifier_add_irq,
132 	.notifier_del = notifier_del_irq,
133 	.notifier_hangup = notifier_hangup_irq,
134 };
135 
hvterm_hvsi_get_chars(uint32_t vtermno,char * buf,int count)136 static int hvterm_hvsi_get_chars(uint32_t vtermno, char *buf, int count)
137 {
138 	struct hvterm_priv *pv = hvterm_privs[vtermno];
139 
140 	if (WARN_ON(!pv))
141 		return 0;
142 
143 	return hvsilib_get_chars(&pv->hvsi, buf, count);
144 }
145 
hvterm_hvsi_put_chars(uint32_t vtermno,const char * buf,int count)146 static int hvterm_hvsi_put_chars(uint32_t vtermno, const char *buf, int count)
147 {
148 	struct hvterm_priv *pv = hvterm_privs[vtermno];
149 
150 	if (WARN_ON(!pv))
151 		return 0;
152 
153 	return hvsilib_put_chars(&pv->hvsi, buf, count);
154 }
155 
hvterm_hvsi_open(struct hvc_struct * hp,int data)156 static int hvterm_hvsi_open(struct hvc_struct *hp, int data)
157 {
158 	struct hvterm_priv *pv = hvterm_privs[hp->vtermno];
159 	int rc;
160 
161 	pr_devel("HVSI@%x: open !\n", pv->termno);
162 
163 	rc = notifier_add_irq(hp, data);
164 	if (rc)
165 		return rc;
166 
167 	return hvsilib_open(&pv->hvsi, hp);
168 }
169 
hvterm_hvsi_close(struct hvc_struct * hp,int data)170 static void hvterm_hvsi_close(struct hvc_struct *hp, int data)
171 {
172 	struct hvterm_priv *pv = hvterm_privs[hp->vtermno];
173 
174 	pr_devel("HVSI@%x: do close !\n", pv->termno);
175 
176 	hvsilib_close(&pv->hvsi, hp);
177 
178 	notifier_del_irq(hp, data);
179 }
180 
hvterm_hvsi_hangup(struct hvc_struct * hp,int data)181 static void hvterm_hvsi_hangup(struct hvc_struct *hp, int data)
182 {
183 	struct hvterm_priv *pv = hvterm_privs[hp->vtermno];
184 
185 	pr_devel("HVSI@%x: do hangup !\n", pv->termno);
186 
187 	hvsilib_close(&pv->hvsi, hp);
188 
189 	notifier_hangup_irq(hp, data);
190 }
191 
hvterm_hvsi_tiocmget(struct hvc_struct * hp)192 static int hvterm_hvsi_tiocmget(struct hvc_struct *hp)
193 {
194 	struct hvterm_priv *pv = hvterm_privs[hp->vtermno];
195 
196 	if (!pv)
197 		return -EINVAL;
198 	return pv->hvsi.mctrl;
199 }
200 
hvterm_hvsi_tiocmset(struct hvc_struct * hp,unsigned int set,unsigned int clear)201 static int hvterm_hvsi_tiocmset(struct hvc_struct *hp, unsigned int set,
202 				unsigned int clear)
203 {
204 	struct hvterm_priv *pv = hvterm_privs[hp->vtermno];
205 
206 	pr_devel("HVSI@%x: Set modem control, set=%x,clr=%x\n",
207 		 pv->termno, set, clear);
208 
209 	if (set & TIOCM_DTR)
210 		hvsilib_write_mctrl(&pv->hvsi, 1);
211 	else if (clear & TIOCM_DTR)
212 		hvsilib_write_mctrl(&pv->hvsi, 0);
213 
214 	return 0;
215 }
216 
217 static const struct hv_ops hvterm_hvsi_ops = {
218 	.get_chars = hvterm_hvsi_get_chars,
219 	.put_chars = hvterm_hvsi_put_chars,
220 	.notifier_add = hvterm_hvsi_open,
221 	.notifier_del = hvterm_hvsi_close,
222 	.notifier_hangup = hvterm_hvsi_hangup,
223 	.tiocmget = hvterm_hvsi_tiocmget,
224 	.tiocmset = hvterm_hvsi_tiocmset,
225 };
226 
udbg_hvc_putc(char c)227 static void udbg_hvc_putc(char c)
228 {
229 	int count = -1;
230 	unsigned char bounce_buffer[16];
231 
232 	if (!hvterm_privs[0])
233 		return;
234 
235 	if (c == '\n')
236 		udbg_hvc_putc('\r');
237 
238 	do {
239 		switch(hvterm_privs[0]->proto) {
240 		case HV_PROTOCOL_RAW:
241 			/*
242 			 * hvterm_raw_put_chars requires at least a 16-byte
243 			 * buffer, so go via the bounce buffer
244 			 */
245 			bounce_buffer[0] = c;
246 			count = hvterm_raw_put_chars(0, bounce_buffer, 1);
247 			break;
248 		case HV_PROTOCOL_HVSI:
249 			count = hvterm_hvsi_put_chars(0, &c, 1);
250 			break;
251 		}
252 	} while (count == 0 || count == -EAGAIN);
253 }
254 
udbg_hvc_getc_poll(void)255 static int udbg_hvc_getc_poll(void)
256 {
257 	int rc = 0;
258 	char c;
259 
260 	if (!hvterm_privs[0])
261 		return -1;
262 
263 	switch(hvterm_privs[0]->proto) {
264 	case HV_PROTOCOL_RAW:
265 		rc = hvterm_raw_get_chars(0, &c, 1);
266 		break;
267 	case HV_PROTOCOL_HVSI:
268 		rc = hvterm_hvsi_get_chars(0, &c, 1);
269 		break;
270 	}
271 	if (!rc)
272 		return -1;
273 	return c;
274 }
275 
udbg_hvc_getc(void)276 static int udbg_hvc_getc(void)
277 {
278 	int ch;
279 
280 	if (!hvterm_privs[0])
281 		return -1;
282 
283 	for (;;) {
284 		ch = udbg_hvc_getc_poll();
285 		if (ch == -1) {
286 			/* This shouldn't be needed...but... */
287 			volatile unsigned long delay;
288 			for (delay=0; delay < 2000000; delay++)
289 				;
290 		} else {
291 			return ch;
292 		}
293 	}
294 }
295 
hvc_vio_probe(struct vio_dev * vdev,const struct vio_device_id * id)296 static int hvc_vio_probe(struct vio_dev *vdev,
297 				   const struct vio_device_id *id)
298 {
299 	const struct hv_ops *ops;
300 	struct hvc_struct *hp;
301 	struct hvterm_priv *pv;
302 	hv_protocol_t proto;
303 	int i, termno = -1;
304 
305 	/* probed with invalid parameters. */
306 	if (!vdev || !id)
307 		return -EPERM;
308 
309 	if (of_device_is_compatible(vdev->dev.of_node, "hvterm1")) {
310 		proto = HV_PROTOCOL_RAW;
311 		ops = &hvterm_raw_ops;
312 	} else if (of_device_is_compatible(vdev->dev.of_node, "hvterm-protocol")) {
313 		proto = HV_PROTOCOL_HVSI;
314 		ops = &hvterm_hvsi_ops;
315 	} else {
316 		pr_err("hvc_vio: Unknown protocol for %pOF\n", vdev->dev.of_node);
317 		return -ENXIO;
318 	}
319 
320 	pr_devel("hvc_vio_probe() device %pOF, using %s protocol\n",
321 		 vdev->dev.of_node,
322 		 proto == HV_PROTOCOL_RAW ? "raw" : "hvsi");
323 
324 	/* Is it our boot one ? */
325 	if (hvterm_privs[0] == &hvterm_priv0 &&
326 	    vdev->unit_address == hvterm_priv0.termno) {
327 		pv = hvterm_privs[0];
328 		termno = 0;
329 		pr_devel("->boot console, using termno 0\n");
330 	}
331 	/* nope, allocate a new one */
332 	else {
333 		for (i = 0; i < MAX_NR_HVC_CONSOLES && termno < 0; i++)
334 			if (!hvterm_privs[i])
335 				termno = i;
336 		pr_devel("->non-boot console, using termno %d\n", termno);
337 		if (termno < 0)
338 			return -ENODEV;
339 		pv = kzalloc(sizeof(struct hvterm_priv), GFP_KERNEL);
340 		if (!pv)
341 			return -ENOMEM;
342 		pv->termno = vdev->unit_address;
343 		pv->proto = proto;
344 		spin_lock_init(&pv->buf_lock);
345 		hvterm_privs[termno] = pv;
346 		hvsilib_init(&pv->hvsi, hvc_get_chars, hvc_put_chars,
347 			     pv->termno, 0);
348 	}
349 
350 	hp = hvc_alloc(termno, vdev->irq, ops, MAX_VIO_PUT_CHARS);
351 	if (IS_ERR(hp))
352 		return PTR_ERR(hp);
353 	dev_set_drvdata(&vdev->dev, hp);
354 
355 	/* register udbg if it's not there already for console 0 */
356 	if (hp->index == 0 && !udbg_putc) {
357 		udbg_putc = udbg_hvc_putc;
358 		udbg_getc = udbg_hvc_getc;
359 		udbg_getc_poll = udbg_hvc_getc_poll;
360 	}
361 
362 	return 0;
363 }
364 
365 static struct vio_driver hvc_vio_driver = {
366 	.id_table	= hvc_driver_table,
367 	.probe		= hvc_vio_probe,
368 	.name		= hvc_driver_name,
369 	.driver = {
370 		.suppress_bind_attrs	= true,
371 	},
372 };
373 
hvc_vio_init(void)374 static int __init hvc_vio_init(void)
375 {
376 	int rc;
377 
378 	/* Register as a vio device to receive callbacks */
379 	rc = vio_register_driver(&hvc_vio_driver);
380 
381 	return rc;
382 }
383 device_initcall(hvc_vio_init); /* after drivers/tty/hvc/hvc_console.c */
384 
hvc_vio_init_early(void)385 void __init hvc_vio_init_early(void)
386 {
387 	const __be32 *termno;
388 	const struct hv_ops *ops;
389 
390 	/* find the boot console from /chosen/stdout */
391 	/* Check if it's a virtual terminal */
392 	if (!of_node_name_prefix(of_stdout, "vty"))
393 		return;
394 	termno = of_get_property(of_stdout, "reg", NULL);
395 	if (termno == NULL)
396 		return;
397 	hvterm_priv0.termno = of_read_number(termno, 1);
398 	spin_lock_init(&hvterm_priv0.buf_lock);
399 	hvterm_privs[0] = &hvterm_priv0;
400 
401 	/* Check the protocol */
402 	if (of_device_is_compatible(of_stdout, "hvterm1")) {
403 		hvterm_priv0.proto = HV_PROTOCOL_RAW;
404 		ops = &hvterm_raw_ops;
405 	}
406 	else if (of_device_is_compatible(of_stdout, "hvterm-protocol")) {
407 		hvterm_priv0.proto = HV_PROTOCOL_HVSI;
408 		ops = &hvterm_hvsi_ops;
409 		hvsilib_init(&hvterm_priv0.hvsi, hvc_get_chars, hvc_put_chars,
410 			     hvterm_priv0.termno, 1);
411 		/* HVSI, perform the handshake now */
412 		hvsilib_establish(&hvterm_priv0.hvsi);
413 	} else
414 		return;
415 	udbg_putc = udbg_hvc_putc;
416 	udbg_getc = udbg_hvc_getc;
417 	udbg_getc_poll = udbg_hvc_getc_poll;
418 #ifdef HVC_OLD_HVSI
419 	/* When using the old HVSI driver don't register the HVC
420 	 * backend for HVSI, only do udbg
421 	 */
422 	if (hvterm_priv0.proto == HV_PROTOCOL_HVSI)
423 		return;
424 #endif
425 	/* Check whether the user has requested a different console. */
426 	if (!strstr(boot_command_line, "console="))
427 		add_preferred_console("hvc", 0, NULL);
428 	hvc_instantiate(0, 0, ops);
429 }
430 
431 /* call this from early_init() for a working debug console on
432  * vterm capable LPAR machines
433  */
434 #ifdef CONFIG_PPC_EARLY_DEBUG_LPAR
udbg_init_debug_lpar(void)435 void __init udbg_init_debug_lpar(void)
436 {
437 	/*
438 	 * If we're running as a hypervisor then we definitely can't call the
439 	 * hypervisor to print debug output (we *are* the hypervisor), so don't
440 	 * register if we detect that MSR_HV=1.
441 	 */
442 	if (mfmsr() & MSR_HV)
443 		return;
444 
445 	hvterm_privs[0] = &hvterm_priv0;
446 	hvterm_priv0.termno = 0;
447 	hvterm_priv0.proto = HV_PROTOCOL_RAW;
448 	spin_lock_init(&hvterm_priv0.buf_lock);
449 	udbg_putc = udbg_hvc_putc;
450 	udbg_getc = udbg_hvc_getc;
451 	udbg_getc_poll = udbg_hvc_getc_poll;
452 }
453 #endif /* CONFIG_PPC_EARLY_DEBUG_LPAR */
454 
455 #ifdef CONFIG_PPC_EARLY_DEBUG_LPAR_HVSI
udbg_init_debug_lpar_hvsi(void)456 void __init udbg_init_debug_lpar_hvsi(void)
457 {
458 	/* See comment above in udbg_init_debug_lpar() */
459 	if (mfmsr() & MSR_HV)
460 		return;
461 
462 	hvterm_privs[0] = &hvterm_priv0;
463 	hvterm_priv0.termno = CONFIG_PPC_EARLY_DEBUG_HVSI_VTERMNO;
464 	hvterm_priv0.proto = HV_PROTOCOL_HVSI;
465 	spin_lock_init(&hvterm_priv0.buf_lock);
466 	udbg_putc = udbg_hvc_putc;
467 	udbg_getc = udbg_hvc_getc;
468 	udbg_getc_poll = udbg_hvc_getc_poll;
469 	hvsilib_init(&hvterm_priv0.hvsi, hvc_get_chars, hvc_put_chars,
470 		     hvterm_priv0.termno, 1);
471 	hvsilib_establish(&hvterm_priv0.hvsi);
472 }
473 #endif /* CONFIG_PPC_EARLY_DEBUG_LPAR_HVSI */
474