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
41static const char hvc_driver_name[] = "hvc_console";
42
43static 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
51typedef enum hv_protocol {
52	HV_PROTOCOL_RAW,
53	HV_PROTOCOL_HVSI
54} hv_protocol_t;
55
56struct 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};
65static struct hvterm_priv *hvterm_privs[MAX_NR_HVC_CONSOLES];
66/* For early boot console */
67static struct hvterm_priv hvterm_priv0;
68
69static 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 */
118static 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
129static 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
137static 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
147static 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
158static 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
172static 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
183static 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
194static 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
203static 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
219static 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
229static 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
257static 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
278static 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
298static 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
367static 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
376static 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}
385device_initcall(hvc_vio_init); /* after drivers/tty/hvc/hvc_console.c */
386
387void __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
437void __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
458void __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