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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * SCLP line mode console driver
4 *
5 * Copyright IBM Corp. 1999, 2009
6 * Author(s): Martin Peschke <mpeschke@de.ibm.com>
7 * Martin Schwidefsky <schwidefsky@de.ibm.com>
8 */
9
10#include <linux/kmod.h>
11#include <linux/console.h>
12#include <linux/init.h>
13#include <linux/panic_notifier.h>
14#include <linux/timer.h>
15#include <linux/jiffies.h>
16#include <linux/termios.h>
17#include <linux/err.h>
18#include <linux/reboot.h>
19#include <linux/gfp.h>
20
21#include "sclp.h"
22#include "sclp_rw.h"
23#include "sclp_tty.h"
24
25#define sclp_console_major 4 /* TTYAUX_MAJOR */
26#define sclp_console_minor 64
27#define sclp_console_name "ttyS"
28
29/* Lock to guard over changes to global variables */
30static DEFINE_SPINLOCK(sclp_con_lock);
31/* List of free pages that can be used for console output buffering */
32static LIST_HEAD(sclp_con_pages);
33/* List of full struct sclp_buffer structures ready for output */
34static LIST_HEAD(sclp_con_outqueue);
35/* Pointer to current console buffer */
36static struct sclp_buffer *sclp_conbuf;
37/* Timer for delayed output of console messages */
38static struct timer_list sclp_con_timer;
39/* Flag that output queue is currently running */
40static int sclp_con_queue_running;
41
42/* Output format for console messages */
43#define SCLP_CON_COLUMNS 320
44#define SPACES_PER_TAB 8
45
46static void
47sclp_conbuf_callback(struct sclp_buffer *buffer, int rc)
48{
49 unsigned long flags;
50 void *page;
51
52 do {
53 page = sclp_unmake_buffer(buffer);
54 spin_lock_irqsave(&sclp_con_lock, flags);
55
56 /* Remove buffer from outqueue */
57 list_del(&buffer->list);
58 list_add_tail((struct list_head *) page, &sclp_con_pages);
59
60 /* Check if there is a pending buffer on the out queue. */
61 buffer = NULL;
62 if (!list_empty(&sclp_con_outqueue))
63 buffer = list_first_entry(&sclp_con_outqueue,
64 struct sclp_buffer, list);
65 if (!buffer) {
66 sclp_con_queue_running = 0;
67 spin_unlock_irqrestore(&sclp_con_lock, flags);
68 break;
69 }
70 spin_unlock_irqrestore(&sclp_con_lock, flags);
71 } while (sclp_emit_buffer(buffer, sclp_conbuf_callback));
72}
73
74/*
75 * Finalize and emit first pending buffer.
76 */
77static void sclp_conbuf_emit(void)
78{
79 struct sclp_buffer* buffer;
80 unsigned long flags;
81 int rc;
82
83 spin_lock_irqsave(&sclp_con_lock, flags);
84 if (sclp_conbuf)
85 list_add_tail(&sclp_conbuf->list, &sclp_con_outqueue);
86 sclp_conbuf = NULL;
87 if (sclp_con_queue_running)
88 goto out_unlock;
89 if (list_empty(&sclp_con_outqueue))
90 goto out_unlock;
91 buffer = list_first_entry(&sclp_con_outqueue, struct sclp_buffer,
92 list);
93 sclp_con_queue_running = 1;
94 spin_unlock_irqrestore(&sclp_con_lock, flags);
95
96 rc = sclp_emit_buffer(buffer, sclp_conbuf_callback);
97 if (rc)
98 sclp_conbuf_callback(buffer, rc);
99 return;
100out_unlock:
101 spin_unlock_irqrestore(&sclp_con_lock, flags);
102}
103
104/*
105 * Wait until out queue is empty
106 */
107static void sclp_console_sync_queue(void)
108{
109 unsigned long flags;
110
111 spin_lock_irqsave(&sclp_con_lock, flags);
112 del_timer(&sclp_con_timer);
113 while (sclp_con_queue_running) {
114 spin_unlock_irqrestore(&sclp_con_lock, flags);
115 sclp_sync_wait();
116 spin_lock_irqsave(&sclp_con_lock, flags);
117 }
118 spin_unlock_irqrestore(&sclp_con_lock, flags);
119}
120
121/*
122 * When this routine is called from the timer then we flush the
123 * temporary write buffer without further waiting on a final new line.
124 */
125static void
126sclp_console_timeout(struct timer_list *unused)
127{
128 sclp_conbuf_emit();
129}
130
131/*
132 * Drop oldest console buffer if sclp_con_drop is set
133 */
134static int
135sclp_console_drop_buffer(void)
136{
137 struct list_head *list;
138 struct sclp_buffer *buffer;
139 void *page;
140
141 if (!sclp_console_drop)
142 return 0;
143 list = sclp_con_outqueue.next;
144 if (sclp_con_queue_running)
145 /* The first element is in I/O */
146 list = list->next;
147 if (list == &sclp_con_outqueue)
148 return 0;
149 list_del(list);
150 buffer = list_entry(list, struct sclp_buffer, list);
151 page = sclp_unmake_buffer(buffer);
152 list_add_tail((struct list_head *) page, &sclp_con_pages);
153 return 1;
154}
155
156/*
157 * Writes the given message to S390 system console
158 */
159static void
160sclp_console_write(struct console *console, const char *message,
161 unsigned int count)
162{
163 unsigned long flags;
164 void *page;
165 int written;
166
167 if (count == 0)
168 return;
169 spin_lock_irqsave(&sclp_con_lock, flags);
170 /*
171 * process escape characters, write message into buffer,
172 * send buffer to SCLP
173 */
174 do {
175 /* make sure we have a console output buffer */
176 if (sclp_conbuf == NULL) {
177 if (list_empty(&sclp_con_pages))
178 sclp_console_full++;
179 while (list_empty(&sclp_con_pages)) {
180 if (sclp_console_drop_buffer())
181 break;
182 spin_unlock_irqrestore(&sclp_con_lock, flags);
183 sclp_sync_wait();
184 spin_lock_irqsave(&sclp_con_lock, flags);
185 }
186 page = sclp_con_pages.next;
187 list_del((struct list_head *) page);
188 sclp_conbuf = sclp_make_buffer(page, SCLP_CON_COLUMNS,
189 SPACES_PER_TAB);
190 }
191 /* try to write the string to the current output buffer */
192 written = sclp_write(sclp_conbuf, (const unsigned char *)
193 message, count);
194 if (written == count)
195 break;
196 /*
197 * Not all characters could be written to the current
198 * output buffer. Emit the buffer, create a new buffer
199 * and then output the rest of the string.
200 */
201 spin_unlock_irqrestore(&sclp_con_lock, flags);
202 sclp_conbuf_emit();
203 spin_lock_irqsave(&sclp_con_lock, flags);
204 message += written;
205 count -= written;
206 } while (count > 0);
207 /* Setup timer to output current console buffer after 1/10 second */
208 if (sclp_conbuf != NULL && sclp_chars_in_buffer(sclp_conbuf) != 0 &&
209 !timer_pending(&sclp_con_timer)) {
210 mod_timer(&sclp_con_timer, jiffies + HZ / 10);
211 }
212 spin_unlock_irqrestore(&sclp_con_lock, flags);
213}
214
215static struct tty_driver *
216sclp_console_device(struct console *c, int *index)
217{
218 *index = c->index;
219 return sclp_tty_driver;
220}
221
222/*
223 * This panic/reboot notifier makes sure that all buffers
224 * will be flushed to the SCLP.
225 */
226static int sclp_console_notify(struct notifier_block *self,
227 unsigned long event, void *data)
228{
229 /*
230 * Perform the lock check before effectively getting the
231 * lock on sclp_conbuf_emit() / sclp_console_sync_queue()
232 * to prevent potential lockups in atomic context.
233 */
234 if (spin_is_locked(&sclp_con_lock))
235 return NOTIFY_DONE;
236
237 sclp_conbuf_emit();
238 sclp_console_sync_queue();
239
240 return NOTIFY_DONE;
241}
242
243static struct notifier_block on_panic_nb = {
244 .notifier_call = sclp_console_notify,
245 .priority = INT_MIN + 1, /* run the callback late */
246};
247
248static struct notifier_block on_reboot_nb = {
249 .notifier_call = sclp_console_notify,
250 .priority = INT_MIN + 1, /* run the callback late */
251};
252
253/*
254 * used to register the SCLP console to the kernel and to
255 * give printk necessary information
256 */
257static struct console sclp_console =
258{
259 .name = sclp_console_name,
260 .write = sclp_console_write,
261 .device = sclp_console_device,
262 .flags = CON_PRINTBUFFER,
263 .index = 0 /* ttyS0 */
264};
265
266/*
267 * called by console_init() in drivers/char/tty_io.c at boot-time.
268 */
269static int __init
270sclp_console_init(void)
271{
272 void *page;
273 int i;
274 int rc;
275
276 /* SCLP consoles are handled together */
277 if (!(CONSOLE_IS_SCLP || CONSOLE_IS_VT220))
278 return 0;
279 rc = sclp_rw_init();
280 if (rc)
281 return rc;
282 /* Allocate pages for output buffering */
283 for (i = 0; i < sclp_console_pages; i++) {
284 page = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
285 list_add_tail(page, &sclp_con_pages);
286 }
287 sclp_conbuf = NULL;
288 timer_setup(&sclp_con_timer, sclp_console_timeout, 0);
289
290 /* enable printk-access to this driver */
291 atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb);
292 register_reboot_notifier(&on_reboot_nb);
293 register_console(&sclp_console);
294 return 0;
295}
296
297console_initcall(sclp_console_init);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * SCLP line mode console driver
4 *
5 * Copyright IBM Corp. 1999, 2009
6 * Author(s): Martin Peschke <mpeschke@de.ibm.com>
7 * Martin Schwidefsky <schwidefsky@de.ibm.com>
8 */
9
10#include <linux/kmod.h>
11#include <linux/console.h>
12#include <linux/init.h>
13#include <linux/timer.h>
14#include <linux/jiffies.h>
15#include <linux/termios.h>
16#include <linux/err.h>
17#include <linux/reboot.h>
18#include <linux/gfp.h>
19
20#include "sclp.h"
21#include "sclp_rw.h"
22#include "sclp_tty.h"
23
24#define sclp_console_major 4 /* TTYAUX_MAJOR */
25#define sclp_console_minor 64
26#define sclp_console_name "ttyS"
27
28/* Lock to guard over changes to global variables */
29static spinlock_t sclp_con_lock;
30/* List of free pages that can be used for console output buffering */
31static struct list_head sclp_con_pages;
32/* List of full struct sclp_buffer structures ready for output */
33static struct list_head sclp_con_outqueue;
34/* Pointer to current console buffer */
35static struct sclp_buffer *sclp_conbuf;
36/* Timer for delayed output of console messages */
37static struct timer_list sclp_con_timer;
38/* Suspend mode flag */
39static int sclp_con_suspended;
40/* Flag that output queue is currently running */
41static int sclp_con_queue_running;
42
43/* Output format for console messages */
44static unsigned short sclp_con_columns;
45static unsigned short sclp_con_width_htab;
46
47static void
48sclp_conbuf_callback(struct sclp_buffer *buffer, int rc)
49{
50 unsigned long flags;
51 void *page;
52
53 do {
54 page = sclp_unmake_buffer(buffer);
55 spin_lock_irqsave(&sclp_con_lock, flags);
56
57 /* Remove buffer from outqueue */
58 list_del(&buffer->list);
59 list_add_tail((struct list_head *) page, &sclp_con_pages);
60
61 /* Check if there is a pending buffer on the out queue. */
62 buffer = NULL;
63 if (!list_empty(&sclp_con_outqueue))
64 buffer = list_first_entry(&sclp_con_outqueue,
65 struct sclp_buffer, list);
66 if (!buffer || sclp_con_suspended) {
67 sclp_con_queue_running = 0;
68 spin_unlock_irqrestore(&sclp_con_lock, flags);
69 break;
70 }
71 spin_unlock_irqrestore(&sclp_con_lock, flags);
72 } while (sclp_emit_buffer(buffer, sclp_conbuf_callback));
73}
74
75/*
76 * Finalize and emit first pending buffer.
77 */
78static void sclp_conbuf_emit(void)
79{
80 struct sclp_buffer* buffer;
81 unsigned long flags;
82 int rc;
83
84 spin_lock_irqsave(&sclp_con_lock, flags);
85 if (sclp_conbuf)
86 list_add_tail(&sclp_conbuf->list, &sclp_con_outqueue);
87 sclp_conbuf = NULL;
88 if (sclp_con_queue_running || sclp_con_suspended)
89 goto out_unlock;
90 if (list_empty(&sclp_con_outqueue))
91 goto out_unlock;
92 buffer = list_first_entry(&sclp_con_outqueue, struct sclp_buffer,
93 list);
94 sclp_con_queue_running = 1;
95 spin_unlock_irqrestore(&sclp_con_lock, flags);
96
97 rc = sclp_emit_buffer(buffer, sclp_conbuf_callback);
98 if (rc)
99 sclp_conbuf_callback(buffer, rc);
100 return;
101out_unlock:
102 spin_unlock_irqrestore(&sclp_con_lock, flags);
103}
104
105/*
106 * Wait until out queue is empty
107 */
108static void sclp_console_sync_queue(void)
109{
110 unsigned long flags;
111
112 spin_lock_irqsave(&sclp_con_lock, flags);
113 if (timer_pending(&sclp_con_timer))
114 del_timer(&sclp_con_timer);
115 while (sclp_con_queue_running) {
116 spin_unlock_irqrestore(&sclp_con_lock, flags);
117 sclp_sync_wait();
118 spin_lock_irqsave(&sclp_con_lock, flags);
119 }
120 spin_unlock_irqrestore(&sclp_con_lock, flags);
121}
122
123/*
124 * When this routine is called from the timer then we flush the
125 * temporary write buffer without further waiting on a final new line.
126 */
127static void
128sclp_console_timeout(struct timer_list *unused)
129{
130 sclp_conbuf_emit();
131}
132
133/*
134 * Drop oldest console buffer if sclp_con_drop is set
135 */
136static int
137sclp_console_drop_buffer(void)
138{
139 struct list_head *list;
140 struct sclp_buffer *buffer;
141 void *page;
142
143 if (!sclp_console_drop)
144 return 0;
145 list = sclp_con_outqueue.next;
146 if (sclp_con_queue_running)
147 /* The first element is in I/O */
148 list = list->next;
149 if (list == &sclp_con_outqueue)
150 return 0;
151 list_del(list);
152 buffer = list_entry(list, struct sclp_buffer, list);
153 page = sclp_unmake_buffer(buffer);
154 list_add_tail((struct list_head *) page, &sclp_con_pages);
155 return 1;
156}
157
158/*
159 * Writes the given message to S390 system console
160 */
161static void
162sclp_console_write(struct console *console, const char *message,
163 unsigned int count)
164{
165 unsigned long flags;
166 void *page;
167 int written;
168
169 if (count == 0)
170 return;
171 spin_lock_irqsave(&sclp_con_lock, flags);
172 /*
173 * process escape characters, write message into buffer,
174 * send buffer to SCLP
175 */
176 do {
177 /* make sure we have a console output buffer */
178 if (sclp_conbuf == NULL) {
179 if (list_empty(&sclp_con_pages))
180 sclp_console_full++;
181 while (list_empty(&sclp_con_pages)) {
182 if (sclp_con_suspended)
183 goto out;
184 if (sclp_console_drop_buffer())
185 break;
186 spin_unlock_irqrestore(&sclp_con_lock, flags);
187 sclp_sync_wait();
188 spin_lock_irqsave(&sclp_con_lock, flags);
189 }
190 page = sclp_con_pages.next;
191 list_del((struct list_head *) page);
192 sclp_conbuf = sclp_make_buffer(page, sclp_con_columns,
193 sclp_con_width_htab);
194 }
195 /* try to write the string to the current output buffer */
196 written = sclp_write(sclp_conbuf, (const unsigned char *)
197 message, count);
198 if (written == count)
199 break;
200 /*
201 * Not all characters could be written to the current
202 * output buffer. Emit the buffer, create a new buffer
203 * and then output the rest of the string.
204 */
205 spin_unlock_irqrestore(&sclp_con_lock, flags);
206 sclp_conbuf_emit();
207 spin_lock_irqsave(&sclp_con_lock, flags);
208 message += written;
209 count -= written;
210 } while (count > 0);
211 /* Setup timer to output current console buffer after 1/10 second */
212 if (sclp_conbuf != NULL && sclp_chars_in_buffer(sclp_conbuf) != 0 &&
213 !timer_pending(&sclp_con_timer)) {
214 mod_timer(&sclp_con_timer, jiffies + HZ / 10);
215 }
216out:
217 spin_unlock_irqrestore(&sclp_con_lock, flags);
218}
219
220static struct tty_driver *
221sclp_console_device(struct console *c, int *index)
222{
223 *index = c->index;
224 return sclp_tty_driver;
225}
226
227/*
228 * Make sure that all buffers will be flushed to the SCLP.
229 */
230static void
231sclp_console_flush(void)
232{
233 sclp_conbuf_emit();
234 sclp_console_sync_queue();
235}
236
237/*
238 * Resume console: If there are cached messages, emit them.
239 */
240static void sclp_console_resume(void)
241{
242 unsigned long flags;
243
244 spin_lock_irqsave(&sclp_con_lock, flags);
245 sclp_con_suspended = 0;
246 spin_unlock_irqrestore(&sclp_con_lock, flags);
247 sclp_conbuf_emit();
248}
249
250/*
251 * Suspend console: Set suspend flag and flush console
252 */
253static void sclp_console_suspend(void)
254{
255 unsigned long flags;
256
257 spin_lock_irqsave(&sclp_con_lock, flags);
258 sclp_con_suspended = 1;
259 spin_unlock_irqrestore(&sclp_con_lock, flags);
260 sclp_console_flush();
261}
262
263static int sclp_console_notify(struct notifier_block *self,
264 unsigned long event, void *data)
265{
266 sclp_console_flush();
267 return NOTIFY_OK;
268}
269
270static struct notifier_block on_panic_nb = {
271 .notifier_call = sclp_console_notify,
272 .priority = SCLP_PANIC_PRIO_CLIENT,
273};
274
275static struct notifier_block on_reboot_nb = {
276 .notifier_call = sclp_console_notify,
277 .priority = 1,
278};
279
280/*
281 * used to register the SCLP console to the kernel and to
282 * give printk necessary information
283 */
284static struct console sclp_console =
285{
286 .name = sclp_console_name,
287 .write = sclp_console_write,
288 .device = sclp_console_device,
289 .flags = CON_PRINTBUFFER,
290 .index = 0 /* ttyS0 */
291};
292
293/*
294 * This function is called for SCLP suspend and resume events.
295 */
296void sclp_console_pm_event(enum sclp_pm_event sclp_pm_event)
297{
298 switch (sclp_pm_event) {
299 case SCLP_PM_EVENT_FREEZE:
300 sclp_console_suspend();
301 break;
302 case SCLP_PM_EVENT_RESTORE:
303 case SCLP_PM_EVENT_THAW:
304 sclp_console_resume();
305 break;
306 }
307}
308
309/*
310 * called by console_init() in drivers/char/tty_io.c at boot-time.
311 */
312static int __init
313sclp_console_init(void)
314{
315 void *page;
316 int i;
317 int rc;
318
319 /* SCLP consoles are handled together */
320 if (!(CONSOLE_IS_SCLP || CONSOLE_IS_VT220))
321 return 0;
322 rc = sclp_rw_init();
323 if (rc)
324 return rc;
325 /* Allocate pages for output buffering */
326 INIT_LIST_HEAD(&sclp_con_pages);
327 for (i = 0; i < sclp_console_pages; i++) {
328 page = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
329 list_add_tail(page, &sclp_con_pages);
330 }
331 INIT_LIST_HEAD(&sclp_con_outqueue);
332 spin_lock_init(&sclp_con_lock);
333 sclp_conbuf = NULL;
334 timer_setup(&sclp_con_timer, sclp_console_timeout, 0);
335
336 /* Set output format */
337 if (MACHINE_IS_VM)
338 /*
339 * save 4 characters for the CPU number
340 * written at start of each line by VM/CP
341 */
342 sclp_con_columns = 76;
343 else
344 sclp_con_columns = 80;
345 sclp_con_width_htab = 8;
346
347 /* enable printk-access to this driver */
348 atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb);
349 register_reboot_notifier(&on_reboot_nb);
350 register_console(&sclp_console);
351 return 0;
352}
353
354console_initcall(sclp_console_init);