2 * drivers/s390/char/sclp_con.c
3 * SCLP line mode console driver
6 * Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
7 * Author(s): Martin Peschke <mpeschke@de.ibm.com>
8 * Martin Schwidefsky <schwidefsky@de.ibm.com>
11 #include <linux/kmod.h>
12 #include <linux/console.h>
13 #include <linux/init.h>
14 #include <linux/timer.h>
15 #include <linux/jiffies.h>
16 #include <linux/bootmem.h>
17 #include <linux/termios.h>
18 #include <linux/err.h>
24 #define sclp_console_major 4 /* TTYAUX_MAJOR */
25 #define sclp_console_minor 64
26 #define sclp_console_name "ttyS"
28 /* Lock to guard over changes to global variables */
29 static spinlock_t sclp_con_lock
;
30 /* List of free pages that can be used for console output buffering */
31 static struct list_head sclp_con_pages
;
32 /* List of full struct sclp_buffer structures ready for output */
33 static struct list_head sclp_con_outqueue
;
34 /* Counter how many buffers are emitted (max 1) and how many */
35 /* are on the output queue. */
36 static int sclp_con_buffer_count
;
37 /* Pointer to current console buffer */
38 static struct sclp_buffer
*sclp_conbuf
;
39 /* Timer for delayed output of console messages */
40 static struct timer_list sclp_con_timer
;
42 /* Output format for console messages */
43 static unsigned short sclp_con_columns
;
44 static unsigned short sclp_con_width_htab
;
47 sclp_conbuf_callback(struct sclp_buffer
*buffer
, int rc
)
53 page
= sclp_unmake_buffer(buffer
);
54 spin_lock_irqsave(&sclp_con_lock
, flags
);
55 /* Remove buffer from outqueue */
56 list_del(&buffer
->list
);
57 sclp_con_buffer_count
--;
58 list_add_tail((struct list_head
*) page
, &sclp_con_pages
);
59 /* Check if there is a pending buffer on the out queue. */
61 if (!list_empty(&sclp_con_outqueue
))
62 buffer
= list_entry(sclp_con_outqueue
.next
,
63 struct sclp_buffer
, list
);
64 spin_unlock_irqrestore(&sclp_con_lock
, flags
);
65 } while (buffer
&& sclp_emit_buffer(buffer
, sclp_conbuf_callback
));
69 sclp_conbuf_emit(void)
71 struct sclp_buffer
* buffer
;
76 spin_lock_irqsave(&sclp_con_lock
, flags
);
80 spin_unlock_irqrestore(&sclp_con_lock
, flags
);
83 list_add_tail(&buffer
->list
, &sclp_con_outqueue
);
84 count
= sclp_con_buffer_count
++;
85 spin_unlock_irqrestore(&sclp_con_lock
, flags
);
88 rc
= sclp_emit_buffer(buffer
, sclp_conbuf_callback
);
90 sclp_conbuf_callback(buffer
, rc
);
94 * When this routine is called from the timer then we flush the
95 * temporary write buffer without further waiting on a final new line.
98 sclp_console_timeout(unsigned long data
)
104 * Writes the given message to S390 system console
107 sclp_console_write(struct console
*console
, const char *message
,
116 spin_lock_irqsave(&sclp_con_lock
, flags
);
118 * process escape characters, write message into buffer,
119 * send buffer to SCLP
122 /* make sure we have a console output buffer */
123 if (sclp_conbuf
== NULL
) {
124 while (list_empty(&sclp_con_pages
)) {
125 spin_unlock_irqrestore(&sclp_con_lock
, flags
);
127 spin_lock_irqsave(&sclp_con_lock
, flags
);
129 page
= sclp_con_pages
.next
;
130 list_del((struct list_head
*) page
);
131 sclp_conbuf
= sclp_make_buffer(page
, sclp_con_columns
,
132 sclp_con_width_htab
);
134 /* try to write the string to the current output buffer */
135 written
= sclp_write(sclp_conbuf
, (const unsigned char *)
137 if (written
== count
)
140 * Not all characters could be written to the current
141 * output buffer. Emit the buffer, create a new buffer
142 * and then output the rest of the string.
144 spin_unlock_irqrestore(&sclp_con_lock
, flags
);
146 spin_lock_irqsave(&sclp_con_lock
, flags
);
150 /* Setup timer to output current console buffer after 1/10 second */
151 if (sclp_conbuf
!= NULL
&& sclp_chars_in_buffer(sclp_conbuf
) != 0 &&
152 !timer_pending(&sclp_con_timer
)) {
153 init_timer(&sclp_con_timer
);
154 sclp_con_timer
.function
= sclp_console_timeout
;
155 sclp_con_timer
.data
= 0UL;
156 sclp_con_timer
.expires
= jiffies
+ HZ
/10;
157 add_timer(&sclp_con_timer
);
159 spin_unlock_irqrestore(&sclp_con_lock
, flags
);
162 static struct tty_driver
*
163 sclp_console_device(struct console
*c
, int *index
)
166 return sclp_tty_driver
;
170 * This routine is called from panic when the kernel
171 * is going to give up. We have to make sure that all buffers
172 * will be flushed to the SCLP.
175 sclp_console_unblank(void)
180 spin_lock_irqsave(&sclp_con_lock
, flags
);
181 if (timer_pending(&sclp_con_timer
))
182 del_timer(&sclp_con_timer
);
183 while (sclp_con_buffer_count
> 0) {
184 spin_unlock_irqrestore(&sclp_con_lock
, flags
);
186 spin_lock_irqsave(&sclp_con_lock
, flags
);
188 spin_unlock_irqrestore(&sclp_con_lock
, flags
);
192 * used to register the SCLP console to the kernel and to
193 * give printk necessary information
195 static struct console sclp_console
=
197 .name
= sclp_console_name
,
198 .write
= sclp_console_write
,
199 .device
= sclp_console_device
,
200 .unblank
= sclp_console_unblank
,
201 .flags
= CON_PRINTBUFFER
,
202 .index
= 0 /* ttyS0 */
206 * called by console_init() in drivers/char/tty_io.c at boot-time.
209 sclp_console_init(void)
215 if (!CONSOLE_IS_SCLP
)
220 /* Allocate pages for output buffering */
221 INIT_LIST_HEAD(&sclp_con_pages
);
222 for (i
= 0; i
< MAX_CONSOLE_PAGES
; i
++) {
223 page
= alloc_bootmem_low_pages(PAGE_SIZE
);
224 list_add_tail((struct list_head
*) page
, &sclp_con_pages
);
226 INIT_LIST_HEAD(&sclp_con_outqueue
);
227 spin_lock_init(&sclp_con_lock
);
228 sclp_con_buffer_count
= 0;
230 init_timer(&sclp_con_timer
);
232 /* Set output format */
235 * save 4 characters for the CPU number
236 * written at start of each line by VM/CP
238 sclp_con_columns
= 76;
240 sclp_con_columns
= 80;
241 sclp_con_width_htab
= 8;
243 /* enable printk-access to this driver */
244 register_console(&sclp_console
);
248 console_initcall(sclp_console_init
);