1 // SPDX-License-Identifier: GPL-2.0
3  * driver: reading from and writing to system console on S/390 via SCLP
23  * The room for the SCCB (only for writing) is not equal to a pages size
24  * (as it is specified as the maximum size in the SCLP documentation)
25  * because of the additional data structure described above.
27 #define MAX_SCCB_ROOM (PAGE_SIZE - sizeof(struct sclp_buffer))
36  * a pointer to a struct sclp_buffer structure that is located at the
37  * end of the input page. This reduces the buffer space by a few
48 	 * We keep the struct sclp_buffer structure at the end  in sclp_make_buffer()
49 	 * of the sccb page.  in sclp_make_buffer()
51 	buffer = ((struct sclp_buffer *) ((addr_t) sccb + PAGE_SIZE)) - 1;  in sclp_make_buffer()
52 	buffer->sccb = sccb;  in sclp_make_buffer()
53 	buffer->retry_count = 0;  in sclp_make_buffer()
54 	buffer->messages = 0;  in sclp_make_buffer()
55 	buffer->char_sum = 0;  in sclp_make_buffer()
56 	buffer->current_line = NULL;  in sclp_make_buffer()
57 	buffer->current_length = 0;  in sclp_make_buffer()
58 	buffer->columns = columns;  in sclp_make_buffer()
59 	buffer->htab = htab;  in sclp_make_buffer()
63 	sccb->length = sizeof(struct sccb_header);  in sclp_make_buffer()
69  * Return a pointer to the original page that has been used to create
70  * the buffer.
75 	return buffer->sccb;  in sclp_unmake_buffer()
79  * Initialize a new message the end of the provided buffer with
80  * enough room for max_len characters. Return 0 on success.
88 	struct go *go;  in sclp_initialize_mto()  local
95 	/* check if current buffer sccb can contain the mto */  in sclp_initialize_mto()
96 	sccb = buffer->sccb;  in sclp_initialize_mto()
97 	if ((MAX_SCCB_ROOM - sccb->length) < msg_size)  in sclp_initialize_mto()
98 		return -ENOMEM;  in sclp_initialize_mto()
100 	msg = (struct msg_buf *)((addr_t) sccb + sccb->length);  in sclp_initialize_mto()
102 	msg->header.length = sizeof(struct msg_buf);  in sclp_initialize_mto()
103 	msg->header.type = EVTYP_MSG;  in sclp_initialize_mto()
105 	mdb = &msg->mdb;  in sclp_initialize_mto()
106 	mdb->header.length = sizeof(struct mdb);  in sclp_initialize_mto()
107 	mdb->header.type = 1;  in sclp_initialize_mto()
108 	mdb->header.tag = 0xD4C4C240;	/* ebcdic "MDB " */  in sclp_initialize_mto()
109 	mdb->header.revision_code = 1;  in sclp_initialize_mto()
111 	go = &mdb->go;  in sclp_initialize_mto()
112 	go->length = sizeof(struct go);  in sclp_initialize_mto()
113 	go->type = 1;  in sclp_initialize_mto()
115 	mto = &mdb->mto;  in sclp_initialize_mto()
116 	mto->length = sizeof(struct mto);  in sclp_initialize_mto()
117 	mto->type = 4;	/* message text object */  in sclp_initialize_mto()
118 	mto->line_type_flags = LNTPFLGS_ENDTEXT; /* end text */  in sclp_initialize_mto()
121 	buffer->current_msg = msg;  in sclp_initialize_mto()
122 	buffer->current_line = (char *) (mto + 1);  in sclp_initialize_mto()
123 	buffer->current_length = 0;  in sclp_initialize_mto()
130  * updating the sizes of MTO, enclosing MDB, event buffer and SCCB.
142 	sccb = buffer->sccb;  in sclp_finalize_mto()
143 	msg = buffer->current_msg;  in sclp_finalize_mto()
144 	msg->header.length += buffer->current_length;  in sclp_finalize_mto()
145 	msg->mdb.header.length += buffer->current_length;  in sclp_finalize_mto()
146 	msg->mdb.mto.length += buffer->current_length;  in sclp_finalize_mto()
147 	sccb->length += msg->header.length;  in sclp_finalize_mto()
152 	 * for the SCCB currently used for buffering and at all  in sclp_finalize_mto()
154 	buffer->messages++;  in sclp_finalize_mto()
155 	buffer->char_sum += buffer->current_length;  in sclp_finalize_mto()
157 	buffer->current_line = NULL;  in sclp_finalize_mto()
158 	buffer->current_length = 0;  in sclp_finalize_mto()
159 	buffer->current_msg = NULL;  in sclp_finalize_mto()
164  * returns number of characters written to the output sccb
165  * ("processed" means that is not guaranteed that the character have already
166  *  been sent to the SCLP but that it will be done at least next time the SCLP
180 	 * these characters on the native machine and only partial support  in sclp_write()
181 	 * under VM (Why does VM interpret \n but the native machine doesn't ?)  in sclp_write()
183 	 * Depending on i/o-control setting the message is always written  in sclp_write()
184 	 * immediately or we wait for a final new line maybe coming with the  in sclp_write()
191 	 * previous output that have already been accepted by the SCLP.  in sclp_write()
195 	 * previous \t and decreases the current position by one column.  in sclp_write()
202 			if (buffer->current_line == NULL) {  in sclp_write()
211 			if (buffer->current_line == NULL) {  in sclp_write()
213 							 buffer->columns);  in sclp_write()
217 			buffer->current_msg->mdb.go.general_msg_flags |=  in sclp_write()
222 			if (buffer->current_line == NULL) {  in sclp_write()
224 							 buffer->columns);  in sclp_write()
228 			/* "go to (next htab-boundary + 1, same line)" */  in sclp_write()
230 				if (buffer->current_length >= buffer->columns)  in sclp_write()
233 				*buffer->current_line++ = 0x40;  in sclp_write()
234 				buffer->current_length++;  in sclp_write()
235 			} while (buffer->current_length % buffer->htab);  in sclp_write()
239 			/* "go to (actual column, actual line + 1)" */  in sclp_write()
241 			if (buffer->current_line != NULL) {  in sclp_write()
242 				spaces = buffer->current_length;  in sclp_write()
245 							 buffer->columns);  in sclp_write()
248 				memset(buffer->current_line, 0x40, spaces);  in sclp_write()
249 				buffer->current_line += spaces;  in sclp_write()
250 				buffer->current_length = spaces;  in sclp_write()
252 				/* one an empty line this is the same as \n */  in sclp_write()
254 							 buffer->columns);  in sclp_write()
261 			/* "go to (actual column - 1, actual line)" */  in sclp_write()
264 			if (buffer->current_line != NULL &&  in sclp_write()
265 			    buffer->current_length > 0) {  in sclp_write()
266 				buffer->current_length--;  in sclp_write()
267 				buffer->current_line--;  in sclp_write()
272 			if (buffer->current_line != NULL)  in sclp_write()
274 			/* skip the rest of the message including the 0 byte */  in sclp_write()
275 			i_msg = count - 1;  in sclp_write()
282 			if (buffer->current_line == NULL) {  in sclp_write()
284 							 buffer->columns);  in sclp_write()
288 			*buffer->current_line++ = sclp_ascebc(msg[i_msg]);  in sclp_write()
289 			buffer->current_length++;  in sclp_write()
293 		if (buffer->current_line != NULL &&  in sclp_write()
294 		    buffer->current_length >= buffer->columns)  in sclp_write()
303  * Return the number of free bytes in the sccb
311 	sccb = buffer->sccb;  in sclp_buffer_space()
312 	count = MAX_SCCB_ROOM - sccb->length;  in sclp_buffer_space()
313 	if (buffer->current_line != NULL)  in sclp_buffer_space()
314 		count -= sizeof(struct msg_buf) + buffer->current_length;  in sclp_buffer_space()
326 	count = buffer->char_sum;  in sclp_chars_in_buffer()
327 	if (buffer->current_line != NULL)  in sclp_chars_in_buffer()
328 		count += buffer->current_length;  in sclp_chars_in_buffer()
353  * second half of Write Event Data-function that has to be done after
364 	sccb = buffer->sccb;  in sclp_writedata_callback()
366 	if (request->status == SCLP_REQ_FAILED) {  in sclp_writedata_callback()
367 		if (buffer->callback != NULL)  in sclp_writedata_callback()
368 			buffer->callback(buffer, -EIO);  in sclp_writedata_callback()
372 	switch (sccb->response_code) {  in sclp_writedata_callback()
379 		if (++buffer->retry_count > SCLP_BUFFER_MAX_RETRY) {  in sclp_writedata_callback()
380 			rc = -EIO;  in sclp_writedata_callback()
386 			sccb->response_code = 0x0000;  in sclp_writedata_callback()
387 			buffer->request.status = SCLP_REQ_FILLED;  in sclp_writedata_callback()
397 		if (++buffer->retry_count > SCLP_BUFFER_MAX_RETRY) {  in sclp_writedata_callback()
398 			rc = -EIO;  in sclp_writedata_callback()
402 		sccb->response_code = 0x0000;  in sclp_writedata_callback()
403 		buffer->request.status = SCLP_REQ_FILLED;  in sclp_writedata_callback()
409 		if (sccb->response_code == 0x71f0)  in sclp_writedata_callback()
410 			rc = -ENOMEM;  in sclp_writedata_callback()
412 			rc = -EINVAL;  in sclp_writedata_callback()
415 	if (buffer->callback != NULL)  in sclp_writedata_callback()
416 		buffer->callback(buffer, rc);  in sclp_writedata_callback()
420  * Setup the request structure in the struct sclp_buffer to do SCLP Write
421  * Event Data and pass the request to the core SCLP loop. Return zero on
422  * success, non-zero otherwise.
429 	if (buffer->current_line != NULL)  in sclp_emit_buffer()
432 	/* Are there messages in the output buffer ? */  in sclp_emit_buffer()
433 	if (buffer->messages == 0)  in sclp_emit_buffer()
434 		return -EIO;  in sclp_emit_buffer()
436 	buffer->request.command = SCLP_CMDW_WRITE_EVENT_DATA;  in sclp_emit_buffer()
437 	buffer->request.status = SCLP_REQ_FILLED;  in sclp_emit_buffer()
438 	buffer->request.callback = sclp_writedata_callback;  in sclp_emit_buffer()
439 	buffer->request.callback_data = buffer;  in sclp_emit_buffer()
440 	buffer->request.sccb = buffer->sccb;  in sclp_emit_buffer()
441 	buffer->callback = callback;  in sclp_emit_buffer()
442 	return sclp_add_request(&buffer->request);  in sclp_emit_buffer()