Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 443 insertions, 0 deletions

diff --git a/drivers/s390/char/sclp_rw.c b/drivers/s390/char/sclp_rw.c
new file mode 100644
index 000000000..169032655
--- /dev/null
+++ b/drivers/s390/char/sclp_rw.c
@@ -0,0 +1,443 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * driver: reading from and writing to system console on S/390 via SCLP
+ *
+ * Copyright IBM Corp. 1999, 2009
+ *
+ * Author(s): Martin Peschke <mpeschke@de.ibm.com>
+ *	      Martin Schwidefsky <schwidefsky@de.ibm.com>
+ */
+
+#include <linux/kmod.h>
+#include <linux/types.h>
+#include <linux/err.h>
+#include <linux/string.h>
+#include <linux/spinlock.h>
+#include <linux/ctype.h>
+#include <linux/uaccess.h>
+
+#include "sclp.h"
+#include "sclp_rw.h"
+
+/*
+ * The room for the SCCB (only for writing) is not equal to a pages size
+ * (as it is specified as the maximum size in the SCLP documentation)
+ * because of the additional data structure described above.
+ */
+#define MAX_SCCB_ROOM (PAGE_SIZE - sizeof(struct sclp_buffer))
+
+/* Event type structure for write message and write priority message */
+static struct sclp_register sclp_rw_event = {
+	.send_mask = EVTYP_MSG_MASK,
+};
+
+/*
+ * Setup a sclp write buffer. Gets a page as input (4K) and returns
+ * a pointer to a struct sclp_buffer structure that is located at the
+ * end of the input page. This reduces the buffer space by a few
+ * bytes but simplifies things.
+ */
+struct sclp_buffer *
+sclp_make_buffer(void *page, unsigned short columns, unsigned short htab)
+{
+	struct sclp_buffer *buffer;
+	struct sccb_header *sccb;
+
+	sccb = (struct sccb_header *) page;
+	/*
+	 * We keep the struct sclp_buffer structure at the end
+	 * of the sccb page.
+	 */
+	buffer = ((struct sclp_buffer *) ((addr_t) sccb + PAGE_SIZE)) - 1;
+	buffer->sccb = sccb;
+	buffer->retry_count = 0;
+	buffer->messages = 0;
+	buffer->char_sum = 0;
+	buffer->current_line = NULL;
+	buffer->current_length = 0;
+	buffer->columns = columns;
+	buffer->htab = htab;
+
+	/* initialize sccb */
+	memset(sccb, 0, sizeof(struct sccb_header));
+	sccb->length = sizeof(struct sccb_header);
+
+	return buffer;
+}
+
+/*
+ * Return a pointer to the original page that has been used to create
+ * the buffer.
+ */
+void *
+sclp_unmake_buffer(struct sclp_buffer *buffer)
+{
+	return buffer->sccb;
+}
+
+/*
+ * Initialize a new message the end of the provided buffer with
+ * enough room for max_len characters. Return 0 on success.
+ */
+static int
+sclp_initialize_mto(struct sclp_buffer *buffer, int max_len)
+{
+	struct sccb_header *sccb;
+	struct msg_buf *msg;
+	struct mdb *mdb;
+	struct go *go;
+	struct mto *mto;
+	int msg_size;
+
+	/* max size of new message including message text  */
+	msg_size = sizeof(struct msg_buf) + max_len;
+
+	/* check if current buffer sccb can contain the mto */
+	sccb = buffer->sccb;
+	if ((MAX_SCCB_ROOM - sccb->length) < msg_size)
+		return -ENOMEM;
+
+	msg = (struct msg_buf *)((addr_t) sccb + sccb->length);
+	memset(msg, 0, sizeof(struct msg_buf));
+	msg->header.length = sizeof(struct msg_buf);
+	msg->header.type = EVTYP_MSG;
+
+	mdb = &msg->mdb;
+	mdb->header.length = sizeof(struct mdb);
+	mdb->header.type = 1;
+	mdb->header.tag = 0xD4C4C240;	/* ebcdic "MDB " */
+	mdb->header.revision_code = 1;
+
+	go = &mdb->go;
+	go->length = sizeof(struct go);
+	go->type = 1;
+
+	mto = &mdb->mto;
+	mto->length = sizeof(struct mto);
+	mto->type = 4;	/* message text object */
+	mto->line_type_flags = LNTPFLGS_ENDTEXT; /* end text */
+
+	/* set pointer to first byte after struct mto. */
+	buffer->current_msg = msg;
+	buffer->current_line = (char *) (mto + 1);
+	buffer->current_length = 0;
+
+	return 0;
+}
+
+/*
+ * Finalize message initialized by sclp_initialize_mto(),
+ * updating the sizes of MTO, enclosing MDB, event buffer and SCCB.
+ */
+static void
+sclp_finalize_mto(struct sclp_buffer *buffer)
+{
+	struct sccb_header *sccb;
+	struct msg_buf *msg;
+
+	/*
+	 * update values of sizes
+	 * (SCCB, Event(Message) Buffer, Message Data Block)
+	 */
+	sccb = buffer->sccb;
+	msg = buffer->current_msg;
+	msg->header.length += buffer->current_length;
+	msg->mdb.header.length += buffer->current_length;
+	msg->mdb.mto.length += buffer->current_length;
+	sccb->length += msg->header.length;
+
+	/*
+	 * count number of buffered messages (= number of Message Text
+	 * Objects) and number of buffered characters
+	 * for the SCCB currently used for buffering and at all
+	 */
+	buffer->messages++;
+	buffer->char_sum += buffer->current_length;
+
+	buffer->current_line = NULL;
+	buffer->current_length = 0;
+	buffer->current_msg = NULL;
+}
+
+/*
+ * processing of a message including escape characters,
+ * returns number of characters written to the output sccb
+ * ("processed" means that is not guaranteed that the character have already
+ *  been sent to the SCLP but that it will be done at least next time the SCLP
+ *  is not busy)
+ */
+int
+sclp_write(struct sclp_buffer *buffer, const unsigned char *msg, int count)
+{
+	int spaces, i_msg;
+	int rc;
+
+	/*
+	 * parse msg for escape sequences (\t,\v ...) and put formated
+	 * msg into an mto (created by sclp_initialize_mto).
+	 *
+	 * We have to do this work ourselfs because there is no support for
+	 * these characters on the native machine and only partial support
+	 * under VM (Why does VM interpret \n but the native machine doesn't ?)
+	 *
+	 * Depending on i/o-control setting the message is always written
+	 * immediately or we wait for a final new line maybe coming with the
+	 * next message. Besides we avoid a buffer overrun by writing its
+	 * content.
+	 *
+	 * RESTRICTIONS:
+	 *
+	 * \r and \b work within one line because we are not able to modify
+	 * previous output that have already been accepted by the SCLP.
+	 *
+	 * \t combined with following \r is not correctly represented because
+	 * \t is expanded to some spaces but \r does not know about a
+	 * previous \t and decreases the current position by one column.
+	 * This is in order to a slim and quick implementation.
+	 */
+	for (i_msg = 0; i_msg < count; i_msg++) {
+		switch (msg[i_msg]) {
+		case '\n':	/* new line, line feed (ASCII)	*/
+			/* check if new mto needs to be created */
+			if (buffer->current_line == NULL) {
+				rc = sclp_initialize_mto(buffer, 0);
+				if (rc)
+					return i_msg;
+			}
+			sclp_finalize_mto(buffer);
+			break;
+		case '\a':	/* bell, one for several times	*/
+			/* set SCLP sound alarm bit in General Object */
+			if (buffer->current_line == NULL) {
+				rc = sclp_initialize_mto(buffer,
+							 buffer->columns);
+				if (rc)
+					return i_msg;
+			}
+			buffer->current_msg->mdb.go.general_msg_flags |=
+				GNRLMSGFLGS_SNDALRM;
+			break;
+		case '\t':	/* horizontal tabulator	 */
+			/* check if new mto needs to be created */
+			if (buffer->current_line == NULL) {
+				rc = sclp_initialize_mto(buffer,
+							 buffer->columns);
+				if (rc)
+					return i_msg;
+			}
+			/* "go to (next htab-boundary + 1, same line)" */
+			do {
+				if (buffer->current_length >= buffer->columns)
+					break;
+				/* ok, add a blank */
+				*buffer->current_line++ = 0x40;
+				buffer->current_length++;
+			} while (buffer->current_length % buffer->htab);
+			break;
+		case '\f':	/* form feed  */
+		case '\v':	/* vertical tabulator  */
+			/* "go to (actual column, actual line + 1)" */
+			/* = new line, leading spaces */
+			if (buffer->current_line != NULL) {
+				spaces = buffer->current_length;
+				sclp_finalize_mto(buffer);
+				rc = sclp_initialize_mto(buffer,
+							 buffer->columns);
+				if (rc)
+					return i_msg;
+				memset(buffer->current_line, 0x40, spaces);
+				buffer->current_line += spaces;
+				buffer->current_length = spaces;
+			} else {
+				/* one an empty line this is the same as \n */
+				rc = sclp_initialize_mto(buffer,
+							 buffer->columns);
+				if (rc)
+					return i_msg;
+				sclp_finalize_mto(buffer);
+			}
+			break;
+		case '\b':	/* backspace  */
+			/* "go to (actual column - 1, actual line)" */
+			/* decrement counter indicating position, */
+			/* do not remove last character */
+			if (buffer->current_line != NULL &&
+			    buffer->current_length > 0) {
+				buffer->current_length--;
+				buffer->current_line--;
+			}
+			break;
+		case 0x00:	/* end of string  */
+			/* transfer current line to SCCB */
+			if (buffer->current_line != NULL)
+				sclp_finalize_mto(buffer);
+			/* skip the rest of the message including the 0 byte */
+			i_msg = count - 1;
+			break;
+		default:	/* no escape character	*/
+			/* do not output unprintable characters */
+			if (!isprint(msg[i_msg]))
+				break;
+			/* check if new mto needs to be created */
+			if (buffer->current_line == NULL) {
+				rc = sclp_initialize_mto(buffer,
+							 buffer->columns);
+				if (rc)
+					return i_msg;
+			}
+			*buffer->current_line++ = sclp_ascebc(msg[i_msg]);
+			buffer->current_length++;
+			break;
+		}
+		/* check if current mto is full */
+		if (buffer->current_line != NULL &&
+		    buffer->current_length >= buffer->columns)
+			sclp_finalize_mto(buffer);
+	}
+
+	/* return number of processed characters */
+	return i_msg;
+}
+
+/*
+ * Return the number of free bytes in the sccb
+ */
+int
+sclp_buffer_space(struct sclp_buffer *buffer)
+{
+	struct sccb_header *sccb;
+	int count;
+
+	sccb = buffer->sccb;
+	count = MAX_SCCB_ROOM - sccb->length;
+	if (buffer->current_line != NULL)
+		count -= sizeof(struct msg_buf) + buffer->current_length;
+	return count;
+}
+
+/*
+ * Return number of characters in buffer
+ */
+unsigned int
+sclp_chars_in_buffer(struct sclp_buffer *buffer)
+{
+	unsigned int count;
+
+	count = buffer->char_sum;
+	if (buffer->current_line != NULL)
+		count += buffer->current_length;
+	return count;
+}
+
+/*
+ * called by sclp_console_init and/or sclp_tty_init
+ */
+int
+sclp_rw_init(void)
+{
+	static int init_done = 0;
+	int rc;
+
+	if (init_done)
+		return 0;
+
+	rc = sclp_register(&sclp_rw_event);
+	if (rc == 0)
+		init_done = 1;
+	return rc;
+}
+
+#define SCLP_BUFFER_MAX_RETRY		1
+
+/*
+ * second half of Write Event Data-function that has to be done after
+ * interruption indicating completion of Service Call.
+ */
+static void
+sclp_writedata_callback(struct sclp_req *request, void *data)
+{
+	int rc;
+	struct sclp_buffer *buffer;
+	struct sccb_header *sccb;
+
+	buffer = (struct sclp_buffer *) data;
+	sccb = buffer->sccb;
+
+	if (request->status == SCLP_REQ_FAILED) {
+		if (buffer->callback != NULL)
+			buffer->callback(buffer, -EIO);
+		return;
+	}
+	/* check SCLP response code and choose suitable action	*/
+	switch (sccb->response_code) {
+	case 0x0020 :
+		/* Normal completion, buffer processed, message(s) sent */
+		rc = 0;
+		break;
+
+	case 0x0340: /* Contained SCLP equipment check */
+		if (++buffer->retry_count > SCLP_BUFFER_MAX_RETRY) {
+			rc = -EIO;
+			break;
+		}
+		/* remove processed buffers and requeue rest */
+		if (sclp_remove_processed((struct sccb_header *) sccb) > 0) {
+			/* not all buffers were processed */
+			sccb->response_code = 0x0000;
+			buffer->request.status = SCLP_REQ_FILLED;
+			rc = sclp_add_request(request);
+			if (rc == 0)
+				return;
+		} else
+			rc = 0;
+		break;
+
+	case 0x0040: /* SCLP equipment check */
+	case 0x05f0: /* Target resource in improper state */
+		if (++buffer->retry_count > SCLP_BUFFER_MAX_RETRY) {
+			rc = -EIO;
+			break;
+		}
+		/* retry request */
+		sccb->response_code = 0x0000;
+		buffer->request.status = SCLP_REQ_FILLED;
+		rc = sclp_add_request(request);
+		if (rc == 0)
+			return;
+		break;
+	default:
+		if (sccb->response_code == 0x71f0)
+			rc = -ENOMEM;
+		else
+			rc = -EINVAL;
+		break;
+	}
+	if (buffer->callback != NULL)
+		buffer->callback(buffer, rc);
+}
+
+/*
+ * Setup the request structure in the struct sclp_buffer to do SCLP Write
+ * Event Data and pass the request to the core SCLP loop. Return zero on
+ * success, non-zero otherwise.
+ */
+int
+sclp_emit_buffer(struct sclp_buffer *buffer,
+		 void (*callback)(struct sclp_buffer *, int))
+{
+	/* add current line if there is one */
+	if (buffer->current_line != NULL)
+		sclp_finalize_mto(buffer);
+
+	/* Are there messages in the output buffer ? */
+	if (buffer->messages == 0)
+		return -EIO;
+
+	buffer->request.command = SCLP_CMDW_WRITE_EVENT_DATA;
+	buffer->request.status = SCLP_REQ_FILLED;
+	buffer->request.callback = sclp_writedata_callback;
+	buffer->request.callback_data = buffer;
+	buffer->request.sccb = buffer->sccb;
+	buffer->callback = callback;
+	return sclp_add_request(&buffer->request);
+}