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path: root/drivers/s390/char/sclp_rw.c
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Diffstat (limited to 'drivers/s390/char/sclp_rw.c')
-rw-r--r--drivers/s390/char/sclp_rw.c443
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 0000000000..1690326553
--- /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);
+}
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