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