1 files changed, 471 insertions, 0 deletions

diff --git a/drivers/s390/char/sclp_rw.c b/drivers/s390/char/sclp_rw.c
new file mode 100644
index 000000000000..ac10dfb20a62
--- /dev/null
+++ b/drivers/s390/char/sclp_rw.c
@@ -0,0 +1,471 @@
+/*
+ *  drivers/s390/char/sclp_rw.c
+ *     driver: reading from and writing to system console on S/390 via SCLP
+ *
+ *  S390 version
+ *    Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
+ *    Author(s): Martin Peschke <mpeschke@de.ibm.com>
+ *               Martin Schwidefsky <schwidefsky@de.ibm.com>
+ */
+
+#include <linux/config.h>
+#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 <asm/uaccess.h>
+
+#include "sclp.h"
+#include "sclp_rw.h"
+
+#define SCLP_RW_PRINT_HEADER "sclp low level driver: "
+
+/*
+ * 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 the SCLP ducumentation)
+ * 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 | EvTyp_PMsgCmd_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 write_sccb *sccb;
+
+        sccb = (struct write_sccb *) 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->mto_number = 0;
+        buffer->mto_char_sum = 0;
+        buffer->current_line = NULL;
+        buffer->current_length = 0;
+        buffer->columns = columns;
+        buffer->htab = htab;
+
+        /* initialize sccb */
+        memset(sccb, 0, sizeof(struct write_sccb));
+        sccb->header.length = sizeof(struct write_sccb);
+        sccb->msg_buf.header.length = sizeof(struct msg_buf);
+        sccb->msg_buf.header.type = EvTyp_Msg;
+        sccb->msg_buf.mdb.header.length = sizeof(struct mdb);
+        sccb->msg_buf.mdb.header.type = 1;
+        sccb->msg_buf.mdb.header.tag = 0xD4C4C240;      /* ebcdic "MDB " */
+        sccb->msg_buf.mdb.header.revision_code = 1;
+        sccb->msg_buf.mdb.go.length = sizeof(struct go);
+        sccb->msg_buf.mdb.go.type = 1;
+
+        return buffer;
+}
+
+/*
+ * Return a pointer to the orignal page that has been used to create
+ * the buffer.
+ */
+void *
+sclp_unmake_buffer(struct sclp_buffer *buffer)
+{
+        return buffer->sccb;
+}
+
+/*
+ * Initialize a new Message Text Object (MTO) at 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 write_sccb *sccb;
+        struct mto *mto;
+        int mto_size;
+
+        /* max size of new Message Text Object including message text  */
+        mto_size = sizeof(struct mto) + max_len;
+
+        /* check if current buffer sccb can contain the mto */
+        sccb = buffer->sccb;
+        if ((MAX_SCCB_ROOM - sccb->header.length) < mto_size)
+                return -ENOMEM;
+
+        /* find address of new message text object */
+        mto = (struct mto *)(((addr_t) sccb) + sccb->header.length);
+
+        /*
+         * fill the new Message-Text Object,
+         * starting behind the former last byte of the SCCB
+         */
+        memset(mto, 0, sizeof(struct 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_line = (char *) (mto + 1);
+        buffer->current_length = 0;
+
+        return 0;
+}
+
+/*
+ * Finalize MTO 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 write_sccb *sccb;
+        struct mto *mto;
+        int str_len, mto_size;
+
+        str_len = buffer->current_length;
+        buffer->current_line = NULL;
+        buffer->current_length = 0;
+
+        /* real size of new Message Text Object including message text  */
+        mto_size = sizeof(struct mto) + str_len;
+
+        /* find address of new message text object */
+        sccb = buffer->sccb;
+        mto = (struct mto *)(((addr_t) sccb) + sccb->header.length);
+
+        /* set size of message text object */
+        mto->length = mto_size;
+
+        /*
+         * update values of sizes
+         * (SCCB, Event(Message) Buffer, Message Data Block)
+         */
+        sccb->header.length += mto_size;
+        sccb->msg_buf.header.length += mto_size;
+        sccb->msg_buf.mdb.header.length += mto_size;
+
+        /*
+         * 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->mto_number++;
+        buffer->mto_char_sum += str_len;
+}
+
+/*
+ * 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 */
+                        buffer->sccb->msg_buf.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)
+{
+        int count;
+
+        count = MAX_SCCB_ROOM - buffer->sccb->header.length;
+        if (buffer->current_line != NULL)
+                count -= sizeof(struct mto) + buffer->current_length;
+        return count;
+}
+
+/*
+ * Return number of characters in buffer
+ */
+int
+sclp_chars_in_buffer(struct sclp_buffer *buffer)
+{
+        int count;
+
+        count = buffer->mto_char_sum;
+        if (buffer->current_line != NULL)
+                count += buffer->current_length;
+        return count;
+}
+
+/*
+ * sets or provides some values that influence the drivers behaviour
+ */
+void
+sclp_set_columns(struct sclp_buffer *buffer, unsigned short columns)
+{
+        buffer->columns = columns;
+        if (buffer->current_line != NULL &&
+            buffer->current_length > buffer->columns)
+                sclp_finalize_mto(buffer);
+}
+
+void
+sclp_set_htab(struct sclp_buffer *buffer, unsigned short htab)
+{
+        buffer->htab = htab;
+}
+
+/*
+ * 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 write_sccb *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->header.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->header.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->header.response_code = 0x0000;
+                buffer->request.status = SCLP_REQ_FILLED;
+                rc = sclp_add_request(request);
+                if (rc == 0)
+                        return;
+                break;
+        default:
+                if (sccb->header.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))
+{
+        struct write_sccb *sccb;
+
+        /* 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->mto_number == 0)
+                return -EIO;
+
+        sccb = buffer->sccb;
+        if (sclp_rw_event.sclp_send_mask & EvTyp_Msg_Mask)
+                /* Use normal write message */
+                sccb->msg_buf.header.type = EvTyp_Msg;
+        else if (sclp_rw_event.sclp_send_mask & EvTyp_PMsgCmd_Mask)
+                /* Use write priority message */
+                sccb->msg_buf.header.type = EvTyp_PMsgCmd;
+        else
+                return -ENOSYS;
+        buffer->request.command = SCLP_CMDW_WRITEDATA;
+        buffer->request.status = SCLP_REQ_FILLED;
+        buffer->request.callback = sclp_writedata_callback;
+        buffer->request.callback_data = buffer;
+        buffer->request.sccb = sccb;
+        buffer->callback = callback;
+        return sclp_add_request(&buffer->request);
+}