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Diffstat (limited to '')
| -rw-r--r-- | drivers/s390/char/sclp_rw.c | 450 |
1 files changed, 450 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..d6c84e354 --- /dev/null +++ b/drivers/s390/char/sclp_rw.c @@ -0,0 +1,450 @@ +// 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)) + +static void sclp_rw_pm_event(struct sclp_register *reg, + enum sclp_pm_event sclp_pm_event) +{ + sclp_console_pm_event(sclp_pm_event); +} + +/* Event type structure for write message and write priority message */ +static struct sclp_register sclp_rw_event = { + .send_mask = EVTYP_MSG_MASK, + .pm_event_fn = sclp_rw_pm_event, +}; + +/* + * 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 + */ +int +sclp_chars_in_buffer(struct sclp_buffer *buffer) +{ + 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); +} |