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linux/drivers/s390/char/sclp_vt220.c

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/*
* drivers/s390/char/sclp_vt220.c
* SCLP VT220 terminal driver.
*
* S390 version
* Copyright (C) 2003 IBM Deutschland Entwicklung GmbH, IBM Corporation
* Author(s): Peter Oberparleiter <Peter.Oberparleiter@de.ibm.com>
*/
#include <linux/config.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/list.h>
#include <linux/wait.h>
#include <linux/timer.h>
#include <linux/kernel.h>
#include <linux/tty.h>
#include <linux/tty_driver.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/major.h>
#include <linux/console.h>
#include <linux/kdev_t.h>
#include <linux/bootmem.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <asm/uaccess.h>
#include "sclp.h"
#define SCLP_VT220_PRINT_HEADER "sclp vt220 tty driver: "
#define SCLP_VT220_MAJOR TTY_MAJOR
#define SCLP_VT220_MINOR 65
#define SCLP_VT220_DRIVER_NAME "sclp_vt220"
#define SCLP_VT220_DEVICE_NAME "ttysclp"
#define SCLP_VT220_CONSOLE_NAME "ttyS"
#define SCLP_VT220_CONSOLE_INDEX 1 /* console=ttyS1 */
#define SCLP_VT220_BUF_SIZE 80
/* Representation of a single write request */
struct sclp_vt220_request {
struct list_head list;
struct sclp_req sclp_req;
int retry_count;
};
/* VT220 SCCB */
struct sclp_vt220_sccb {
struct sccb_header header;
struct evbuf_header evbuf;
};
#define SCLP_VT220_MAX_CHARS_PER_BUFFER (PAGE_SIZE - \
sizeof(struct sclp_vt220_request) - \
sizeof(struct sclp_vt220_sccb))
/* Structures and data needed to register tty driver */
static struct tty_driver *sclp_vt220_driver;
/* The tty_struct that the kernel associated with us */
static struct tty_struct *sclp_vt220_tty;
/* Lock to protect internal data from concurrent access */
static spinlock_t sclp_vt220_lock;
/* List of empty pages to be used as write request buffers */
static struct list_head sclp_vt220_empty;
/* List of pending requests */
static struct list_head sclp_vt220_outqueue;
/* Number of requests in outqueue */
static int sclp_vt220_outqueue_count;
/* Wait queue used to delay write requests while we've run out of buffers */
static wait_queue_head_t sclp_vt220_waitq;
/* Timer used for delaying write requests to merge subsequent messages into
* a single buffer */
static struct timer_list sclp_vt220_timer;
/* Pointer to current request buffer which has been partially filled but not
* yet sent */
static struct sclp_vt220_request *sclp_vt220_current_request;
/* Number of characters in current request buffer */
static int sclp_vt220_buffered_chars;
/* Flag indicating whether this driver has already been initialized */
static int sclp_vt220_initialized = 0;
/* Flag indicating that sclp_vt220_current_request should really
* have been already queued but wasn't because the SCLP was processing
* another buffer */
static int sclp_vt220_flush_later;
static void sclp_vt220_receiver_fn(struct evbuf_header *evbuf);
static int __sclp_vt220_emit(struct sclp_vt220_request *request);
static void sclp_vt220_emit_current(void);
/* Registration structure for our interest in SCLP event buffers */
static struct sclp_register sclp_vt220_register = {
.send_mask = EvTyp_VT220Msg_Mask,
.receive_mask = EvTyp_VT220Msg_Mask,
.state_change_fn = NULL,
.receiver_fn = sclp_vt220_receiver_fn
};
/*
* Put provided request buffer back into queue and check emit pending
* buffers if necessary.
*/
static void
sclp_vt220_process_queue(struct sclp_vt220_request *request)
{
unsigned long flags;
void *page;
do {
/* Put buffer back to list of empty buffers */
page = request->sclp_req.sccb;
spin_lock_irqsave(&sclp_vt220_lock, flags);
/* Move request from outqueue to empty queue */
list_del(&request->list);
sclp_vt220_outqueue_count--;
list_add_tail((struct list_head *) page, &sclp_vt220_empty);
/* Check if there is a pending buffer on the out queue. */
request = NULL;
if (!list_empty(&sclp_vt220_outqueue))
request = list_entry(sclp_vt220_outqueue.next,
struct sclp_vt220_request, list);
spin_unlock_irqrestore(&sclp_vt220_lock, flags);
} while (request && __sclp_vt220_emit(request));
if (request == NULL && sclp_vt220_flush_later)
sclp_vt220_emit_current();
wake_up(&sclp_vt220_waitq);
/* Check if the tty needs a wake up call */
if (sclp_vt220_tty != NULL) {
tty_wakeup(sclp_vt220_tty);
}
}
#define SCLP_BUFFER_MAX_RETRY 1
/*
* Callback through which the result of a write request is reported by the
* SCLP.
*/
static void
sclp_vt220_callback(struct sclp_req *request, void *data)
{
struct sclp_vt220_request *vt220_request;
struct sclp_vt220_sccb *sccb;
vt220_request = (struct sclp_vt220_request *) data;
if (request->status == SCLP_REQ_FAILED) {
sclp_vt220_process_queue(vt220_request);
return;
}
sccb = (struct sclp_vt220_sccb *) vt220_request->sclp_req.sccb;
/* Check SCLP response code and choose suitable action */
switch (sccb->header.response_code) {
case 0x0020 :
break;
case 0x05f0: /* Target resource in improper state */
break;
case 0x0340: /* Contained SCLP equipment check */
if (++vt220_request->retry_count > SCLP_BUFFER_MAX_RETRY)
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;
vt220_request->sclp_req.status = SCLP_REQ_FILLED;
if (sclp_add_request(request) == 0)
return;
}
break;
case 0x0040: /* SCLP equipment check */
if (++vt220_request->retry_count > SCLP_BUFFER_MAX_RETRY)
break;
sccb->header.response_code = 0x0000;
vt220_request->sclp_req.status = SCLP_REQ_FILLED;
if (sclp_add_request(request) == 0)
return;
break;
default:
break;
}
sclp_vt220_process_queue(vt220_request);
}
/*
* Emit vt220 request buffer to SCLP. Return zero on success, non-zero
* otherwise.
*/
static int
__sclp_vt220_emit(struct sclp_vt220_request *request)
{
if (!(sclp_vt220_register.sclp_send_mask & EvTyp_VT220Msg_Mask)) {
request->sclp_req.status = SCLP_REQ_FAILED;
return -EIO;
}
request->sclp_req.command = SCLP_CMDW_WRITEDATA;
request->sclp_req.status = SCLP_REQ_FILLED;
request->sclp_req.callback = sclp_vt220_callback;
request->sclp_req.callback_data = (void *) request;
return sclp_add_request(&request->sclp_req);
}
/*
* Queue and emit given request.
*/
static void
sclp_vt220_emit(struct sclp_vt220_request *request)
{
unsigned long flags;
int count;
spin_lock_irqsave(&sclp_vt220_lock, flags);
list_add_tail(&request->list, &sclp_vt220_outqueue);
count = sclp_vt220_outqueue_count++;
spin_unlock_irqrestore(&sclp_vt220_lock, flags);
/* Emit only the first buffer immediately - callback takes care of
* the rest */
if (count == 0 && __sclp_vt220_emit(request))
sclp_vt220_process_queue(request);
}
/*
* Queue and emit current request. Return zero on success, non-zero otherwise.
*/
static void
sclp_vt220_emit_current(void)
{
unsigned long flags;
struct sclp_vt220_request *request;
struct sclp_vt220_sccb *sccb;
spin_lock_irqsave(&sclp_vt220_lock, flags);
request = NULL;
if (sclp_vt220_current_request != NULL) {
sccb = (struct sclp_vt220_sccb *)
sclp_vt220_current_request->sclp_req.sccb;
/* Only emit buffers with content */
if (sccb->header.length != sizeof(struct sclp_vt220_sccb)) {
request = sclp_vt220_current_request;
sclp_vt220_current_request = NULL;
if (timer_pending(&sclp_vt220_timer))
del_timer(&sclp_vt220_timer);
}
sclp_vt220_flush_later = 0;
}
spin_unlock_irqrestore(&sclp_vt220_lock, flags);
if (request != NULL)
sclp_vt220_emit(request);
}
#define SCLP_NORMAL_WRITE 0x00
/*
* Helper function to initialize a page with the sclp request structure.
*/
static struct sclp_vt220_request *
sclp_vt220_initialize_page(void *page)
{
struct sclp_vt220_request *request;
struct sclp_vt220_sccb *sccb;
/* Place request structure at end of page */
request = ((struct sclp_vt220_request *)
((addr_t) page + PAGE_SIZE)) - 1;
request->retry_count = 0;
request->sclp_req.sccb = page;
/* SCCB goes at start of page */
sccb = (struct sclp_vt220_sccb *) page;
memset((void *) sccb, 0, sizeof(struct sclp_vt220_sccb));
sccb->header.length = sizeof(struct sclp_vt220_sccb);
sccb->header.function_code = SCLP_NORMAL_WRITE;
sccb->header.response_code = 0x0000;
sccb->evbuf.type = EvTyp_VT220Msg;
sccb->evbuf.length = sizeof(struct evbuf_header);
return request;
}
static inline unsigned int
sclp_vt220_space_left(struct sclp_vt220_request *request)
{
struct sclp_vt220_sccb *sccb;
sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
return PAGE_SIZE - sizeof(struct sclp_vt220_request) -
sccb->header.length;
}
static inline unsigned int
sclp_vt220_chars_stored(struct sclp_vt220_request *request)
{
struct sclp_vt220_sccb *sccb;
sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
return sccb->evbuf.length - sizeof(struct evbuf_header);
}
/*
* Add msg to buffer associated with request. Return the number of characters
* added.
*/
static int
sclp_vt220_add_msg(struct sclp_vt220_request *request,
const unsigned char *msg, int count, int convertlf)
{
struct sclp_vt220_sccb *sccb;
void *buffer;
unsigned char c;
int from;
int to;
if (count > sclp_vt220_space_left(request))
count = sclp_vt220_space_left(request);
if (count <= 0)
return 0;
sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
buffer = (void *) ((addr_t) sccb + sccb->header.length);
if (convertlf) {
/* Perform Linefeed conversion (0x0a -> 0x0a 0x0d)*/
for (from=0, to=0;
(from < count) && (to < sclp_vt220_space_left(request));
from++) {
/* Retrieve character */
c = msg[from];
/* Perform conversion */
if (c == 0x0a) {
if (to + 1 < sclp_vt220_space_left(request)) {
((unsigned char *) buffer)[to++] = c;
((unsigned char *) buffer)[to++] = 0x0d;
} else
break;
} else
((unsigned char *) buffer)[to++] = c;
}
sccb->header.length += to;
sccb->evbuf.length += to;
return from;
} else {
memcpy(buffer, (const void *) msg, count);
sccb->header.length += count;
sccb->evbuf.length += count;
return count;
}
}
/*
* Emit buffer after having waited long enough for more data to arrive.
*/
static void
sclp_vt220_timeout(unsigned long data)
{
sclp_vt220_emit_current();
}
#define BUFFER_MAX_DELAY HZ/2
/*
* Internal implementation of the write function. Write COUNT bytes of data
* from memory at BUF
* to the SCLP interface. In case that the data does not fit into the current
* write buffer, emit the current one and allocate a new one. If there are no
* more empty buffers available, wait until one gets emptied. If DO_SCHEDULE
* is non-zero, the buffer will be scheduled for emitting after a timeout -
* otherwise the user has to explicitly call the flush function.
* A non-zero CONVERTLF parameter indicates that 0x0a characters in the message
* buffer should be converted to 0x0a 0x0d. After completion, return the number
* of bytes written.
*/
static int
__sclp_vt220_write(const unsigned char *buf, int count, int do_schedule,
int convertlf)
{
unsigned long flags;
void *page;
int written;
int overall_written;
if (count <= 0)
return 0;
overall_written = 0;
spin_lock_irqsave(&sclp_vt220_lock, flags);
do {
/* Create a sclp output buffer if none exists yet */
if (sclp_vt220_current_request == NULL) {
while (list_empty(&sclp_vt220_empty)) {
spin_unlock_irqrestore(&sclp_vt220_lock,
flags);
if (in_interrupt())
sclp_sync_wait();
else
wait_event(sclp_vt220_waitq,
!list_empty(&sclp_vt220_empty));
spin_lock_irqsave(&sclp_vt220_lock, flags);
}
page = (void *) sclp_vt220_empty.next;
list_del((struct list_head *) page);
sclp_vt220_current_request =
sclp_vt220_initialize_page(page);
}
/* Try to write the string to the current request buffer */
written = sclp_vt220_add_msg(sclp_vt220_current_request,
buf, count, convertlf);
overall_written += written;
if (written == count)
break;
/*
* Not all characters could be written to the current
* output buffer. Emit the buffer, create a new buffer
* and then output the rest of the string.
*/
spin_unlock_irqrestore(&sclp_vt220_lock, flags);
sclp_vt220_emit_current();
spin_lock_irqsave(&sclp_vt220_lock, flags);
buf += written;
count -= written;
} while (count > 0);
/* Setup timer to output current console buffer after some time */
if (sclp_vt220_current_request != NULL &&
!timer_pending(&sclp_vt220_timer) && do_schedule) {
sclp_vt220_timer.function = sclp_vt220_timeout;
sclp_vt220_timer.data = 0UL;
sclp_vt220_timer.expires = jiffies + BUFFER_MAX_DELAY;
add_timer(&sclp_vt220_timer);
}
spin_unlock_irqrestore(&sclp_vt220_lock, flags);
return overall_written;
}
/*
* This routine is called by the kernel to write a series of
* characters to the tty device. The characters may come from
* user space or kernel space. This routine will return the
* number of characters actually accepted for writing.
*/
static int
sclp_vt220_write(struct tty_struct *tty, const unsigned char *buf, int count)
{
return __sclp_vt220_write(buf, count, 1, 0);
}
#define SCLP_VT220_SESSION_ENDED 0x01
#define SCLP_VT220_SESSION_STARTED 0x80
#define SCLP_VT220_SESSION_DATA 0x00
/*
* Called by the SCLP to report incoming event buffers.
*/
static void
sclp_vt220_receiver_fn(struct evbuf_header *evbuf)
{
char *buffer;
unsigned int count;
/* Ignore input if device is not open */
if (sclp_vt220_tty == NULL)
return;
buffer = (char *) ((addr_t) evbuf + sizeof(struct evbuf_header));
count = evbuf->length - sizeof(struct evbuf_header);
switch (*buffer) {
case SCLP_VT220_SESSION_ENDED:
case SCLP_VT220_SESSION_STARTED:
break;
case SCLP_VT220_SESSION_DATA:
/* Send input to line discipline */
buffer++;
count--;
/* Prevent buffer overrun by discarding input. Note that
* because buffer_push works asynchronously, we cannot wait
* for the buffer to be emptied. */
if (count + sclp_vt220_tty->flip.count > TTY_FLIPBUF_SIZE)
count = TTY_FLIPBUF_SIZE - sclp_vt220_tty->flip.count;
memcpy(sclp_vt220_tty->flip.char_buf_ptr, buffer, count);
memset(sclp_vt220_tty->flip.flag_buf_ptr, TTY_NORMAL, count);
sclp_vt220_tty->flip.char_buf_ptr += count;
sclp_vt220_tty->flip.flag_buf_ptr += count;
sclp_vt220_tty->flip.count += count;
tty_flip_buffer_push(sclp_vt220_tty);
break;
}
}
/*
* This routine is called when a particular tty device is opened.
*/
static int
sclp_vt220_open(struct tty_struct *tty, struct file *filp)
{
if (tty->count == 1) {
sclp_vt220_tty = tty;
tty->driver_data = kmalloc(SCLP_VT220_BUF_SIZE, GFP_KERNEL);
if (tty->driver_data == NULL)
return -ENOMEM;
tty->low_latency = 0;
}
return 0;
}
/*
* This routine is called when a particular tty device is closed.
*/
static void
sclp_vt220_close(struct tty_struct *tty, struct file *filp)
{
if (tty->count == 1) {
sclp_vt220_tty = NULL;
kfree(tty->driver_data);
tty->driver_data = NULL;
}
}
/*
* This routine is called by the kernel to write a single
* character to the tty device. If the kernel uses this routine,
* it must call the flush_chars() routine (if defined) when it is
* done stuffing characters into the driver.
*
* NOTE: include/linux/tty_driver.h specifies that a character should be
* ignored if there is no room in the queue. This driver implements a different
* semantic in that it will block when there is no more room left.
*/
static void
sclp_vt220_put_char(struct tty_struct *tty, unsigned char ch)
{
__sclp_vt220_write(&ch, 1, 0, 0);
}
/*
* This routine is called by the kernel after it has written a
* series of characters to the tty device using put_char().
*/
static void
sclp_vt220_flush_chars(struct tty_struct *tty)
{
if (sclp_vt220_outqueue_count == 0)
sclp_vt220_emit_current();
else
sclp_vt220_flush_later = 1;
}
/*
* This routine returns the numbers of characters the tty driver
* will accept for queuing to be written. This number is subject
* to change as output buffers get emptied, or if the output flow
* control is acted.
*/
static int
sclp_vt220_write_room(struct tty_struct *tty)
{
unsigned long flags;
struct list_head *l;
int count;
spin_lock_irqsave(&sclp_vt220_lock, flags);
count = 0;
if (sclp_vt220_current_request != NULL)
count = sclp_vt220_space_left(sclp_vt220_current_request);
list_for_each(l, &sclp_vt220_empty)
count += SCLP_VT220_MAX_CHARS_PER_BUFFER;
spin_unlock_irqrestore(&sclp_vt220_lock, flags);
return count;
}
/*
* Return number of buffered chars.
*/
static int
sclp_vt220_chars_in_buffer(struct tty_struct *tty)
{
unsigned long flags;
struct list_head *l;
struct sclp_vt220_request *r;
int count;
spin_lock_irqsave(&sclp_vt220_lock, flags);
count = 0;
if (sclp_vt220_current_request != NULL)
count = sclp_vt220_chars_stored(sclp_vt220_current_request);
list_for_each(l, &sclp_vt220_outqueue) {
r = list_entry(l, struct sclp_vt220_request, list);
count += sclp_vt220_chars_stored(r);
}
spin_unlock_irqrestore(&sclp_vt220_lock, flags);
return count;
}
static void
__sclp_vt220_flush_buffer(void)
{
unsigned long flags;
sclp_vt220_emit_current();
spin_lock_irqsave(&sclp_vt220_lock, flags);
if (timer_pending(&sclp_vt220_timer))
del_timer(&sclp_vt220_timer);
while (sclp_vt220_outqueue_count > 0) {
spin_unlock_irqrestore(&sclp_vt220_lock, flags);
sclp_sync_wait();
spin_lock_irqsave(&sclp_vt220_lock, flags);
}
spin_unlock_irqrestore(&sclp_vt220_lock, flags);
}
/*
* Pass on all buffers to the hardware. Return only when there are no more
* buffers pending.
*/
static void
sclp_vt220_flush_buffer(struct tty_struct *tty)
{
sclp_vt220_emit_current();
}
/*
* Initialize all relevant components and register driver with system.
*/
static int
__sclp_vt220_init(int early)
{
void *page;
int i;
if (sclp_vt220_initialized)
return 0;
sclp_vt220_initialized = 1;
spin_lock_init(&sclp_vt220_lock);
INIT_LIST_HEAD(&sclp_vt220_empty);
INIT_LIST_HEAD(&sclp_vt220_outqueue);
init_waitqueue_head(&sclp_vt220_waitq);
init_timer(&sclp_vt220_timer);
sclp_vt220_current_request = NULL;
sclp_vt220_buffered_chars = 0;
sclp_vt220_outqueue_count = 0;
sclp_vt220_tty = NULL;
sclp_vt220_flush_later = 0;
/* Allocate pages for output buffering */
for (i = 0; i < (early ? MAX_CONSOLE_PAGES : MAX_KMEM_PAGES); i++) {
if (early)
page = alloc_bootmem_low_pages(PAGE_SIZE);
else
page = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
if (!page)
return -ENOMEM;
list_add_tail((struct list_head *) page, &sclp_vt220_empty);
}
return 0;
}
static struct tty_operations sclp_vt220_ops = {
.open = sclp_vt220_open,
.close = sclp_vt220_close,
.write = sclp_vt220_write,
.put_char = sclp_vt220_put_char,
.flush_chars = sclp_vt220_flush_chars,
.write_room = sclp_vt220_write_room,
.chars_in_buffer = sclp_vt220_chars_in_buffer,
.flush_buffer = sclp_vt220_flush_buffer
};
/*
* Register driver with SCLP and Linux and initialize internal tty structures.
*/
int __init
sclp_vt220_tty_init(void)
{
struct tty_driver *driver;
int rc;
/* Note: we're not testing for CONSOLE_IS_SCLP here to preserve
* symmetry between VM and LPAR systems regarding ttyS1. */
driver = alloc_tty_driver(1);
if (!driver)
return -ENOMEM;
rc = __sclp_vt220_init(0);
if (rc) {
put_tty_driver(driver);
return rc;
}
rc = sclp_register(&sclp_vt220_register);
if (rc) {
printk(KERN_ERR SCLP_VT220_PRINT_HEADER
"could not register tty - "
"sclp_register returned %d\n", rc);
put_tty_driver(driver);
return rc;
}
driver->owner = THIS_MODULE;
driver->driver_name = SCLP_VT220_DRIVER_NAME;
driver->name = SCLP_VT220_DEVICE_NAME;
driver->major = SCLP_VT220_MAJOR;
driver->minor_start = SCLP_VT220_MINOR;
driver->type = TTY_DRIVER_TYPE_SYSTEM;
driver->subtype = SYSTEM_TYPE_TTY;
driver->init_termios = tty_std_termios;
driver->flags = TTY_DRIVER_REAL_RAW;
tty_set_operations(driver, &sclp_vt220_ops);
rc = tty_register_driver(driver);
if (rc) {
printk(KERN_ERR SCLP_VT220_PRINT_HEADER
"could not register tty - "
"tty_register_driver returned %d\n", rc);
put_tty_driver(driver);
return rc;
}
sclp_vt220_driver = driver;
return 0;
}
module_init(sclp_vt220_tty_init);
#ifdef CONFIG_SCLP_VT220_CONSOLE
static void
sclp_vt220_con_write(struct console *con, const char *buf, unsigned int count)
{
__sclp_vt220_write((const unsigned char *) buf, count, 1, 1);
}
static struct tty_driver *
sclp_vt220_con_device(struct console *c, int *index)
{
*index = 0;
return sclp_vt220_driver;
}
/*
* This routine is called from panic when the kernel is going to give up.
* We have to make sure that all buffers will be flushed to the SCLP.
* Note that this function may be called from within an interrupt context.
*/
static void
sclp_vt220_con_unblank(void)
{
__sclp_vt220_flush_buffer();
}
/* Structure needed to register with printk */
static struct console sclp_vt220_console =
{
.name = SCLP_VT220_CONSOLE_NAME,
.write = sclp_vt220_con_write,
.device = sclp_vt220_con_device,
.unblank = sclp_vt220_con_unblank,
.flags = CON_PRINTBUFFER,
.index = SCLP_VT220_CONSOLE_INDEX
};
static int __init
sclp_vt220_con_init(void)
{
int rc;
if (!CONSOLE_IS_SCLP)
return 0;
rc = __sclp_vt220_init(1);
if (rc)
return rc;
/* Attach linux console */
register_console(&sclp_vt220_console);
return 0;
}
console_initcall(sclp_vt220_con_init);
#endif /* CONFIG_SCLP_VT220_CONSOLE */
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