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/*
* SCLP VT220 terminal driver.
*
* Copyright IBM Corp. 2003, 2009
*
* Author(s): Peter Oberparleiter <Peter.Oberparleiter@de.ibm.com>
*/
#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/tty_flip.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/major.h>
#include <linux/console.h>
#include <linux/kdev_t.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/reboot.h>
#include <linux/slab.h>
#include <asm/uaccess.h>
#include "sclp.h"
#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 */
/* 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;
static struct tty_port sclp_vt220_port;
/* 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;
/* Suspend mode flag */
static int sclp_vt220_suspended;
/* Flag that output queue is currently running */
static int sclp_vt220_queue_running;
/* 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;
/* Counter controlling core driver initialization. */
static int __initdata sclp_vt220_init_count;
/* 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 void sclp_vt220_pm_event_fn(struct sclp_register *reg,
enum sclp_pm_event sclp_pm_event);
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,
.pm_event_fn = sclp_vt220_pm_event_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);
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);
if (!request || sclp_vt220_suspended) {
sclp_vt220_queue_running = 0;
spin_unlock_irqrestore(&sclp_vt220_lock, flags);
break;
}
spin_unlock_irqrestore(&sclp_vt220_lock, flags);
} while (__sclp_vt220_emit(request));
if (request == NULL && sclp_vt220_flush_later)
sclp_vt220_emit_current();
tty_port_tty_wakeup(&sclp_vt220_port);
}
#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_receive_mask & EVTYP_VT220MSG_MASK)) {
request->sclp_req.status = SCLP_REQ_FAILED;
return -EIO;
}
request->sclp_req.command = SCLP_CMDW_WRITE_EVENT_DATA;
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 current request.
*/
static void
sclp_vt220_emit_current(void)
{
unsigned long flags;
struct sclp_vt220_request *request
|