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linux-stable/drivers/s390/char/con3215.c
Guilherme G. Piccoli 4ae46db99c s390/consoles: improve panic notifiers reliability 
Currently many console drivers for s390 rely on panic/reboot notifiers
to invoke callbacks on these events. The panic() function disables local
IRQs, secondary CPUs and preemption, so callbacks invoked on panic are
effectively running in atomic context.

Happens that most of these console callbacks from s390 doesn't take the
proper care with regards to atomic context, like taking spinlocks that
might be taken in other function/CPU and hence will cause a lockup
situation.

The goal for this patch is to improve the notifiers reliability, acting
on 4 console drivers, as detailed below:

(1) con3215: changed a regular spinlock to the trylock alternative.

(2) con3270: also changed a regular spinlock to its trylock counterpart,
but here we also have another problem: raw3270_activate_view() takes a
different spinlock. So, we worked a helper to validate if this other lock
is safe to acquire, and if so, raw3270_activate_view() should be safe.

Notice though that there is a functional change here: it's now possible
to continue the notifier code [reaching con3270_wait_write() and
con3270_rebuild_update()] without executing raw3270_activate_view().

(3) sclp: a global lock is used heavily in the functions called from
the notifier, so we added a check here - if the lock is taken already,
we just bail-out, preventing the lockup.

(4) sclp_vt220: same as (3), a lock validation was added to prevent the
potential lockup problem.

Besides (1)-(4), we also removed useless void functions, adding the
code called from the notifier inside its own body, and changed the
priority of such notifiers to execute late, since they are "heavyweight"
for the panic environment, so we aim to reduce risks here.
Changed return values to NOTIFY_DONE as well, the standard one.

Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Link: https://lore.kernel.org/r/20220427224924.592546-14-gpiccoli@igalia.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2022-05-06 20:45:13 +02:00

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// SPDX-License-Identifier: GPL-2.0
/*
* 3215 line mode terminal driver.
*
* Copyright IBM Corp. 1999, 2009
* Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
*
* Updated:
* Aug-2000: Added tab support
* Dan Morrison, IBM Corporation <dmorriso@cse.buffalo.edu>
*/
#include <linux/types.h>
#include <linux/kdev_t.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/vt_kern.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/interrupt.h>
#include <linux/err.h>
#include <linux/panic_notifier.h>
#include <linux/reboot.h>
#include <linux/serial.h> /* ASYNC_* flags */
#include <linux/slab.h>
#include <asm/ccwdev.h>
#include <asm/cio.h>
#include <asm/io.h>
#include <asm/ebcdic.h>
#include <linux/uaccess.h>
#include <asm/delay.h>
#include <asm/cpcmd.h>
#include <asm/setup.h>
#include "ctrlchar.h"
#define NR_3215 1
#define NR_3215_REQ (4*NR_3215)
#define RAW3215_BUFFER_SIZE 65536 /* output buffer size */
#define RAW3215_INBUF_SIZE 256 /* input buffer size */
#define RAW3215_MIN_SPACE 128 /* minimum free space for wakeup */
#define RAW3215_MIN_WRITE 1024 /* min. length for immediate output */
#define RAW3215_MAX_BYTES 3968 /* max. bytes to write with one ssch */
#define RAW3215_MAX_NEWLINE 50 /* max. lines to write with one ssch */
#define RAW3215_NR_CCWS 3
#define RAW3215_TIMEOUT HZ/10 /* time for delayed output */
#define RAW3215_FIXED 1 /* 3215 console device is not be freed */
#define RAW3215_WORKING 4 /* set if a request is being worked on */
#define RAW3215_THROTTLED 8 /* set if reading is disabled */
#define RAW3215_STOPPED 16 /* set if writing is disabled */
#define RAW3215_TIMER_RUNS 64 /* set if the output delay timer is on */
#define RAW3215_FLUSHING 128 /* set to flush buffer (no delay) */
#define TAB_STOP_SIZE 8 /* tab stop size */
/*
* Request types for a 3215 device
*/
enum raw3215_type {
RAW3215_FREE, RAW3215_READ, RAW3215_WRITE
};
/*
* Request structure for a 3215 device
*/
struct raw3215_req {
enum raw3215_type type; /* type of the request */
int start, len; /* start index & len in output buffer */
int delayable; /* indication to wait for more data */
int residual; /* residual count for read request */
struct ccw1 ccws[RAW3215_NR_CCWS]; /* space for the channel program */
struct raw3215_info *info; /* pointer to main structure */
struct raw3215_req *next; /* pointer to next request */
} __attribute__ ((aligned(8)));
struct raw3215_info {
struct tty_port port;
struct ccw_device *cdev; /* device for tty driver */
spinlock_t *lock; /* pointer to irq lock */
int flags; /* state flags */
char *buffer; /* pointer to output buffer */
char *inbuf; /* pointer to input buffer */
int head; /* first free byte in output buffer */
int count; /* number of bytes in output buffer */
int written; /* number of bytes in write requests */
struct raw3215_req *queued_read; /* pointer to queued read requests */
struct raw3215_req *queued_write;/* pointer to queued write requests */
wait_queue_head_t empty_wait; /* wait queue for flushing */
struct timer_list timer; /* timer for delayed output */
int line_pos; /* position on the line (for tabs) */
char ubuffer[80]; /* copy_from_user buffer */
};
/* array of 3215 devices structures */
static struct raw3215_info *raw3215[NR_3215];
/* spinlock to protect the raw3215 array */
static DEFINE_SPINLOCK(raw3215_device_lock);
/* list of free request structures */
static struct raw3215_req *raw3215_freelist;
/* spinlock to protect free list */
static DEFINE_SPINLOCK(raw3215_freelist_lock);
static struct tty_driver *tty3215_driver;
/*
* Get a request structure from the free list
*/
static inline struct raw3215_req *raw3215_alloc_req(void)
{
struct raw3215_req *req;
unsigned long flags;
spin_lock_irqsave(&raw3215_freelist_lock, flags);
req = raw3215_freelist;
raw3215_freelist = req->next;
spin_unlock_irqrestore(&raw3215_freelist_lock, flags);
return req;
}
/*
* Put a request structure back to the free list
*/
static inline void raw3215_free_req(struct raw3215_req *req)
{
unsigned long flags;
if (req->type == RAW3215_FREE)
return; /* don't free a free request */
req->type = RAW3215_FREE;
spin_lock_irqsave(&raw3215_freelist_lock, flags);
req->next = raw3215_freelist;
raw3215_freelist = req;
spin_unlock_irqrestore(&raw3215_freelist_lock, flags);
}
/*
* Set up a read request that reads up to 160 byte from the 3215 device.
* If there is a queued read request it is used, but that shouldn't happen
* because a 3215 terminal won't accept a new read before the old one is
* completed.
*/
static void raw3215_mk_read_req(struct raw3215_info *raw)
{
struct raw3215_req *req;
struct ccw1 *ccw;
/* there can only be ONE read request at a time */
req = raw->queued_read;
if (req == NULL) {
/* no queued read request, use new req structure */
req = raw3215_alloc_req();
req->type = RAW3215_READ;
req->info = raw;
raw->queued_read = req;
}
ccw = req->ccws;
ccw->cmd_code = 0x0A; /* read inquiry */
ccw->flags = 0x20; /* ignore incorrect length */
ccw->count = 160;
ccw->cda = (__u32) __pa(raw->inbuf);
}
/*
* Set up a write request with the information from the main structure.
* A ccw chain is created that writes as much as possible from the output
* buffer to the 3215 device. If a queued write exists it is replaced by
* the new, probably lengthened request.
*/
static void raw3215_mk_write_req(struct raw3215_info *raw)
{
struct raw3215_req *req;
struct ccw1 *ccw;
int len, count, ix, lines;
if (raw->count <= raw->written)
return;
/* check if there is a queued write request */
req = raw->queued_write;
if (req == NULL) {
/* no queued write request, use new req structure */
req = raw3215_alloc_req();
req->type = RAW3215_WRITE;
req->info = raw;
raw->queued_write = req;
} else {
raw->written -= req->len;
}
ccw = req->ccws;
req->start = (raw->head - raw->count + raw->written) &
(RAW3215_BUFFER_SIZE - 1);
/*
* now we have to count newlines. We can at max accept
* RAW3215_MAX_NEWLINE newlines in a single ssch due to
* a restriction in VM
*/
lines = 0;
ix = req->start;
while (lines < RAW3215_MAX_NEWLINE && ix != raw->head) {
if (raw->buffer[ix] == 0x15)
lines++;
ix = (ix + 1) & (RAW3215_BUFFER_SIZE - 1);
}
len = ((ix - 1 - req->start) & (RAW3215_BUFFER_SIZE - 1)) + 1;
if (len > RAW3215_MAX_BYTES)
len = RAW3215_MAX_BYTES;
req->len = len;
raw->written += len;
/* set the indication if we should try to enlarge this request */
req->delayable = (ix == raw->head) && (len < RAW3215_MIN_WRITE);
ix = req->start;
while (len > 0) {
if (ccw > req->ccws)
ccw[-1].flags |= 0x40; /* use command chaining */
ccw->cmd_code = 0x01; /* write, auto carrier return */
ccw->flags = 0x20; /* ignore incorrect length ind. */
ccw->cda =
(__u32) __pa(raw->buffer + ix);
count = len;
if (ix + count > RAW3215_BUFFER_SIZE)
count = RAW3215_BUFFER_SIZE - ix;
ccw->count = count;
len -= count;
ix = (ix + count) & (RAW3215_BUFFER_SIZE - 1);
ccw++;
}
/*
* Add a NOP to the channel program. 3215 devices are purely
* emulated and its much better to avoid the channel end
* interrupt in this case.
*/
if (ccw > req->ccws)
ccw[-1].flags |= 0x40; /* use command chaining */
ccw->cmd_code = 0x03; /* NOP */
ccw->flags = 0;
ccw->cda = 0;
ccw->count = 1;
}
/*
* Start a read or a write request
*/
static void raw3215_start_io(struct raw3215_info *raw)
{
struct raw3215_req *req;
int res;
req = raw->queued_read;
if (req != NULL &&
!(raw->flags & (RAW3215_WORKING | RAW3215_THROTTLED))) {
/* dequeue request */
raw->queued_read = NULL;
res = ccw_device_start(raw->cdev, req->ccws,
(unsigned long) req, 0, 0);
if (res != 0) {
/* do_IO failed, put request back to queue */
raw->queued_read = req;
} else {
raw->flags |= RAW3215_WORKING;
}
}
req = raw->queued_write;
if (req != NULL &&
!(raw->flags & (RAW3215_WORKING | RAW3215_STOPPED))) {
/* dequeue request */
raw->queued_write = NULL;
res = ccw_device_start(raw->cdev, req->ccws,
(unsigned long) req, 0, 0);
if (res != 0) {
/* do_IO failed, put request back to queue */
raw->queued_write = req;
} else {
raw->flags |= RAW3215_WORKING;
}
}
}
/*
* Function to start a delayed output after RAW3215_TIMEOUT seconds
*/
static void raw3215_timeout(struct timer_list *t)
{
struct raw3215_info *raw = from_timer(raw, t, timer);
unsigned long flags;
spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
raw->flags &= ~RAW3215_TIMER_RUNS;
raw3215_mk_write_req(raw);
raw3215_start_io(raw);
if ((raw->queued_read || raw->queued_write) &&
!(raw->flags & RAW3215_WORKING) &&
!(raw->flags & RAW3215_TIMER_RUNS)) {
raw->timer.expires = RAW3215_TIMEOUT + jiffies;
add_timer(&raw->timer);
raw->flags |= RAW3215_TIMER_RUNS;
}
spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
}
/*
* Function to conditionally start an IO. A read is started immediately,
* a write is only started immediately if the flush flag is on or the
* amount of data is bigger than RAW3215_MIN_WRITE. If a write is not
* done immediately a timer is started with a delay of RAW3215_TIMEOUT.
*/
static inline void raw3215_try_io(struct raw3215_info *raw)
{
if (!tty_port_initialized(&raw->port))
return;
if (raw->queued_read != NULL)
raw3215_start_io(raw);
else if (raw->queued_write != NULL) {
if ((raw->queued_write->delayable == 0) ||
(raw->flags & RAW3215_FLUSHING)) {
/* execute write requests bigger than minimum size */
raw3215_start_io(raw);
}
}
if ((raw->queued_read || raw->queued_write) &&
!(raw->flags & RAW3215_WORKING) &&
!(raw->flags & RAW3215_TIMER_RUNS)) {
raw->timer.expires = RAW3215_TIMEOUT + jiffies;
add_timer(&raw->timer);
raw->flags |= RAW3215_TIMER_RUNS;
}
}
/*
* Try to start the next IO and wake up processes waiting on the tty.
*/
static void raw3215_next_io(struct raw3215_info *raw, struct tty_struct *tty)
{
raw3215_mk_write_req(raw);
raw3215_try_io(raw);
if (tty && RAW3215_BUFFER_SIZE - raw->count >= RAW3215_MIN_SPACE)
tty_wakeup(tty);
}
/*
* Interrupt routine, called from common io layer
*/
static void raw3215_irq(struct ccw_device *cdev, unsigned long intparm,
struct irb *irb)
{
struct raw3215_info *raw;
struct raw3215_req *req;
struct tty_struct *tty;
int cstat, dstat;
int count;
raw = dev_get_drvdata(&cdev->dev);
req = (struct raw3215_req *) intparm;
tty = tty_port_tty_get(&raw->port);
cstat = irb->scsw.cmd.cstat;
dstat = irb->scsw.cmd.dstat;
if (cstat != 0)
raw3215_next_io(raw, tty);
if (dstat & 0x01) { /* we got a unit exception */
dstat &= ~0x01; /* we can ignore it */
}
switch (dstat) {
case 0x80:
if (cstat != 0)
break;
/* Attention interrupt, someone hit the enter key */
raw3215_mk_read_req(raw);
raw3215_next_io(raw, tty);
break;
case 0x08:
case 0x0C:
/* Channel end interrupt. */
if ((raw = req->info) == NULL)
goto put_tty; /* That shouldn't happen ... */
if (req->type == RAW3215_READ) {
/* store residual count, then wait for device end */
req->residual = irb->scsw.cmd.count;
}
if (dstat == 0x08)
break;
fallthrough;
case 0x04:
/* Device end interrupt. */
if ((raw = req->info) == NULL)
goto put_tty; /* That shouldn't happen ... */
if (req->type == RAW3215_READ && tty != NULL) {
unsigned int cchar;
count = 160 - req->residual;
EBCASC(raw->inbuf, count);
cchar = ctrlchar_handle(raw->inbuf, count, tty);
switch (cchar & CTRLCHAR_MASK) {
case CTRLCHAR_SYSRQ:
break;
case CTRLCHAR_CTRL:
tty_insert_flip_char(&raw->port, cchar,
TTY_NORMAL);
tty_flip_buffer_push(&raw->port);
break;
case CTRLCHAR_NONE:
if (count < 2 ||
(strncmp(raw->inbuf+count-2, "\252n", 2) &&
strncmp(raw->inbuf+count-2, "^n", 2)) ) {
/* add the auto \n */
raw->inbuf[count] = '\n';
count++;
} else
count -= 2;
tty_insert_flip_string(&raw->port, raw->inbuf,
count);
tty_flip_buffer_push(&raw->port);
break;
}
} else if (req->type == RAW3215_WRITE) {
raw->count -= req->len;
raw->written -= req->len;
}
raw->flags &= ~RAW3215_WORKING;
raw3215_free_req(req);
/* check for empty wait */
if (waitqueue_active(&raw->empty_wait) &&
raw->queued_write == NULL &&
raw->queued_read == NULL) {
wake_up_interruptible(&raw->empty_wait);
}
raw3215_next_io(raw, tty);
break;
default:
/* Strange interrupt, I'll do my best to clean up */
if (req != NULL && req->type != RAW3215_FREE) {
if (req->type == RAW3215_WRITE) {
raw->count -= req->len;
raw->written -= req->len;
}
raw->flags &= ~RAW3215_WORKING;
raw3215_free_req(req);
}
raw3215_next_io(raw, tty);
}
put_tty:
tty_kref_put(tty);
}
/*
* Wait until length bytes are available int the output buffer.
* Has to be called with the s390irq lock held. Can be called
* disabled.
*/
static void raw3215_make_room(struct raw3215_info *raw, unsigned int length)
{
while (RAW3215_BUFFER_SIZE - raw->count < length) {
/* there might be a request pending */
raw->flags |= RAW3215_FLUSHING;
raw3215_mk_write_req(raw);
raw3215_try_io(raw);
raw->flags &= ~RAW3215_FLUSHING;
#ifdef CONFIG_TN3215_CONSOLE
ccw_device_wait_idle(raw->cdev);
#endif
/* Enough room freed up ? */
if (RAW3215_BUFFER_SIZE - raw->count >= length)
break;
/* there might be another cpu waiting for the lock */
spin_unlock(get_ccwdev_lock(raw->cdev));
udelay(100);
spin_lock(get_ccwdev_lock(raw->cdev));
}
}
/*
* String write routine for 3215 devices
*/
static void raw3215_write(struct raw3215_info *raw, const char *str,
unsigned int length)
{
unsigned long flags;
int c, count;
while (length > 0) {
spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
count = (length > RAW3215_BUFFER_SIZE) ?
RAW3215_BUFFER_SIZE : length;
length -= count;
raw3215_make_room(raw, count);
/* copy string to output buffer and convert it to EBCDIC */
while (1) {
c = min_t(int, count,
min(RAW3215_BUFFER_SIZE - raw->count,
RAW3215_BUFFER_SIZE - raw->head));
if (c <= 0)
break;
memcpy(raw->buffer + raw->head, str, c);
ASCEBC(raw->buffer + raw->head, c);
raw->head = (raw->head + c) & (RAW3215_BUFFER_SIZE - 1);
raw->count += c;
raw->line_pos += c;
str += c;
count -= c;
}
if (!(raw->flags & RAW3215_WORKING)) {
raw3215_mk_write_req(raw);
/* start or queue request */
raw3215_try_io(raw);
}
spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
}
}
/*
* Put character routine for 3215 devices
*/
static void raw3215_putchar(struct raw3215_info *raw, unsigned char ch)
{
unsigned long flags;
unsigned int length, i;
spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
if (ch == '\t') {
length = TAB_STOP_SIZE - (raw->line_pos%TAB_STOP_SIZE);
raw->line_pos += length;
ch = ' ';
} else if (ch == '\n') {
length = 1;
raw->line_pos = 0;
} else {
length = 1;
raw->line_pos++;
}
raw3215_make_room(raw, length);
for (i = 0; i < length; i++) {
raw->buffer[raw->head] = (char) _ascebc[(int) ch];
raw->head = (raw->head + 1) & (RAW3215_BUFFER_SIZE - 1);
raw->count++;
}
if (!(raw->flags & RAW3215_WORKING)) {
raw3215_mk_write_req(raw);
/* start or queue request */
raw3215_try_io(raw);
}
spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
}
/*
* Flush routine, it simply sets the flush flag and tries to start
* pending IO.
*/
static void raw3215_flush_buffer(struct raw3215_info *raw)
{
unsigned long flags;
spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
if (raw->count > 0) {
raw->flags |= RAW3215_FLUSHING;
raw3215_try_io(raw);
raw->flags &= ~RAW3215_FLUSHING;
}
spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
}
/*
* Fire up a 3215 device.
*/
static int raw3215_startup(struct raw3215_info *raw)
{
unsigned long flags;
if (tty_port_initialized(&raw->port))
return 0;
raw->line_pos = 0;
tty_port_set_initialized(&raw->port, 1);
spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
raw3215_try_io(raw);
spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
return 0;
}
/*
* Shutdown a 3215 device.
*/
static void raw3215_shutdown(struct raw3215_info *raw)
{
DECLARE_WAITQUEUE(wait, current);
unsigned long flags;
if (!tty_port_initialized(&raw->port) || (raw->flags & RAW3215_FIXED))
return;
/* Wait for outstanding requests, then free irq */
spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
if ((raw->flags & RAW3215_WORKING) ||
raw->queued_write != NULL ||
raw->queued_read != NULL) {
add_wait_queue(&raw->empty_wait, &wait);
set_current_state(TASK_INTERRUPTIBLE);
spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
schedule();
spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
remove_wait_queue(&raw->empty_wait, &wait);
set_current_state(TASK_RUNNING);
tty_port_set_initialized(&raw->port, 1);
}
spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
}
static struct raw3215_info *raw3215_alloc_info(void)
{
struct raw3215_info *info;
info = kzalloc(sizeof(struct raw3215_info), GFP_KERNEL | GFP_DMA);
if (!info)
return NULL;
info->buffer = kzalloc(RAW3215_BUFFER_SIZE, GFP_KERNEL | GFP_DMA);
info->inbuf = kzalloc(RAW3215_INBUF_SIZE, GFP_KERNEL | GFP_DMA);
if (!info->buffer || !info->inbuf) {
kfree(info->inbuf);
kfree(info->buffer);
kfree(info);
return NULL;
}
timer_setup(&info->timer, raw3215_timeout, 0);
init_waitqueue_head(&info->empty_wait);
tty_port_init(&info->port);
return info;
}
static void raw3215_free_info(struct raw3215_info *raw)
{
kfree(raw->inbuf);
kfree(raw->buffer);
tty_port_destroy(&raw->port);
kfree(raw);
}
static int raw3215_probe (struct ccw_device *cdev)
{
struct raw3215_info *raw;
int line;
/* Console is special. */
if (raw3215[0] && (raw3215[0] == dev_get_drvdata(&cdev->dev)))
return 0;
raw = raw3215_alloc_info();
if (raw == NULL)
return -ENOMEM;
raw->cdev = cdev;
dev_set_drvdata(&cdev->dev, raw);
cdev->handler = raw3215_irq;
spin_lock(&raw3215_device_lock);
for (line = 0; line < NR_3215; line++) {
if (!raw3215[line]) {
raw3215[line] = raw;
break;
}
}
spin_unlock(&raw3215_device_lock);
if (line == NR_3215) {
raw3215_free_info(raw);
return -ENODEV;
}
return 0;
}
static void raw3215_remove (struct ccw_device *cdev)
{
struct raw3215_info *raw;
unsigned int line;
ccw_device_set_offline(cdev);
raw = dev_get_drvdata(&cdev->dev);
if (raw) {
spin_lock(&raw3215_device_lock);
for (line = 0; line < NR_3215; line++)
if (raw3215[line] == raw)
break;
raw3215[line] = NULL;
spin_unlock(&raw3215_device_lock);
dev_set_drvdata(&cdev->dev, NULL);
raw3215_free_info(raw);
}
}
static int raw3215_set_online (struct ccw_device *cdev)
{
struct raw3215_info *raw;
raw = dev_get_drvdata(&cdev->dev);
if (!raw)
return -ENODEV;
return raw3215_startup(raw);
}
static int raw3215_set_offline (struct ccw_device *cdev)
{
struct raw3215_info *raw;
raw = dev_get_drvdata(&cdev->dev);
if (!raw)
return -ENODEV;
raw3215_shutdown(raw);
return 0;
}
static struct ccw_device_id raw3215_id[] = {
{ CCW_DEVICE(0x3215, 0) },
{ /* end of list */ },
};
static struct ccw_driver raw3215_ccw_driver = {
.driver = {
.name = "3215",
.owner = THIS_MODULE,
},
.ids = raw3215_id,
.probe = &raw3215_probe,
.remove = &raw3215_remove,
.set_online = &raw3215_set_online,
.set_offline = &raw3215_set_offline,
.int_class = IRQIO_C15,
};
#ifdef CONFIG_TN3215_CONSOLE
/*
* Write a string to the 3215 console
*/
static void con3215_write(struct console *co, const char *str,
unsigned int count)
{
struct raw3215_info *raw;
int i;
if (count <= 0)
return;
raw = raw3215[0]; /* console 3215 is the first one */
while (count > 0) {
for (i = 0; i < count; i++)
if (str[i] == '\t' || str[i] == '\n')
break;
raw3215_write(raw, str, i);
count -= i;
str += i;
if (count > 0) {
raw3215_putchar(raw, *str);
count--;
str++;
}
}
}
static struct tty_driver *con3215_device(struct console *c, int *index)
{
*index = c->index;
return tty3215_driver;
}
/*
* The below function is called as a panic/reboot notifier before the
* system enters a disabled, endless loop.
*
* Notice we must use the spin_trylock() alternative, to prevent lockups
* in atomic context (panic routine runs with secondary CPUs, local IRQs
* and preemption disabled).
*/
static int con3215_notify(struct notifier_block *self,
unsigned long event, void *data)
{
struct raw3215_info *raw;
unsigned long flags;
raw = raw3215[0]; /* console 3215 is the first one */
if (!spin_trylock_irqsave(get_ccwdev_lock(raw->cdev), flags))
return NOTIFY_DONE;
raw3215_make_room(raw, RAW3215_BUFFER_SIZE);
spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
return NOTIFY_DONE;
}
static struct notifier_block on_panic_nb = {
.notifier_call = con3215_notify,
.priority = INT_MIN + 1, /* run the callback late */
};
static struct notifier_block on_reboot_nb = {
.notifier_call = con3215_notify,
.priority = INT_MIN + 1, /* run the callback late */
};
/*
* The console structure for the 3215 console
*/
static struct console con3215 = {
.name = "ttyS",
.write = con3215_write,
.device = con3215_device,
.flags = CON_PRINTBUFFER,
};
/*
* 3215 console initialization code called from console_init().
*/
static int __init con3215_init(void)
{
struct ccw_device *cdev;
struct raw3215_info *raw;
struct raw3215_req *req;
int i;
/* Check if 3215 is to be the console */
if (!CONSOLE_IS_3215)
return -ENODEV;
/* Set the console mode for VM */
if (MACHINE_IS_VM) {
cpcmd("TERM CONMODE 3215", NULL, 0, NULL);
cpcmd("TERM AUTOCR OFF", NULL, 0, NULL);
}
/* allocate 3215 request structures */
raw3215_freelist = NULL;
for (i = 0; i < NR_3215_REQ; i++) {
req = kzalloc(sizeof(struct raw3215_req), GFP_KERNEL | GFP_DMA);
if (!req)
return -ENOMEM;
req->next = raw3215_freelist;
raw3215_freelist = req;
}
cdev = ccw_device_create_console(&raw3215_ccw_driver);
if (IS_ERR(cdev))
return -ENODEV;
raw3215[0] = raw = raw3215_alloc_info();
raw->cdev = cdev;
dev_set_drvdata(&cdev->dev, raw);
cdev->handler = raw3215_irq;
raw->flags |= RAW3215_FIXED;
if (ccw_device_enable_console(cdev)) {
ccw_device_destroy_console(cdev);
raw3215_free_info(raw);
raw3215[0] = NULL;
return -ENODEV;
}
/* Request the console irq */
if (raw3215_startup(raw) != 0) {
raw3215_free_info(raw);
raw3215[0] = NULL;
return -ENODEV;
}
atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb);
register_reboot_notifier(&on_reboot_nb);
register_console(&con3215);
return 0;
}
console_initcall(con3215_init);
#endif
static int tty3215_install(struct tty_driver *driver, struct tty_struct *tty)
{
struct raw3215_info *raw;
raw = raw3215[tty->index];
if (raw == NULL)
return -ENODEV;
tty->driver_data = raw;
return tty_port_install(&raw->port, driver, tty);
}
/*
* tty3215_open
*
* This routine is called whenever a 3215 tty is opened.
*/
static int tty3215_open(struct tty_struct *tty, struct file * filp)
{
struct raw3215_info *raw = tty->driver_data;
tty_port_tty_set(&raw->port, tty);
/*
* Start up 3215 device
*/
return raw3215_startup(raw);
}
/*
* tty3215_close()
*
* This routine is called when the 3215 tty is closed. We wait
* for the remaining request to be completed. Then we clean up.
*/
static void tty3215_close(struct tty_struct *tty, struct file * filp)
{
struct raw3215_info *raw = tty->driver_data;
if (raw == NULL || tty->count > 1)
return;
tty->closing = 1;
/* Shutdown the terminal */
raw3215_shutdown(raw);
tty->closing = 0;
tty_port_tty_set(&raw->port, NULL);
}
/*
* Returns the amount of free space in the output buffer.
*/
static unsigned int tty3215_write_room(struct tty_struct *tty)
{
struct raw3215_info *raw = tty->driver_data;
/* Subtract TAB_STOP_SIZE to allow for a tab, 8 <<< 64K */
if ((RAW3215_BUFFER_SIZE - raw->count - TAB_STOP_SIZE) >= 0)
return RAW3215_BUFFER_SIZE - raw->count - TAB_STOP_SIZE;
else
return 0;
}
/*
* String write routine for 3215 ttys
*/
static int tty3215_write(struct tty_struct * tty,
const unsigned char *buf, int count)
{
struct raw3215_info *raw = tty->driver_data;
int i, written;
written = count;
while (count > 0) {
for (i = 0; i < count; i++)
if (buf[i] == '\t' || buf[i] == '\n')
break;
raw3215_write(raw, buf, i);
count -= i;
buf += i;
if (count > 0) {
raw3215_putchar(raw, *buf);
count--;
buf++;
}
}
return written;
}
/*
* Put character routine for 3215 ttys
*/
static int tty3215_put_char(struct tty_struct *tty, unsigned char ch)
{
struct raw3215_info *raw = tty->driver_data;
raw3215_putchar(raw, ch);
return 1;
}
static void tty3215_flush_chars(struct tty_struct *tty)
{
}
/*
* Returns the number of characters in the output buffer
*/
static unsigned int tty3215_chars_in_buffer(struct tty_struct *tty)
{
struct raw3215_info *raw = tty->driver_data;
return raw->count;
}
static void tty3215_flush_buffer(struct tty_struct *tty)
{
struct raw3215_info *raw = tty->driver_data;
raw3215_flush_buffer(raw);
tty_wakeup(tty);
}
/*
* Disable reading from a 3215 tty
*/
static void tty3215_throttle(struct tty_struct * tty)
{
struct raw3215_info *raw = tty->driver_data;
raw->flags |= RAW3215_THROTTLED;
}
/*
* Enable reading from a 3215 tty
*/
static void tty3215_unthrottle(struct tty_struct * tty)
{
struct raw3215_info *raw = tty->driver_data;
unsigned long flags;
if (raw->flags & RAW3215_THROTTLED) {
spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
raw->flags &= ~RAW3215_THROTTLED;
raw3215_try_io(raw);
spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
}
}
/*
* Disable writing to a 3215 tty
*/
static void tty3215_stop(struct tty_struct *tty)
{
struct raw3215_info *raw = tty->driver_data;
raw->flags |= RAW3215_STOPPED;
}
/*
* Enable writing to a 3215 tty
*/
static void tty3215_start(struct tty_struct *tty)
{
struct raw3215_info *raw = tty->driver_data;
unsigned long flags;
if (raw->flags & RAW3215_STOPPED) {
spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
raw->flags &= ~RAW3215_STOPPED;
raw3215_try_io(raw);
spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
}
}
static const struct tty_operations tty3215_ops = {
.install = tty3215_install,
.open = tty3215_open,
.close = tty3215_close,
.write = tty3215_write,
.put_char = tty3215_put_char,
.flush_chars = tty3215_flush_chars,
.write_room = tty3215_write_room,
.chars_in_buffer = tty3215_chars_in_buffer,
.flush_buffer = tty3215_flush_buffer,
.throttle = tty3215_throttle,
.unthrottle = tty3215_unthrottle,
.stop = tty3215_stop,
.start = tty3215_start,
};
/*
* 3215 tty registration code called from tty_init().
* Most kernel services (incl. kmalloc) are available at this poimt.
*/
static int __init tty3215_init(void)
{
struct tty_driver *driver;
int ret;
if (!CONSOLE_IS_3215)
return 0;
driver = tty_alloc_driver(NR_3215, TTY_DRIVER_REAL_RAW);
if (IS_ERR(driver))
return PTR_ERR(driver);
ret = ccw_driver_register(&raw3215_ccw_driver);
if (ret) {
tty_driver_kref_put(driver);
return ret;
}
/*
* Initialize the tty_driver structure
* Entries in tty3215_driver that are NOT initialized:
* proc_entry, set_termios, flush_buffer, set_ldisc, write_proc
*/
driver->driver_name = "tty3215";
driver->name = "ttyS";
driver->major = TTY_MAJOR;
driver->minor_start = 64;
driver->type = TTY_DRIVER_TYPE_SYSTEM;
driver->subtype = SYSTEM_TYPE_TTY;
driver->init_termios = tty_std_termios;
driver->init_termios.c_iflag = IGNBRK | IGNPAR;
driver->init_termios.c_oflag = ONLCR;
driver->init_termios.c_lflag = ISIG;
tty_set_operations(driver, &tty3215_ops);
ret = tty_register_driver(driver);
if (ret) {
tty_driver_kref_put(driver);
return ret;
}
tty3215_driver = driver;
return 0;
}
device_initcall(tty3215_init);
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