linux/drivers/isdn/gigaset/ser-gigaset.c
Tilman Schmidt 81fa7b8257 isdn/gigaset: unify function return values
Various functions in the Gigaset driver were using different
conventions for the meaning of their int return values.
Align them to the usual negative error numbers convention.

Inspired-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-05-07 22:37:56 -04:00

820 lines
18 KiB
C

/* This is the serial hardware link layer (HLL) for the Gigaset 307x isdn
* DECT base (aka Sinus 45 isdn) using the RS232 DECT data module M101,
* written as a line discipline.
*
* =====================================================================
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
* =====================================================================
*/
#include "gigaset.h"
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/platform_device.h>
#include <linux/completion.h>
/* Version Information */
#define DRIVER_AUTHOR "Tilman Schmidt"
#define DRIVER_DESC "Serial Driver for Gigaset 307x using Siemens M101"
#define GIGASET_MINORS 1
#define GIGASET_MINOR 0
#define GIGASET_MODULENAME "ser_gigaset"
#define GIGASET_DEVNAME "ttyGS"
/* length limit according to Siemens 3070usb-protokoll.doc ch. 2.1 */
#define IF_WRITEBUF 264
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");
MODULE_ALIAS_LDISC(N_GIGASET_M101);
static int startmode = SM_ISDN;
module_param(startmode, int, S_IRUGO);
MODULE_PARM_DESC(startmode, "initial operation mode");
static int cidmode = 1;
module_param(cidmode, int, S_IRUGO);
MODULE_PARM_DESC(cidmode, "stay in CID mode when idle");
static struct gigaset_driver *driver;
struct ser_cardstate {
struct platform_device dev;
struct tty_struct *tty;
atomic_t refcnt;
struct completion dead_cmp;
};
static struct platform_driver device_driver = {
.driver = {
.name = GIGASET_MODULENAME,
},
};
static void flush_send_queue(struct cardstate *);
/* transmit data from current open skb
* result: number of bytes sent or error code < 0
*/
static int write_modem(struct cardstate *cs)
{
struct tty_struct *tty = cs->hw.ser->tty;
struct bc_state *bcs = &cs->bcs[0]; /* only one channel */
struct sk_buff *skb = bcs->tx_skb;
int sent = -EOPNOTSUPP;
if (!tty || !tty->driver || !skb)
return -EINVAL;
if (!skb->len) {
dev_kfree_skb_any(skb);
bcs->tx_skb = NULL;
return -EINVAL;
}
set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
if (tty->ops->write)
sent = tty->ops->write(tty, skb->data, skb->len);
gig_dbg(DEBUG_OUTPUT, "write_modem: sent %d", sent);
if (sent < 0) {
/* error */
flush_send_queue(cs);
return sent;
}
skb_pull(skb, sent);
if (!skb->len) {
/* skb sent completely */
gigaset_skb_sent(bcs, skb);
gig_dbg(DEBUG_INTR, "kfree skb (Adr: %lx)!",
(unsigned long) skb);
dev_kfree_skb_any(skb);
bcs->tx_skb = NULL;
}
return sent;
}
/*
* transmit first queued command buffer
* result: number of bytes sent or error code < 0
*/
static int send_cb(struct cardstate *cs)
{
struct tty_struct *tty = cs->hw.ser->tty;
struct cmdbuf_t *cb, *tcb;
unsigned long flags;
int sent = 0;
if (!tty || !tty->driver)
return -EFAULT;
cb = cs->cmdbuf;
if (!cb)
return 0; /* nothing to do */
if (cb->len) {
set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
sent = tty->ops->write(tty, cb->buf + cb->offset, cb->len);
if (sent < 0) {
/* error */
gig_dbg(DEBUG_OUTPUT, "send_cb: write error %d", sent);
flush_send_queue(cs);
return sent;
}
cb->offset += sent;
cb->len -= sent;
gig_dbg(DEBUG_OUTPUT, "send_cb: sent %d, left %u, queued %u",
sent, cb->len, cs->cmdbytes);
}
while (cb && !cb->len) {
spin_lock_irqsave(&cs->cmdlock, flags);
cs->cmdbytes -= cs->curlen;
tcb = cb;
cs->cmdbuf = cb = cb->next;
if (cb) {
cb->prev = NULL;
cs->curlen = cb->len;
} else {
cs->lastcmdbuf = NULL;
cs->curlen = 0;
}
spin_unlock_irqrestore(&cs->cmdlock, flags);
if (tcb->wake_tasklet)
tasklet_schedule(tcb->wake_tasklet);
kfree(tcb);
}
return sent;
}
/*
* send queue tasklet
* If there is already a skb opened, put data to the transfer buffer
* by calling "write_modem".
* Otherwise take a new skb out of the queue.
*/
static void gigaset_modem_fill(unsigned long data)
{
struct cardstate *cs = (struct cardstate *) data;
struct bc_state *bcs;
struct sk_buff *nextskb;
int sent = 0;
if (!cs) {
gig_dbg(DEBUG_OUTPUT, "%s: no cardstate", __func__);
return;
}
bcs = cs->bcs;
if (!bcs) {
gig_dbg(DEBUG_OUTPUT, "%s: no cardstate", __func__);
return;
}
if (!bcs->tx_skb) {
/* no skb is being sent; send command if any */
sent = send_cb(cs);
gig_dbg(DEBUG_OUTPUT, "%s: send_cb -> %d", __func__, sent);
if (sent)
/* something sent or error */
return;
/* no command to send; get skb */
nextskb = skb_dequeue(&bcs->squeue);
if (!nextskb)
/* no skb either, nothing to do */
return;
bcs->tx_skb = nextskb;
gig_dbg(DEBUG_INTR, "Dequeued skb (Adr: %lx)",
(unsigned long) bcs->tx_skb);
}
/* send skb */
gig_dbg(DEBUG_OUTPUT, "%s: tx_skb", __func__);
if (write_modem(cs) < 0)
gig_dbg(DEBUG_OUTPUT, "%s: write_modem failed", __func__);
}
/*
* throw away all data queued for sending
*/
static void flush_send_queue(struct cardstate *cs)
{
struct sk_buff *skb;
struct cmdbuf_t *cb;
unsigned long flags;
/* command queue */
spin_lock_irqsave(&cs->cmdlock, flags);
while ((cb = cs->cmdbuf) != NULL) {
cs->cmdbuf = cb->next;
if (cb->wake_tasklet)
tasklet_schedule(cb->wake_tasklet);
kfree(cb);
}
cs->cmdbuf = cs->lastcmdbuf = NULL;
cs->cmdbytes = cs->curlen = 0;
spin_unlock_irqrestore(&cs->cmdlock, flags);
/* data queue */
if (cs->bcs->tx_skb)
dev_kfree_skb_any(cs->bcs->tx_skb);
while ((skb = skb_dequeue(&cs->bcs->squeue)) != NULL)
dev_kfree_skb_any(skb);
}
/* Gigaset Driver Interface */
/* ======================== */
/*
* queue an AT command string for transmission to the Gigaset device
* parameters:
* cs controller state structure
* buf buffer containing the string to send
* len number of characters to send
* wake_tasklet tasklet to run when transmission is complete, or NULL
* return value:
* number of bytes queued, or error code < 0
*/
static int gigaset_write_cmd(struct cardstate *cs, struct cmdbuf_t *cb)
{
unsigned long flags;
gigaset_dbg_buffer(cs->mstate != MS_LOCKED ?
DEBUG_TRANSCMD : DEBUG_LOCKCMD,
"CMD Transmit", cb->len, cb->buf);
spin_lock_irqsave(&cs->cmdlock, flags);
cb->prev = cs->lastcmdbuf;
if (cs->lastcmdbuf)
cs->lastcmdbuf->next = cb;
else {
cs->cmdbuf = cb;
cs->curlen = cb->len;
}
cs->cmdbytes += cb->len;
cs->lastcmdbuf = cb;
spin_unlock_irqrestore(&cs->cmdlock, flags);
spin_lock_irqsave(&cs->lock, flags);
if (cs->connected)
tasklet_schedule(&cs->write_tasklet);
spin_unlock_irqrestore(&cs->lock, flags);
return cb->len;
}
/*
* tty_driver.write_room interface routine
* return number of characters the driver will accept to be written
* parameter:
* controller state structure
* return value:
* number of characters
*/
static int gigaset_write_room(struct cardstate *cs)
{
unsigned bytes;
bytes = cs->cmdbytes;
return bytes < IF_WRITEBUF ? IF_WRITEBUF - bytes : 0;
}
/*
* tty_driver.chars_in_buffer interface routine
* return number of characters waiting to be sent
* parameter:
* controller state structure
* return value:
* number of characters
*/
static int gigaset_chars_in_buffer(struct cardstate *cs)
{
return cs->cmdbytes;
}
/*
* implementation of ioctl(GIGASET_BRKCHARS)
* parameter:
* controller state structure
* return value:
* -EINVAL (unimplemented function)
*/
static int gigaset_brkchars(struct cardstate *cs, const unsigned char buf[6])
{
/* not implemented */
return -EINVAL;
}
/*
* Open B channel
* Called by "do_action" in ev-layer.c
*/
static int gigaset_init_bchannel(struct bc_state *bcs)
{
/* nothing to do for M10x */
gigaset_bchannel_up(bcs);
return 0;
}
/*
* Close B channel
* Called by "do_action" in ev-layer.c
*/
static int gigaset_close_bchannel(struct bc_state *bcs)
{
/* nothing to do for M10x */
gigaset_bchannel_down(bcs);
return 0;
}
/*
* Set up B channel structure
* This is called by "gigaset_initcs" in common.c
*/
static int gigaset_initbcshw(struct bc_state *bcs)
{
/* unused */
bcs->hw.ser = NULL;
return 0;
}
/*
* Free B channel structure
* Called by "gigaset_freebcs" in common.c
*/
static void gigaset_freebcshw(struct bc_state *bcs)
{
/* unused */
}
/*
* Reinitialize B channel structure
* This is called by "bcs_reinit" in common.c
*/
static void gigaset_reinitbcshw(struct bc_state *bcs)
{
/* nothing to do for M10x */
}
/*
* Free hardware specific device data
* This will be called by "gigaset_freecs" in common.c
*/
static void gigaset_freecshw(struct cardstate *cs)
{
tasklet_kill(&cs->write_tasklet);
if (!cs->hw.ser)
return;
dev_set_drvdata(&cs->hw.ser->dev.dev, NULL);
platform_device_unregister(&cs->hw.ser->dev);
kfree(cs->hw.ser);
cs->hw.ser = NULL;
}
static void gigaset_device_release(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
/* adapted from platform_device_release() in drivers/base/platform.c */
kfree(dev->platform_data);
kfree(pdev->resource);
}
/*
* Set up hardware specific device data
* This is called by "gigaset_initcs" in common.c
*/
static int gigaset_initcshw(struct cardstate *cs)
{
int rc;
struct ser_cardstate *scs;
scs = kzalloc(sizeof(struct ser_cardstate), GFP_KERNEL);
if (!scs) {
pr_err("out of memory\n");
return -ENOMEM;
}
cs->hw.ser = scs;
cs->hw.ser->dev.name = GIGASET_MODULENAME;
cs->hw.ser->dev.id = cs->minor_index;
cs->hw.ser->dev.dev.release = gigaset_device_release;
rc = platform_device_register(&cs->hw.ser->dev);
if (rc != 0) {
pr_err("error %d registering platform device\n", rc);
kfree(cs->hw.ser);
cs->hw.ser = NULL;
return rc;
}
dev_set_drvdata(&cs->hw.ser->dev.dev, cs);
tasklet_init(&cs->write_tasklet,
gigaset_modem_fill, (unsigned long) cs);
return 0;
}
/*
* set modem control lines
* Parameters:
* card state structure
* modem control line state ([TIOCM_DTR]|[TIOCM_RTS])
* Called by "gigaset_start" and "gigaset_enterconfigmode" in common.c
* and by "if_lock" and "if_termios" in interface.c
*/
static int gigaset_set_modem_ctrl(struct cardstate *cs, unsigned old_state,
unsigned new_state)
{
struct tty_struct *tty = cs->hw.ser->tty;
unsigned int set, clear;
if (!tty || !tty->driver || !tty->ops->tiocmset)
return -EINVAL;
set = new_state & ~old_state;
clear = old_state & ~new_state;
if (!set && !clear)
return 0;
gig_dbg(DEBUG_IF, "tiocmset set %x clear %x", set, clear);
return tty->ops->tiocmset(tty, set, clear);
}
static int gigaset_baud_rate(struct cardstate *cs, unsigned cflag)
{
return -EINVAL;
}
static int gigaset_set_line_ctrl(struct cardstate *cs, unsigned cflag)
{
return -EINVAL;
}
static const struct gigaset_ops ops = {
gigaset_write_cmd,
gigaset_write_room,
gigaset_chars_in_buffer,
gigaset_brkchars,
gigaset_init_bchannel,
gigaset_close_bchannel,
gigaset_initbcshw,
gigaset_freebcshw,
gigaset_reinitbcshw,
gigaset_initcshw,
gigaset_freecshw,
gigaset_set_modem_ctrl,
gigaset_baud_rate,
gigaset_set_line_ctrl,
gigaset_m10x_send_skb, /* asyncdata.c */
gigaset_m10x_input, /* asyncdata.c */
};
/* Line Discipline Interface */
/* ========================= */
/* helper functions for cardstate refcounting */
static struct cardstate *cs_get(struct tty_struct *tty)
{
struct cardstate *cs = tty->disc_data;
if (!cs || !cs->hw.ser) {
gig_dbg(DEBUG_ANY, "%s: no cardstate", __func__);
return NULL;
}
atomic_inc(&cs->hw.ser->refcnt);
return cs;
}
static void cs_put(struct cardstate *cs)
{
if (atomic_dec_and_test(&cs->hw.ser->refcnt))
complete(&cs->hw.ser->dead_cmp);
}
/*
* Called by the tty driver when the line discipline is pushed onto the tty.
* Called in process context.
*/
static int
gigaset_tty_open(struct tty_struct *tty)
{
struct cardstate *cs;
int rc;
gig_dbg(DEBUG_INIT, "Starting HLL for Gigaset M101");
pr_info(DRIVER_DESC "\n");
if (!driver) {
pr_err("%s: no driver structure\n", __func__);
return -ENODEV;
}
/* allocate memory for our device state and initialize it */
cs = gigaset_initcs(driver, 1, 1, 0, cidmode, GIGASET_MODULENAME);
if (!cs) {
rc = -ENODEV;
goto error;
}
cs->dev = &cs->hw.ser->dev.dev;
cs->hw.ser->tty = tty;
atomic_set(&cs->hw.ser->refcnt, 1);
init_completion(&cs->hw.ser->dead_cmp);
tty->disc_data = cs;
/* OK.. Initialization of the datastructures and the HW is done.. Now
* startup system and notify the LL that we are ready to run
*/
if (startmode == SM_LOCKED)
cs->mstate = MS_LOCKED;
rc = gigaset_start(cs);
if (rc < 0) {
tasklet_kill(&cs->write_tasklet);
goto error;
}
gig_dbg(DEBUG_INIT, "Startup of HLL done");
return 0;
error:
gig_dbg(DEBUG_INIT, "Startup of HLL failed");
tty->disc_data = NULL;
gigaset_freecs(cs);
return rc;
}
/*
* Called by the tty driver when the line discipline is removed.
* Called from process context.
*/
static void
gigaset_tty_close(struct tty_struct *tty)
{
struct cardstate *cs = tty->disc_data;
gig_dbg(DEBUG_INIT, "Stopping HLL for Gigaset M101");
if (!cs) {
gig_dbg(DEBUG_INIT, "%s: no cardstate", __func__);
return;
}
/* prevent other callers from entering ldisc methods */
tty->disc_data = NULL;
if (!cs->hw.ser)
pr_err("%s: no hw cardstate\n", __func__);
else {
/* wait for running methods to finish */
if (!atomic_dec_and_test(&cs->hw.ser->refcnt))
wait_for_completion(&cs->hw.ser->dead_cmp);
}
/* stop operations */
gigaset_stop(cs);
tasklet_kill(&cs->write_tasklet);
flush_send_queue(cs);
cs->dev = NULL;
gigaset_freecs(cs);
gig_dbg(DEBUG_INIT, "Shutdown of HLL done");
}
/*
* Called by the tty driver when the tty line is hung up.
* Wait for I/O to driver to complete and unregister ISDN device.
* This is already done by the close routine, so just call that.
* Called from process context.
*/
static int gigaset_tty_hangup(struct tty_struct *tty)
{
gigaset_tty_close(tty);
return 0;
}
/*
* Read on the tty.
* Unused, received data goes only to the Gigaset driver.
*/
static ssize_t
gigaset_tty_read(struct tty_struct *tty, struct file *file,
unsigned char __user *buf, size_t count)
{
return -EAGAIN;
}
/*
* Write on the tty.
* Unused, transmit data comes only from the Gigaset driver.
*/
static ssize_t
gigaset_tty_write(struct tty_struct *tty, struct file *file,
const unsigned char *buf, size_t count)
{
return -EAGAIN;
}
/*
* Ioctl on the tty.
* Called in process context only.
* May be re-entered by multiple ioctl calling threads.
*/
static int
gigaset_tty_ioctl(struct tty_struct *tty, struct file *file,
unsigned int cmd, unsigned long arg)
{
struct cardstate *cs = cs_get(tty);
int rc, val;
int __user *p = (int __user *)arg;
if (!cs)
return -ENXIO;
switch (cmd) {
case FIONREAD:
/* unused, always return zero */
val = 0;
rc = put_user(val, p);
break;
case TCFLSH:
/* flush our buffers and the serial port's buffer */
switch (arg) {
case TCIFLUSH:
/* no own input buffer to flush */
break;
case TCIOFLUSH:
case TCOFLUSH:
flush_send_queue(cs);
break;
}
/* Pass through */
default:
/* pass through to underlying serial device */
rc = n_tty_ioctl_helper(tty, file, cmd, arg);
break;
}
cs_put(cs);
return rc;
}
/*
* Called by the tty driver when a block of data has been received.
* Will not be re-entered while running but other ldisc functions
* may be called in parallel.
* Can be called from hard interrupt level as well as soft interrupt
* level or mainline.
* Parameters:
* tty tty structure
* buf buffer containing received characters
* cflags buffer containing error flags for received characters (ignored)
* count number of received characters
*/
static void
gigaset_tty_receive(struct tty_struct *tty, const unsigned char *buf,
char *cflags, int count)
{
struct cardstate *cs = cs_get(tty);
unsigned tail, head, n;
struct inbuf_t *inbuf;
if (!cs)
return;
inbuf = cs->inbuf;
if (!inbuf) {
dev_err(cs->dev, "%s: no inbuf\n", __func__);
cs_put(cs);
return;
}
tail = inbuf->tail;
head = inbuf->head;
gig_dbg(DEBUG_INTR, "buffer state: %u -> %u, receive %u bytes",
head, tail, count);
if (head <= tail) {
/* possible buffer wraparound */
n = min_t(unsigned, count, RBUFSIZE - tail);
memcpy(inbuf->data + tail, buf, n);
tail = (tail + n) % RBUFSIZE;
buf += n;
count -= n;
}
if (count > 0) {
/* tail < head and some data left */
n = head - tail - 1;
if (count > n) {
dev_err(cs->dev,
"inbuf overflow, discarding %d bytes\n",
count - n);
count = n;
}
memcpy(inbuf->data + tail, buf, count);
tail += count;
}
gig_dbg(DEBUG_INTR, "setting tail to %u", tail);
inbuf->tail = tail;
/* Everything was received .. Push data into handler */
gig_dbg(DEBUG_INTR, "%s-->BH", __func__);
gigaset_schedule_event(cs);
cs_put(cs);
}
/*
* Called by the tty driver when there's room for more data to send.
*/
static void
gigaset_tty_wakeup(struct tty_struct *tty)
{
struct cardstate *cs = cs_get(tty);
clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
if (!cs)
return;
tasklet_schedule(&cs->write_tasklet);
cs_put(cs);
}
static struct tty_ldisc_ops gigaset_ldisc = {
.owner = THIS_MODULE,
.magic = TTY_LDISC_MAGIC,
.name = "ser_gigaset",
.open = gigaset_tty_open,
.close = gigaset_tty_close,
.hangup = gigaset_tty_hangup,
.read = gigaset_tty_read,
.write = gigaset_tty_write,
.ioctl = gigaset_tty_ioctl,
.receive_buf = gigaset_tty_receive,
.write_wakeup = gigaset_tty_wakeup,
};
/* Initialization / Shutdown */
/* ========================= */
static int __init ser_gigaset_init(void)
{
int rc;
gig_dbg(DEBUG_INIT, "%s", __func__);
rc = platform_driver_register(&device_driver);
if (rc != 0) {
pr_err("error %d registering platform driver\n", rc);
return rc;
}
/* allocate memory for our driver state and initialize it */
driver = gigaset_initdriver(GIGASET_MINOR, GIGASET_MINORS,
GIGASET_MODULENAME, GIGASET_DEVNAME,
&ops, THIS_MODULE);
if (!driver)
goto error;
rc = tty_register_ldisc(N_GIGASET_M101, &gigaset_ldisc);
if (rc != 0) {
pr_err("error %d registering line discipline\n", rc);
goto error;
}
return 0;
error:
if (driver) {
gigaset_freedriver(driver);
driver = NULL;
}
platform_driver_unregister(&device_driver);
return rc;
}
static void __exit ser_gigaset_exit(void)
{
int rc;
gig_dbg(DEBUG_INIT, "%s", __func__);
if (driver) {
gigaset_freedriver(driver);
driver = NULL;
}
rc = tty_unregister_ldisc(N_GIGASET_M101);
if (rc != 0)
pr_err("error %d unregistering line discipline\n", rc);
platform_driver_unregister(&device_driver);
}
module_init(ser_gigaset_init);
module_exit(ser_gigaset_exit);