linux/drivers/char/ppdev.c
Michael Buesch 81fc401e42 ppdev: reduce kernel log spam
One of my programs frequently grabs the parport, does something with it
and then drops it again. This results in spamming of the kernel log with

"... registered pardevice"
"... unregistered pardevice"

These messages are completely useless, except for debugging ppdev,
probably.  So put them under DEBUG (or dynamic debug).

Signed-off-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-18 13:03:54 -07:00

813 lines
19 KiB
C

/*
* linux/drivers/char/ppdev.c
*
* This is the code behind /dev/parport* -- it allows a user-space
* application to use the parport subsystem.
*
* Copyright (C) 1998-2000, 2002 Tim Waugh <tim@cyberelk.net>
*
* 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.
*
* A /dev/parportx device node represents an arbitrary device
* on port 'x'. The following operations are possible:
*
* open do nothing, set up default IEEE 1284 protocol to be COMPAT
* close release port and unregister device (if necessary)
* ioctl
* EXCL register device exclusively (may fail)
* CLAIM (register device first time) parport_claim_or_block
* RELEASE parport_release
* SETMODE set the IEEE 1284 protocol to use for read/write
* SETPHASE set the IEEE 1284 phase of a particular mode. Not to be
* confused with ioctl(fd, SETPHASER, &stun). ;-)
* DATADIR data_forward / data_reverse
* WDATA write_data
* RDATA read_data
* WCONTROL write_control
* RCONTROL read_control
* FCONTROL frob_control
* RSTATUS read_status
* NEGOT parport_negotiate
* YIELD parport_yield_blocking
* WCTLONIRQ on interrupt, set control lines
* CLRIRQ clear (and return) interrupt count
* SETTIME sets device timeout (struct timeval)
* GETTIME gets device timeout (struct timeval)
* GETMODES gets hardware supported modes (unsigned int)
* GETMODE gets the current IEEE1284 mode
* GETPHASE gets the current IEEE1284 phase
* GETFLAGS gets current (user-visible) flags
* SETFLAGS sets current (user-visible) flags
* read/write read or write in current IEEE 1284 protocol
* select wait for interrupt (in readfds)
*
* Changes:
* Added SETTIME/GETTIME ioctl, Fred Barnes, 1999.
*
* Arnaldo Carvalho de Melo <acme@conectiva.com.br> 2000/08/25
* - On error, copy_from_user and copy_to_user do not return -EFAULT,
* They return the positive number of bytes *not* copied due to address
* space errors.
*
* Added GETMODES/GETMODE/GETPHASE ioctls, Fred Barnes <frmb2@ukc.ac.uk>, 03/01/2001.
* Added GETFLAGS/SETFLAGS ioctls, Fred Barnes, 04/2001
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/device.h>
#include <linux/ioctl.h>
#include <linux/parport.h>
#include <linux/ctype.h>
#include <linux/poll.h>
#include <linux/major.h>
#include <linux/ppdev.h>
#include <linux/smp_lock.h>
#include <linux/uaccess.h>
#define PP_VERSION "ppdev: user-space parallel port driver"
#define CHRDEV "ppdev"
struct pp_struct {
struct pardevice * pdev;
wait_queue_head_t irq_wait;
atomic_t irqc;
unsigned int flags;
int irqresponse;
unsigned char irqctl;
struct ieee1284_info state;
struct ieee1284_info saved_state;
long default_inactivity;
};
/* pp_struct.flags bitfields */
#define PP_CLAIMED (1<<0)
#define PP_EXCL (1<<1)
/* Other constants */
#define PP_INTERRUPT_TIMEOUT (10 * HZ) /* 10s */
#define PP_BUFFER_SIZE 1024
#define PARDEVICE_MAX 8
/* ROUND_UP macro from fs/select.c */
#define ROUND_UP(x,y) (((x)+(y)-1)/(y))
static inline void pp_enable_irq (struct pp_struct *pp)
{
struct parport *port = pp->pdev->port;
port->ops->enable_irq (port);
}
static ssize_t pp_read (struct file * file, char __user * buf, size_t count,
loff_t * ppos)
{
unsigned int minor = iminor(file->f_path.dentry->d_inode);
struct pp_struct *pp = file->private_data;
char * kbuffer;
ssize_t bytes_read = 0;
struct parport *pport;
int mode;
if (!(pp->flags & PP_CLAIMED)) {
/* Don't have the port claimed */
pr_debug(CHRDEV "%x: claim the port first\n", minor);
return -EINVAL;
}
/* Trivial case. */
if (count == 0)
return 0;
kbuffer = kmalloc(min_t(size_t, count, PP_BUFFER_SIZE), GFP_KERNEL);
if (!kbuffer) {
return -ENOMEM;
}
pport = pp->pdev->port;
mode = pport->ieee1284.mode & ~(IEEE1284_DEVICEID | IEEE1284_ADDR);
parport_set_timeout (pp->pdev,
(file->f_flags & O_NONBLOCK) ?
PARPORT_INACTIVITY_O_NONBLOCK :
pp->default_inactivity);
while (bytes_read == 0) {
ssize_t need = min_t(unsigned long, count, PP_BUFFER_SIZE);
if (mode == IEEE1284_MODE_EPP) {
/* various specials for EPP mode */
int flags = 0;
size_t (*fn)(struct parport *, void *, size_t, int);
if (pp->flags & PP_W91284PIC) {
flags |= PARPORT_W91284PIC;
}
if (pp->flags & PP_FASTREAD) {
flags |= PARPORT_EPP_FAST;
}
if (pport->ieee1284.mode & IEEE1284_ADDR) {
fn = pport->ops->epp_read_addr;
} else {
fn = pport->ops->epp_read_data;
}
bytes_read = (*fn)(pport, kbuffer, need, flags);
} else {
bytes_read = parport_read (pport, kbuffer, need);
}
if (bytes_read != 0)
break;
if (file->f_flags & O_NONBLOCK) {
bytes_read = -EAGAIN;
break;
}
if (signal_pending (current)) {
bytes_read = -ERESTARTSYS;
break;
}
cond_resched();
}
parport_set_timeout (pp->pdev, pp->default_inactivity);
if (bytes_read > 0 && copy_to_user (buf, kbuffer, bytes_read))
bytes_read = -EFAULT;
kfree (kbuffer);
pp_enable_irq (pp);
return bytes_read;
}
static ssize_t pp_write (struct file * file, const char __user * buf,
size_t count, loff_t * ppos)
{
unsigned int minor = iminor(file->f_path.dentry->d_inode);
struct pp_struct *pp = file->private_data;
char * kbuffer;
ssize_t bytes_written = 0;
ssize_t wrote;
int mode;
struct parport *pport;
if (!(pp->flags & PP_CLAIMED)) {
/* Don't have the port claimed */
pr_debug(CHRDEV "%x: claim the port first\n", minor);
return -EINVAL;
}
kbuffer = kmalloc(min_t(size_t, count, PP_BUFFER_SIZE), GFP_KERNEL);
if (!kbuffer) {
return -ENOMEM;
}
pport = pp->pdev->port;
mode = pport->ieee1284.mode & ~(IEEE1284_DEVICEID | IEEE1284_ADDR);
parport_set_timeout (pp->pdev,
(file->f_flags & O_NONBLOCK) ?
PARPORT_INACTIVITY_O_NONBLOCK :
pp->default_inactivity);
while (bytes_written < count) {
ssize_t n = min_t(unsigned long, count - bytes_written, PP_BUFFER_SIZE);
if (copy_from_user (kbuffer, buf + bytes_written, n)) {
bytes_written = -EFAULT;
break;
}
if ((pp->flags & PP_FASTWRITE) && (mode == IEEE1284_MODE_EPP)) {
/* do a fast EPP write */
if (pport->ieee1284.mode & IEEE1284_ADDR) {
wrote = pport->ops->epp_write_addr (pport,
kbuffer, n, PARPORT_EPP_FAST);
} else {
wrote = pport->ops->epp_write_data (pport,
kbuffer, n, PARPORT_EPP_FAST);
}
} else {
wrote = parport_write (pp->pdev->port, kbuffer, n);
}
if (wrote <= 0) {
if (!bytes_written) {
bytes_written = wrote;
}
break;
}
bytes_written += wrote;
if (file->f_flags & O_NONBLOCK) {
if (!bytes_written)
bytes_written = -EAGAIN;
break;
}
if (signal_pending (current)) {
if (!bytes_written) {
bytes_written = -EINTR;
}
break;
}
cond_resched();
}
parport_set_timeout (pp->pdev, pp->default_inactivity);
kfree (kbuffer);
pp_enable_irq (pp);
return bytes_written;
}
static void pp_irq (void *private)
{
struct pp_struct *pp = private;
if (pp->irqresponse) {
parport_write_control (pp->pdev->port, pp->irqctl);
pp->irqresponse = 0;
}
atomic_inc (&pp->irqc);
wake_up_interruptible (&pp->irq_wait);
}
static int register_device (int minor, struct pp_struct *pp)
{
struct parport *port;
struct pardevice * pdev = NULL;
char *name;
int fl;
name = kmalloc (strlen (CHRDEV) + 3, GFP_KERNEL);
if (name == NULL)
return -ENOMEM;
sprintf (name, CHRDEV "%x", minor);
port = parport_find_number (minor);
if (!port) {
printk (KERN_WARNING "%s: no associated port!\n", name);
kfree (name);
return -ENXIO;
}
fl = (pp->flags & PP_EXCL) ? PARPORT_FLAG_EXCL : 0;
pdev = parport_register_device (port, name, NULL,
NULL, pp_irq, fl, pp);
parport_put_port (port);
if (!pdev) {
printk (KERN_WARNING "%s: failed to register device!\n", name);
kfree (name);
return -ENXIO;
}
pp->pdev = pdev;
pr_debug("%s: registered pardevice\n", name);
return 0;
}
static enum ieee1284_phase init_phase (int mode)
{
switch (mode & ~(IEEE1284_DEVICEID
| IEEE1284_ADDR)) {
case IEEE1284_MODE_NIBBLE:
case IEEE1284_MODE_BYTE:
return IEEE1284_PH_REV_IDLE;
}
return IEEE1284_PH_FWD_IDLE;
}
static int pp_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
unsigned int minor = iminor(file->f_path.dentry->d_inode);
struct pp_struct *pp = file->private_data;
struct parport * port;
void __user *argp = (void __user *)arg;
/* First handle the cases that don't take arguments. */
switch (cmd) {
case PPCLAIM:
{
struct ieee1284_info *info;
int ret;
if (pp->flags & PP_CLAIMED) {
pr_debug(CHRDEV "%x: you've already got it!\n", minor);
return -EINVAL;
}
/* Deferred device registration. */
if (!pp->pdev) {
int err = register_device (minor, pp);
if (err) {
return err;
}
}
ret = parport_claim_or_block (pp->pdev);
if (ret < 0)
return ret;
pp->flags |= PP_CLAIMED;
/* For interrupt-reporting to work, we need to be
* informed of each interrupt. */
pp_enable_irq (pp);
/* We may need to fix up the state machine. */
info = &pp->pdev->port->ieee1284;
pp->saved_state.mode = info->mode;
pp->saved_state.phase = info->phase;
info->mode = pp->state.mode;
info->phase = pp->state.phase;
pp->default_inactivity = parport_set_timeout (pp->pdev, 0);
parport_set_timeout (pp->pdev, pp->default_inactivity);
return 0;
}
case PPEXCL:
if (pp->pdev) {
pr_debug(CHRDEV "%x: too late for PPEXCL; "
"already registered\n", minor);
if (pp->flags & PP_EXCL)
/* But it's not really an error. */
return 0;
/* There's no chance of making the driver happy. */
return -EINVAL;
}
/* Just remember to register the device exclusively
* when we finally do the registration. */
pp->flags |= PP_EXCL;
return 0;
case PPSETMODE:
{
int mode;
if (copy_from_user (&mode, argp, sizeof (mode)))
return -EFAULT;
/* FIXME: validate mode */
pp->state.mode = mode;
pp->state.phase = init_phase (mode);
if (pp->flags & PP_CLAIMED) {
pp->pdev->port->ieee1284.mode = mode;
pp->pdev->port->ieee1284.phase = pp->state.phase;
}
return 0;
}
case PPGETMODE:
{
int mode;
if (pp->flags & PP_CLAIMED) {
mode = pp->pdev->port->ieee1284.mode;
} else {
mode = pp->state.mode;
}
if (copy_to_user (argp, &mode, sizeof (mode))) {
return -EFAULT;
}
return 0;
}
case PPSETPHASE:
{
int phase;
if (copy_from_user (&phase, argp, sizeof (phase))) {
return -EFAULT;
}
/* FIXME: validate phase */
pp->state.phase = phase;
if (pp->flags & PP_CLAIMED) {
pp->pdev->port->ieee1284.phase = phase;
}
return 0;
}
case PPGETPHASE:
{
int phase;
if (pp->flags & PP_CLAIMED) {
phase = pp->pdev->port->ieee1284.phase;
} else {
phase = pp->state.phase;
}
if (copy_to_user (argp, &phase, sizeof (phase))) {
return -EFAULT;
}
return 0;
}
case PPGETMODES:
{
unsigned int modes;
port = parport_find_number (minor);
if (!port)
return -ENODEV;
modes = port->modes;
if (copy_to_user (argp, &modes, sizeof (modes))) {
return -EFAULT;
}
return 0;
}
case PPSETFLAGS:
{
int uflags;
if (copy_from_user (&uflags, argp, sizeof (uflags))) {
return -EFAULT;
}
pp->flags &= ~PP_FLAGMASK;
pp->flags |= (uflags & PP_FLAGMASK);
return 0;
}
case PPGETFLAGS:
{
int uflags;
uflags = pp->flags & PP_FLAGMASK;
if (copy_to_user (argp, &uflags, sizeof (uflags))) {
return -EFAULT;
}
return 0;
}
} /* end switch() */
/* Everything else requires the port to be claimed, so check
* that now. */
if ((pp->flags & PP_CLAIMED) == 0) {
pr_debug(CHRDEV "%x: claim the port first\n", minor);
return -EINVAL;
}
port = pp->pdev->port;
switch (cmd) {
struct ieee1284_info *info;
unsigned char reg;
unsigned char mask;
int mode;
int ret;
struct timeval par_timeout;
long to_jiffies;
case PPRSTATUS:
reg = parport_read_status (port);
if (copy_to_user (argp, &reg, sizeof (reg)))
return -EFAULT;
return 0;
case PPRDATA:
reg = parport_read_data (port);
if (copy_to_user (argp, &reg, sizeof (reg)))
return -EFAULT;
return 0;
case PPRCONTROL:
reg = parport_read_control (port);
if (copy_to_user (argp, &reg, sizeof (reg)))
return -EFAULT;
return 0;
case PPYIELD:
parport_yield_blocking (pp->pdev);
return 0;
case PPRELEASE:
/* Save the state machine's state. */
info = &pp->pdev->port->ieee1284;
pp->state.mode = info->mode;
pp->state.phase = info->phase;
info->mode = pp->saved_state.mode;
info->phase = pp->saved_state.phase;
parport_release (pp->pdev);
pp->flags &= ~PP_CLAIMED;
return 0;
case PPWCONTROL:
if (copy_from_user (&reg, argp, sizeof (reg)))
return -EFAULT;
parport_write_control (port, reg);
return 0;
case PPWDATA:
if (copy_from_user (&reg, argp, sizeof (reg)))
return -EFAULT;
parport_write_data (port, reg);
return 0;
case PPFCONTROL:
if (copy_from_user (&mask, argp,
sizeof (mask)))
return -EFAULT;
if (copy_from_user (&reg, 1 + (unsigned char __user *) arg,
sizeof (reg)))
return -EFAULT;
parport_frob_control (port, mask, reg);
return 0;
case PPDATADIR:
if (copy_from_user (&mode, argp, sizeof (mode)))
return -EFAULT;
if (mode)
port->ops->data_reverse (port);
else
port->ops->data_forward (port);
return 0;
case PPNEGOT:
if (copy_from_user (&mode, argp, sizeof (mode)))
return -EFAULT;
switch ((ret = parport_negotiate (port, mode))) {
case 0: break;
case -1: /* handshake failed, peripheral not IEEE 1284 */
ret = -EIO;
break;
case 1: /* handshake succeeded, peripheral rejected mode */
ret = -ENXIO;
break;
}
pp_enable_irq (pp);
return ret;
case PPWCTLONIRQ:
if (copy_from_user (&reg, argp, sizeof (reg)))
return -EFAULT;
/* Remember what to set the control lines to, for next
* time we get an interrupt. */
pp->irqctl = reg;
pp->irqresponse = 1;
return 0;
case PPCLRIRQ:
ret = atomic_read (&pp->irqc);
if (copy_to_user (argp, &ret, sizeof (ret)))
return -EFAULT;
atomic_sub (ret, &pp->irqc);
return 0;
case PPSETTIME:
if (copy_from_user (&par_timeout, argp, sizeof(struct timeval))) {
return -EFAULT;
}
/* Convert to jiffies, place in pp->pdev->timeout */
if ((par_timeout.tv_sec < 0) || (par_timeout.tv_usec < 0)) {
return -EINVAL;
}
to_jiffies = ROUND_UP(par_timeout.tv_usec, 1000000/HZ);
to_jiffies += par_timeout.tv_sec * (long)HZ;
if (to_jiffies <= 0) {
return -EINVAL;
}
pp->pdev->timeout = to_jiffies;
return 0;
case PPGETTIME:
to_jiffies = pp->pdev->timeout;
par_timeout.tv_sec = to_jiffies / HZ;
par_timeout.tv_usec = (to_jiffies % (long)HZ) * (1000000/HZ);
if (copy_to_user (argp, &par_timeout, sizeof(struct timeval)))
return -EFAULT;
return 0;
default:
pr_debug(CHRDEV "%x: What? (cmd=0x%x)\n", minor, cmd);
return -EINVAL;
}
/* Keep the compiler happy */
return 0;
}
static long pp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
long ret;
lock_kernel();
ret = pp_do_ioctl(file, cmd, arg);
unlock_kernel();
return ret;
}
static int pp_open (struct inode * inode, struct file * file)
{
unsigned int minor = iminor(inode);
struct pp_struct *pp;
cycle_kernel_lock();
if (minor >= PARPORT_MAX)
return -ENXIO;
pp = kmalloc (sizeof (struct pp_struct), GFP_KERNEL);
if (!pp)
return -ENOMEM;
pp->state.mode = IEEE1284_MODE_COMPAT;
pp->state.phase = init_phase (pp->state.mode);
pp->flags = 0;
pp->irqresponse = 0;
atomic_set (&pp->irqc, 0);
init_waitqueue_head (&pp->irq_wait);
/* Defer the actual device registration until the first claim.
* That way, we know whether or not the driver wants to have
* exclusive access to the port (PPEXCL).
*/
pp->pdev = NULL;
file->private_data = pp;
return 0;
}
static int pp_release (struct inode * inode, struct file * file)
{
unsigned int minor = iminor(inode);
struct pp_struct *pp = file->private_data;
int compat_negot;
compat_negot = 0;
if (!(pp->flags & PP_CLAIMED) && pp->pdev &&
(pp->state.mode != IEEE1284_MODE_COMPAT)) {
struct ieee1284_info *info;
/* parport released, but not in compatibility mode */
parport_claim_or_block (pp->pdev);
pp->flags |= PP_CLAIMED;
info = &pp->pdev->port->ieee1284;
pp->saved_state.mode = info->mode;
pp->saved_state.phase = info->phase;
info->mode = pp->state.mode;
info->phase = pp->state.phase;
compat_negot = 1;
} else if ((pp->flags & PP_CLAIMED) && pp->pdev &&
(pp->pdev->port->ieee1284.mode != IEEE1284_MODE_COMPAT)) {
compat_negot = 2;
}
if (compat_negot) {
parport_negotiate (pp->pdev->port, IEEE1284_MODE_COMPAT);
pr_debug(CHRDEV "%x: negotiated back to compatibility "
"mode because user-space forgot\n", minor);
}
if (pp->flags & PP_CLAIMED) {
struct ieee1284_info *info;
info = &pp->pdev->port->ieee1284;
pp->state.mode = info->mode;
pp->state.phase = info->phase;
info->mode = pp->saved_state.mode;
info->phase = pp->saved_state.phase;
parport_release (pp->pdev);
if (compat_negot != 1) {
pr_debug(CHRDEV "%x: released pardevice "
"because user-space forgot\n", minor);
}
}
if (pp->pdev) {
const char *name = pp->pdev->name;
parport_unregister_device (pp->pdev);
kfree (name);
pp->pdev = NULL;
pr_debug(CHRDEV "%x: unregistered pardevice\n", minor);
}
kfree (pp);
return 0;
}
/* No kernel lock held - fine */
static unsigned int pp_poll (struct file * file, poll_table * wait)
{
struct pp_struct *pp = file->private_data;
unsigned int mask = 0;
poll_wait (file, &pp->irq_wait, wait);
if (atomic_read (&pp->irqc))
mask |= POLLIN | POLLRDNORM;
return mask;
}
static struct class *ppdev_class;
static const struct file_operations pp_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.read = pp_read,
.write = pp_write,
.poll = pp_poll,
.unlocked_ioctl = pp_ioctl,
.open = pp_open,
.release = pp_release,
};
static void pp_attach(struct parport *port)
{
device_create(ppdev_class, port->dev, MKDEV(PP_MAJOR, port->number),
NULL, "parport%d", port->number);
}
static void pp_detach(struct parport *port)
{
device_destroy(ppdev_class, MKDEV(PP_MAJOR, port->number));
}
static struct parport_driver pp_driver = {
.name = CHRDEV,
.attach = pp_attach,
.detach = pp_detach,
};
static int __init ppdev_init (void)
{
int err = 0;
if (register_chrdev (PP_MAJOR, CHRDEV, &pp_fops)) {
printk (KERN_WARNING CHRDEV ": unable to get major %d\n",
PP_MAJOR);
return -EIO;
}
ppdev_class = class_create(THIS_MODULE, CHRDEV);
if (IS_ERR(ppdev_class)) {
err = PTR_ERR(ppdev_class);
goto out_chrdev;
}
if (parport_register_driver(&pp_driver)) {
printk (KERN_WARNING CHRDEV ": unable to register with parport\n");
goto out_class;
}
printk (KERN_INFO PP_VERSION "\n");
goto out;
out_class:
class_destroy(ppdev_class);
out_chrdev:
unregister_chrdev(PP_MAJOR, CHRDEV);
out:
return err;
}
static void __exit ppdev_cleanup (void)
{
/* Clean up all parport stuff */
parport_unregister_driver(&pp_driver);
class_destroy(ppdev_class);
unregister_chrdev (PP_MAJOR, CHRDEV);
}
module_init(ppdev_init);
module_exit(ppdev_cleanup);
MODULE_LICENSE("GPL");
MODULE_ALIAS_CHARDEV_MAJOR(PP_MAJOR);