skypopen: added a proof of concept standalone OSS audio driver (for Skype-oss clients)

This commit is contained in:
Giovanni Maruzzelli 2010-12-11 13:19:49 -06:00
parent 009c41d460
commit 577d7b5538
4 changed files with 584 additions and 0 deletions

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# Comment/uncomment the following line to disable/enable debugging
#DEBUG = y
LDDINC=/usr/src/linux-headers-2.6.32-26-server/include
# Add your debugging flag (or not) to CFLAGS
ifeq ($(DEBUG),y)
DEBFLAGS = -O -g -DSCULL_DEBUG # "-O" is needed to expand inlines
else
DEBFLAGS = -O2 -Wall
endif
EXTRA_CFLAGS += $(DEBFLAGS)
EXTRA_CFLAGS += -I$(LDDINC)
ifneq ($(KERNELRELEASE),)
# call from kernel build system
scull-objs := main.o
obj-m := scull.o
else
KERNELDIR ?= /lib/modules/$(shell uname -r)/build
PWD := $(shell pwd)
modules:
$(MAKE) -C $(KERNELDIR) M=$(PWD) LDDINC=$(PWD)/../include modules
endif
clean:
rm -rf *.o *~ core .depend .*.cmd *.ko *.mod.c .tmp_versions
depend .depend dep:
$(CC) $(EXTRA_CFLAGS) -M *.c > .depend
ifeq (.depend,$(wildcard .depend))
include .depend
endif

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/*
* main.c -- the bare scull char module
*
* Copyright (C) 2010 Giovanni Maruzzelli
* Copyright (C) 2001 Alessandro Rubini and Jonathan Corbet
* Copyright (C) 2001 O'Reilly & Associates
*
* The source code in this file can be freely used, adapted,
* and redistributed in source or binary form, so long as an
* acknowledgment appears in derived source files. The citation
* should list that the code comes from the book "Linux Device
* Drivers" by Alessandro Rubini and Jonathan Corbet, published
* by O'Reilly & Associates. No warranty is attached;
* we cannot take responsibility for errors or fitness for use.
*
*/
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/kernel.h> /* printk() */
#include <linux/slab.h> /* kmalloc() */
#include <linux/fs.h> /* everything... */
#include <linux/errno.h> /* error codes */
#include <linux/types.h> /* size_t */
#include <linux/proc_fs.h>
#include <linux/fcntl.h> /* O_ACCMODE */
#include <linux/seq_file.h>
#include <linux/cdev.h>
#include <asm/system.h> /* cli(), *_flags */
#include <asm/uaccess.h> /* copy_*_user */
#include <linux/soundcard.h>
#include <linux/delay.h>
#include <linux/hrtimer.h>
#include <linux/sched.h>
#include <linux/time.h>
#include <linux/jiffies.h>
#include <linux/hrtimer.h>
#include <linux/ktime.h>
#include "scull.h" /* local definitions */
/*
* Our parameters which can be set at load time.
*/
int scull_major = SCULL_MAJOR;
int scull_minor = 3;
int scull_nr_devs = SCULL_NR_DEVS; /* number of bare scull devices */
module_param(scull_major, int, S_IRUGO);
module_param(scull_minor, int, S_IRUGO);
module_param(scull_nr_devs, int, S_IRUGO);
MODULE_AUTHOR("Original: Alessandro Rubini, Jonathan Corbet. Heavy modified by: Giovanni Maruzzelli");
MODULE_LICENSE("Dual BSD/GPL");
static struct scull_dev *scull_devices; /* allocated in scull_init_module */
#define GIOVA_BLK 3840
#define GIOVA_SLEEP 40000
void my_timer_callback_inq( unsigned long data )
{
struct scull_dev *dev = (void *)data;
wake_up_interruptible(&dev->inq);
mod_timer( &dev->timer_inq, jiffies + msecs_to_jiffies(GIOVA_SLEEP/1000) );
}
void my_timer_callback_outq( unsigned long data )
{
struct scull_dev *dev = (void *)data;
wake_up_interruptible(&dev->outq);
mod_timer( &dev->timer_outq, jiffies + msecs_to_jiffies(GIOVA_SLEEP/1000) );
}
/* The clone-specific data structure includes a key field */
struct scull_listitem {
struct scull_dev device;
dev_t key;
struct list_head list;
};
/* The list of devices, and a lock to protect it */
static LIST_HEAD(scull_c_list);
static spinlock_t scull_c_lock = SPIN_LOCK_UNLOCKED;
/* Look for a device or create one if missing */
static struct scull_dev *scull_c_lookfor_device(dev_t key)
{
struct scull_listitem *lptr;
list_for_each_entry(lptr, &scull_c_list, list) {
if (lptr->key == key)
return &(lptr->device);
}
/* not found */
lptr = kmalloc(sizeof(struct scull_listitem), GFP_KERNEL);
if (!lptr)
return NULL;
/* initialize the device */
memset(lptr, 0, sizeof(struct scull_listitem));
lptr->key = key;
init_waitqueue_head(&lptr->device.inq);
init_waitqueue_head(&lptr->device.outq);
printk(" Timer installing\n");
setup_timer( &lptr->device.timer_inq, my_timer_callback_inq, (long int)lptr );
setup_timer( &lptr->device.timer_outq, my_timer_callback_outq, (long int)lptr );
printk( "Starting timer to fire in %dms (%ld)\n", GIOVA_SLEEP/1000, jiffies );
mod_timer( &lptr->device.timer_inq, jiffies + msecs_to_jiffies(GIOVA_SLEEP/1000) );
mod_timer( &lptr->device.timer_outq, jiffies + msecs_to_jiffies(GIOVA_SLEEP/1000) );
/* place it in the list */
list_add(&lptr->list, &scull_c_list);
return &(lptr->device);
}
static int scull_c_open(struct inode *inode, struct file *filp)
{
struct scull_dev *dev;
dev_t key;
if (!current->pid) {
printk("Process \"%s\" has no pid\n", current->comm);
return -EINVAL;
}
key = current->pid;
/* look for a scullc device in the list */
spin_lock(&scull_c_lock);
dev = scull_c_lookfor_device(key);
spin_unlock(&scull_c_lock);
if (!dev)
return -ENOMEM;
/* then, everything else is copied from the bare scull device */
filp->private_data = dev;
return 0; /* success */
}
static int scull_c_release(struct inode *inode, struct file *filp)
{
/*
* Nothing to do, because the device is persistent.
* A `real' cloned device should be freed on last close
*/
return 0;
}
/*************************************************************/
/*
* Open and close
*/
ssize_t scull_read(struct file *filp, char __user *buf, size_t count,
loff_t *f_pos)
{
struct scull_dev *dev = filp->private_data;
DEFINE_WAIT(wait);
prepare_to_wait(&dev->inq, &wait, TASK_INTERRUPTIBLE);
schedule();
finish_wait(&dev->inq, &wait);
return count;
}
ssize_t scull_write(struct file *filp, const char __user *buf, size_t count,
loff_t *f_pos)
{
struct scull_dev *dev = filp->private_data;
DEFINE_WAIT(wait);
prepare_to_wait(&dev->outq, &wait, TASK_INTERRUPTIBLE);
schedule();
finish_wait(&dev->outq, &wait);
return count;
}
/*
* The ioctl() implementation
*/
int scull_ioctl(struct inode *inode, struct file *filp,
unsigned int cmd, unsigned long arg)
{
void __user *argp = (void __user *)arg;
int __user *p = argp;
switch (cmd) {
case OSS_GETVERSION:
return put_user(SOUND_VERSION, p);
case SNDCTL_DSP_GETBLKSIZE:
return put_user(GIOVA_BLK, p);
case SNDCTL_DSP_GETFMTS:
return put_user(28731, p);
default:
return 0;
}
}
struct file_operations scull_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.read = scull_read,
.write = scull_write,
.ioctl = scull_ioctl,
.open = scull_c_open,
.release = scull_c_release,
};
/*
* Finally, the module stuff
*/
/*
* The cleanup function is used to handle initialization failures as well.
* Thefore, it must be careful to work correctly even if some of the items
* have not been initialized
*/
void scull_cleanup_module(void)
{
int i;
int ret;
struct scull_listitem *lptr, *next;
dev_t devno = MKDEV(scull_major, scull_minor);
/* Get rid of our char dev entries */
if (scull_devices) {
for (i = 0; i < scull_nr_devs; i++) {
cdev_del(&scull_devices[i].cdev);
}
kfree(scull_devices);
}
/* And all the cloned devices */
list_for_each_entry_safe(lptr, next, &scull_c_list, list) {
ret= del_timer( &lptr->device.timer_inq );
if (ret) printk("The inq timer was still in use...\n");
ret= del_timer( &lptr->device.timer_outq );
if (ret) printk("The outq timer was still in use...\n");
list_del(&lptr->list);
kfree(lptr);
}
printk("Timer uninstalling\n");
/* cleanup_module is never called if registering failed */
unregister_chrdev_region(devno, scull_nr_devs);
}
/*
* Set up the char_dev structure for this device.
*/
static void scull_setup_cdev(struct scull_dev *dev, int index)
{
int err, devno = MKDEV(scull_major, scull_minor + index);
cdev_init(&dev->cdev, &scull_fops);
dev->cdev.owner = THIS_MODULE;
dev->cdev.ops = &scull_fops;
err = cdev_add (&dev->cdev, devno, 1);
/* Fail gracefully if need be */
if (err)
printk(KERN_NOTICE "Error %d adding scull%d", err, index);
}
int scull_init_module(void)
{
int result, i;
dev_t dev = 0;
/*
* Get a range of minor numbers to work with, asking for a dynamic
* major unless directed otherwise at load time.
*/
if (scull_major) {
dev = MKDEV(scull_major, scull_minor);
result = register_chrdev_region(dev, scull_nr_devs, "dsp");
} else {
result = alloc_chrdev_region(&dev, scull_minor, scull_nr_devs,
"dsp");
scull_major = MAJOR(dev);
}
if (result < 0) {
printk(KERN_WARNING "scull: can't get major %d\n", scull_major);
return result;
}
/*
* allocate the devices -- we can't have them static, as the number
* can be specified at load time
*/
scull_devices = kmalloc(scull_nr_devs * sizeof(struct scull_dev), GFP_KERNEL);
if (!scull_devices) {
result = -ENOMEM;
goto fail; /* Make this more graceful */
}
memset(scull_devices, 0, scull_nr_devs * sizeof(struct scull_dev));
/* Initialize each device. */
for (i = 0; i < scull_nr_devs; i++) {
scull_setup_cdev(&scull_devices[i], i);
}
/* At this point call the init function for any friend device */
dev = MKDEV(scull_major, scull_minor + scull_nr_devs);
return 0; /* succeed */
fail:
scull_cleanup_module();
return result;
}
module_init(scull_init_module);
module_exit(scull_cleanup_module);

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/*
* scull.h -- definitions for the char module
*
* Copyright (C) 2001 Alessandro Rubini and Jonathan Corbet
* Copyright (C) 2001 O'Reilly & Associates
*
* The source code in this file can be freely used, adapted,
* and redistributed in source or binary form, so long as an
* acknowledgment appears in derived source files. The citation
* should list that the code comes from the book "Linux Device
* Drivers" by Alessandro Rubini and Jonathan Corbet, published
* by O'Reilly & Associates. No warranty is attached;
* we cannot take responsibility for errors or fitness for use.
*
* $Id: scull.h,v 1.15 2004/11/04 17:51:18 rubini Exp $
*/
#ifndef _SCULL_H_
#define _SCULL_H_
#include <linux/ioctl.h> /* needed for the _IOW etc stuff used later */
#ifndef SCULL_MAJOR
#define SCULL_MAJOR 14 /* dynamic major by default */
#endif
#ifndef SCULL_NR_DEVS
#define SCULL_NR_DEVS 1 /* scull0 through scull3 */
#endif
struct scull_dev {
struct cdev cdev; /* Char device structure */
wait_queue_head_t inq; /* read and write queues */
wait_queue_head_t outq; /* read and write queues */
struct timer_list timer_inq;
struct timer_list timer_outq;
//unsigned long read_howmany;
//unsigned long write_howmany;
//unsigned long read_sleeped_acc;
//unsigned long write_sleeped_acc;
//double read_delay; /* how much delay last time */
//double write_delay; /* how much delay last time */
};
/*
* The different configurable parameters
*/
extern int scull_major; /* main.c */
extern int scull_nr_devs;
/*
* Prototypes for shared functions
*/
ssize_t scull_read(struct file *filp, char __user *buf, size_t count,
loff_t *f_pos);
ssize_t scull_write(struct file *filp, const char __user *buf, size_t count,
loff_t *f_pos);
int scull_ioctl(struct inode *inode, struct file *filp,
unsigned int cmd, unsigned long arg);
#endif /* _SCULL_H_ */

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#!/bin/bash
# Sample init script for the a driver module <rubini@linux.it>
DEVICE="scull"
SECTION="misc"
# The list of filenames and minor numbers: $PREFIX is prefixed to all names
PREFIX="scull"
FILES=" 0 0 1 1 2 2 3 3 priv 16
pipe0 32 pipe1 33 pipe2 34 pipe3 35
single 48 uid 64 wuid 80"
INSMOD=/sbin/insmod; # use /sbin/modprobe if you prefer
function device_specific_post_load () {
true; # fill at will
}
function device_specific_pre_unload () {
true; # fill at will
}
# Everything below this line should work unchanged for any char device.
# Obviously, however, no options on the command line: either in
# /etc/${DEVICE}.conf or /etc/modules.conf (if modprobe is used)
# Optional configuration file: format is
# owner <ownername>
# group <groupname>
# mode <modename>
# options <insmod options>
CFG=/etc/${DEVICE}.conf
# kernel version, used to look for modules
KERNEL=`uname -r`
#FIXME: it looks like there is no misc section. Where should it be?
MODDIR="/lib/modules/${KERNEL}/kernel/drivers/${SECTION}"
if [ ! -d $MODDIR ]; then MODDIR="/lib/modules/${KERNEL}/${SECTION}"; fi
# Root or die
if [ "$(id -u)" != "0" ]
then
echo "You must be root to load or unload kernel modules"
exit 1
fi
# Read configuration file
if [ -r $CFG ]; then
OWNER=`awk "\\$1==\"owner\" {print \\$2}" $CFG`
GROUP=`awk "\\$1==\"group\" {print \\$2}" $CFG`
MODE=`awk "\\$1==\"mode\" {print \\$2}" $CFG`
# The options string may include extra blanks or only blanks
OPTIONS=`sed -n '/^options / s/options //p' $CFG`
fi
# Create device files
function create_files () {
cd /dev
local devlist=""
local file
while true; do
if [ $# -lt 2 ]; then break; fi
file="${DEVICE}$1"
mknod $file c $MAJOR $2
devlist="$devlist $file"
shift 2
done
if [ -n "$OWNER" ]; then chown $OWNER $devlist; fi
if [ -n "$GROUP" ]; then chgrp $GROUP $devlist; fi
if [ -n "$MODE" ]; then chmod $MODE $devlist; fi
}
# Remove device files
function remove_files () {
cd /dev
local devlist=""
local file
while true; do
if [ $# -lt 2 ]; then break; fi
file="${DEVICE}$1"
devlist="$devlist $file"
shift 2
done
rm -f $devlist
}
# Load and create files
function load_device () {
if [ -f $MODDIR/$DEVICE.o ]; then
devpath=$MODDIR/$DEVICE.o
else if [ -f ./$DEVICE.o ]; then
devpath=./$DEVICE.o
else
devpath=$DEVICE; # let insmod/modprobe guess
fi; fi
if [ "$devpath" != "$DEVICE" ]; then
echo -n " (loading file $devpath)"
fi
if $INSMOD $devpath $OPTIONS; then
MAJOR=`awk "\\$2==\"$DEVICE\" {print \\$1}" /proc/devices`
remove_files $FILES
create_files $FILES
device_specific_post_load
else
echo " FAILED!"
fi
}
# Unload and remove files
function unload_device () {
device_specific_pre_unload
/sbin/rmmod $DEVICE
remove_files $FILES
}
case "$1" in
start)
echo -n "Loading $DEVICE"
load_device
echo "."
;;
stop)
echo -n "Unloading $DEVICE"
unload_device
echo "."
;;
force-reload|restart)
echo -n "Reloading $DEVICE"
unload_device
load_device
echo "."
;;
*)
echo "Usage: $0 {start|stop|restart|force-reload}"
exit 1
esac
exit 0