Hi,
Using the usb-skeleton driver, I can successfully read from my own USB
device in user mode. I have added a function with the name
'fpga_update_read_buffer' to the driver to read from the device in
kernel mode using the 'usb_bulk_msg' commad (the code is somehow the
same as skel_read). I can call the function and get the data from the
device when I call it in the module_init. But whenever I use the
function in a thread I receive a Kernel Panic. Could anyone solve the
problem? My code is attached to the email.
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/config.h>
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/poll.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/list.h>
#include <linux/smp_lock.h>
#include <pthread.h>
#include "fpga-usb.h"
/* Version Information */
#define DRIVER_VERSION "v0.4"
#define DRIVER_AUTHOR "Greg Kroah-Hartman, greg@xxxxxxxxx"
#define DRIVER_DESC "USB Skeleton Driver"
/* Define these values to match your device */
#define USB_SKEL_VENDOR_ID 0x045E//0xfff0
#define USB_SKEL_PRODUCT_ID 0x930A//0xfff0
/* table of devices that work with this driver */
static struct usb_device_id skel_table [] = {
{ USB_DEVICE(USB_SKEL_VENDOR_ID, USB_SKEL_PRODUCT_ID) },
{ } /* Terminating entry */
};
MODULE_DEVICE_TABLE (usb, skel_table);
/* Get a minor range for your devices from the usb maintainer */
#define USB_SKEL_MINOR_BASE 192
/* we can have up to this number of device plugged in at once */
#define MAX_DEVICES 16
pthread_t thread;
static short fpga_count = 0;
struct usb_fpga_device *fpga_dev = NULL;
short *fpga_write_buffer;
short *fpga_read_buffer;
pthread_mutex_t fpga_write_buffer_mutex;
EXPORT_SYMBOL_NOVERS( fpga_write_buffer );
EXPORT_SYMBOL_NOVERS( fpga_read_buffer );
EXPORT_SYMBOL_NOVERS( fpga_dev );
EXPORT_SYMBOL_NOVERS( fpga_write_buffer_mutex );
/* the global usb devfs handle */
extern devfs_handle_t usb_devfs_handle;
/* local function prototypes */
static ssize_t skel_read (struct file *file, char *buffer, size_t count, loff_t *ppos);
static ssize_t skel_write (struct file *file, const char *buffer, size_t count, loff_t *ppos);
static int skel_open (struct inode *inode, struct file *file);
static int skel_release (struct inode *inode, struct file *file);
static void * skel_probe (struct usb_device *dev, unsigned int ifnum, const struct usb_device_id *id);
static void skel_disconnect (struct usb_device *dev, void *ptr);
static void skel_write_bulk_callback (struct urb *urb);
static void skel_read_bulk_callback (struct urb *urb);
/* array of pointers to our devices that are currently connected */
static struct usb_fpga_device *minor_table[MAX_DEVICES];
/* lock to protect the minor_table structure */
static DECLARE_MUTEX (minor_table_mutex);
static struct file_operations skel_fops = {
owner: THIS_MODULE,
read: skel_read,
write: skel_write,
open: skel_open,
release: skel_release,
};
static struct usb_driver skel_driver = {
name: "FPGA Card",
probe: skel_probe,
disconnect: skel_disconnect,
fops: &skel_fops,
minor: USB_SKEL_MINOR_BASE,
id_table: skel_table,
};
static inline void skel_delete ( struct usb_fpga_device *dev )
{
minor_table[dev->minor] = NULL;
if (dev->bulk_in_buffer != NULL)
kfree (dev->bulk_in_buffer);
if (dev->bulk_out_buffer != NULL)
kfree (dev->bulk_out_buffer);
if (dev->write_urb != NULL)
usb_free_urb (dev->write_urb);
kfree (dev);
}
static int skel_open (struct inode *inode, struct file *file)
{
struct usb_fpga_device *dev = NULL;
int subminor;
int retval = 0;
subminor = MINOR (inode->i_rdev) - USB_SKEL_MINOR_BASE;
if ((subminor < 0) ||
(subminor >= MAX_DEVICES)) {
return -ENODEV;
}
MOD_INC_USE_COUNT;
down (&minor_table_mutex);
dev = minor_table[subminor];
if (dev == NULL) {
up (&minor_table_mutex);
MOD_DEC_USE_COUNT;
return -ENODEV;
}
down (&dev->sem);
up (&minor_table_mutex);
++dev->open_count;
file->private_data = dev;
up (&dev->sem);
return retval;
}
static int skel_release (struct inode *inode, struct file *file)
{
struct usb_fpga_device *dev;
int retval = 0;
dev = (struct usb_fpga_device *) file->private_data;
if (dev == NULL) {
return -ENODEV;
}
down (&minor_table_mutex);
down (&dev->sem);
if (dev->open_count <= 0) {
retval = -ENODEV;
goto exit_not_opened;
}
if (dev->udev == NULL) {
/* the device was unplugged before the file was released */
up (&dev->sem);
skel_delete (dev);
up (&minor_table_mutex);
MOD_DEC_USE_COUNT;
return 0;
}
/* decrement our usage count for the device */
--dev->open_count;
if (dev->open_count <= 0) {
/* shutdown any bulk writes that might be going on */
usb_unlink_urb (dev->write_urb);
dev->open_count = 0;
}
/* decrement our usage count for the module */
MOD_DEC_USE_COUNT;
exit_not_opened:
up (&dev->sem);
up (&minor_table_mutex);
return retval;
}
static ssize_t skel_read (struct file *file, char *buffer, size_t count, loff_t *ppos)
{
struct usb_fpga_device *dev;
int retval = 0;
dev = (struct usb_fpga_device *)file->private_data;
down (&dev->sem);
/* verify that the device wasn't unplugged */
if (dev->udev == NULL) {
up (&dev->sem);
return -ENODEV;
}
/* do an immediate bulk read to get data from the device */
retval = usb_bulk_msg (dev->udev,
usb_rcvbulkpipe (dev->udev, dev->bulk_in_endpointAddr),
dev->bulk_in_buffer, dev->bulk_in_size,
&count, HZ*10);
/* if the read was successful, copy the data to userspace */
if (!retval) {
if (copy_to_user (buffer, dev->bulk_in_buffer, count))
retval = -EFAULT;
else
retval = count;
}
/* unlock the device */
up (&dev->sem);
return retval;
}
static ssize_t skel_write (struct file *file, const char *buffer, size_t count, loff_t *ppos)
{
struct usb_fpga_device *dev;
ssize_t bytes_written = 0;
int retval = 0;
printk( "USB device wrote.\n" );
dev = (struct usb_fpga_device *)file->private_data;
down (&dev->sem);
/* verify that the device wasn't unplugged */
if (dev->udev == NULL) {
retval = -ENODEV;
goto exit;
}
/* verify that we actually have some data to write */
if (count == 0) {
goto exit;
}
/* see if we are already in the middle of a write */
if (dev->write_urb->status == -EINPROGRESS) {
goto exit;
}
/* we can only write as much as 1 urb will hold */
bytes_written = (count > dev->bulk_out_size) ?
dev->bulk_out_size : count;
/* copy the data from userspace into our urb */
if (copy_from_user(dev->write_urb->transfer_buffer, buffer,
bytes_written)) {
retval = -EFAULT;
goto exit;
}
// usb_skel_debug_data (__FUNCTION__, bytes_written, dev->write_urb->transfer_buffer);
/* set up our urb */
FILL_BULK_URB(dev->write_urb, dev->udev,
usb_sndbulkpipe(dev->udev, dev->bulk_out_endpointAddr),
dev->write_urb->transfer_buffer, bytes_written,
skel_write_bulk_callback, dev);
/* send the data out the bulk port */
retval = usb_submit_urb(dev->write_urb);
if (retval) {
err(__FUNCTION__ " - failed submitting write urb, error %d",
retval);
} else {
retval = bytes_written;
}
exit:
/* unlock the device */
up (&dev->sem);
return retval;
}
static void skel_write_bulk_callback (struct urb *urb)
{
return;
}
static void * skel_probe(struct usb_device *udev, unsigned int ifnum, const struct usb_device_id *id)
{
struct usb_fpga_device *dev = NULL;
struct usb_interface *interface;
struct usb_interface_descriptor *iface_desc;
struct usb_endpoint_descriptor *endpoint;
int minor;
int buffer_size;
int i;
char name[10];
/* See if the device offered us matches what we can accept */
if ((udev->descriptor.idVendor != USB_SKEL_VENDOR_ID) ||
(udev->descriptor.idProduct != USB_SKEL_PRODUCT_ID)) {
return NULL;
}
/* select a "subminor" number (part of a minor number) */
down (&minor_table_mutex);
for (minor = 0; minor < MAX_DEVICES; ++minor) {
if (minor_table[minor] == NULL)
break;
}
if (minor >= MAX_DEVICES) {
info ("Too many devices plugged in, can not handle this device.");
goto exit;
}
if( fpga_count > 0 )
{
info( "This driver support only one FPGA card to be available in the system." );
goto exit;
}
fpga_count++;
/* allocate memory for our device state and intialize it */
dev = kmalloc (sizeof(struct usb_fpga_device), GFP_KERNEL);
if (dev == NULL) {
err ("Out of memory");
goto exit;
}
fpga_dev = dev;
memset (dev, 0x00, sizeof (*dev));
minor_table[minor] = dev;
interface = &udev->actconfig->interface[ifnum];
init_MUTEX (&dev->sem);
dev->udev = udev;
dev->interface = interface;
dev->minor = minor;
/* set up the endpoint information */
/* check out the endpoints */
iface_desc = &interface->altsetting[0];
char read_endpoint_found = 0;
char write_endpoint_found = 0;
for (i = 0; i < iface_desc->bNumEndpoints; ++i) {
//for (i = iface_desc->bNumEndpoints-1; i >= 0; --i) {
endpoint = &iface_desc->endpoint[i];
if ((endpoint->bEndpointAddress & 0x80) &&
((endpoint->bmAttributes & 3) == 0x02)) {
/* we found a bulk in endpoint */
buffer_size = endpoint->wMaxPacketSize;
dev->bulk_in_size = buffer_size;
dev->bulk_in_endpointAddr = endpoint->bEndpointAddress;
dev->bulk_in_buffer = kmalloc (buffer_size, GFP_KERNEL);
if (!dev->bulk_in_buffer) {
err("Couldn't allocate bulk_in_buffer");
goto error;
}
if( write_endpoint_found )
break;
}
if (((endpoint->bEndpointAddress & 0x80) == 0x00) &&
((endpoint->bmAttributes & 3) == 0x02)) {
/* we found a bulk out endpoint */
dev->write_urb = usb_alloc_urb(0);
if (!dev->write_urb) {
err("No free urbs available");
goto error;
}
buffer_size = endpoint->wMaxPacketSize;
dev->bulk_out_size = buffer_size;
dev->bulk_out_endpointAddr = endpoint->bEndpointAddress;
dev->bulk_out_buffer = kmalloc (buffer_size, GFP_KERNEL);
if (!dev->bulk_out_buffer) {
err("Couldn't allocate bulk_out_buffer");
goto error;
}
FILL_BULK_URB(dev->write_urb, udev,
usb_sndbulkpipe(udev,
endpoint->bEndpointAddress),
dev->bulk_out_buffer, buffer_size,
skel_write_bulk_callback, dev);
if( read_endpoint_found )
break;
}
}
/* initialize the devfs node for this device and register it */
sprintf(name, "skel%d", dev->minor);
dev->devfs = devfs_register (usb_devfs_handle, name,
DEVFS_FL_DEFAULT, USB_MAJOR,
USB_SKEL_MINOR_BASE + dev->minor,
S_IFCHR | S_IRUSR | S_IWUSR |
S_IRGRP | S_IWGRP | S_IROTH,
&skel_fops, NULL);
fpga_write_buffer = dev->write_urb->transfer_buffer;
fpga_read_buffer = dev->bulk_in_buffer;
/* let the user know what node this device is now attached to */
info ("USB Skeleton device now attached to USBSkel%d", dev->minor);
goto exit;
error:
skel_delete (dev);
dev = NULL;
exit:
up (&minor_table_mutex);
return dev;
}
static void skel_disconnect(struct usb_device *udev, void *ptr)
{
struct usb_fpga_device *dev;
int minor;
dev = (struct usb_fpga_device *)ptr;
down (&minor_table_mutex);
down (&dev->sem);
minor = dev->minor;
/* remove our devfs node */
devfs_unregister(dev->devfs);
/* if the device is not opened, then we clean up right now */
if (!dev->open_count) {
up (&dev->sem);
skel_delete (dev);
} else {
dev->udev = NULL;
up (&dev->sem);
}
fpga_dev = NULL;
fpga_count = 0;
info("USB Skeleton #%d now disconnected", minor);
up (&minor_table_mutex);
}
ssize_t fpga_flush_write_buffer()
{
struct usb_fpga_device *dev;
ssize_t bytes_written = 0;
int retval = 0;
dev = fpga_dev;
if( dev == NULL )
{
retval = -ENODEV;
goto exit;
}
/* lock this object */
down (&dev->sem);
/* verify that the device wasn't unplugged */
if (dev->udev == NULL)
{
retval = -ENODEV;
goto exit;
}
/* see if we are already in the middle of a write */
if (dev->write_urb->status == -EINPROGRESS)
goto exit;
/* we can only write as much as 1 urb will hold */
bytes_written = dev->bulk_out_size;
// usb_skel_debug_data (__FUNCTION__, bytes_written, dev->write_urb->transfer_buffer);
/* set up our urb */
FILL_BULK_URB(dev->write_urb, dev->udev,
usb_sndbulkpipe(dev->udev, dev->bulk_out_endpointAddr),
dev->write_urb->transfer_buffer, bytes_written,
skel_write_bulk_callback, dev);
/* send the data out the bulk port */
retval = usb_submit_urb(dev->write_urb);
if (retval) {
err(__FUNCTION__ " - failed submitting write urb, error %d",
retval);
} else {
retval = bytes_written;
}
exit:
/* unlock the device */
up (&dev->sem);
return retval;
}
EXPORT_SYMBOL_NOVERS( fpga_flush_write_buffer );
static void fpga_update_read_buffer()
{
struct usb_fpga_device *dev;
int count = 64;
int bytes_read;
dev = fpga_dev;
rtl_printf( "Flag 0.5\n" );
if( dev == NULL )
return;
rtl_printf( "Flag 01\n" );
down ( &dev->sem );
rtl_printf( "Flag 02\n" );
/* verify that the device wasn't unplugged */
if (dev->udev == NULL)
{
up (&dev->sem);
return;
}
rtl_printf( "Flag 03\n" );
rtl_printf( "Flag 04\n" );
/* do an immediate bulk read to get data from the device */
usb_bulk_msg( dev->udev,
usb_rcvbulkpipe (dev->udev, dev->bulk_in_endpointAddr),
dev->bulk_in_buffer, dev->bulk_in_size,
&count, HZ*10 );
rtl_printf( "Flag 05\n" );
up ( &dev->sem );
}
void * fpga_write_thread_routine(void *arg)
{
struct sched_param p;
p . sched_priority = 1;
pthread_setschedparam (pthread_self(), SCHED_FIFO, &p);
while (1)
{
fpga_flush_write_buffer();
fpga_update_read_buffer();
pthread_mutex_lock( &fpga_write_buffer_mutex );
}
return 0;
}
static int __init usb_skel_init(void)
{
int result;
result = usb_register(&skel_driver);
if (result < 0)
{
err("usb_register failed for the "__FILE__" driver. Error number %d", result);
return -1;
}
info(DRIVER_DESC " " DRIVER_VERSION);
pthread_mutex_init( &fpga_write_buffer_mutex, NULL );
pthread_mutex_lock( &fpga_write_buffer_mutex );
rtl_printf( "Flag 00\n" );
fpga_flush_write_buffer();
fpga_update_read_buffer();
rtl_printf( "Flag 10" );
return pthread_create (&thread, NULL, fpga_write_thread_routine, 0); //The problem goes here
return 0;
}
static void __exit usb_skel_exit(void)
{
pthread_delete_np (thread);
pthread_mutex_destroy( &fpga_write_buffer_mutex );
usb_deregister(&skel_driver);
}
module_init (usb_skel_init);
module_exit (usb_skel_exit);
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");
