linux/drivers/usb/misc/legousbtower.c

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/*
* LEGO USB Tower driver
*
* Copyright (C) 2003 David Glance <davidgsf@sourceforge.net>
* 2001-2004 Juergen Stuber <starblue@users.sourceforge.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.
*
* derived from USB Skeleton driver - 0.5
* Copyright (C) 2001 Greg Kroah-Hartman (greg@kroah.com)
*
* History:
*
* 2001-10-13 - 0.1 js
* - first version
* 2001-11-03 - 0.2 js
* - simplified buffering, one-shot URBs for writing
* 2001-11-10 - 0.3 js
* - removed IOCTL (setting power/mode is more complicated, postponed)
* 2001-11-28 - 0.4 js
* - added vendor commands for mode of operation and power level in open
* 2001-12-04 - 0.5 js
* - set IR mode by default (by oversight 0.4 set VLL mode)
* 2002-01-11 - 0.5? pcchan
* - make read buffer reusable and work around bytes_to_write issue between
* uhci and legusbtower
* 2002-09-23 - 0.52 david (david@csse.uwa.edu.au)
* - imported into lejos project
* - changed wake_up to wake_up_interruptible
* - changed to use lego0 rather than tower0
* - changed dbg() to use __func__ rather than deprecated __func__
* 2003-01-12 - 0.53 david (david@csse.uwa.edu.au)
* - changed read and write to write everything or
* timeout (from a patch by Chris Riesen and Brett Thaeler driver)
* - added ioctl functionality to set timeouts
* 2003-07-18 - 0.54 davidgsf (david@csse.uwa.edu.au)
* - initial import into LegoUSB project
* - merge of existing LegoUSB.c driver
* 2003-07-18 - 0.56 davidgsf (david@csse.uwa.edu.au)
* - port to 2.6 style driver
* 2004-02-29 - 0.6 Juergen Stuber <starblue@users.sourceforge.net>
* - fix locking
* - unlink read URBs which are no longer needed
* - allow increased buffer size, eliminates need for timeout on write
* - have read URB running continuously
* - added poll
* - forbid seeking
* - added nonblocking I/O
* - changed back __func__ to __func__
* - read and log tower firmware version
* - reset tower on probe, avoids failure of first write
* 2004-03-09 - 0.7 Juergen Stuber <starblue@users.sourceforge.net>
* - timeout read now only after inactivity, shorten default accordingly
* 2004-03-11 - 0.8 Juergen Stuber <starblue@users.sourceforge.net>
* - log major, minor instead of possibly confusing device filename
* - whitespace cleanup
* 2004-03-12 - 0.9 Juergen Stuber <starblue@users.sourceforge.net>
* - normalize whitespace in debug messages
* - take care about endianness in control message responses
* 2004-03-13 - 0.91 Juergen Stuber <starblue@users.sourceforge.net>
* - make default intervals longer to accommodate current EHCI driver
* 2004-03-19 - 0.92 Juergen Stuber <starblue@users.sourceforge.net>
* - replaced atomic_t by memory barriers
* 2004-04-21 - 0.93 Juergen Stuber <starblue@users.sourceforge.net>
* - wait for completion of write urb in release (needed for remotecontrol)
* - corrected poll for write direction (missing negation)
* 2004-04-22 - 0.94 Juergen Stuber <starblue@users.sourceforge.net>
* - make device locking interruptible
* 2004-04-30 - 0.95 Juergen Stuber <starblue@users.sourceforge.net>
* - check for valid udev on resubmitting and unlinking urbs
* 2004-08-03 - 0.96 Juergen Stuber <starblue@users.sourceforge.net>
* - move reset into open to clean out spurious data
*/
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/completion.h>
#include <linux/mutex.h>
#include <asm/uaccess.h>
#include <linux/usb.h>
#include <linux/poll.h>
#ifdef CONFIG_USB_DEBUG
static int debug = 4;
#else
static int debug = 0;
#endif
/* Use our own dbg macro */
#undef dbg
#define dbg(lvl, format, arg...) do { if (debug >= lvl) printk(KERN_DEBUG __FILE__ ": " format "\n", ## arg); } while (0)
/* Version Information */
#define DRIVER_VERSION "v0.96"
#define DRIVER_AUTHOR "Juergen Stuber <starblue@sourceforge.net>"
#define DRIVER_DESC "LEGO USB Tower Driver"
/* Module parameters */
module_param(debug, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug, "Debug enabled or not");
/* The defaults are chosen to work with the latest versions of leJOS and NQC.
*/
/* Some legacy software likes to receive packets in one piece.
* In this case read_buffer_size should exceed the maximal packet length
* (417 for datalog uploads), and packet_timeout should be set.
*/
static int read_buffer_size = 480;
module_param(read_buffer_size, int, 0);
MODULE_PARM_DESC(read_buffer_size, "Read buffer size");
/* Some legacy software likes to send packets in one piece.
* In this case write_buffer_size should exceed the maximal packet length
* (417 for firmware and program downloads).
* A problem with long writes is that the following read may time out
* if the software is not prepared to wait long enough.
*/
static int write_buffer_size = 480;
module_param(write_buffer_size, int, 0);
MODULE_PARM_DESC(write_buffer_size, "Write buffer size");
/* Some legacy software expects reads to contain whole LASM packets.
* To achieve this, characters which arrive before a packet timeout
* occurs will be returned in a single read operation.
* A problem with long reads is that the software may time out
* if it is not prepared to wait long enough.
* The packet timeout should be greater than the time between the
* reception of subsequent characters, which should arrive about
* every 5ms for the standard 2400 baud.
* Set it to 0 to disable.
*/
static int packet_timeout = 50;
module_param(packet_timeout, int, 0);
MODULE_PARM_DESC(packet_timeout, "Packet timeout in ms");
/* Some legacy software expects blocking reads to time out.
* Timeout occurs after the specified time of read and write inactivity.
* Set it to 0 to disable.
*/
static int read_timeout = 200;
module_param(read_timeout, int, 0);
MODULE_PARM_DESC(read_timeout, "Read timeout in ms");
/* As of kernel version 2.6.4 ehci-hcd uses an
* "only one interrupt transfer per frame" shortcut
* to simplify the scheduling of periodic transfers.
* This conflicts with our standard 1ms intervals for in and out URBs.
* We use default intervals of 2ms for in and 8ms for out transfers,
* which is fast enough for 2400 baud and allows a small additional load.
* Increase the interval to allow more devices that do interrupt transfers,
* or set to 0 to use the standard interval from the endpoint descriptors.
*/
static int interrupt_in_interval = 2;
module_param(interrupt_in_interval, int, 0);
MODULE_PARM_DESC(interrupt_in_interval, "Interrupt in interval in ms");
static int interrupt_out_interval = 8;
module_param(interrupt_out_interval, int, 0);
MODULE_PARM_DESC(interrupt_out_interval, "Interrupt out interval in ms");
/* Define these values to match your device */
#define LEGO_USB_TOWER_VENDOR_ID 0x0694
#define LEGO_USB_TOWER_PRODUCT_ID 0x0001
/* Vendor requests */
#define LEGO_USB_TOWER_REQUEST_RESET 0x04
#define LEGO_USB_TOWER_REQUEST_GET_VERSION 0xFD
struct tower_reset_reply {
__le16 size; /* little-endian */
__u8 err_code;
__u8 spare;
} __attribute__ ((packed));
struct tower_get_version_reply {
__le16 size; /* little-endian */
__u8 err_code;
__u8 spare;
__u8 major;
__u8 minor;
__le16 build_no; /* little-endian */
} __attribute__ ((packed));
/* table of devices that work with this driver */
static struct usb_device_id tower_table [] = {
{ USB_DEVICE(LEGO_USB_TOWER_VENDOR_ID, LEGO_USB_TOWER_PRODUCT_ID) },
{ } /* Terminating entry */
};
MODULE_DEVICE_TABLE (usb, tower_table);
static DEFINE_MUTEX(open_disc_mutex);
#define LEGO_USB_TOWER_MINOR_BASE 160
/* Structure to hold all of our device specific stuff */
struct lego_usb_tower {
struct mutex lock; /* locks this structure */
struct usb_device* udev; /* save off the usb device pointer */
unsigned char minor; /* the starting minor number for this device */
int open_count; /* number of times this port has been opened */
char* read_buffer;
size_t read_buffer_length; /* this much came in */
size_t read_packet_length; /* this much will be returned on read */
spinlock_t read_buffer_lock;
int packet_timeout_jiffies;
unsigned long read_last_arrival;
wait_queue_head_t read_wait;
wait_queue_head_t write_wait;
char* interrupt_in_buffer;
struct usb_endpoint_descriptor* interrupt_in_endpoint;
struct urb* interrupt_in_urb;
int interrupt_in_interval;
int interrupt_in_running;
int interrupt_in_done;
char* interrupt_out_buffer;
struct usb_endpoint_descriptor* interrupt_out_endpoint;
struct urb* interrupt_out_urb;
int interrupt_out_interval;
int interrupt_out_busy;
};
/* local function prototypes */
static ssize_t tower_read (struct file *file, char __user *buffer, size_t count, loff_t *ppos);
static ssize_t tower_write (struct file *file, const char __user *buffer, size_t count, loff_t *ppos);
static inline void tower_delete (struct lego_usb_tower *dev);
static int tower_open (struct inode *inode, struct file *file);
static int tower_release (struct inode *inode, struct file *file);
static unsigned int tower_poll (struct file *file, poll_table *wait);
static loff_t tower_llseek (struct file *file, loff_t off, int whence);
static void tower_abort_transfers (struct lego_usb_tower *dev);
static void tower_check_for_read_packet (struct lego_usb_tower *dev);
IRQ: Maintain regs pointer globally rather than passing to IRQ handlers Maintain a per-CPU global "struct pt_regs *" variable which can be used instead of passing regs around manually through all ~1800 interrupt handlers in the Linux kernel. The regs pointer is used in few places, but it potentially costs both stack space and code to pass it around. On the FRV arch, removing the regs parameter from all the genirq function results in a 20% speed up of the IRQ exit path (ie: from leaving timer_interrupt() to leaving do_IRQ()). Where appropriate, an arch may override the generic storage facility and do something different with the variable. On FRV, for instance, the address is maintained in GR28 at all times inside the kernel as part of general exception handling. Having looked over the code, it appears that the parameter may be handed down through up to twenty or so layers of functions. Consider a USB character device attached to a USB hub, attached to a USB controller that posts its interrupts through a cascaded auxiliary interrupt controller. A character device driver may want to pass regs to the sysrq handler through the input layer which adds another few layers of parameter passing. I've build this code with allyesconfig for x86_64 and i386. I've runtested the main part of the code on FRV and i386, though I can't test most of the drivers. I've also done partial conversion for powerpc and MIPS - these at least compile with minimal configurations. This will affect all archs. Mostly the changes should be relatively easy. Take do_IRQ(), store the regs pointer at the beginning, saving the old one: struct pt_regs *old_regs = set_irq_regs(regs); And put the old one back at the end: set_irq_regs(old_regs); Don't pass regs through to generic_handle_irq() or __do_IRQ(). In timer_interrupt(), this sort of change will be necessary: - update_process_times(user_mode(regs)); - profile_tick(CPU_PROFILING, regs); + update_process_times(user_mode(get_irq_regs())); + profile_tick(CPU_PROFILING); I'd like to move update_process_times()'s use of get_irq_regs() into itself, except that i386, alone of the archs, uses something other than user_mode(). Some notes on the interrupt handling in the drivers: (*) input_dev() is now gone entirely. The regs pointer is no longer stored in the input_dev struct. (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking. It does something different depending on whether it's been supplied with a regs pointer or not. (*) Various IRQ handler function pointers have been moved to type irq_handler_t. Signed-Off-By: David Howells <dhowells@redhat.com> (cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
2006-10-05 13:55:46 +00:00
static void tower_interrupt_in_callback (struct urb *urb);
static void tower_interrupt_out_callback (struct urb *urb);
static int tower_probe (struct usb_interface *interface, const struct usb_device_id *id);
static void tower_disconnect (struct usb_interface *interface);
/* file operations needed when we register this driver */
static const struct file_operations tower_fops = {
.owner = THIS_MODULE,
.read = tower_read,
.write = tower_write,
.open = tower_open,
.release = tower_release,
.poll = tower_poll,
.llseek = tower_llseek,
};
/*
* usb class driver info in order to get a minor number from the usb core,
* and to have the device registered with the driver core
*/
static struct usb_class_driver tower_class = {
.name = "legousbtower%d",
.fops = &tower_fops,
.minor_base = LEGO_USB_TOWER_MINOR_BASE,
};
/* usb specific object needed to register this driver with the usb subsystem */
static struct usb_driver tower_driver = {
.name = "legousbtower",
.probe = tower_probe,
.disconnect = tower_disconnect,
.id_table = tower_table,
};
/**
* lego_usb_tower_debug_data
*/
static inline void lego_usb_tower_debug_data (int level, const char *function, int size, const unsigned char *data)
{
int i;
if (debug < level)
return;
printk (KERN_DEBUG __FILE__": %s - length = %d, data = ", function, size);
for (i = 0; i < size; ++i) {
printk ("%.2x ", data[i]);
}
printk ("\n");
}
/**
* tower_delete
*/
static inline void tower_delete (struct lego_usb_tower *dev)
{
dbg(2, "%s: enter", __func__);
tower_abort_transfers (dev);
/* free data structures */
usb_free_urb(dev->interrupt_in_urb);
usb_free_urb(dev->interrupt_out_urb);
kfree (dev->read_buffer);
kfree (dev->interrupt_in_buffer);
kfree (dev->interrupt_out_buffer);
kfree (dev);
dbg(2, "%s: leave", __func__);
}
/**
* tower_open
*/
static int tower_open (struct inode *inode, struct file *file)
{
struct lego_usb_tower *dev = NULL;
int subminor;
int retval = 0;
struct usb_interface *interface;
struct tower_reset_reply reset_reply;
int result;
dbg(2, "%s: enter", __func__);
nonseekable_open(inode, file);
subminor = iminor(inode);
interface = usb_find_interface (&tower_driver, subminor);
if (!interface) {
err ("%s - error, can't find device for minor %d",
__func__, subminor);
retval = -ENODEV;
goto exit;
}
mutex_lock(&open_disc_mutex);
dev = usb_get_intfdata(interface);
if (!dev) {
mutex_unlock(&open_disc_mutex);
retval = -ENODEV;
goto exit;
}
/* lock this device */
if (mutex_lock_interruptible(&dev->lock)) {
mutex_unlock(&open_disc_mutex);
retval = -ERESTARTSYS;
goto exit;
}
/* allow opening only once */
if (dev->open_count) {
mutex_unlock(&open_disc_mutex);
retval = -EBUSY;
goto unlock_exit;
}
dev->open_count = 1;
mutex_unlock(&open_disc_mutex);
/* reset the tower */
result = usb_control_msg (dev->udev,
usb_rcvctrlpipe(dev->udev, 0),
LEGO_USB_TOWER_REQUEST_RESET,
USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
0,
0,
&reset_reply,
sizeof(reset_reply),
1000);
if (result < 0) {
err("LEGO USB Tower reset control request failed");
retval = result;
goto unlock_exit;
}
/* initialize in direction */
dev->read_buffer_length = 0;
dev->read_packet_length = 0;
usb_fill_int_urb (dev->interrupt_in_urb,
dev->udev,
usb_rcvintpipe(dev->udev, dev->interrupt_in_endpoint->bEndpointAddress),
dev->interrupt_in_buffer,
le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize),
tower_interrupt_in_callback,
dev,
dev->interrupt_in_interval);
dev->interrupt_in_running = 1;
dev->interrupt_in_done = 0;
mb();
retval = usb_submit_urb (dev->interrupt_in_urb, GFP_KERNEL);
if (retval) {
err("Couldn't submit interrupt_in_urb %d", retval);
dev->interrupt_in_running = 0;
dev->open_count = 0;
goto unlock_exit;
}
/* save device in the file's private structure */
file->private_data = dev;
unlock_exit:
mutex_unlock(&dev->lock);
exit:
dbg(2, "%s: leave, return value %d ", __func__, retval);
return retval;
}
/**
* tower_release
*/
static int tower_release (struct inode *inode, struct file *file)
{
struct lego_usb_tower *dev;
int retval = 0;
dbg(2, "%s: enter", __func__);
dev = (struct lego_usb_tower *)file->private_data;
if (dev == NULL) {
dbg(1, "%s: object is NULL", __func__);
retval = -ENODEV;
goto exit_nolock;
}
mutex_lock(&open_disc_mutex);
if (mutex_lock_interruptible(&dev->lock)) {
retval = -ERESTARTSYS;
goto exit;
}
if (dev->open_count != 1) {
dbg(1, "%s: device not opened exactly once", __func__);
retval = -ENODEV;
goto unlock_exit;
}
if (dev->udev == NULL) {
/* the device was unplugged before the file was released */
/* unlock here as tower_delete frees dev */
mutex_unlock(&dev->lock);
tower_delete (dev);
goto exit;
}
/* wait until write transfer is finished */
if (dev->interrupt_out_busy) {
wait_event_interruptible_timeout (dev->write_wait, !dev->interrupt_out_busy, 2 * HZ);
}
tower_abort_transfers (dev);
dev->open_count = 0;
unlock_exit:
mutex_unlock(&dev->lock);
exit:
mutex_unlock(&open_disc_mutex);
exit_nolock:
dbg(2, "%s: leave, return value %d", __func__, retval);
return retval;
}
/**
* tower_abort_transfers
* aborts transfers and frees associated data structures
*/
static void tower_abort_transfers (struct lego_usb_tower *dev)
{
dbg(2, "%s: enter", __func__);
if (dev == NULL) {
dbg(1, "%s: dev is null", __func__);
goto exit;
}
/* shutdown transfer */
if (dev->interrupt_in_running) {
dev->interrupt_in_running = 0;
mb();
if (dev->udev)
usb_kill_urb (dev->interrupt_in_urb);
}
if (dev->interrupt_out_busy && dev->udev)
usb_kill_urb(dev->interrupt_out_urb);
exit:
dbg(2, "%s: leave", __func__);
}
/**
* tower_check_for_read_packet
*
* To get correct semantics for signals and non-blocking I/O
* with packetizing we pretend not to see any data in the read buffer
* until it has been there unchanged for at least
* dev->packet_timeout_jiffies, or until the buffer is full.
*/
static void tower_check_for_read_packet (struct lego_usb_tower *dev)
{
spin_lock_irq (&dev->read_buffer_lock);
if (!packet_timeout
|| time_after(jiffies, dev->read_last_arrival + dev->packet_timeout_jiffies)
|| dev->read_buffer_length == read_buffer_size) {
dev->read_packet_length = dev->read_buffer_length;
}
dev->interrupt_in_done = 0;
spin_unlock_irq (&dev->read_buffer_lock);
}
/**
* tower_poll
*/
static unsigned int tower_poll (struct file *file, poll_table *wait)
{
struct lego_usb_tower *dev;
unsigned int mask = 0;
dbg(2, "%s: enter", __func__);
dev = file->private_data;
poll_wait(file, &dev->read_wait, wait);
poll_wait(file, &dev->write_wait, wait);
tower_check_for_read_packet(dev);
if (dev->read_packet_length > 0) {
mask |= POLLIN | POLLRDNORM;
}
if (!dev->interrupt_out_busy) {
mask |= POLLOUT | POLLWRNORM;
}
dbg(2, "%s: leave, mask = %d", __func__, mask);
return mask;
}
/**
* tower_llseek
*/
static loff_t tower_llseek (struct file *file, loff_t off, int whence)
{
return -ESPIPE; /* unseekable */
}
/**
* tower_read
*/
static ssize_t tower_read (struct file *file, char __user *buffer, size_t count, loff_t *ppos)
{
struct lego_usb_tower *dev;
size_t bytes_to_read;
int i;
int retval = 0;
unsigned long timeout = 0;
dbg(2, "%s: enter, count = %Zd", __func__, count);
dev = (struct lego_usb_tower *)file->private_data;
/* lock this object */
if (mutex_lock_interruptible(&dev->lock)) {
retval = -ERESTARTSYS;
goto exit;
}
/* verify that the device wasn't unplugged */
if (dev->udev == NULL) {
retval = -ENODEV;
err("No device or device unplugged %d", retval);
goto unlock_exit;
}
/* verify that we actually have some data to read */
if (count == 0) {
dbg(1, "%s: read request of 0 bytes", __func__);
goto unlock_exit;
}
if (read_timeout) {
timeout = jiffies + read_timeout * HZ / 1000;
}
/* wait for data */
tower_check_for_read_packet (dev);
while (dev->read_packet_length == 0) {
if (file->f_flags & O_NONBLOCK) {
retval = -EAGAIN;
goto unlock_exit;
}
retval = wait_event_interruptible_timeout(dev->read_wait, dev->interrupt_in_done, dev->packet_timeout_jiffies);
if (retval < 0) {
goto unlock_exit;
}
/* reset read timeout during read or write activity */
if (read_timeout
&& (dev->read_buffer_length || dev->interrupt_out_busy)) {
timeout = jiffies + read_timeout * HZ / 1000;
}
/* check for read timeout */
if (read_timeout && time_after (jiffies, timeout)) {
retval = -ETIMEDOUT;
goto unlock_exit;
}
tower_check_for_read_packet (dev);
}
/* copy the data from read_buffer into userspace */
bytes_to_read = min(count, dev->read_packet_length);
if (copy_to_user (buffer, dev->read_buffer, bytes_to_read)) {
retval = -EFAULT;
goto unlock_exit;
}
spin_lock_irq (&dev->read_buffer_lock);
dev->read_buffer_length -= bytes_to_read;
dev->read_packet_length -= bytes_to_read;
for (i=0; i<dev->read_buffer_length; i++) {
dev->read_buffer[i] = dev->read_buffer[i+bytes_to_read];
}
spin_unlock_irq (&dev->read_buffer_lock);
retval = bytes_to_read;
unlock_exit:
/* unlock the device */
mutex_unlock(&dev->lock);
exit:
dbg(2, "%s: leave, return value %d", __func__, retval);
return retval;
}
/**
* tower_write
*/
static ssize_t tower_write (struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
{
struct lego_usb_tower *dev;
size_t bytes_to_write;
int retval = 0;
dbg(2, "%s: enter, count = %Zd", __func__, count);
dev = (struct lego_usb_tower *)file->private_data;
/* lock this object */
if (mutex_lock_interruptible(&dev->lock)) {
retval = -ERESTARTSYS;
goto exit;
}
/* verify that the device wasn't unplugged */
if (dev->udev == NULL) {
retval = -ENODEV;
err("No device or device unplugged %d", retval);
goto unlock_exit;
}
/* verify that we actually have some data to write */
if (count == 0) {
dbg(1, "%s: write request of 0 bytes", __func__);
goto unlock_exit;
}
/* wait until previous transfer is finished */
while (dev->interrupt_out_busy) {
if (file->f_flags & O_NONBLOCK) {
retval = -EAGAIN;
goto unlock_exit;
}
retval = wait_event_interruptible (dev->write_wait, !dev->interrupt_out_busy);
if (retval) {
goto unlock_exit;
}
}
/* write the data into interrupt_out_buffer from userspace */
bytes_to_write = min_t(int, count, write_buffer_size);
dbg(4, "%s: count = %Zd, bytes_to_write = %Zd", __func__, count, bytes_to_write);
if (copy_from_user (dev->interrupt_out_buffer, buffer, bytes_to_write)) {
retval = -EFAULT;
goto unlock_exit;
}
/* send off the urb */
usb_fill_int_urb(dev->interrupt_out_urb,
dev->udev,
usb_sndintpipe(dev->udev, dev->interrupt_out_endpoint->bEndpointAddress),
dev->interrupt_out_buffer,
bytes_to_write,
tower_interrupt_out_callback,
dev,
dev->interrupt_out_interval);
dev->interrupt_out_busy = 1;
wmb();
retval = usb_submit_urb (dev->interrupt_out_urb, GFP_KERNEL);
if (retval) {
dev->interrupt_out_busy = 0;
err("Couldn't submit interrupt_out_urb %d", retval);
goto unlock_exit;
}
retval = bytes_to_write;
unlock_exit:
/* unlock the device */
mutex_unlock(&dev->lock);
exit:
dbg(2, "%s: leave, return value %d", __func__, retval);
return retval;
}
/**
* tower_interrupt_in_callback
*/
IRQ: Maintain regs pointer globally rather than passing to IRQ handlers Maintain a per-CPU global "struct pt_regs *" variable which can be used instead of passing regs around manually through all ~1800 interrupt handlers in the Linux kernel. The regs pointer is used in few places, but it potentially costs both stack space and code to pass it around. On the FRV arch, removing the regs parameter from all the genirq function results in a 20% speed up of the IRQ exit path (ie: from leaving timer_interrupt() to leaving do_IRQ()). Where appropriate, an arch may override the generic storage facility and do something different with the variable. On FRV, for instance, the address is maintained in GR28 at all times inside the kernel as part of general exception handling. Having looked over the code, it appears that the parameter may be handed down through up to twenty or so layers of functions. Consider a USB character device attached to a USB hub, attached to a USB controller that posts its interrupts through a cascaded auxiliary interrupt controller. A character device driver may want to pass regs to the sysrq handler through the input layer which adds another few layers of parameter passing. I've build this code with allyesconfig for x86_64 and i386. I've runtested the main part of the code on FRV and i386, though I can't test most of the drivers. I've also done partial conversion for powerpc and MIPS - these at least compile with minimal configurations. This will affect all archs. Mostly the changes should be relatively easy. Take do_IRQ(), store the regs pointer at the beginning, saving the old one: struct pt_regs *old_regs = set_irq_regs(regs); And put the old one back at the end: set_irq_regs(old_regs); Don't pass regs through to generic_handle_irq() or __do_IRQ(). In timer_interrupt(), this sort of change will be necessary: - update_process_times(user_mode(regs)); - profile_tick(CPU_PROFILING, regs); + update_process_times(user_mode(get_irq_regs())); + profile_tick(CPU_PROFILING); I'd like to move update_process_times()'s use of get_irq_regs() into itself, except that i386, alone of the archs, uses something other than user_mode(). Some notes on the interrupt handling in the drivers: (*) input_dev() is now gone entirely. The regs pointer is no longer stored in the input_dev struct. (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking. It does something different depending on whether it's been supplied with a regs pointer or not. (*) Various IRQ handler function pointers have been moved to type irq_handler_t. Signed-Off-By: David Howells <dhowells@redhat.com> (cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
2006-10-05 13:55:46 +00:00
static void tower_interrupt_in_callback (struct urb *urb)
{
struct lego_usb_tower *dev = urb->context;
int status = urb->status;
int retval;
dbg(4, "%s: enter, status %d", __func__, status);
lego_usb_tower_debug_data(5, __func__, urb->actual_length, urb->transfer_buffer);
if (status) {
if (status == -ENOENT ||
status == -ECONNRESET ||
status == -ESHUTDOWN) {
goto exit;
} else {
dbg(1, "%s: nonzero status received: %d", __func__, status);
goto resubmit; /* maybe we can recover */
}
}
if (urb->actual_length > 0) {
spin_lock (&dev->read_buffer_lock);
if (dev->read_buffer_length + urb->actual_length < read_buffer_size) {
memcpy (dev->read_buffer + dev->read_buffer_length,
dev->interrupt_in_buffer,
urb->actual_length);
dev->read_buffer_length += urb->actual_length;
dev->read_last_arrival = jiffies;
dbg(3, "%s: received %d bytes", __func__, urb->actual_length);
} else {
printk(KERN_WARNING "%s: read_buffer overflow, %d bytes dropped", __func__, urb->actual_length);
}
spin_unlock (&dev->read_buffer_lock);
}
resubmit:
/* resubmit if we're still running */
if (dev->interrupt_in_running && dev->udev) {
retval = usb_submit_urb (dev->interrupt_in_urb, GFP_ATOMIC);
if (retval) {
err("%s: usb_submit_urb failed (%d)", __func__, retval);
}
}
exit:
dev->interrupt_in_done = 1;
wake_up_interruptible (&dev->read_wait);
lego_usb_tower_debug_data(5, __func__, urb->actual_length, urb->transfer_buffer);
dbg(4, "%s: leave, status %d", __func__, status);
}
/**
* tower_interrupt_out_callback
*/
IRQ: Maintain regs pointer globally rather than passing to IRQ handlers Maintain a per-CPU global "struct pt_regs *" variable which can be used instead of passing regs around manually through all ~1800 interrupt handlers in the Linux kernel. The regs pointer is used in few places, but it potentially costs both stack space and code to pass it around. On the FRV arch, removing the regs parameter from all the genirq function results in a 20% speed up of the IRQ exit path (ie: from leaving timer_interrupt() to leaving do_IRQ()). Where appropriate, an arch may override the generic storage facility and do something different with the variable. On FRV, for instance, the address is maintained in GR28 at all times inside the kernel as part of general exception handling. Having looked over the code, it appears that the parameter may be handed down through up to twenty or so layers of functions. Consider a USB character device attached to a USB hub, attached to a USB controller that posts its interrupts through a cascaded auxiliary interrupt controller. A character device driver may want to pass regs to the sysrq handler through the input layer which adds another few layers of parameter passing. I've build this code with allyesconfig for x86_64 and i386. I've runtested the main part of the code on FRV and i386, though I can't test most of the drivers. I've also done partial conversion for powerpc and MIPS - these at least compile with minimal configurations. This will affect all archs. Mostly the changes should be relatively easy. Take do_IRQ(), store the regs pointer at the beginning, saving the old one: struct pt_regs *old_regs = set_irq_regs(regs); And put the old one back at the end: set_irq_regs(old_regs); Don't pass regs through to generic_handle_irq() or __do_IRQ(). In timer_interrupt(), this sort of change will be necessary: - update_process_times(user_mode(regs)); - profile_tick(CPU_PROFILING, regs); + update_process_times(user_mode(get_irq_regs())); + profile_tick(CPU_PROFILING); I'd like to move update_process_times()'s use of get_irq_regs() into itself, except that i386, alone of the archs, uses something other than user_mode(). Some notes on the interrupt handling in the drivers: (*) input_dev() is now gone entirely. The regs pointer is no longer stored in the input_dev struct. (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking. It does something different depending on whether it's been supplied with a regs pointer or not. (*) Various IRQ handler function pointers have been moved to type irq_handler_t. Signed-Off-By: David Howells <dhowells@redhat.com> (cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
2006-10-05 13:55:46 +00:00
static void tower_interrupt_out_callback (struct urb *urb)
{
struct lego_usb_tower *dev = urb->context;
int status = urb->status;
dbg(4, "%s: enter, status %d", __func__, status);
lego_usb_tower_debug_data(5, __func__, urb->actual_length, urb->transfer_buffer);
/* sync/async unlink faults aren't errors */
if (status && !(status == -ENOENT ||
status == -ECONNRESET ||
status == -ESHUTDOWN)) {
dbg(1, "%s - nonzero write bulk status received: %d",
__func__, status);
}
dev->interrupt_out_busy = 0;
wake_up_interruptible(&dev->write_wait);
lego_usb_tower_debug_data(5, __func__, urb->actual_length, urb->transfer_buffer);
dbg(4, "%s: leave, status %d", __func__, status);
}
/**
* tower_probe
*
* Called by the usb core when a new device is connected that it thinks
* this driver might be interested in.
*/
static int tower_probe (struct usb_interface *interface, const struct usb_device_id *id)
{
struct usb_device *udev = interface_to_usbdev(interface);
struct lego_usb_tower *dev = NULL;
struct usb_host_interface *iface_desc;
struct usb_endpoint_descriptor* endpoint;
struct tower_get_version_reply get_version_reply;
int i;
int retval = -ENOMEM;
int result;
dbg(2, "%s: enter", __func__);
if (udev == NULL)
dev_info(&interface->dev, "udev is NULL.\n");
/* allocate memory for our device state and initialize it */
dev = kmalloc (sizeof(struct lego_usb_tower), GFP_KERNEL);
if (dev == NULL) {
err ("Out of memory");
goto exit;
}
mutex_init(&dev->lock);
dev->udev = udev;
dev->open_count = 0;
dev->read_buffer = NULL;
dev->read_buffer_length = 0;
dev->read_packet_length = 0;
spin_lock_init (&dev->read_buffer_lock);
dev->packet_timeout_jiffies = packet_timeout * HZ / 1000;
dev->read_last_arrival = jiffies;
init_waitqueue_head (&dev->read_wait);
init_waitqueue_head (&dev->write_wait);
dev->interrupt_in_buffer = NULL;
dev->interrupt_in_endpoint = NULL;
dev->interrupt_in_urb = NULL;
dev->interrupt_in_running = 0;
dev->interrupt_in_done = 0;
dev->interrupt_out_buffer = NULL;
dev->interrupt_out_endpoint = NULL;
dev->interrupt_out_urb = NULL;
dev->interrupt_out_busy = 0;
iface_desc = interface->cur_altsetting;
/* set up the endpoint information */
for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
endpoint = &iface_desc->endpoint[i].desc;
if (usb_endpoint_xfer_int(endpoint)) {
if (usb_endpoint_dir_in(endpoint))
dev->interrupt_in_endpoint = endpoint;
else
dev->interrupt_out_endpoint = endpoint;
}
}
if(dev->interrupt_in_endpoint == NULL) {
err("interrupt in endpoint not found");
goto error;
}
if (dev->interrupt_out_endpoint == NULL) {
err("interrupt out endpoint not found");
goto error;
}
dev->read_buffer = kmalloc (read_buffer_size, GFP_KERNEL);
if (!dev->read_buffer) {
err("Couldn't allocate read_buffer");
goto error;
}
dev->interrupt_in_buffer = kmalloc (le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize), GFP_KERNEL);
if (!dev->interrupt_in_buffer) {
err("Couldn't allocate interrupt_in_buffer");
goto error;
}
dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
if (!dev->interrupt_in_urb) {
err("Couldn't allocate interrupt_in_urb");
goto error;
}
dev->interrupt_out_buffer = kmalloc (write_buffer_size, GFP_KERNEL);
if (!dev->interrupt_out_buffer) {
err("Couldn't allocate interrupt_out_buffer");
goto error;
}
dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
if (!dev->interrupt_out_urb) {
err("Couldn't allocate interrupt_out_urb");
goto error;
}
dev->interrupt_in_interval = interrupt_in_interval ? interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
dev->interrupt_out_interval = interrupt_out_interval ? interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;
/* we can register the device now, as it is ready */
usb_set_intfdata (interface, dev);
retval = usb_register_dev (interface, &tower_class);
if (retval) {
/* something prevented us from registering this driver */
err ("Not able to get a minor for this device.");
usb_set_intfdata (interface, NULL);
goto error;
}
dev->minor = interface->minor;
/* let the user know what node this device is now attached to */
dev_info(&interface->dev, "LEGO USB Tower #%d now attached to major "
"%d minor %d\n", (dev->minor - LEGO_USB_TOWER_MINOR_BASE),
USB_MAJOR, dev->minor);
/* get the firmware version and log it */
result = usb_control_msg (udev,
usb_rcvctrlpipe(udev, 0),
LEGO_USB_TOWER_REQUEST_GET_VERSION,
USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
0,
0,
&get_version_reply,
sizeof(get_version_reply),
1000);
if (result < 0) {
err("LEGO USB Tower get version control request failed");
retval = result;
goto error;
}
dev_info(&interface->dev, "LEGO USB Tower firmware version is %d.%d "
"build %d\n", get_version_reply.major,
get_version_reply.minor,
le16_to_cpu(get_version_reply.build_no));
exit:
dbg(2, "%s: leave, return value 0x%.8lx (dev)", __func__, (long) dev);
return retval;
error:
tower_delete(dev);
return retval;
}
/**
* tower_disconnect
*
* Called by the usb core when the device is removed from the system.
*/
static void tower_disconnect (struct usb_interface *interface)
{
struct lego_usb_tower *dev;
int minor;
dbg(2, "%s: enter", __func__);
dev = usb_get_intfdata (interface);
mutex_lock(&open_disc_mutex);
usb_set_intfdata (interface, NULL);
minor = dev->minor;
/* give back our minor */
usb_deregister_dev (interface, &tower_class);
mutex_lock(&dev->lock);
mutex_unlock(&open_disc_mutex);
/* if the device is not opened, then we clean up right now */
if (!dev->open_count) {
mutex_unlock(&dev->lock);
tower_delete (dev);
} else {
dev->udev = NULL;
mutex_unlock(&dev->lock);
}
dev_info(&interface->dev, "LEGO USB Tower #%d now disconnected\n",
(minor - LEGO_USB_TOWER_MINOR_BASE));
dbg(2, "%s: leave", __func__);
}
/**
* lego_usb_tower_init
*/
static int __init lego_usb_tower_init(void)
{
int result;
int retval = 0;
dbg(2, "%s: enter", __func__);
/* register this driver with the USB subsystem */
result = usb_register(&tower_driver);
if (result < 0) {
err("usb_register failed for the "__FILE__" driver. Error number %d", result);
retval = -1;
goto exit;
}
printk(KERN_INFO KBUILD_MODNAME ": " DRIVER_VERSION ":"
DRIVER_DESC "\n");
exit:
dbg(2, "%s: leave, return value %d", __func__, retval);
return retval;
}
/**
* lego_usb_tower_exit
*/
static void __exit lego_usb_tower_exit(void)
{
dbg(2, "%s: enter", __func__);
/* deregister this driver with the USB subsystem */
usb_deregister (&tower_driver);
dbg(2, "%s: leave", __func__);
}
module_init (lego_usb_tower_init);
module_exit (lego_usb_tower_exit);
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
#ifdef MODULE_LICENSE
MODULE_LICENSE("GPL");
#endif