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usbtmc.c
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/**
* drivers/usb/class/usbtmc.c - USB Test & Measurement class driver
*
* Copyright (C) 2007 Stefan Kopp, Gechingen, Germany
* Copyright (C) 2008 Novell, Inc.
* Copyright (C) 2008 Greg Kroah-Hartman <gregkh@suse.de>
* Copyright (C) 2018 IVI Foundation, Inc.
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* The GNU General Public License is available at
* http://www.gnu.org/copyleft/gpl.html.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/uaccess.h>
#include <linux/kref.h>
#include <linux/slab.h>
#include <linux/poll.h>
#include <linux/mutex.h>
#include <linux/usb.h>
#include <linux/compiler.h>
#include <linux/compat.h>
#include "tmc.h"
#define VERBOSE 0
/* Increment API VERSION when changing tmc.h with new flags or ioctls
* or when changing a significant behavior of the driver.
*/
#define USBTMC_API_VERSION (2)
#define USBTMC_HEADER_SIZE 12
#define USBTMC_MINOR_BASE 176
/* Minimum USB timeout (in milliseconds) */
#define USBTMC_MIN_TIMEOUT 100
/* Default USB timeout (in milliseconds) */
#define USBTMC_TIMEOUT 5000
/* Max number of urbs used in write transfers */
#define MAX_URBS_IN_FLIGHT 16
/* I/O buffer size used in generic read/write functions */
#define USBTMC_BUFSIZE (4096)
/*
* Maximum number of read cycles to empty bulk in endpoint during CLEAR and
* ABORT_BULK_IN requests. Ends the loop if (for whatever reason) a short
* packet is never read.
*/
#define USBTMC_MAX_READS_TO_CLEAR_BULK_IN 100
static const struct usb_device_id usbtmc_devices[] = {
{ USB_INTERFACE_INFO(USB_CLASS_APP_SPEC, 3, 0), },
{ USB_INTERFACE_INFO(USB_CLASS_APP_SPEC, 3, 1), },
{ 0, } /* terminating entry */
};
MODULE_DEVICE_TABLE(usb, usbtmc_devices);
/*
* This structure is the capabilities for the device
* See section 4.2.1.8 of the USBTMC specification,
* and section 4.2.2 of the USBTMC usb488 subclass
* specification for details.
*/
struct usbtmc_dev_capabilities {
__u8 interface_capabilities;
__u8 device_capabilities;
__u8 usb488_interface_capabilities;
__u8 usb488_device_capabilities;
};
/* This structure holds private data for each USBTMC device. One copy is
* allocated for each USBTMC device in the driver's probe function.
*/
struct usbtmc_device_data {
const struct usb_device_id *id;
struct usb_device *usb_dev;
struct usb_interface *intf;
struct list_head file_list;
unsigned int bulk_in;
unsigned int bulk_out;
u8 bTag;
u8 bTag_last_write; /* needed for abort */
u8 bTag_last_read; /* needed for abort */
/* packet size of IN bulk */
u16 wMaxPacketSize;
/* data for interrupt in endpoint handling */
u8 bNotify1;
u8 bNotify2;
u16 ifnum;
u8 iin_bTag;
u8 *iin_buffer;
atomic_t iin_data_valid;
unsigned int iin_ep;
int iin_ep_present;
int iin_interval;
struct urb *iin_urb;
u16 iin_wMaxPacketSize;
/* coalesced usb488_caps from usbtmc_dev_capabilities */
__u8 usb488_caps;
bool zombie; /* fd of disconnected device */
struct usbtmc_dev_capabilities capabilities;
struct kref kref;
struct mutex io_mutex; /* only one i/o function running at a time */
wait_queue_head_t waitq;
struct fasync_struct *fasync;
spinlock_t dev_lock; /* lock for file_list */
};
#define to_usbtmc_data(d) container_of(d, struct usbtmc_device_data, kref)
/*
* This structure holds private data for each USBTMC file handle.
*/
struct usbtmc_file_data {
struct usbtmc_device_data *data;
struct list_head file_elem;
u32 timeout;
u8 srq_byte;
atomic_t srq_asserted;
atomic_t closing;
u8 bmTransferAttributes; /* member of DEV_DEP_MSG_IN */
u8 eom_val;
u8 term_char;
bool term_char_enabled;
bool auto_abort;
spinlock_t err_lock; /* lock for errors */
struct usb_anchor submitted;
/* data for generic_write */
struct semaphore limit_write_sem;
u32 out_transfer_size;
int out_status;
/* data for generic_read */
u32 in_transfer_size;
int in_status;
int in_urbs_used;
struct usb_anchor in_anchor;
wait_queue_head_t wait_bulk_in;
};
/* Forward declarations */
static struct usb_driver usbtmc_driver;
static void usbtmc_draw_down(struct usbtmc_file_data *file_data);
static void usbtmc_delete(struct kref *kref)
{
struct usbtmc_device_data *data = to_usbtmc_data(kref);
pr_debug("%s - called\n", __func__);
usb_put_dev(data->usb_dev);
kfree(data);
}
static int usbtmc_open(struct inode *inode, struct file *filp)
{
struct usb_interface *intf;
struct usbtmc_device_data *data;
struct usbtmc_file_data *file_data;
intf = usb_find_interface(&usbtmc_driver, iminor(inode));
if (!intf) {
pr_err("can not find device for minor %d", iminor(inode));
return -ENODEV;
}
file_data = kzalloc(sizeof(*file_data), GFP_KERNEL);
if (!file_data)
return -ENOMEM;
pr_debug("%s - called\n", __func__);
spin_lock_init(&file_data->err_lock);
sema_init(&file_data->limit_write_sem, MAX_URBS_IN_FLIGHT);
init_usb_anchor(&file_data->submitted);
init_usb_anchor(&file_data->in_anchor);
init_waitqueue_head(&file_data->wait_bulk_in);
data = usb_get_intfdata(intf);
/* Protect reference to data from file structure until release */
kref_get(&data->kref);
mutex_lock(&data->io_mutex);
file_data->data = data;
atomic_set(&file_data->closing, 0);
file_data->timeout = USBTMC_TIMEOUT;
file_data->term_char = '\n';
file_data->term_char_enabled = 0;
file_data->auto_abort = 0;
file_data->eom_val = 1;
INIT_LIST_HEAD(&file_data->file_elem);
spin_lock_irq(&data->dev_lock);
list_add_tail(&file_data->file_elem, &data->file_list);
spin_unlock_irq(&data->dev_lock);
mutex_unlock(&data->io_mutex);
/* Store pointer in file structure's private data field */
filp->private_data = file_data;
return 0;
}
/*
* usbtmc_flush - called before file handle is closed
*/
static int usbtmc_flush(struct file *file, fl_owner_t id)
{
struct usbtmc_file_data *file_data;
struct usbtmc_device_data *data;
file_data = file->private_data;
if (file_data == NULL)
return -ENODEV;
atomic_set(&file_data->closing, 1);
data = file_data->data;
/* wait for io to stop */
mutex_lock(&data->io_mutex);
usbtmc_draw_down(file_data);
spin_lock_irq(&file_data->err_lock);
file_data->in_status = 0;
file_data->in_transfer_size = 0;
file_data->in_urbs_used = 0;
file_data->out_status = 0;
file_data->out_transfer_size = 0;
spin_unlock_irq(&file_data->err_lock);
wake_up_interruptible_all(&data->waitq);
pr_debug("%s - called\n", __func__);
mutex_unlock(&data->io_mutex);
return 0;
}
static int usbtmc_release(struct inode *inode, struct file *file)
{
struct usbtmc_file_data *file_data = file->private_data;
pr_debug("%s - called\n", __func__);
/* prevent IO _AND_ usbtmc_interrupt */
mutex_lock(&file_data->data->io_mutex);
spin_lock_irq(&file_data->data->dev_lock);
list_del(&file_data->file_elem);
spin_unlock_irq(&file_data->data->dev_lock);
mutex_unlock(&file_data->data->io_mutex);
kref_put(&file_data->data->kref, usbtmc_delete);
file_data->data = NULL;
kfree(file_data);
return 0;
}
static int usbtmc_ioctl_abort_bulk_in_tag(struct usbtmc_device_data *data,
u8 tag)
{
u8 *buffer;
struct device *dev;
int rv;
int n;
int actual;
dev = &data->intf->dev;
buffer = kmalloc(USBTMC_BUFSIZE, GFP_KERNEL);
if (!buffer)
return -ENOMEM;
rv = usb_control_msg(data->usb_dev,
usb_rcvctrlpipe(data->usb_dev, 0),
USBTMC_REQUEST_INITIATE_ABORT_BULK_IN,
USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT,
tag, data->bulk_in,
buffer, 2, USB_CTRL_GET_TIMEOUT);
if (rv < 0) {
dev_err(dev, "usb_control_msg returned %d\n", rv);
goto exit;
}
dev_dbg(dev, "INITIATE_ABORT_BULK_IN returned %x with tag %02x\n",
buffer[0], buffer[1]);
if (buffer[0] == USBTMC_STATUS_FAILED) {
/* No transfer in progress and the Bulk-OUT FIFO is empty. */
rv = 0;
goto exit;
}
if (buffer[0] == USBTMC_STATUS_TRANSFER_NOT_IN_PROGRESS) {
/* The device returns this status if either:
* - There is a transfer in progress, but the specified bTag
* does not match.
* - There is no transfer in progress, but the Bulk-OUT FIFO
* is not empty.
*/
rv = -ENOMSG;
goto exit;
}
if (buffer[0] != USBTMC_STATUS_SUCCESS) {
dev_err(dev, "INITIATE_ABORT_BULK_IN returned %x\n",
buffer[0]);
rv = -EPERM;
goto exit;
}
n = 0;
usbtmc_abort_bulk_in_status:
dev_dbg(dev, "Reading from bulk in EP\n");
actual = 0;
/* Data must be present. So use low timeout 300 ms */
rv = usb_bulk_msg(data->usb_dev,
usb_rcvbulkpipe(data->usb_dev,
data->bulk_in),
buffer, USBTMC_BUFSIZE,
&actual, 300);
#if VERBOSE
print_hex_dump_debug("usbtmc ", DUMP_PREFIX_NONE, 16, 1,
buffer, actual, true);
#endif
n++;
if (rv < 0) {
dev_err(dev, "usb_bulk_msg returned %d\n", rv);
if (rv != -ETIMEDOUT)
goto exit;
}
if (actual == USBTMC_BUFSIZE)
goto usbtmc_abort_bulk_in_status;
if (n >= USBTMC_MAX_READS_TO_CLEAR_BULK_IN) {
dev_err(dev, "Couldn't clear device buffer within %d cycles\n",
USBTMC_MAX_READS_TO_CLEAR_BULK_IN);
rv = -EPERM;
goto exit;
}
rv = usb_control_msg(data->usb_dev,
usb_rcvctrlpipe(data->usb_dev, 0),
USBTMC_REQUEST_CHECK_ABORT_BULK_IN_STATUS,
USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT,
0, data->bulk_in, buffer, 0x08,
USB_CTRL_GET_TIMEOUT);
if (rv < 0) {
dev_err(dev, "usb_control_msg returned %d\n", rv);
goto exit;
}
dev_dbg(dev, "CHECK_ABORT_BULK_IN returned %x\n", buffer[0]);
if (buffer[0] == USBTMC_STATUS_SUCCESS) {
rv = 0;
goto exit;
}
if (buffer[0] != USBTMC_STATUS_PENDING) {
dev_err(dev, "CHECK_ABORT_BULK_IN returned %x\n", buffer[0]);
rv = -EPERM;
goto exit;
}
if ((buffer[1] & 1) > 0) {
/* The device has 1 or more queued packets the Host can read */
goto usbtmc_abort_bulk_in_status;
}
/* The Host must send CHECK_ABORT_BULK_IN_STATUS at a later time. */
rv = -EAGAIN;
exit:
kfree(buffer);
return rv;
}
static int usbtmc_ioctl_abort_bulk_in(struct usbtmc_device_data *data)
{
return usbtmc_ioctl_abort_bulk_in_tag(data, data->bTag_last_read);
}
static int usbtmc_ioctl_abort_bulk_out_tag(struct usbtmc_device_data *data,
u8 tag)
{
struct device *dev;
u8 *buffer;
int rv;
int n;
dev = &data->intf->dev;
buffer = kmalloc(8, GFP_KERNEL);
if (!buffer)
return -ENOMEM;
rv = usb_control_msg(data->usb_dev,
usb_rcvctrlpipe(data->usb_dev, 0),
USBTMC_REQUEST_INITIATE_ABORT_BULK_OUT,
USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT,
tag, data->bulk_out,
buffer, 2, USB_CTRL_GET_TIMEOUT);
if (rv < 0) {
dev_err(dev, "usb_control_msg returned %d\n", rv);
goto exit;
}
dev_dbg(dev, "INITIATE_ABORT_BULK_OUT returned %x\n", buffer[0]);
if (buffer[0] != USBTMC_STATUS_SUCCESS) {
dev_err(dev, "INITIATE_ABORT_BULK_OUT returned %x\n",
buffer[0]);
rv = -EPERM;
goto exit;
}
n = 0;
usbtmc_abort_bulk_out_check_status:
/* do not stress device with subsequent requests */
msleep(50);
rv = usb_control_msg(data->usb_dev,
usb_rcvctrlpipe(data->usb_dev, 0),
USBTMC_REQUEST_CHECK_ABORT_BULK_OUT_STATUS,
USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT,
0, data->bulk_out, buffer, 0x08,
USB_CTRL_GET_TIMEOUT);
n++;
if (rv < 0) {
dev_err(dev, "usb_control_msg returned %d\n", rv);
goto exit;
}
dev_dbg(dev, "CHECK_ABORT_BULK_OUT returned %x\n", buffer[0]);
if (buffer[0] == USBTMC_STATUS_SUCCESS)
goto usbtmc_abort_bulk_out_clear_halt;
if ((buffer[0] == USBTMC_STATUS_PENDING) &&
(n < USBTMC_MAX_READS_TO_CLEAR_BULK_IN))
goto usbtmc_abort_bulk_out_check_status;
rv = -EPERM;
goto exit;
usbtmc_abort_bulk_out_clear_halt:
rv = usb_clear_halt(data->usb_dev,
usb_sndbulkpipe(data->usb_dev, data->bulk_out));
if (rv < 0) {
dev_err(dev, "usb_control_msg returned %d\n", rv);
goto exit;
}
rv = 0;
exit:
kfree(buffer);
return rv;
}
static int usbtmc_ioctl_abort_bulk_out(struct usbtmc_device_data *data)
{
return usbtmc_ioctl_abort_bulk_out_tag(data, data->bTag_last_write);
}
static int usbtmc488_ioctl_read_stb(struct usbtmc_file_data *file_data,
void __user *arg)
{
struct usbtmc_device_data *data = file_data->data;
struct device *dev = &data->intf->dev;
int srq_asserted = 0;
u8 *buffer;
u8 tag;
__u8 stb;
int rv;
dev_dbg(dev, "Enter ioctl_read_stb iin_ep_present: %d\n",
data->iin_ep_present);
spin_lock_irq(&data->dev_lock);
srq_asserted = atomic_xchg(&file_data->srq_asserted, srq_asserted);
if (srq_asserted) {
/* a STB with SRQ is already received */
stb = file_data->srq_byte;
spin_unlock_irq(&data->dev_lock);
rv = put_user(stb, (__u8 __user *)arg);
dev_dbg(dev, "stb:0x%02x with srq received %d\n",
(unsigned int)stb, rv);
return rv;
}
spin_unlock_irq(&data->dev_lock);
buffer = kmalloc(8, GFP_KERNEL);
if (!buffer)
return -ENOMEM;
atomic_set(&data->iin_data_valid, 0);
rv = usb_control_msg(data->usb_dev,
usb_rcvctrlpipe(data->usb_dev, 0),
USBTMC488_REQUEST_READ_STATUS_BYTE,
USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
data->iin_bTag,
data->ifnum,
buffer, 0x03, USB_CTRL_GET_TIMEOUT);
if (rv < 0) {
dev_err(dev, "stb usb_control_msg returned %d\n", rv);
goto exit;
}
if (buffer[0] != USBTMC_STATUS_SUCCESS) {
dev_err(dev, "control status returned %x\n", buffer[0]);
rv = -EIO;
goto exit;
}
if (data->iin_ep_present) {
rv = wait_event_interruptible_timeout(
data->waitq,
atomic_read(&data->iin_data_valid) != 0,
file_data->timeout);
if (rv < 0) {
dev_dbg(dev, "wait interrupted %d\n", rv);
goto exit;
}
if (rv == 0) {
dev_dbg(dev, "wait timed out\n");
rv = -ETIMEDOUT;
goto exit;
}
tag = data->bNotify1 & 0x7f;
if (tag != data->iin_bTag) {
dev_err(dev, "expected bTag %x got %x\n",
data->iin_bTag, tag);
}
stb = data->bNotify2;
} else {
stb = buffer[2];
}
rv = put_user(stb, (__u8 __user *)arg);
dev_dbg(dev, "stb:0x%02x received %d\n", (unsigned int)stb, rv);
exit:
/* bump interrupt bTag */
data->iin_bTag += 1;
if (data->iin_bTag > 127)
/* 1 is for SRQ see USBTMC-USB488 subclass spec section 4.3.1 */
data->iin_bTag = 2;
kfree(buffer);
return rv;
}
static int usbtmc488_ioctl_wait_srq(struct usbtmc_file_data *file_data,
__u32 __user *arg)
{
struct usbtmc_device_data *data = file_data->data;
struct device *dev = &data->intf->dev;
int rv;
u32 timeout;
unsigned long expire;
if (!data->iin_ep_present) {
dev_dbg(dev, "no interrupt endpoint present\n");
return -EFAULT;
}
if (get_user(timeout, arg))
return -EFAULT;
expire = msecs_to_jiffies(timeout);
mutex_unlock(&data->io_mutex);
rv = wait_event_interruptible_timeout(
data->waitq,
atomic_read(&file_data->srq_asserted) != 0 ||
atomic_read(&file_data->closing),
expire);
mutex_lock(&data->io_mutex);
/* Note! disconnect or close could be called in the meantime */
if (atomic_read(&file_data->closing) || data->zombie)
rv = -ENODEV;
if (rv < 0) {
/* dev can be invalid now! */
pr_debug("%s - wait interrupted %d\n", __func__, rv);
return rv;
}
if (rv == 0) {
dev_dbg(dev, "%s - wait timed out\n", __func__);
return -ETIMEDOUT;
}
dev_dbg(dev, "%s - srq asserted\n", __func__);
return 0;
}
static int usbtmc488_ioctl_simple(struct usbtmc_device_data *data,
void __user *arg, unsigned int cmd)
{
struct device *dev = &data->intf->dev;
__u8 val;
u8 *buffer;
u16 wValue;
int rv;
if (!(data->usb488_caps & USBTMC488_CAPABILITY_SIMPLE))
return -EINVAL;
buffer = kmalloc(8, GFP_KERNEL);
if (!buffer)
return -ENOMEM;
if (cmd == USBTMC488_REQUEST_REN_CONTROL) {
rv = copy_from_user(&val, arg, sizeof(val));
if (rv) {
rv = -EFAULT;
goto exit;
}
wValue = val ? 1 : 0;
} else {
wValue = 0;
}
rv = usb_control_msg(data->usb_dev,
usb_rcvctrlpipe(data->usb_dev, 0),
cmd,
USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
wValue,
data->ifnum,
buffer, 0x01, USB_CTRL_GET_TIMEOUT);
if (rv < 0) {
dev_err(dev, "simple usb_control_msg failed %d\n", rv);
goto exit;
} else if (rv != 1) {
dev_warn(dev, "simple usb_control_msg returned %d\n", rv);
rv = -EIO;
goto exit;
}
if (buffer[0] != USBTMC_STATUS_SUCCESS) {
dev_err(dev, "simple control status returned %x\n", buffer[0]);
rv = -EIO;
goto exit;
}
rv = 0;
exit:
kfree(buffer);
return rv;
}
/*
* Sends a TRIGGER Bulk-OUT command message
* See the USBTMC-USB488 specification, Table 2.
*
* Also updates bTag_last_write.
*/
static int usbtmc488_ioctl_trigger(struct usbtmc_file_data *file_data)
{
struct usbtmc_device_data *data = file_data->data;
int retval;
u8 *buffer;
int actual;
buffer = kzalloc(USBTMC_HEADER_SIZE, GFP_KERNEL);
if (!buffer)
return -ENOMEM;
buffer[0] = 128;
buffer[1] = data->bTag;
buffer[2] = ~data->bTag;
retval = usb_bulk_msg(data->usb_dev,
usb_sndbulkpipe(data->usb_dev,
data->bulk_out),
buffer, USBTMC_HEADER_SIZE,
&actual, file_data->timeout);
/* Store bTag (in case we need to abort) */
data->bTag_last_write = data->bTag;
/* Increment bTag -- and increment again if zero */
data->bTag++;
if (!data->bTag)
data->bTag++;
kfree(buffer);
if (retval < 0) {
dev_err(&data->intf->dev, "%s returned %d\n",
__func__, retval);
return retval;
}
return 0;
}
static struct urb *usbtmc_create_urb(void)
{
const size_t bufsize = USBTMC_BUFSIZE;
u8 *dmabuf = NULL;
struct urb *urb = usb_alloc_urb(0, GFP_KERNEL);
if (!urb)
return NULL;
dmabuf = kmalloc(bufsize, GFP_KERNEL);
if (!dmabuf) {
usb_free_urb(urb);
return NULL;
}
urb->transfer_buffer = dmabuf;
urb->transfer_buffer_length = bufsize;
urb->transfer_flags |= URB_FREE_BUFFER;
return urb;
}
static void usbtmc_read_bulk_cb(struct urb *urb)
{
struct usbtmc_file_data *file_data = urb->context;
int status = urb->status;
unsigned long flags;
/* sync/async unlink faults aren't errors */
if (status) {
if (!(/* status == -ENOENT || */
status == -ECONNRESET ||
status == -EREMOTEIO || /* Short packet */
status == -ESHUTDOWN))
dev_err(&file_data->data->intf->dev,
"%s - nonzero read bulk status received: %d\n",
__func__, status);
spin_lock_irqsave(&file_data->err_lock, flags);
if (!file_data->in_status)
file_data->in_status = status;
spin_unlock_irqrestore(&file_data->err_lock, flags);
}
spin_lock_irqsave(&file_data->err_lock, flags);
file_data->in_transfer_size += urb->actual_length;
dev_dbg(&file_data->data->intf->dev,
"%s - total size: %u current: %d status: %d\n",
__func__, file_data->in_transfer_size,
urb->actual_length, status);
spin_unlock_irqrestore(&file_data->err_lock, flags);
usb_anchor_urb(urb, &file_data->in_anchor);
wake_up_interruptible(&file_data->wait_bulk_in);
wake_up_interruptible(&file_data->data->waitq);
}
static inline bool usbtmc_do_transfer(struct usbtmc_file_data *file_data)
{
bool data_or_error;
spin_lock_irq(&file_data->err_lock);
data_or_error = !usb_anchor_empty(&file_data->in_anchor)
|| file_data->in_status;
spin_unlock_irq(&file_data->err_lock);
dev_dbg(&file_data->data->intf->dev, "%s: returns %d\n", __func__,
data_or_error);
return data_or_error;
}
static ssize_t usbtmc_generic_read(struct usbtmc_file_data *file_data,
void __user *user_buffer,
u32 transfer_size,
u32 *transferred,
u32 flags)
{
struct usbtmc_device_data *data = file_data->data;
struct device *dev = &data->intf->dev;
u32 done = 0;
u32 remaining;
const u32 bufsize = USBTMC_BUFSIZE;
int retval = 0;
u32 max_transfer_size;
unsigned long expire;
int bufcount = 1;
int again = 0;
/* mutex already locked */
*transferred = done;
max_transfer_size = transfer_size;
if (flags & USBTMC_FLAG_IGNORE_TRAILER) {
/* The device may send extra alignment bytes (up to
* wMaxPacketSize – 1) to avoid sending a zero-length
* packet
*/
remaining = transfer_size;
if ((max_transfer_size % data->wMaxPacketSize) == 0)
max_transfer_size += (data->wMaxPacketSize - 1);
} else {
/* round down to bufsize to avoid truncated data left */
if (max_transfer_size > bufsize) {
max_transfer_size =
roundup(max_transfer_size + 1 - bufsize,
bufsize);
}
remaining = max_transfer_size;
}
spin_lock_irq(&file_data->err_lock);
if (file_data->in_status) {
/* return the very first error */
retval = file_data->in_status;
spin_unlock_irq(&file_data->err_lock);
goto error;
}
if (flags & USBTMC_FLAG_ASYNC) {
if (usb_anchor_empty(&file_data->in_anchor))
again = 1;
if (file_data->in_urbs_used == 0) {
file_data->in_transfer_size = 0;
file_data->in_status = 0;
}
} else {
file_data->in_transfer_size = 0;
file_data->in_status = 0;
}
if (max_transfer_size == 0) {
bufcount = 0;
} else {
bufcount = roundup(max_transfer_size, bufsize) / bufsize;
if (bufcount > file_data->in_urbs_used)
bufcount -= file_data->in_urbs_used;
else
bufcount = 0;
if (bufcount + file_data->in_urbs_used > MAX_URBS_IN_FLIGHT) {
bufcount = MAX_URBS_IN_FLIGHT -
file_data->in_urbs_used;
}
}
spin_unlock_irq(&file_data->err_lock);
dev_dbg(dev, "%s: requested=%u flags=0x%X size=%u bufs=%d used=%d\n",
__func__, transfer_size, flags,
max_transfer_size, bufcount, file_data->in_urbs_used);
while (bufcount > 0) {
u8 *dmabuf = NULL;
struct urb *urb = usbtmc_create_urb();
if (!urb) {
retval = -ENOMEM;
goto error;
}
dmabuf = urb->transfer_buffer;
usb_fill_bulk_urb(urb, data->usb_dev,
usb_rcvbulkpipe(data->usb_dev, data->bulk_in),
dmabuf, bufsize,
usbtmc_read_bulk_cb, file_data);
usb_anchor_urb(urb, &file_data->submitted);
retval = usb_submit_urb(urb, GFP_KERNEL);
/* urb is anchored. We can release our reference. */
usb_free_urb(urb);
if (unlikely(retval)) {
usb_unanchor_urb(urb);
goto error;
}
file_data->in_urbs_used++;
bufcount--;
}
if (again) {
dev_dbg(dev, "%s: ret=again\n", __func__);
return -EAGAIN;
}
if (user_buffer == NULL)
return -EINVAL;
expire = msecs_to_jiffies(file_data->timeout);
while (max_transfer_size > 0) {
u32 this_part;
struct urb *urb = NULL;
if (!(flags & USBTMC_FLAG_ASYNC)) {
dev_dbg(dev, "%s: before wait time %lu\n",
__func__, expire);
retval = wait_event_interruptible_timeout(
file_data->wait_bulk_in,
usbtmc_do_transfer(file_data),
expire);
dev_dbg(dev, "%s: wait returned %d\n",
__func__, retval);
if (retval <= 0) {
if (retval == 0)
retval = -ETIMEDOUT;
goto error;
}
}
urb = usb_get_from_anchor(&file_data->in_anchor);
if (!urb) {
if (!(flags & USBTMC_FLAG_ASYNC)) {
/* synchronous case: must not happen */
retval = -EFAULT;
goto error;
}
/* asynchronous case: ready, do not block or wait */
*transferred = done;
dev_dbg(dev, "%s: (async) done=%u ret=0\n",
__func__, done);
return 0;
}
file_data->in_urbs_used--;
if (max_transfer_size > urb->actual_length)
max_transfer_size -= urb->actual_length;
else
max_transfer_size = 0;
if (remaining > urb->actual_length)
this_part = urb->actual_length;
else
this_part = remaining;
#if VERBOSE
print_hex_dump_debug("usbtmc ", DUMP_PREFIX_NONE, 16, 1,
urb->transfer_buffer, urb->actual_length, true);
#endif
if (copy_to_user(user_buffer + done,
urb->transfer_buffer, this_part)) {
usb_free_urb(urb);
retval = -EFAULT;
goto error;
}
remaining -= this_part;
done += this_part;
spin_lock_irq(&file_data->err_lock);
if (urb->status) {
/* return the very first error */
retval = file_data->in_status;
spin_unlock_irq(&file_data->err_lock);
usb_free_urb(urb);
goto error;
}
spin_unlock_irq(&file_data->err_lock);