/*
* Intel Wireless WiMAX Connection 2400m
* USB specific TX handling
*
*
* Copyright (C) 2007-2008 Intel Corporation. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Intel Corporation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*
* Intel Corporation <linux-wimax@intel.com>
* Yanir Lubetkin <yanirx.lubetkin@intel.com>
* - Initial implementation
* Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
* - Split transport/device specific
*
*
* Takes the TX messages in the i2400m's driver TX FIFO and sends them
* to the device until there are no more.
*
* If we fail sending the message, we just drop it. There isn't much
* we can do at this point. We could also retry, but the USB stack has
* already retried and still failed, so there is not much of a
* point. As well, most of the traffic is network, which has recovery
* methods for dropped packets.
*
* For sending we just obtain a FIFO buffer to send, send it to the
* USB bulk out, tell the TX FIFO code we have sent it; query for
* another one, etc... until done.
*
* We use a thread so we can call usb_autopm_enable() and
* usb_autopm_disable() for each transaction; this way when the device
* goes idle, it will suspend. It also has less overhead than a
* dedicated workqueue, as it is being used for a single task.
*
* ROADMAP
*
* i2400mu_tx_setup()
* i2400mu_tx_release()
*
* i2400mu_bus_tx_kick() - Called by the tx.c code when there
* is new data in the FIFO.
* i2400mu_txd()
* i2400m_tx_msg_get()
* i2400m_tx_msg_sent()
*/
#include "i2400m-usb.h"
#define D_SUBMODULE tx
#include "usb-debug-levels.h"
/*
* Get the next TX message in the TX FIFO and send it to the device
*
* Note that any iteration consumes a message to be sent, no matter if
* it succeeds or fails (we have no real way to retry or complain).
*
* Return: 0 if ok, < 0 errno code on hard error.
*/
static
int i2400mu_tx(struct i2400mu *i2400mu, struct i2400m_msg_hdr *tx_msg,
size_t tx_msg_size)
{
int result = 0;
struct i2400m *i2400m = &i2400mu->i2400m;
struct device *dev = &i2400mu->usb_iface->dev;
int usb_pipe, sent_size, do_autopm;
struct usb_endpoint_descriptor *epd;
d_fnstart(4, dev, "(i2400mu %p)\n", i2400mu);
do_autopm = atomic_read(&i2400mu->do_autopm);
result = do_autopm ?
usb_autopm_get_interface(i2400mu->usb_iface) : 0;
if (result < 0) {
dev_err(dev, "TX: can't get autopm: %d\n", result);
do_autopm = 0;
}
epd = usb_get_epd(i2400mu->usb_iface, i2400mu->endpoint_cfg.bulk_out);
usb_pipe = usb_sndbulkpipe(i2400mu->usb_dev, epd->bEndpointAddress);
retry:
result = usb_bulk_msg(i2400mu->usb_dev, usb_pipe,
tx_msg, tx_msg_size, &sent_size, 200);
usb_mark_last_busy(i2400mu->usb_dev);
switch (result) {
case 0:
if (sent_size != tx_msg_size) { /* Too short? drop it */
dev_err(dev, "TX: short write (%d B vs %zu "
"expected)\n", sent_size, tx_msg_size);
result = -EIO;
}
break;
case -EPIPE:
/*
* Stall -- maybe the device is choking with our
* requests. Clear it and give it some time. If they
* happen to often, it might be another symptom, so we
* reset.
*
* No error handling for usb_clear_halt(0; if it
* works, the retry works; if it fails, this switch
* does the error handling for us.
*/
if (edc_inc(&i2400mu->urb_edc,
10 * EDC_MAX_ERRORS, EDC_ERROR_TIMEFRAME)) {
dev_err(dev, "BM-CMD: too many stalls in "
"URB; resetting device\n");
usb_queue_reset_device(i2400mu->usb_iface);
/* fallthrough */
} else {
usb_clear_halt(i2400mu->usb_dev, usb_pipe);
msleep(10); /* give the device some time */
goto retry;
}
case -EINVAL: /* while removing driver */
case -ENODEV: /* dev disconnect ... */
case -ENOENT: /* just ignore it */
case -ESHUTDOWN: /* and exit */
case -ECONNRESET:
result = -ESHUTDOWN;
break;
default: /* Some error? */
if (edc_inc(&i2400mu->urb_edc,
EDC_MAX_ERRORS, EDC_ERROR_TIMEFRAME)) {
dev_err(dev, "TX: maximum errors in URB "
"exceeded; resetting device\n");
usb_queue_reset_device(i2400mu->usb_iface);
} else {
dev_err(dev, "TX: cannot send URB; retrying. "
"tx_msg @%zu %zu B [%d sent]: %d\n",
(void *) tx_msg - i2400m->tx_buf,
tx_msg_size, sent_size, result);
goto retry;
}
}
if (do_autopm)
usb_autopm_put_interface(i2400mu->usb_iface);
d_fnend(4, dev, "(i2400mu %p) = result\n", i2400mu);
return result;
}
/*
* Get the next TX message in the TX FIFO and send it to the device
*
* Note we exit the loop if i2400mu_tx() fails; that funtion only
* fails on hard error (failing to tx a buffer not being one of them,
* see its doc).
*
* Return: 0
*/
static
int i2400mu_txd(void *_i2400mu)
{
int result = 0;
struct i2400mu *i2400mu = _i2400mu;
struct i2400m *i2400m = &i2400mu->i2400m;
struct device *dev = &i2400mu->usb_iface->dev;
struct i2400m_msg_hdr *tx_msg;
size_t tx_msg_size;
unsigned long flags;
d_fnstart(4, dev, "(i2400mu %p)\n", i2400mu);
spin_lock_irqsave(&i2400m->tx_lock, flags);
BUG_ON(i2400mu->tx_kthread != NULL);
i2400mu->tx_kthread = current;
spin_unlock_irqrestore(&i2400m->tx_lock, flags);
while (1) {
d_printf(2, dev, "TX: waiting for messages\n");
tx_msg = NULL;
wait_event_interruptible(
i2400mu->tx_wq,
(kthread_should_stop() /* check this first! */
|| (tx_msg = i2400m_tx_msg_get(i2400m, &tx_msg_size)))
);
if (kthread_should_stop())
break;
WARN_ON(tx_msg == NULL); /* should not happen...*/
d_printf(2, dev, "TX: submitting %zu bytes\n", tx_msg_size);
d_dump(5, dev, tx_msg, tx_msg_size);
/* Yeah, we ignore errors ... not much we can do */
i2400mu_tx(i2400mu, tx_msg, tx_msg_size);
i2400m_tx_msg_sent(i2400m); /* ack it, advance the FIFO */
if (result < 0)
break;
}
spin_lock_irqsave(&i2400m->tx_lock, flags);
i2400mu->tx_kthread = NULL;
spin_unlock_irqrestore(&i2400m->tx_lock, flags);
d_fnend(4, dev, "(i2400mu %p) = %d\n", i2400mu, result);
return result;
}
/*
* i2400m TX engine notifies us that there is data in the FIFO ready
* for TX
*
* If there is a URB in flight, don't do anything; when it finishes,
* it will see there is data in the FIFO and send it. Else, just
* submit a write.
*/
void i2400mu_bus_tx_kick(struct i2400m *i2400m)
{
struct i2400mu *i2400mu = container_of(i2400m, struct i2400mu, i2400m);
struct device *dev = &i2400mu->usb_iface->dev;
d_fnstart(3, dev, "(i2400m %p) = void\n", i2400m);
wake_up_all(&i2400mu->tx_wq);
d_fnend(3, dev, "(i2400m %p) = void\n", i2400m);
}
int i2400mu_tx_setup(struct i2400mu *i2400mu)
{
int result = 0;
struct i2400m *i2400m = &i2400mu->i2400m;
struct device *dev = &i2400mu->usb_iface->dev;
struct wimax_dev *wimax_dev = &i2400m->wimax_dev;
struct task_struct *kthread;
kthread = kthread_run(i2400mu_txd, i2400mu, "%s-tx",
wimax_dev->name);
/* the kthread function sets i2400mu->tx_thread */
if (IS_ERR(kthread)) {
result = PTR_ERR(kthread);
dev_err(dev, "TX: cannot start thread: %d\n", result);
}
return result;
}
void i2400mu_tx_release(struct i2400mu *i2400mu)
{
unsigned long flags;
struct i2400m *i2400m = &i2400mu->i2400m;
struct device *dev = i2400m_dev(i2400m);
struct task_struct *kthread;
spin_lock_irqsave(&i2400m->tx_lock, flags);
kthread = i2400mu->tx_kthread;
i2400mu->tx_kthread = NULL;
spin_unlock_irqrestore(&i2400m->tx_lock, flags);
if (kthread)
kthread_stop(kthread);
else
d_printf(1, dev, "TX: kthread had already exited\n");
}
