1 files changed, 273 insertions, 0 deletions
diff --git a/drivers/net/wimax/i2400m/usb-tx.c b/drivers/net/wimax/i2400m/usb-tx.c
new file mode 100644
index 000000000..3ba9d70cc
--- /dev/null
+++ b/drivers/net/wimax/i2400m/usb-tx.c
@@ -0,0 +1,273 @@
+/*
+ * 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);
+		} else {
+			usb_clear_halt(i2400mu->usb_dev, usb_pipe);
+			msleep(10);	/* give the device some time */
+			goto retry;
+		}
+		fallthrough;
+	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 function 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)
+{
+	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 */
+	}
+
+	spin_lock_irqsave(&i2400m->tx_lock, flags);
+	i2400mu->tx_kthread = NULL;
+	spin_unlock_irqrestore(&i2400m->tx_lock, flags);
+
+	d_fnend(4, dev, "(i2400mu %p)\n", i2400mu);
+	return 0;
+}
+
+
+/*
+ * 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");
+}