cregit-Linux how code gets into the kernel

Release 4.7 drivers/net/wimax/i2400m/usb-tx.c

/*
 * 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; }

Contributors

PersonTokensPropCommitsCommitProp
inaky perez-gonzalezinaky perez-gonzalez37998.70%375.00%
dirk brandewiedirk brandewie51.30%125.00%
Total384100.00%4100.00%

/* * 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; }

Contributors

PersonTokensPropCommitsCommitProp
inaky perez-gonzalezinaky perez-gonzalez23199.14%266.67%
dan carpenterdan carpenter20.86%133.33%
Total233100.00%3100.00%

/* * 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); }

Contributors

PersonTokensPropCommitsCommitProp
inaky perez-gonzalezinaky perez-gonzalez67100.00%1100.00%
Total67100.00%1100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
inaky perez-gonzalezinaky perez-gonzalez96100.00%2100.00%
Total96100.00%2100.00%


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"); }

Contributors

PersonTokensPropCommitsCommitProp
inaky perez-gonzalezinaky perez-gonzalez90100.00%2100.00%
Total90100.00%2100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
inaky perez-gonzalezinaky perez-gonzalez87699.10%457.14%
dirk brandewiedirk brandewie50.57%114.29%
dan carpenterdan carpenter20.23%114.29%
lucas de marchilucas de marchi10.11%114.29%
Total884100.00%7100.00%
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