466 lines
15 KiB
C
466 lines
15 KiB
C
/*
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* Intel Wireless WiMAX Connection 2400m
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* USB RX handling
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*
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*
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* Copyright (C) 2007-2008 Intel Corporation. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* * Neither the name of Intel Corporation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*
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* Intel Corporation <linux-wimax@intel.com>
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* Yanir Lubetkin <yanirx.lubetkin@intel.com>
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* - Initial implementation
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* Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
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* - Use skb_clone(), break up processing in chunks
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* - Split transport/device specific
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* - Make buffer size dynamic to exert less memory pressure
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*
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*
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* This handles the RX path on USB.
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*
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* When a notification is received that says 'there is RX data ready',
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* we call i2400mu_rx_kick(); that wakes up the RX kthread, which
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* reads a buffer from USB and passes it to i2400m_rx() in the generic
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* handling code. The RX buffer has an specific format that is
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* described in rx.c.
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*
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* We use a kernel thread in a loop because:
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*
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* - we want to be able to call the USB power management get/put
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* functions (blocking) before each transaction.
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*
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* - We might get a lot of notifications and we don't want to submit
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* a zillion reads; by serializing, we are throttling.
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*
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* - RX data processing can get heavy enough so that it is not
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* appropriate for doing it in the USB callback; thus we run it in a
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* process context.
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*
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* We provide a read buffer of an arbitrary size (short of a page); if
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* the callback reports -EOVERFLOW, it means it was too small, so we
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* just double the size and retry (being careful to append, as
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* sometimes the device provided some data). Every now and then we
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* check if the average packet size is smaller than the current packet
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* size and if so, we halve it. At the end, the size of the
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* preallocated buffer should be following the average received
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* transaction size, adapting dynamically to it.
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*
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* ROADMAP
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*
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* i2400mu_rx_kick() Called from notif.c when we get a
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* 'data ready' notification
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* i2400mu_rxd() Kernel RX daemon
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* i2400mu_rx() Receive USB data
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* i2400m_rx() Send data to generic i2400m RX handling
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*
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* i2400mu_rx_setup() called from i2400mu_bus_dev_start()
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*
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* i2400mu_rx_release() called from i2400mu_bus_dev_stop()
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*/
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#include <linux/workqueue.h>
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#include <linux/slab.h>
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#include <linux/usb.h>
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#include "i2400m-usb.h"
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#define D_SUBMODULE rx
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#include "usb-debug-levels.h"
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/*
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* Dynamic RX size
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*
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* We can't let the rx_size be a multiple of 512 bytes (the RX
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* endpoint's max packet size). On some USB host controllers (we
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* haven't been able to fully characterize which), if the device is
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* about to send (for example) X bytes and we only post a buffer to
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* receive n*512, it will fail to mark that as babble (so that
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* i2400mu_rx() [case -EOVERFLOW] can resize the buffer and get the
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* rest).
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*
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* So on growing or shrinking, if it is a multiple of the
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* maxpacketsize, we remove some (instead of incresing some, so in a
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* buddy allocator we try to waste less space).
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*
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* Note we also need a hook for this on i2400mu_rx() -- when we do the
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* first read, we are sure we won't hit this spot because
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* i240mm->rx_size has been set properly. However, if we have to
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* double because of -EOVERFLOW, when we launch the read to get the
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* rest of the data, we *have* to make sure that also is not a
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* multiple of the max_pkt_size.
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*/
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static
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size_t i2400mu_rx_size_grow(struct i2400mu *i2400mu)
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{
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struct device *dev = &i2400mu->usb_iface->dev;
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size_t rx_size;
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const size_t max_pkt_size = 512;
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rx_size = 2 * i2400mu->rx_size;
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if (rx_size % max_pkt_size == 0) {
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rx_size -= 8;
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d_printf(1, dev,
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"RX: expected size grew to %zu [adjusted -8] "
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"from %zu\n",
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rx_size, i2400mu->rx_size);
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} else
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d_printf(1, dev,
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"RX: expected size grew to %zu from %zu\n",
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rx_size, i2400mu->rx_size);
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return rx_size;
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}
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static
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void i2400mu_rx_size_maybe_shrink(struct i2400mu *i2400mu)
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{
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const size_t max_pkt_size = 512;
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struct device *dev = &i2400mu->usb_iface->dev;
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if (unlikely(i2400mu->rx_size_cnt >= 100
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&& i2400mu->rx_size_auto_shrink)) {
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size_t avg_rx_size =
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i2400mu->rx_size_acc / i2400mu->rx_size_cnt;
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size_t new_rx_size = i2400mu->rx_size / 2;
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if (avg_rx_size < new_rx_size) {
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if (new_rx_size % max_pkt_size == 0) {
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new_rx_size -= 8;
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d_printf(1, dev,
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"RX: expected size shrank to %zu "
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"[adjusted -8] from %zu\n",
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new_rx_size, i2400mu->rx_size);
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} else
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d_printf(1, dev,
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"RX: expected size shrank to %zu "
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"from %zu\n",
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new_rx_size, i2400mu->rx_size);
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i2400mu->rx_size = new_rx_size;
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i2400mu->rx_size_cnt = 0;
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i2400mu->rx_size_acc = i2400mu->rx_size;
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}
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}
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}
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/*
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* Receive a message with payloads from the USB bus into an skb
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*
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* @i2400mu: USB device descriptor
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* @rx_skb: skb where to place the received message
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*
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* Deals with all the USB-specifics of receiving, dynamically
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* increasing the buffer size if so needed. Returns the payload in the
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* skb, ready to process. On a zero-length packet, we retry.
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*
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* On soft USB errors, we retry (until they become too frequent and
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* then are promoted to hard); on hard USB errors, we reset the
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* device. On other errors (skb realloacation, we just drop it and
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* hope for the next invocation to solve it).
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*
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* Returns: pointer to the skb if ok, ERR_PTR on error.
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* NOTE: this function might realloc the skb (if it is too small),
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* so always update with the one returned.
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* ERR_PTR() is < 0 on error.
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* Will return NULL if it cannot reallocate -- this can be
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* considered a transient retryable error.
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*/
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static
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struct sk_buff *i2400mu_rx(struct i2400mu *i2400mu, struct sk_buff *rx_skb)
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{
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int result = 0;
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struct device *dev = &i2400mu->usb_iface->dev;
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int usb_pipe, read_size, rx_size, do_autopm;
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struct usb_endpoint_descriptor *epd;
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const size_t max_pkt_size = 512;
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d_fnstart(4, dev, "(i2400mu %p)\n", i2400mu);
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do_autopm = atomic_read(&i2400mu->do_autopm);
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result = do_autopm ?
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usb_autopm_get_interface(i2400mu->usb_iface) : 0;
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if (result < 0) {
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dev_err(dev, "RX: can't get autopm: %d\n", result);
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do_autopm = 0;
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}
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epd = usb_get_epd(i2400mu->usb_iface, i2400mu->endpoint_cfg.bulk_in);
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usb_pipe = usb_rcvbulkpipe(i2400mu->usb_dev, epd->bEndpointAddress);
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retry:
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rx_size = skb_end_pointer(rx_skb) - rx_skb->data - rx_skb->len;
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if (unlikely(rx_size % max_pkt_size == 0)) {
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rx_size -= 8;
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d_printf(1, dev, "RX: rx_size adapted to %d [-8]\n", rx_size);
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}
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result = usb_bulk_msg(
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i2400mu->usb_dev, usb_pipe, rx_skb->data + rx_skb->len,
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rx_size, &read_size, 200);
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usb_mark_last_busy(i2400mu->usb_dev);
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switch (result) {
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case 0:
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if (read_size == 0)
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goto retry; /* ZLP, just resubmit */
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skb_put(rx_skb, read_size);
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break;
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case -EPIPE:
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/*
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* Stall -- maybe the device is choking with our
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* requests. Clear it and give it some time. If they
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* happen to often, it might be another symptom, so we
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* reset.
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*
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* No error handling for usb_clear_halt(0; if it
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* works, the retry works; if it fails, this switch
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* does the error handling for us.
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*/
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if (edc_inc(&i2400mu->urb_edc,
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10 * EDC_MAX_ERRORS, EDC_ERROR_TIMEFRAME)) {
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dev_err(dev, "BM-CMD: too many stalls in "
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"URB; resetting device\n");
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goto do_reset;
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}
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usb_clear_halt(i2400mu->usb_dev, usb_pipe);
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msleep(10); /* give the device some time */
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goto retry;
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case -EINVAL: /* while removing driver */
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case -ENODEV: /* dev disconnect ... */
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case -ENOENT: /* just ignore it */
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case -ESHUTDOWN:
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case -ECONNRESET:
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break;
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case -EOVERFLOW: { /* too small, reallocate */
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struct sk_buff *new_skb;
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rx_size = i2400mu_rx_size_grow(i2400mu);
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if (rx_size <= (1 << 16)) /* cap it */
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i2400mu->rx_size = rx_size;
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else if (printk_ratelimit()) {
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dev_err(dev, "BUG? rx_size up to %d\n", rx_size);
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result = -EINVAL;
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goto out;
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}
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skb_put(rx_skb, read_size);
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new_skb = skb_copy_expand(rx_skb, 0, rx_size - rx_skb->len,
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GFP_KERNEL);
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if (new_skb == NULL) {
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if (printk_ratelimit())
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dev_err(dev, "RX: Can't reallocate skb to %d; "
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"RX dropped\n", rx_size);
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kfree_skb(rx_skb);
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rx_skb = NULL;
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goto out; /* drop it...*/
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}
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kfree_skb(rx_skb);
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rx_skb = new_skb;
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i2400mu->rx_size_cnt = 0;
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i2400mu->rx_size_acc = i2400mu->rx_size;
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d_printf(1, dev, "RX: size changed to %d, received %d, "
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"copied %d, capacity %ld\n",
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rx_size, read_size, rx_skb->len,
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(long) (skb_end_pointer(new_skb) - new_skb->head));
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goto retry;
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}
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/* In most cases, it happens due to the hardware scheduling a
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* read when there was no data - unfortunately, we have no way
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* to tell this timeout from a USB timeout. So we just ignore
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* it. */
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case -ETIMEDOUT:
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dev_err(dev, "RX: timeout: %d\n", result);
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result = 0;
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break;
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default: /* Any error */
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if (edc_inc(&i2400mu->urb_edc,
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EDC_MAX_ERRORS, EDC_ERROR_TIMEFRAME))
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goto error_reset;
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dev_err(dev, "RX: error receiving URB: %d, retrying\n", result);
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goto retry;
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}
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out:
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if (do_autopm)
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usb_autopm_put_interface(i2400mu->usb_iface);
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d_fnend(4, dev, "(i2400mu %p) = %p\n", i2400mu, rx_skb);
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return rx_skb;
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error_reset:
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dev_err(dev, "RX: maximum errors in URB exceeded; "
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"resetting device\n");
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do_reset:
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usb_queue_reset_device(i2400mu->usb_iface);
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rx_skb = ERR_PTR(result);
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goto out;
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}
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/*
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* Kernel thread for USB reception of data
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*
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* This thread waits for a kick; once kicked, it will allocate an skb
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* and receive a single message to it from USB (using
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* i2400mu_rx()). Once received, it is passed to the generic i2400m RX
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* code for processing.
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*
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* When done processing, it runs some dirty statistics to verify if
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* the last 100 messages received were smaller than half of the
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* current RX buffer size. In that case, the RX buffer size is
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* halved. This will helps lowering the pressure on the memory
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* allocator.
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*
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* Hard errors force the thread to exit.
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*/
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static
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int i2400mu_rxd(void *_i2400mu)
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{
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int result = 0;
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struct i2400mu *i2400mu = _i2400mu;
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struct i2400m *i2400m = &i2400mu->i2400m;
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struct device *dev = &i2400mu->usb_iface->dev;
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struct net_device *net_dev = i2400m->wimax_dev.net_dev;
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size_t pending;
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int rx_size;
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struct sk_buff *rx_skb;
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unsigned long flags;
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d_fnstart(4, dev, "(i2400mu %p)\n", i2400mu);
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spin_lock_irqsave(&i2400m->rx_lock, flags);
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BUG_ON(i2400mu->rx_kthread != NULL);
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i2400mu->rx_kthread = current;
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spin_unlock_irqrestore(&i2400m->rx_lock, flags);
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while (1) {
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d_printf(2, dev, "RX: waiting for messages\n");
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pending = 0;
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wait_event_interruptible(
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i2400mu->rx_wq,
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(kthread_should_stop() /* check this first! */
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|| (pending = atomic_read(&i2400mu->rx_pending_count)))
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);
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if (kthread_should_stop())
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break;
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if (pending == 0)
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continue;
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rx_size = i2400mu->rx_size;
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d_printf(2, dev, "RX: reading up to %d bytes\n", rx_size);
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rx_skb = __netdev_alloc_skb(net_dev, rx_size, GFP_KERNEL);
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if (rx_skb == NULL) {
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dev_err(dev, "RX: can't allocate skb [%d bytes]\n",
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rx_size);
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msleep(50); /* give it some time? */
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continue;
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}
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/* Receive the message with the payloads */
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rx_skb = i2400mu_rx(i2400mu, rx_skb);
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result = PTR_ERR(rx_skb);
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if (IS_ERR(rx_skb))
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goto out;
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atomic_dec(&i2400mu->rx_pending_count);
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if (rx_skb == NULL || rx_skb->len == 0) {
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/* some "ignorable" condition */
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kfree_skb(rx_skb);
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continue;
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}
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/* Deliver the message to the generic i2400m code */
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i2400mu->rx_size_cnt++;
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i2400mu->rx_size_acc += rx_skb->len;
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result = i2400m_rx(i2400m, rx_skb);
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if (result == -EIO
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&& edc_inc(&i2400mu->urb_edc,
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EDC_MAX_ERRORS, EDC_ERROR_TIMEFRAME)) {
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goto error_reset;
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}
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/* Maybe adjust RX buffer size */
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i2400mu_rx_size_maybe_shrink(i2400mu);
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}
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result = 0;
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out:
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spin_lock_irqsave(&i2400m->rx_lock, flags);
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i2400mu->rx_kthread = NULL;
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spin_unlock_irqrestore(&i2400m->rx_lock, flags);
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d_fnend(4, dev, "(i2400mu %p) = %d\n", i2400mu, result);
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return result;
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error_reset:
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dev_err(dev, "RX: maximum errors in received buffer exceeded; "
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"resetting device\n");
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usb_queue_reset_device(i2400mu->usb_iface);
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goto out;
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}
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/*
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* Start reading from the device
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*
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* @i2400m: device instance
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*
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* Notify the RX thread that there is data pending.
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*/
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void i2400mu_rx_kick(struct i2400mu *i2400mu)
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{
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struct i2400m *i2400m = &i2400mu->i2400m;
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struct device *dev = &i2400mu->usb_iface->dev;
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d_fnstart(3, dev, "(i2400mu %p)\n", i2400m);
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atomic_inc(&i2400mu->rx_pending_count);
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wake_up_all(&i2400mu->rx_wq);
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d_fnend(3, dev, "(i2400m %p) = void\n", i2400m);
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}
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int i2400mu_rx_setup(struct i2400mu *i2400mu)
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{
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int result = 0;
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struct i2400m *i2400m = &i2400mu->i2400m;
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struct device *dev = &i2400mu->usb_iface->dev;
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struct wimax_dev *wimax_dev = &i2400m->wimax_dev;
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struct task_struct *kthread;
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kthread = kthread_run(i2400mu_rxd, i2400mu, "%s-rx",
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wimax_dev->name);
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/* the kthread function sets i2400mu->rx_thread */
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if (IS_ERR(kthread)) {
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result = PTR_ERR(kthread);
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dev_err(dev, "RX: cannot start thread: %d\n", result);
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}
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return result;
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}
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void i2400mu_rx_release(struct i2400mu *i2400mu)
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{
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unsigned long flags;
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struct i2400m *i2400m = &i2400mu->i2400m;
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struct device *dev = i2400m_dev(i2400m);
|
|
struct task_struct *kthread;
|
|
|
|
spin_lock_irqsave(&i2400m->rx_lock, flags);
|
|
kthread = i2400mu->rx_kthread;
|
|
i2400mu->rx_kthread = NULL;
|
|
spin_unlock_irqrestore(&i2400m->rx_lock, flags);
|
|
if (kthread)
|
|
kthread_stop(kthread);
|
|
else
|
|
d_printf(1, dev, "RX: kthread had already exited\n");
|
|
}
|
|
|