/*
* WUSB Wire Adapter: WLP interface
* Driver for the Linux Network stack.
*
* Copyright (C) 2005-2006 Intel Corporation
* Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version
* 2 as published by the Free Software Foundation.
*
* 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*
*
* i1480u's RX handling is simple. i1480u will send the received
* network packets broken up in fragments; 1 to N fragments make a
* packet, we assemble them together and deliver the packet with netif_rx().
*
* Beacuse each USB transfer is a *single* fragment (except when the
* transfer contains a first fragment), each URB called thus
* back contains one or two fragments. So we queue N URBs, each with its own
* fragment buffer. When a URB is done, we process it (adding to the
* current skb from the fragment buffer until complete). Once
* processed, we requeue the URB. There is always a bunch of URBs
* ready to take data, so the intergap should be minimal.
*
* An URB's transfer buffer is the data field of a socket buffer. This
* reduces copying as data can be passed directly to network layer. If a
* complete packet or 1st fragment is received the URB's transfer buffer is
* taken away from it and used to send data to the network layer. In this
* case a new transfer buffer is allocated to the URB before being requeued.
* If a "NEXT" or "LAST" fragment is received, the fragment contents is
* appended to the RX packet under construction and the transfer buffer
* is reused. To be able to use this buffer to assemble complete packets
* we set each buffer's size to that of the MAX ethernet packet that can
* be received. There is thus room for improvement in memory usage.
*
* When the max tx fragment size increases, we should be able to read
* data into the skbs directly with very simple code.
*
* ROADMAP:
*
* ENTRY POINTS:
*
* i1480u_rx_setup(): setup RX context [from i1480u_open()]
*
* i1480u_rx_release(): release RX context [from i1480u_stop()]
*
* i1480u_rx_cb(): called when the RX USB URB receives a
* packet. It removes the header and pushes it up
* the Linux netdev stack with netif_rx().
*
* i1480u_rx_buffer()
* i1480u_drop() and i1480u_fix()
* i1480u_skb_deliver
*
*/
#include <linux/gfp.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include "i1480u-wlp.h"
/*
* Setup the RX context
*
* Each URB is provided with a transfer_buffer that is the data field
* of a new socket buffer.
*/
int i1480u_rx_setup(struct i1480u *i1480u)
{
int result, cnt;
struct device *dev = &i1480u->usb_iface->dev;
struct net_device *net_dev = i1480u->net_dev;
struct usb_endpoint_descriptor *epd;
struct sk_buff *skb;
/* Alloc RX stuff */
i1480u->rx_skb = NULL; /* not in process of receiving packet */
result = -ENOMEM;
epd = &i1480u->usb_iface->cur_altsetting->endpoint[1].desc;
for (cnt = 0; cnt < i1480u_RX_BUFS; cnt++) {
struct i1480u_rx_buf *rx_buf = &i1480u->rx_buf[cnt];
rx_buf->i1480u = i1480u;
skb = dev_alloc_skb(i1480u_MAX_RX_PKT_SIZE);
if (!skb) {
dev_err(dev,
"RX: cannot allocate RX buffer %d\n", cnt);
result = -ENOMEM;
goto error;
}
skb->dev = net_dev;
skb->ip_summed = CHECKSUM_NONE;
skb_reserve(skb, 2);
rx_buf->data = skb;
rx_buf->urb = usb_alloc_urb(0, GFP_KERNEL);
if (unlikely(rx_buf->urb == NULL)) {
dev_err(dev, "RX: cannot allocate URB %d\n", cnt);
result = -ENOMEM;
goto error;
}
usb_fill_bulk_urb(rx_buf->urb, i1480u->usb_dev,
usb_rcvbulkpipe(i1480u->usb_dev, epd->bEndpointAddress),
rx_buf->data->data, i1480u_MAX_RX_PKT_SIZE - 2,
i1480u_rx_cb, rx_buf);
result = usb_submit_urb(rx_buf->urb, GFP_NOIO);
if (unlikely(result < 0)) {
dev_err(dev, "RX: cannot submit URB %d: %d\n",
cnt, result);
goto error;
}
}
return 0;
error:
i1480u_rx_release(i1480u);
return result;
}
/* Release resources associated to the rx context */
void i1480u_rx_release(struct i1480u *i1480u)
{
int cnt;
for (cnt = 0; cnt < i1480u_RX_BUFS; cnt++) {
if (i1480u->rx_buf[cnt].data)
dev_kfree_skb(i1480u->rx_buf[cnt].data);
if (i1480u->rx_buf[cnt].urb) {
usb_kill_urb(i1480u->rx_buf[cnt].urb);
usb_free_urb(i1480u->rx_buf[cnt].urb);
}
}
if (i1480u->rx_skb != NULL)
dev_kfree_skb(i1480u->rx_skb);
}
static
void i1480u_rx_unlink_urbs(struct i1480u *i1480u)
{
int cnt;
for (cnt = 0; cnt < i1480u_RX_BUFS; cnt++) {
if (i1480u->rx_buf[cnt].urb)
usb_unlink_urb(i1480u->rx_buf[cnt].urb);
}
}
/* Fix an out-of-sequence packet */
#define i1480u_fix(i1480u, msg...) \
do { \
if (printk_ratelimit()) \
dev_err(&i1480u->usb_iface->dev, msg); \
dev_kfree_skb_irq(i1480u->rx_skb); \
i1480u->rx_skb = NULL; \
i1480u->rx_untd_pkt_size = 0; \
} while (0)
/* Drop an out-of-sequence packet */
#define i1480u_drop(i1480u, msg...) \
do { \
if (printk_ratelimit()) \
dev_err(&i1480u->usb_iface->dev, msg); \
i1480u->net_dev->stats.rx_dropped++; \
} while (0)
/* Finalizes setting up the SKB and delivers it
*
* We first pass the incoming frame to WLP substack for verification. It
* may also be a WLP association frame in which case WLP will take over the
* processing. If WLP does not take it over it will still verify it, if the
* frame is invalid the skb will be freed by WLP and we will not continue
* parsing.
* */
static
void i1480u_skb_deliver(struct i1480u *i1480u)
{
int should_parse;
struct net_device *net_dev = i1480u->net_dev;
struct device *dev = &i1480u->usb_iface->dev;
should_parse = wlp_receive_frame(dev, &i1480u->wlp, i1480u->rx_skb,
&i1480u->rx_srcaddr);
if (!should_parse)
goto out;
i1480u->rx_skb->protocol = eth_type_trans(i1480u->rx_skb, net_dev);
net_dev->stats.rx_packets++;
net_dev->stats.rx_bytes += i1480u->rx_untd_pkt_size;
netif_rx(i1480u->rx_skb); /* deliver */
out:
i1480u->rx_skb = NULL;
i1480u->rx_untd_pkt_size = 0;
}
/*
* Process a buffer of data received from the USB RX endpoint
*
* First fragment arrives with next or last fragment. All other fragments
* arrive alone.
*
* /me hates long functions.
*/
static
void i1480u_rx_buffer(struct i1480u_rx_buf *rx_buf)
{
unsigned pkt_completed = 0; /* !0 when we got all pkt fragments */
size_t untd_hdr_size, untd_frg_size;
size_t i1480u_hdr_size;
struct wlp_rx_hdr *i1480u_hdr = NULL;
struct i1480u *i1480u = rx_buf->i1480u;
struct sk_buff *skb = rx_buf->data;
int size_left = rx_buf->urb->actual_length;
void *ptr = rx_buf->urb->transfer_buffer; /* also rx_buf->data->data */
struct untd_hdr *untd_hdr;
struct net_device *net_dev = i1480u->net_dev;
struct device *dev = &i1480u->usb_iface->dev;
struct sk_buff *new_skb;
#if 0
dev_fnstart(dev,
"(i1480u %p ptr %p size_left %zu)\n", i1480u, ptr, size_left);
dev_err(dev, "RX packet, %zu bytes\n", size_left);
dump_bytes(dev, ptr, size_left);
#endif
i1480u_hdr_size = sizeof(struct wlp_rx_hdr);
while (size_left > 0) {
if (pkt_completed) {
i1480u_drop(i1480u, "RX: fragment follows completed"
"packet in same buffer. Dropping\n");
break;
}
untd_hdr = ptr;
if (size_left < sizeof(*untd_hdr)) { /* Check the UNTD header */
i1480u_drop(i1480u, "RX: short UNTD header! Dropping\n");
goto out;
}
if (unlikely(untd_hdr_rx_tx(untd_hdr) == 0)) { /* Paranoia: TX set? */
i1480u_drop(i1480u, "RX: TX bit set! Dropping\n");
goto out;
}
switch (untd_hdr_type(untd_hdr)) { /* Check the UNTD header type */
case i1480u_PKT_FRAG_1ST: {
struct untd_hdr_1st *untd_hdr_1st = (void *) untd_hdr;
dev_dbg(dev, "1st fragment\n");
untd_hdr_size = sizeof(struct untd_hdr_1st);
if (i1480u->rx_skb != NULL)
i1480u_fix(i1480u, "RX: 1st fragment out of "
"sequence! Fixing\n");
if (size_left < untd_hdr_size + i1480u_hdr_size) {
i1480u_drop(i1480u, "RX: short 1st fragment! "
"Dropping\n");
goto out;
}
i1480u->rx_untd_pkt_size = le16_to_cpu(untd_hdr->len)
- i1480u_hdr_size;
untd_frg_size = le16_to_cpu(untd_hdr_1st->fragment_len);
if (size_left < untd_hdr_size + untd_frg_size) {
i1480u_drop(i1480u,
"RX: short payload! Dropping\n");
goto out;
}
i1480u->rx_skb = skb;
i1480u_hdr = (void *) untd_hdr_1st + untd_hdr_size;
i1480u->rx_srcaddr = i1480u_hdr->srcaddr;
skb_put(i1480u->rx_skb, untd_hdr_size + untd_frg_size);
skb_pull(i1480u->rx_skb, untd_hdr_size + i1480u_hdr_size);
stats_add_sample(&i1480u->lqe_stats, (s8) i1480u_hdr->LQI - 7);
stats_add_sample(&i1480u->rssi_stats, i1480u_hdr->RSSI + 18);
rx_buf->data = NULL; /* need to create new buffer */
break;
}
case i1480u_PKT_FRAG_NXT: {
dev_dbg(dev, "nxt fragment\n");
untd_hdr_size = sizeof(struct untd_hdr_rst);
if (i1480u->rx_skb == NULL) {
i1480u_drop(i1480u, "RX: next fragment out of "
"sequence! Dropping\n");
goto out;
}
if (size_left < untd_hdr_size) {
i1480u_drop(i1480u, "RX: short NXT fragment! "
"Dropping\n");
goto out;
}
untd_frg_size = le16_to_cpu(untd_hdr->len);
if (size_left < untd_hdr_size + untd_frg_size) {
i1480u_drop(i1480u,
"RX: short payload! Dropping\n");
goto out;
}
memmove(skb_put(i1480u->rx_skb, untd_frg_size),
ptr + untd_hdr_size, untd_frg_size);
break;
}
case i1480u_PKT_FRAG_LST: {
dev_dbg(dev, "Lst fragment\n");
untd_hdr_size = sizeof(struct untd_hdr_rst);
if (i1480u->rx_skb == NULL) {
i1480u_drop(i1480u, "RX: last fragment out of "
"sequence! Dropping\n");
goto out;
}
if (size_left < untd_hdr_size) {
i1480u_drop(i1480u, "RX: short LST fragment! "
"Dropping\n");
goto out;
}
untd_frg_size = le16_to_cpu(untd_hdr->len);
if (size_left < untd_frg_size + untd_hdr_size) {
i1480u_drop(i1480u,
"RX: short payload! Dropping\n");
goto out;
}
memmove(skb_put(i1480u->rx_skb, untd_frg_size),
ptr + untd_hdr_size, untd_frg_size);
pkt_completed = 1;
break;
}
case i1480u_PKT_FRAG_CMP: {
dev_dbg(dev, "cmp fragment\n");
untd_hdr_size = sizeof(struct untd_hdr_cmp);
if (i1480u->rx_skb != NULL)
i1480u_fix(i1480u, "RX: fix out-of-sequence CMP"
" fragment!\n");
if (size_left < untd_hdr_size + i1480u_hdr_size) {
i1480u_drop(i1480u, "RX: short CMP fragment! "
"Dropping\n");
goto out;
}
i1480u->rx_untd_pkt_size = le16_to_cpu(untd_hdr->len);
untd_frg_size = i1480u->rx_untd_pkt_size;
if (size_left < i1480u->rx_untd_pkt_size + untd_hdr_size) {
i1480u_drop(i1480u,
"RX: short payload! Dropping\n");
goto out;
}
i1480u->rx_skb = skb;
i1480u_hdr = (void *) untd_hdr + untd_hdr_size;
i1480u->rx_srcaddr = i1480u_hdr->srcaddr;
stats_add_sample(&i1480u->lqe_stats, (s8) i1480u_hdr->LQI - 7);
stats_add_sample(&i1480u->rssi_stats, i1480u_hdr->RSSI + 18);
skb_put(i1480u->rx_skb, untd_hdr_size + i1480u->rx_untd_pkt_size);
skb_pull(i1480u->rx_skb, untd_hdr_size + i1480u_hdr_size);
rx_buf->data = NULL; /* for hand off skb to network stack */
pkt_completed = 1;
i1480u->rx_untd_pkt_size -= i1480u_hdr_size; /* accurate stat */
break;
}
default:
i1480u_drop(i1480u, "RX: unknown packet type %u! "
"Dropping\n", untd_hdr_type(untd_hdr));
goto out;
}
size_left -= untd_hdr_size + untd_frg_size;
if (size_left > 0)
ptr += untd_hdr_size + untd_frg_size;
}
if (pkt_completed)
i1480u_skb_deliver(i1480u);
out:
/* recreate needed RX buffers*/
if (rx_buf->data == NULL) {
/* buffer is being used to receive packet, create new */
new_skb = dev_alloc_skb(i1480u_MAX_RX_PKT_SIZE);
if (!new_skb) {
if (printk_ratelimit())
dev_err(dev,
"RX: cannot allocate RX buffer\n");
} else {
new_skb->dev = net_dev;
new_skb->ip_summed = CHECKSUM_NONE;
skb_reserve(new_skb, 2);
rx_buf->data = new_skb;
}
}
return;
}
/*
* Called when an RX URB has finished receiving or has found some kind
* of error condition.
*
* LIMITATIONS:
*
* - We read USB-transfers, each transfer contains a SINGLE fragment
* (can contain a complete packet, or a 1st, next, or last fragment
* of a packet).
* Looks like a transfer can contain more than one fragment (07/18/06)
*
* - Each transfer buffer is the size of the maximum packet size (minus
* headroom), i1480u_MAX_PKT_SIZE - 2
*
* - We always read the full USB-transfer, no partials.
*
* - Each transfer is read directly into a skb. This skb will be used to
* send data to the upper layers if it is the first fragment or a complete
* packet. In the other cases the data will be copied from the skb to
* another skb that is being prepared for the upper layers from a prev
* first fragment.
*
* It is simply too much of a pain. Gosh, there should be a unified
* SG infrastructure for *everything* [so that I could declare a SG
* buffer, pass it to USB for receiving, append some space to it if
* I wish, receive more until I have the whole chunk, adapt
* pointers on each fragment to remove hardware headers and then
* attach that to an skbuff and netif_rx()].
*/
void i1480u_rx_cb(struct urb *urb)
{
int result;
int do_parse_buffer = 1;
struct i1480u_rx_buf *rx_buf = urb->context;
struct i1480u *i1480u = rx_buf->i1480u;
struct device *dev = &i1480u->usb_iface->dev;
unsigned long flags;
u8 rx_buf_idx = rx_buf - i1480u->rx_buf;
switch (urb->status) {
case 0:
break;
case -ECONNRESET: /* Not an error, but a controlled situation; */
case -ENOENT: /* (we killed the URB)...so, no broadcast */
case -ESHUTDOWN: /* going away! */
dev_err(dev, "RX URB[%u]: goind down %d\n",
rx_buf_idx, urb->status);
goto error;
default:
dev_err(dev, "RX URB[%u]: unknown status %d\n",
rx_buf_idx, urb->status);
if (edc_inc(&i1480u->rx_errors, EDC_MAX_ERRORS,
EDC_ERROR_TIMEFRAME)) {
dev_err(dev, "RX: max acceptable errors exceeded,"
" resetting device.\n");
i1480u_rx_unlink_urbs(i1480u);
wlp_reset_all(&i1480u->wlp);
goto error;
}
do_parse_buffer = 0;
break;
}
spin_lock_irqsave(&i1480u->lock, flags);
/* chew the data fragments, extract network packets */
if (do_parse_buffer) {
i1480u_rx_buffer(rx_buf);
if (rx_buf->data) {
rx_buf->urb->transfer_buffer = rx_buf->data->data;
result = usb_submit_urb(rx_buf->urb, GFP_ATOMIC);
if (result < 0) {
dev_err(dev, "RX URB[%u]: cannot submit %d\n",
rx_buf_idx, result);
}
}
}
spin_unlock_irqrestore(&i1480u->lock, flags);
error:
return;
}
