1 files changed, 486 insertions, 0 deletions

diff --git a/drivers/uwb/i1480/i1480u-wlp/rx.c b/drivers/uwb/i1480/i1480u-wlp/rx.c
new file mode 100644
index 000000000000..9fc035354a76
--- /dev/null
+++ b/drivers/uwb/i1480/i1480u-wlp/rx.c
@@ -0,0 +1,486 @@
+/*
+ * 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/netdevice.h>
+#include <linux/etherdevice.h>
+#include "i1480u-wlp.h"
+
+#define D_LOCAL 0
+#include <linux/uwb/debug.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->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;
+
+        d_printf(6, dev, "RX delivered pre skb(%p), %u bytes\n",
+                 i1480u->rx_skb, i1480u->rx_skb->len);
+        d_dump(7, dev, i1480u->rx_skb->data, i1480u->rx_skb->len);
+        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);
+        d_printf(5, dev, "RX delivered skb(%p), %u bytes\n",
+                 i1480u->rx_skb, i1480u->rx_skb->len);
+        d_dump(7, dev, i1480u->rx_skb->data,
+               i1480u->rx_skb->len > 72 ? 72 : i1480u->rx_skb->len);
+        i1480u->stats.rx_packets++;
+        i1480u->stats.rx_bytes += i1480u->rx_untd_pkt_size;
+        net_dev->last_rx = jiffies;
+        /* FIXME: flow control: check netif_rx() retval */
+
+        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;
+}
+