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/*
* WUSB Wire Adapter: WLP interface
* Deal with TX (massaging data to transmit, handling it)
*
* 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.
*
*
* Transmission engine. Get an skb, create from that a WLP transmit
* context, add a WLP TX header (which we keep prefilled in the
* device's instance), fill out the target-specific fields and
* fire it.
*
* ROADMAP:
*
* Entry points:
*
* i1480u_tx_release(): called by i1480u_disconnect() to release
* pending tx contexts.
*
* i1480u_tx_cb(): callback for TX contexts (USB URBs)
* i1480u_tx_destroy():
*
* i1480u_tx_timeout(): called for timeout handling from the
* network stack.
*
* i1480u_hard_start_xmit(): called for transmitting an skb from
* the network stack. Will interact with WLP
* substack to verify and prepare frame.
* i1480u_xmit_frame(): actual transmission on hardware
*
* i1480u_tx_create() Creates TX context
* i1480u_tx_create_1() For packets in 1 fragment
* i1480u_tx_create_n() For packets in >1 fragments
*
* TODO:
*
* - FIXME: rewrite using usb_sg_*(), add asynch support to
* usb_sg_*(). It might not make too much sense as most of
* the times the MTU will be smaller than one page...
*/
#include "i1480u-wlp.h"
enum {
/* This is only for Next and Last TX packets */
i1480u_MAX_PL_SIZE = i1480u_MAX_FRG_SIZE
- sizeof(struct untd_hdr_rst),
};
/* Free resources allocated to a i1480u tx context. */
static
void i1480u_tx_free(struct i1480u_tx *wtx)
{
kfree(wtx->buf);
if (wtx->skb)
dev_kfree_skb_irq(wtx->skb);
usb_free_urb(wtx->urb);
kfree(wtx);
}
static
void i1480u_tx_destroy(struct i1480u *i1480u, struct i1480u_tx *wtx)
{
unsigned long flags;
spin_lock_irqsave(&i1480u->tx_list_lock, flags); /* not active any more */
list_del(&wtx->list_node);
i1480u_tx_free(wtx);
spin_unlock_irqrestore(&i1480u->tx_list_lock, flags);
}
static
void i1480u_tx_unlink_urbs(struct i1480u *i1480u)
{
unsigned long flags;
struct i1480u_tx *wtx, *next;
spin_lock_irqsave(&i1480u->tx_list_lock, flags);
list_for_each_entry_safe(wtx, next, &i1480u->tx_list, list_node) {
usb_unlink_urb(wtx->urb);
}
spin_unlock_irqrestore(&i1480u->tx_list_lock, flags);
}
/*
* Callback for a completed tx USB URB.
*
* TODO:
*
* - FIXME: recover errors more gracefully
* - FIXME: handle NAKs (I dont think they come here) for flow ctl
*/
static
void i1480u_tx_cb(struct urb *urb)
{
struct i1480u_tx *wtx = urb->context;
struct i1480u *i1480u = wtx->i1480u;
struct net_device *net_dev = i1480u->net_dev;
struct device *dev = &i1480u->usb_iface->dev;
unsigned long flags;
switch (urb->status) {
case 0:
spin_lock_irqsave(&i1480u->lock, flags);
net_dev->stats.tx_packets++;
net_dev->stats.tx_bytes += urb->actual_length;
spin_unlock_irqrestore(&i1480u->lock, flags);
break;
case -ECONNRESET: /* Not an error, but a controlled situation; */
case -ENOENT: /* (we killed the URB)...so, no broadcast */
dev_dbg(dev, "notif endp: reset/noent %d\n", urb->status);
netif_stop_queue(net_dev);
break;
case -ESHUTDOWN: /* going away! */
dev_dbg(dev, "notif endp: down %d\n", urb->status);
netif_stop_queue(net_dev);
break;
default:
dev_err(dev, "TX: unknown URB status %d\n", urb->status);
if (edc_inc(&i1480u->tx_errors, EDC_MAX_ERRORS,
EDC_ERROR_TIMEFRAME)) {
dev_err(dev, "TX: max acceptable errors exceeded."
"Reset device.\n");
netif_stop_queue(net_dev);
i1480u_tx_unlink_urbs(i1480u);
wlp_reset_all(&i1480u->wlp);
}
break;
}
i1480u_tx_destroy(i1480u, wtx);
if (atomic_dec_return(&i1480u->tx_inflight.count)
<= i1480u->tx_inflight.threshold
&& netif_queue_stopped(net_dev)
&& i1480u->tx_inflight.threshold != 0) {
netif_start_queue(net_dev);
atomic_inc(&i1480u->tx_inflight.restart_count);
}
return;
}
/*
* Given a buffer that doesn't fit in a single fragment, create an
* scatter/gather structure for delivery to the USB pipe.
*
* Implements functionality of i1480u_tx_create().
*
* @wtx: tx descriptor
* @skb: skb to send
* @gfp_mask: gfp allocation mask
* @returns: Pointer to @wtx if ok, NULL on error.
*
* Sorry, TOO LONG a function, but breaking it up is kind of hard
*
* This will break the buffer in chunks smaller than
* i1480u_MAX_FRG_SIZE (including the header) and add proper headers
* to each:
*
* 1st header \
* i1480 tx header | fragment 1
* fragment data /
* nxt header \ fragment 2
* fragment data /
* ..
* ..
* last header \ fragment 3
* last fragment data /
*
* This does not fill the i1480 TX header, it is left up to the
* caller to do that; you can get it from @wtx->wlp_tx_hdr.
*
* This function consumes the skb unless there is an error.
*/
static
int i1480u_tx_create_n(struct i1480u_tx *wtx, struct sk_buff *skb,
gfp_t gfp_mask)
{
int result;
void *pl;
size_t pl_size;
void *pl_itr, *buf_itr;
size_t pl_size_left, frgs, pl_size_1st, frg_pl_size = 0;
struct untd_hdr_1st *untd_hdr_1st;
struct wlp_tx_hdr *wlp_tx_hdr;
struct untd_hdr_rst *untd_hdr_rst;
wtx->skb = NULL;
pl = skb->data;
pl_itr = pl;
pl_size = skb->len;
pl_size_left = pl_size; /* payload size */
/* First fragment; fits as much as i1480u_MAX_FRG_SIZE minus
* the headers */
pl_size_1st = i1480u_MAX_FRG_SIZE
- sizeof(struct untd_hdr_1st) - sizeof(struct wlp_tx_hdr);
BUG_ON(pl_size_1st > pl_size);
pl_size_left -= pl_size_1st;
/* The rest have an smaller header (no i1480 TX header). We
* need to break up the payload in blocks smaller than
* i1480u_MAX_PL_SIZE (payload excluding header). */
frgs = (pl_size_left + i1480u_MAX_PL_SIZE - 1) / i1480u_MAX_PL_SIZE;
/* Allocate space for the new buffer. In this new buffer we'll
* place the headers followed by the data fragment, headers,
* data fragments, etc..
*/
result = -ENOMEM;
wtx->buf_size = sizeof(*untd_hdr_1st)
+ sizeof(*wlp_tx_hdr)
+ frgs * sizeof(*untd_hdr_rst)
+ pl_size;
wtx->buf = kmalloc(wtx->buf_size, gfp_mask);
if (wtx->buf == NULL)
goto error_buf_alloc;
buf_itr = wtx->buf; /* We got the space, let's fill it up */
/* Fill 1st fragment */
untd_hdr_1st = buf_itr;
buf_itr += sizeof(*untd_hdr_1st);
untd_hdr_set_type(&untd_hdr_1st->hdr, i1480u_PKT_FRAG_1ST);
untd_hdr_set_rx_tx(&untd_hdr_1st->hdr, 0);
untd_hdr_1st->hdr.len = cpu_to_le16(pl_size + sizeof(*wlp_tx_hdr));
untd_hdr_1st->fragment_len =
cpu_to_le16(pl_size_1st + sizeof(*wlp_tx_hdr));
memset(untd_hdr_1st->padding, 0, sizeof(untd_hdr_1st->padding));
/* Set up i1480 header info */
wlp_tx_hdr = wtx->wlp_tx_hdr = buf_itr;
buf_itr += sizeof(*wlp_tx_hdr);
/* Copy the first fragment */
memcpy(buf_itr, pl_itr, pl_size_1st);
pl_itr += pl_size_1st;
buf_itr += pl_size_1st;
/* Now do each remaining fragment */
result = -EINVAL;
while (pl_size_left > 0) {
if (buf_itr + sizeof(*untd_hdr_rst) - wtx->buf
> wtx->buf_size) {
printk(KERN_ERR "BUG: no space for header\n");
goto error_bug;
}
untd_hdr_rst = buf_itr;
buf_itr += sizeof(*untd_hdr_rst);
if (pl_size_left > i1480u_MAX_PL_SIZE) {
frg_pl_size = i1480u_MAX_PL_SIZE;
untd_hdr_set_type(&untd_hdr_rst->hdr, i1480u_PKT_FRAG_NXT
|