/*
* 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);
i1480u->stats.tx_packets++;
i1480u->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);
} else {
frg_pl_size = pl_size_left;
untd_hdr_set_type(&untd_hdr_rst->hdr, i1480u_PKT_FRAG_LST);
}
untd_hdr_set_rx_tx(&untd_hdr_rst->hdr, 0);
untd_hdr_rst->hdr.len = cpu_to_le16(frg_pl_size);
untd_hdr_rst->padding = 0;
if (buf_itr + frg_pl_size - wtx->buf
> wtx->buf_size) {
printk(KERN_ERR "BUG: no space for payload\n");
goto error_bug;
}
memcpy(buf_itr, pl_itr, frg_pl_size);
buf_itr += frg_pl_size;
pl_itr += frg_pl_size;
pl_size_left -= frg_pl_size;
}
dev_kfree_skb_irq(skb);
return 0;
error_bug:
printk(KERN_ERR
"BUG: skb %u bytes\n"
"BUG: frg_pl_size %zd i1480u_MAX_FRG_SIZE %u\n"
"BUG: buf_itr %zu buf_size %zu pl_size_left %zu\n",
skb->len,
frg_pl_size, i1480u_MAX_FRG_SIZE,
buf_itr - wtx->buf, wtx->buf_size, pl_size_left);
kfree(wtx->buf);
error_buf_alloc:
return result;
}
/*
* Given a buffer that fits in a single fragment, fill out a @wtx
* struct for transmitting it down the USB pipe.
*
* Uses the fact that we have space reserved in front of the skbuff
* for hardware headers :]
*
* 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.
*
* @pl: pointer to payload data
* @pl_size: size of the payuload
*
* This function does not consume the @skb.
*/
static
int i1480u_tx_create_1(struct i1480u_tx *wtx, struct sk_buff *skb,
gfp_t gfp_mask)
{
struct untd_hdr_cmp *untd_hdr_cmp;
struct wlp_tx_hdr *wlp_tx_hdr;
wtx->buf = NULL;
wtx->skb = skb;
BUG_ON(skb_headroom(skb) < sizeof(*wlp_tx_hdr));
wlp_tx_hdr = (void *) __skb_push(skb, sizeof(*wlp_tx_hdr));
wtx->wlp_tx_hdr = wlp_tx_hdr;
BUG_ON(skb_headroom(skb) < sizeof(*untd_hdr_cmp));
untd_hdr_cmp = (void *) __skb_push(skb, sizeof(*untd_hdr_cmp));
untd_hdr_set_type(&untd_hdr_cmp->hdr, i1480u_PKT_FRAG_CMP);
untd_hdr_set_rx_tx(&untd_hdr_cmp->hdr, 0);
untd_hdr_cmp->hdr.len = cpu_to_le16(skb->len - sizeof(*untd_hdr_cmp));
untd_hdr_cmp->padding = 0;
return 0;
}
/*
* Given a skb to transmit, massage it to become palatable for the TX pipe
*
* This will break the buffer in chunks smaller than
* i1480u_MAX_FRG_SIZE 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 /
*
* Each fragment will be always smaller or equal to i1480u_MAX_FRG_SIZE.
*
* If the first fragment is smaller than i1480u_MAX_FRG_SIZE, then the
* following is composed:
*
* complete header \
* i1480 tx header | single fragment
* packet data /
*
* We were going to use s/g support, but because the interface is
* synch and at the end there is plenty of overhead to do it, it
* didn't seem that worth for data that is going to be smaller than
* one page.
*/
static
struct i1480u_tx *i1480u_tx_create(struct i1480u *i1480u,
struct sk_buff *skb, gfp_t gfp_mask)
{
int result;
struct usb_endpoint_descriptor *epd;
int usb_pipe;
unsigned long flags;
struct i1480u_tx *wtx;
const size_t pl_max_size =
i1480u_MAX_FRG_SIZE - sizeof(struct untd_hdr_cmp)
- sizeof(struct wlp_tx_hdr);
wtx = kmalloc(sizeof(*wtx), gfp_mask);
if (wtx == NULL)
goto error_wtx_alloc;
wtx->urb = usb_alloc_urb(0, gfp_mask);
if (wtx->urb == NULL)
goto error_urb_alloc;
epd = &i1480u->usb_iface->cur_altsetting->endpoint[2].desc;
usb_pipe = usb_sndbulkpipe(i1480u->usb_dev, epd->bEndpointAddress);
/* Fits in a single complete packet or need to split? */
if (skb->len > pl_max_size) {
result = i1480u_tx_create_n(wtx, skb, gfp_mask);
if (result < 0)
goto error_create;
usb_fill_bulk_urb(wtx->urb, i1480u->usb_dev, usb_pipe,
wtx->buf, wtx->buf_size, i1480u_tx_cb, wtx);
} else {
result = i1480u_tx_create_1(wtx, skb, gfp_mask);
if (result < 0)
goto error_create;
usb_fill_bulk_urb(wtx->urb, i1480u->usb_dev, usb_pipe,
skb->data, skb->len, i1480u_tx_cb, wtx);
}
spin_lock_irqsave(&i1480u->tx_list_lock, flags);
list_add(&wtx->list_node, &i1480u->tx_list);
spin_unlock_irqrestore(&i1480u->tx_list_lock, flags);
return wtx;
error_create:
kfree(wtx->urb);
error_urb_alloc:
kfree(wtx);
error_wtx_alloc:
return NULL;
}
/*
* Actual fragmentation and transmission of frame
*
* @wlp: WLP substack data structure
* @skb: To be transmitted
* @dst: Device address of destination
* @returns: 0 on success, <0 on failure
*
* This function can also be called directly (not just from
* hard_start_xmit), so we also check here if the interface is up before
* taking sending anything.
*/
int i1480u_xmit_frame(struct wlp *wlp, struct sk_buff *skb,
struct uwb_dev_addr *dst)
{
int result = -ENXIO;
struct i1480u *i1480u = container_of(wlp, struct i1480u, wlp);
struct device *dev = &i1480u->usb_iface->dev;
struct net_device *net_dev = i1480u->net_dev;
struct i1480u_tx *wtx;
struct wlp_tx_hdr *wlp_tx_hdr;
static unsigned char dev_bcast[2] = { 0xff, 0xff };
BUG_ON(i1480u->wlp.rc == NULL);
if ((net_dev->flags & IFF_UP) == 0)
goto out;
result = -EBUSY;
if (atomic_read(&i1480u->tx_inflight.count) >= i1480u->tx_inflight.max) {
netif_stop_queue(net_dev);
goto error_max_inflight;
}
result = -ENOMEM;
wtx = i1480u_tx_create(i1480u, skb, GFP_ATOMIC);
if (unlikely(wtx == NULL)) {
if (printk_ratelimit())
dev_err(dev, "TX: no memory for WLP TX URB,"
"dropping packet (in flight %d)\n",
atomic_read(&i1480u->tx_inflight.count));
netif_stop_queue(net_dev);
goto error_wtx_alloc;
}
wtx->i1480u = i1480u;
/* Fill out the i1480 header; @i1480u->def_tx_hdr read without
* locking. We do so because they are kind of orthogonal to
* each other (and thus not changed in an atomic batch).
* The ETH header is right after the WLP TX header. */
wlp_tx_hdr = wtx->wlp_tx_hdr;
*wlp_tx_hdr = i1480u->options.def_tx_hdr;
wlp_tx_hdr->dstaddr = *dst;
if (!memcmp(&wlp_tx_hdr->dstaddr, dev_bcast, sizeof(dev_bcast))
&& (wlp_tx_hdr_delivery_id_type(wlp_tx_hdr) & WLP_DRP)) {
/*Broadcast message directed to DRP host. Send as best effort
* on PCA. */
wlp_tx_hdr_set_delivery_id_type(wlp_tx_hdr, i1480u->options.pca_base_priority);
}
result = usb_submit_urb(wtx->urb, GFP_ATOMIC); /* Go baby */
if (result < 0) {
dev_err(dev, "TX: cannot submit URB: %d\n", result);
/* We leave the freeing of skb to calling function */
wtx->skb = NULL;
goto error_tx_urb_submit;
}
atomic_inc(&i1480u->tx_inflight.count);
net_dev->trans_start = jiffies;
return result;
error_tx_urb_submit:
i1480u_tx_destroy(i1480u, wtx);
error_wtx_alloc:
error_max_inflight:
out:
return result;
}
/*
* Transmit an skb Called when an skbuf has to be transmitted
*
* The skb is first passed to WLP substack to ensure this is a valid
* frame. If valid the device address of destination will be filled and
* the WLP header prepended to the skb. If this step fails we fake sending
* the frame, if we return an error the network stack will just keep trying.
*
* Broadcast frames inside a WSS needs to be treated special as multicast is
* not supported. A broadcast frame is sent as unicast to each member of the
* WSS - this is done by the WLP substack when it finds a broadcast frame.
* So, we test if the WLP substack took over the skb and only transmit it
* if it has not (been taken over).
*
* @net_dev->xmit_lock is held
*/
int i1480u_hard_start_xmit(struct sk_buff *skb, struct net_device *net_dev)
{
int result;
struct i1480u *i1480u = netdev_priv(net_dev);
struct device *dev = &i1480u->usb_iface->dev;
struct uwb_dev_addr dst;
if ((net_dev->flags & IFF_UP) == 0)
goto error;
result = wlp_prepare_tx_frame(dev, &i1480u->wlp, skb, &dst);
if (result < 0) {
dev_err(dev, "WLP verification of TX frame failed (%d). "
"Dropping packet.\n", result);
goto error;
} else if (result == 1) {
/* trans_start time will be set when WLP actually transmits
* the frame */
goto out;
}
result = i1480u_xmit_frame(&i1480u->wlp, skb, &dst);
if (result < 0) {
dev_err(dev, "Frame TX failed (%d).\n", result);
goto error;
}
return NETDEV_TX_OK;
error:
dev_kfree_skb_any(skb);
i1480u->stats.tx_dropped++;
out:
return NETDEV_TX_OK;
}
/*
* Called when a pkt transmission doesn't complete in a reasonable period
* Device reset may sleep - do it outside of interrupt context (delayed)
*/
void i1480u_tx_timeout(struct net_device *net_dev)
{
struct i1480u *i1480u = netdev_priv(net_dev);
wlp_reset_all(&i1480u->wlp);
}
void i1480u_tx_release(struct i1480u *i1480u)
{
unsigned long flags;
struct i1480u_tx *wtx, *next;
int count = 0, empty;
spin_lock_irqsave(&i1480u->tx_list_lock, flags);
list_for_each_entry_safe(wtx, next, &i1480u->tx_list, list_node) {
count++;
usb_unlink_urb(wtx->urb);
}
spin_unlock_irqrestore(&i1480u->tx_list_lock, flags);
count = count*10; /* i1480ut 200ms per unlinked urb (intervals of 20ms) */
/*
* We don't like this sollution too much (dirty as it is), but
* it is cheaper than putting a refcount on each i1480u_tx and
* i1480uting for all of them to go away...
*
* Called when no more packets can be added to tx_list
* so can i1480ut for it to be empty.
*/
while (1) {
spin_lock_irqsave(&i1480u->tx_list_lock, flags);
empty = list_empty(&i1480u->tx_list);
spin_unlock_irqrestore(&i1480u->tx_list_lock, flags);
if (empty)
break;
count--;
BUG_ON(count == 0);
msleep(20);
}
}
