/*
* Receive a message with payloads from the USB bus into an skb
*
* @i2400mu: USB device descriptor
* @rx_skb: skb where to place the received message
*
* Deals with all the USB-specifics of receiving, dynamically
* increasing the buffer size if so needed. Returns the payload in the
* skb, ready to process. On a zero-length packet, we retry.
*
* On soft USB errors, we retry (until they become too frequent and
* then are promoted to hard); on hard USB errors, we reset the
* device. On other errors (skb realloacation, we just drop it and
* hope for the next invocation to solve it).
*
* Returns: pointer to the skb if ok, ERR_PTR on error.
* NOTE: this function might realloc the skb (if it is too small),
* so always update with the one returned.
* ERR_PTR() is < 0 on error.
* Will return NULL if it cannot reallocate -- this can be
* considered a transient retryable error.
*/
static
struct sk_buff *i2400mu_rx(struct i2400mu *i2400mu, struct sk_buff *rx_skb)
{
int result = 0;
struct device *dev = &i2400mu->usb_iface->dev;
int usb_pipe, read_size, rx_size, do_autopm;
struct usb_endpoint_descriptor *epd;
const size_t max_pkt_size = 512;
d_fnstart(4, dev, "(i2400mu %p)\n", i2400mu);
do_autopm = atomic_read(&i2400mu->do_autopm);
result = do_autopm ?
usb_autopm_get_interface(i2400mu->usb_iface) : 0;
if (result < 0) {
dev_err(dev, "RX: can't get autopm: %d\n", result);
do_autopm = 0;
}
epd = usb_get_epd(i2400mu->usb_iface, i2400mu->endpoint_cfg.bulk_in);
usb_pipe = usb_rcvbulkpipe(i2400mu->usb_dev, epd->bEndpointAddress);
retry:
rx_size = skb_end_pointer(rx_skb) - rx_skb->data - rx_skb->len;
if (unlikely(rx_size % max_pkt_size == 0)) {
rx_size -= 8;
d_printf(1, dev, "RX: rx_size adapted to %d [-8]\n", rx_size);
}
result = usb_bulk_msg(
i2400mu->usb_dev, usb_pipe, rx_skb->data + rx_skb->len,
rx_size, &read_size, 200);
usb_mark_last_busy(i2400mu->usb_dev);
switch (result) {
case 0:
if (read_size == 0)
goto retry; /* ZLP, just resubmit */
skb_put(rx_skb, read_size);
break;
case -EPIPE:
/*
* Stall -- maybe the device is choking with our
* requests. Clear it and give it some time. If they
* happen to often, it might be another symptom, so we
* reset.
*
* No error handling for usb_clear_halt(0; if it
* works, the retry works; if it fails, this switch
* does the error handling for us.
*/
if (edc_inc(&i2400mu->urb_edc,
10 * EDC_MAX_ERRORS, EDC_ERROR_TIMEFRAME)) {
dev_err(dev, "BM-CMD: too many stalls in "
"URB; resetting device\n");
goto do_reset;
}
usb_clear_halt(i2400mu->usb_dev, usb_pipe);
msleep(10); /* give the device some time */
goto retry;
case -EINVAL: /* while removing driver */
case -ENODEV: /* dev disconnect ... */
case -ENOENT: /* just ignore it */
case -ESHUTDOWN:
case -ECONNRESET:
break;
case -EOVERFLOW: { /* too small, reallocate */
struct sk_buff *new_skb;
rx_size = i2400mu_rx_size_grow(i2400mu);
if (rx_size <= (1 << 16)) /* cap it */
i2400mu->rx_size = rx_size;
else if (printk_ratelimit()) {
dev_err(dev, "BUG? rx_size up to %d\n", rx_size);
result = -EINVAL;
goto out;
}
skb_put(rx_skb, read_size);
new_skb = skb_copy_expand(rx_skb, 0, rx_size - rx_skb->len,
GFP_KERNEL);
if (new_skb == NULL) {
if (printk_ratelimit())
dev_err(dev, "RX: Can't reallocate skb to %d; "
"RX dropped\n", rx_size);
kfree_skb(rx_skb);
rx_skb = NULL;
goto out; /* drop it...*/
}
kfree_skb(rx_skb);
rx_skb = new_skb;
i2400mu->rx_size_cnt = 0;
i2400mu->rx_size_acc = i2400mu->rx_size;
d_printf(1, dev, "RX: size changed to %d, received %d, "
"copied %d, capacity %ld\n",
rx_size, read_size, rx_skb->len,
(long) (skb_end_pointer(new_skb) - new_skb->head));
goto retry;
}
/* In most cases, it happens due to the hardware scheduling a
* read when there was no data - unfortunately, we have no way
* to tell this timeout from a USB timeout. So we just ignore
* it. */
case -ETIMEDOUT:
dev_err(dev, "RX: timeout: %d\n", result);
result = 0;
break;
default: /* Any error */
if (edc_inc(&i2400mu->urb_edc,
EDC_MAX_ERRORS, EDC_ERROR_TIMEFRAME))
goto error_reset;
dev_err(dev, "RX: error receiving URB: %d, retrying\n", result);
goto retry;
}
out:
if (do_autopm)
usb_autopm_put_interface(i2400mu->usb_iface);
d_fnend(4, dev, "(i2400mu %p) = %p\n", i2400mu, rx_skb);
return rx_skb;
error_reset:
dev_err(dev, "RX: maximum errors in URB exceeded; "
"resetting device\n");
do_reset:
usb_queue_reset_device(i2400mu->usb_iface);
rx_skb = ERR_PTR(result);
goto out;
}
static
struct sk_buff *i2400mu_rx(struct i2400mu *i2400mu, struct sk_buff *rx_skb)
{
int result = 0;
struct device *dev = &i2400mu->usb_iface->dev;
int usb_pipe, read_size, rx_size, do_autopm;
struct usb_endpoint_descriptor *epd;
const size_t max_pkt_size = 512;
d_fnstart(4, dev, "(i2400mu %p)\n", i2400mu);
do_autopm = atomic_read(&i2400mu->do_autopm);
result = do_autopm ?
usb_autopm_get_interface(i2400mu->usb_iface) : 0;
if (result < 0) {
dev_err(dev, "RX: can't get autopm: %d\n", result);
do_autopm = 0;
}
epd = usb_get_epd(i2400mu->usb_iface, i2400mu->endpoint_cfg.bulk_in);
usb_pipe = usb_rcvbulkpipe(i2400mu->usb_dev, epd->bEndpointAddress);
retry:
rx_size = skb_end_pointer(rx_skb) - rx_skb->data - rx_skb->len;
if (unlikely(rx_size % max_pkt_size == 0)) {
rx_size -= 8;
d_printf(1, dev, "RX: rx_size adapted to %d [-8]\n", rx_size);
}
result = usb_bulk_msg(
i2400mu->usb_dev, usb_pipe, rx_skb->data + rx_skb->len,
rx_size, &read_size, 200);
usb_mark_last_busy(i2400mu->usb_dev);
switch (result) {
case 0:
if (read_size == 0)
goto retry; /* */
skb_put(rx_skb, read_size);
break;
case -EPIPE:
/*
*/
if (edc_inc(&i2400mu->urb_edc,
10 * EDC_MAX_ERRORS, EDC_ERROR_TIMEFRAME)) {
dev_err(dev, "BM-CMD: too many stalls in "
"URB; resetting device\n");
goto do_reset;
}
usb_clear_halt(i2400mu->usb_dev, usb_pipe);
msleep(10); /* */
goto retry;
case -EINVAL: /* */
case -ENODEV: /* */
case -ENOENT: /* */
case -ESHUTDOWN:
case -ECONNRESET:
break;
case -EOVERFLOW: { /* */
struct sk_buff *new_skb;
rx_size = i2400mu_rx_size_grow(i2400mu);
if (rx_size <= (1 << 16)) /* */
i2400mu->rx_size = rx_size;
else if (printk_ratelimit()) {
dev_err(dev, "BUG? rx_size up to %d\n", rx_size);
result = -EINVAL;
goto out;
}
skb_put(rx_skb, read_size);
new_skb = skb_copy_expand(rx_skb, 0, rx_size - rx_skb->len,
GFP_KERNEL);
if (new_skb == NULL) {
if (printk_ratelimit())
dev_err(dev, "RX: Can't reallocate skb to %d; "
"RX dropped\n", rx_size);
kfree_skb(rx_skb);
rx_skb = NULL;
goto out; /* */
}
kfree_skb(rx_skb);
rx_skb = new_skb;
i2400mu->rx_size_cnt = 0;
i2400mu->rx_size_acc = i2400mu->rx_size;
d_printf(1, dev, "RX: size changed to %d, received %d, "
"copied %d, capacity %ld\n",
rx_size, read_size, rx_skb->len,
(long) (skb_end_pointer(new_skb) - new_skb->head));
goto retry;
}
/*
*/
case -ETIMEDOUT:
dev_err(dev, "RX: timeout: %d\n", result);
result = 0;
break;
default: /* */
if (edc_inc(&i2400mu->urb_edc,
EDC_MAX_ERRORS, EDC_ERROR_TIMEFRAME))
goto error_reset;
dev_err(dev, "RX: error receiving URB: %d, retrying\n", result);
goto retry;
}
out:
if (do_autopm)
usb_autopm_put_interface(i2400mu->usb_iface);
d_fnend(4, dev, "(i2400mu %p) = %p\n", i2400mu, rx_skb);
return rx_skb;
error_reset:
dev_err(dev, "RX: maximum errors in URB exceeded; "
"resetting device\n");
do_reset:
usb_queue_reset_device(i2400mu->usb_iface);
rx_skb = ERR_PTR(result);
goto out;
}
