This patch makes the private functions alloc_can_skb() and
alloc_can_err_skb() of the at91_can driver public and adapts all
drivers to use these. While making the patch I realized, that
the skb's are *not* setup consistently. It's now done as shown
below:

  skb->protocol = htons(ETH_P_CAN);
  skb->pkt_type = PACKET_BROADCAST;
  skb->ip_summed = CHECKSUM_UNNECESSARY;
  *cf = (struct can_frame *)skb_put(skb, sizeof(struct can_frame));
  memset(*cf, 0, sizeof(struct can_frame));

The frame is zeroed out to avoid uninitialized data to be passed to
user space. Some drivers or library code did not set "pkt_type" or
"ip_summed". Also,  "__constant_htons()" should not be used for
runtime invocations, as pointed out by David Miller.
Signed-off-by: NWolfgang Grandegger <wg@grandegger.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch allows the CAN controller driver to define the number of echo
skb's used for the local loopback (echo), as suggested by Kurt Van
Dijck, with the function:

  struct net_device *alloc_candev(int sizeof_priv,
                                  unsigned int echo_skb_max);

The CAN drivers have been adapted accordingly. For the ems_usb driver,
as suggested by Sebastian Haas, the number of echo skb's has been
increased to 10, which improves the transmission performance a lot.
Signed-off-by: NWolfgang Grandegger <wg@grandegger.com>
Signed-off-by: NKurt Van Dijck <kurt.van.dijck@eia.be>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch adds the function can_free_echo_skb to the CAN
device interface to allow upcoming drivers to release echo
skb's in case of error.
Signed-off-by: NWolfgang Grandegger <wg@grandegger.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The generic packet receive code takes care of setting
netdev->last_rx when necessary, for the sake of the
bonding ARP monitor.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Acked-by: NNeil Horman <nhorman@txudriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

For 'real' hardware CAN devices the netlink interface is used to set CAN
specific communication parameters. Real CAN hardware can not be created with
the ip tool ...

The invocation of 'ip link add type can' lead to an oops as the standard rtnl
newlink function was called:

http://bugzilla.kernel.org/show_bug.cgi?id=13954

This patch adds a private newlink function for the CAN device driver interface
that unconditionally returns -EOPNOTSUPP.
Signed-off-by: NOliver Hartkopp <oliver@hartkopp.net>
Reported-by: NDmitry Eremin-Solenikov <dbaryshkov@gmail.com>
CC: Patrick McHardy <kaber@trash.net>
CC: Wolfgang Grandegger <wg@grandegger.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch fixes a problem when a device is stopped while in the
bus-off state. Then the carrier remains off forever.
Signed-off-by: NKurt Van Dijck <kurt.van.dijck@skynet.be>
Signed-off-by: NWolfgang Grandegger <wg@grandegger.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If dev_alloc_skb() failed in can_restart(), the device was left behind
in the bus-off state. This patch restarts the device nevertheless.
Signed-off-by: NKurt Van Dijck <kurt.van.dijck@eia.be>
Signed-off-by: NWolfgang Grandegger <wg@grandegger.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch fixes a few errors sneaked into the initial version of the
device driver interface.
Signed-off-by: NWolfgang Grandegger <wg@grandegger.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The CAN network device driver interface provides a generic interface to
setup, configure and monitor CAN network devices. It exports a set of
common data structures and functions, which all real CAN network device
drivers should use. Please have a look to the SJA1000 or MSCAN driver
to understand how to use them. The name of the module is can-dev.ko.

Furthermore, it adds a Netlink interface allowing to configure the CAN
device using the program "ip" from the iproute2 utility suite.

For further information please check "Documentation/networking/can.txt"
Signed-off-by: NWolfgang Grandegger <wg@grandegger.com>
Signed-off-by: NOliver Hartkopp <oliver.hartkopp@volkswagen.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>