This patch enables 'can_dma_sg' flag for ax88179_178a device
if the attached host controller supports building packet from
discontinuous buffers(DMA SG is possible), so TSO can be enabled
and skb fragment buffers can be passed to usb stack via urb->sg
directly.

With the patch, system CPU utilization decreased ~50% and throughput
increased by ~10% when doing iperf client test on one ARM A15 dual
core board.

Cc: Ben Hutchings <bhutchings@solarflare.com>
Cc: Grant Grundler <grundler@google.com>
Cc: Oliver Neukum <oneukum@suse.de>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Freddy Xin <freddy@asix.com.tw>
Signed-off-by: NMing Lei <ming.lei@canonical.com>
Acked-by: NEric Dumazet <edumazet@gmail.com>
Acked-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

usbnet doesn't support yet SG, so drivers should not advertise SG or TSO
capabilities, as they allow TCP stack to build large TSO packets that
need to be linearized and might use order-5 pages.

This adds an extra copy overhead and possible allocation failures.

Current code ignore skb_linearize() return code so crashes are even
possible.

Best is to not pretend SG/TSO is supported, and add this again when/if
usbnet really supports SG for devices who could get a performance gain.

Based on a prior patch from Freddy Xin <freddy@asix.com.tw>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

I tested with the AX88179 usb dongle, if without .reset_resume hook,
after S3/S4 resume you have to enable network interface or reload the
dirver module manually otherwise the network interface can not work.
Signed-off-by: NDavid Chang <dchang@suse.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Correct a typo in description of driver_info, it should be Gigabit
Signed-off-by: NDavid Chang <dchang@suse.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use usbnet_link_change to handle link change centrally.
Signed-off-by: NMing Lei <ming.lei@canonical.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This is a resubmission.
Added kfree() in ax88179_get_eeprom to prevent memory leakage.
Modified "__le16 rxctl" to "u16 rxctl" in "struct ax88179_data" and removed pointless casts.
Removed asix_init and asix_exit functions and added "module_usb_driver(ax88179_178a_driver)".
Fixed endianness issue on big endian systems and verified this driver on iBook G4.
Removed steps that change net->features in ax88179_set_features function.
Added "const" to ethtool_ops structure and fixed the coding style of AX88179_BULKIN_SIZE array.
Fixed the issue that the default MTU is not 1500.
Added ax88179_change_mtu function and enabled the hardware jumbo frame function to support an
MTU higher than 1500.
Fixed indentation and empty line coding style errors.
The _nopm version usb functions were added to access register in suspend and resume functions.
Serveral variables allocted dynamically were removed and replaced by stack variables.
ax88179_get_eeprom were modified from asix_get_eeprom in asix_common.

This patch adds a driver for ASIX's AX88179 family of USB 3.0/2.0
to gigabit ethernet adapters. It's based on the AX88xxx driver but
the usb commands used to access registers for AX88179 are completely different.
This driver had been verified on x86 system with AX88179/AX88178A and
Sitcomm LN-032 USB dongles.
Signed-off-by: NFreddy Xin <freddy@asix.com.tw>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>