nfp: support 48-bit DMA addressing for NFP3800

48-bit DMA addressing is supported in NFP3800 HW and implemented
in NFDK firmware, so enable this feature in driver now. Note that
with this change, NFD3 firmware, which doesn't implement 48-bit
DMA, cannot be used for NFP3800 any more.

RX free list descriptor, used by both NFD3 and NFDK, is also modified
to support 48-bit DMA. That's OK because the top bits is always get
set to 0 when assigned with 40-bit address.

Based on initial work of Jakub Kicinski <jakub.kicinski@netronome.com>.

Signed-off-by: Yinjun Zhang <yinjun.zhang@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

nfp: add support for NFDK data path

Add new data path. The TX is completely different, each packet
has multiple descriptor entries (between 2 and 32). TX ring is
divided into blocks 32 descriptor, and descritors of one packet
can't cross block bounds. The RX side is the same for now.

ABI version 5 or later is required. There is no support for
VLAN insertion on TX. XDP_TX action and AF_XDP zero-copy is not
implemented in NFDK path.

Changes to Jakub's work:
* Move statistics of hw_csum_tx after jumbo packet's segmentation.
* Set L3_CSUM flag to enable recaculating of L3 header checksum
in ipv4 case.
* Mark the case of TSO a packet with metadata prepended as
unsupported.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Xingfeng Hu <xingfeng.hu@corigine.com>
Signed-off-by: Yinjun Zhang <yinjun.zhang@corigine.com>
Signed-off-by: Dianchao Wang <dianchao.wang@corigine.com>
Signed-off-by: Fei Qin <fei.qin@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

nfp: move the fast path code to separate files

In preparation for support for a new datapath format move all
ring and fast path logic into separate files. It is basically
a verbatim move with some wrapping functions, no new structures
and functions added.

The current data path is called NFD3 from the initial version
of the driver ABI it used. The non-fast path, but ring related
functions are moved to nfp_net_dp.c file.

Changes to Jakub's work:
* Rebase on xsk related code.
* Split the patch, move the callback changes to next commit.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Fei Qin <fei.qin@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

nfp: xsk: add AF_XDP zero-copy Rx and Tx support

This patch adds zero-copy Rx and Tx support for AF_XDP sockets. It do so
by adding a separate NAPI poll function that is attached to a each
channel when the XSK socket is attached with XDP_SETUP_XSK_POOL, and
restored when the XSK socket is terminated, this is done per channel.

Support for XDP_TX is implemented and the XDP buffer can safely be moved
from the Rx to the Tx queue and correctly freed and returned to the XSK
pool once it's transmitted.

Note that when AF_XDP zero-copy is enabled, the XDP action XDP_PASS
will allocate a new buffer and copy the zero-copy frame prior
passing it to the kernel stack.

This patch is based on previous work by Jakub Kicinski.

Signed-off-by: Niklas Söderlund <niklas.soderlund@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>