When timestamping is enabled, stmmac_tx_clean will call
stmmac_get_tx_hwtstamp to get tx TS.
But the skb can be NULL because the last of its tx_skbuff is NULL
if this packet frame is filled in more than one descriptors.

To fix the issue, change the code:
- Store TX skb to the tx_skbuff[] of frame's last segment.
- Check skb is not NULL in stmmac_get_tx_hwtstamp.
Signed-off-by: NBruce Liu <damuzi000@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch fixed the condition of extend_desc for jumbo frame.
There is no check routine for extend_desc in the stmmac_jumbo_frm function.
Even though extend_desc is set if dma_tx is used instead of dma_etx.
It causes kernel panic.
Signed-off-by: NByungho An <bh74.an@samsung.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch tidies up the code. I have run Linden (and verified with checkpatch)
many part of the driver trying to reorganize some sections respecting the
codying-style rules in the points where it was not done.
Signed-off-by: NGiuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch enhances the stmmac driver to support IEEE 1588-2002
PTP (Precision Time Protocol) version 1 and IEEE 1588-2008 PPT
version 2.

Precision Time Protocol(PTP),which enables precise synchronization
of clocks in measurement and control systems implemented with
technologies such as network communication,local computing,
& distributed objects.

Both PTPv1 and PTPv2 is selected at run-time using the HW capability
register.

The PTPv1 TimeStamp support can be used on chips that have the normal
descriptor structures and PTPv2 TimeStamp support can be used on chips
that have the Extended descriptors(DES4-5-6-7). All such sanity checks
are done and verified by using HW capability register.

V2: in this version the ethtool support has been included in this patch;
Koptions have been completely removed (previously added to select
PTP and PTPv2). PTPv1 and PTPv2 is now added in a single patch instead of
two patches.
get_timestamp() and get_systemtime() L/H have been combined into single APIs.
Signed-off-by: NRayagond Kokatanur <rayagond@vayavyalabs.com>
Signed-off-by: NGiuseppe Cavallaro <peppe.cavallaro@st.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch adds a new pointer variable called "tx_skbuff_dma" to private
data structure. This variable will holds the physical address of packet
to be transmitted & same will be used to free/unmap the memory once the
corresponding packet is transmitted by device.

Prior to this patch the descriptor buffer pointer(ie des2) itself was
being used for freeing/unmapping the buffer memory. But in case PTP v1
with normal descriptor the field(des2) will be overwritten by device
with timestamp value, hence driver will loose the buffer pointer to be
freed/unmapped.
Signed-off-by: NRayagond Kokatanur <rayagond@vayavyalabs.com>
Acked-by: NGiuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Previously we had two Koptions to decide if the stmmac
had to use either a ring or a chain to manage its descriptors.
This patch removes the Kernel configuration options and it allow us
to use the chain mode by passing a module option.
Ring mode continues to be the default.

Also with this patch, it will be easier to validate the driver built and
guarantee that all the two modes always compile fine.
Signed-off-by: NGiuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

For the higher mtu sizes requiring the buffer size greater than 8192,
the buffers are sent or received using multiple dma descriptors/ same
descriptor with option of multi buffer handling.
It was observed during tests that the driver was missing on data
packets during the normal ping operations if the data buffers being used
catered to jumbo frame handling.

The memory barrriers are added in between preparation of dma descriptors
in the jumbo frame handling path to ensure all instructions before
enabling the dma are complete.
Signed-off-by: NDeepak Sikri <deepak.sikri@st.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch enhances the STMMAC driver to support CHAINED mode of
descriptor.

STMMAC supports DMA descriptor to operate both in dual buffer(RING)
and linked-list(CHAINED) mode. In RING mode (default) each descriptor
points to two data buffer pointers whereas in CHAINED mode they point
to only one data buffer pointer.

In CHAINED mode each descriptor will have pointer to next descriptor in
the list, hence creating the explicit chaining in the descriptor itself,
whereas such explicit chaining is not possible in RING mode.

First version of this work has been done by Rayagond.
Then the patch has been reworked avoiding ifdef inside the C code.
A new header file has been added to define all the functions needed for
managing enhanced and normal descriptors.
In fact, these have to be specialized according to the ring/chain usage.
Two new C files have been also added to implement the helper routines
needed to manage: jumbo frames, chain and ring setup (i.e. desc3).
Signed-off-by: NRayagond Kokatanur <rayagond@vayavyalabs.com>
Signed-off-by: NGiuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>