net: stmmac: add helper to get hardware transmit descriptor

Provide a helper to get the hardware transmit descriptor that takes
account of whether extended format and TBS are being used, returning
the base struct dma_desc pointer. This avoids multiple instances where
these tests are open coded.

We need to update dwmac4_display_ring() to cope the passed head
pointer always pointing at the struct dma_desc by using
dma_desc_to_edesc() to convert it to struct dma_edesc. This is the
only stmmac_display_ring() implementation that this affects.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/E1w1LWe-0000000DGSj-0KtE@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

0 files changed, 0 insertions, 0 deletions