[PATCH net 05/13] net: stmmac: Enable ATDS for chain-mode

[Serge Semin]

It wasn't stated why the Alternate Descriptor Size shouldn't have been
changed for the chained DMA descriptors, while the original commit did
introduce some chain_mode.c modifications. So the ATDS-related change in
commit c24602ef8664 ("stmmac: support extend descriptors") seems
contradicting. Anyway from the DW MAC/GMAC hardware point of view there is
no such limitation - whether the chained descriptors can't be used
together with the extended alternate descriptors. Moreover not setting the
BUS_MODE.ATDS flag will cause the driver malfunction in the framework of
the IPC Full Checksum and Advanced Timestamp feature, since the later
features require the additional 4-7 dwords of the DMA descriptor to set
some flags and a timestamp. So to speak in order to have all these
features working correctly in the chained mode too let's make sure the
ATDS flag is set irrespectively from the DMA descriptors mode.

Fixes: c24602ef8664 ("stmmac: support extend descriptors")
Signed-off-by: Serge Semin <Sergey.Semin at baikalelectronics.ru>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 2ed63acaee5b..ee4297a25521 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -2907,7 +2907,6 @@ static int stmmac_init_dma_engine(struct stmmac_priv *priv)
 	struct stmmac_rx_queue *rx_q;
 	struct stmmac_tx_queue *tx_q;
 	u32 chan = 0;
-	int atds = 0;
 	int ret = 0;
 
 	if (!priv->plat->dma_cfg || !priv->plat->dma_cfg->pbl) {
@@ -2915,9 +2914,6 @@ static int stmmac_init_dma_engine(struct stmmac_priv *priv)
 		return -EINVAL;
 	}
 
-	if (priv->extend_desc && (priv->mode == STMMAC_RING_MODE))
-		atds = 1;
-
 	ret = stmmac_reset(priv, priv->ioaddr);
 	if (ret) {
 		dev_err(priv->device, "Failed to reset the dma\n");
@@ -2925,7 +2921,8 @@ static int stmmac_init_dma_engine(struct stmmac_priv *priv)
 	}
 
 	/* DMA Configuration */
-	stmmac_dma_init(priv, priv->ioaddr, priv->plat->dma_cfg, atds);
+	stmmac_dma_init(priv, priv->ioaddr, priv->plat->dma_cfg,
+			priv->extend_desc);
 
 	if (priv->plat->axi)
 		stmmac_axi(priv, priv->ioaddr, priv->plat->axi);
-- 
2.39.2