[PATCH net-next v3 3/5] net: macb: add no LSO capability (MACB_CAPS_NO_LSO)

["Théo Lebrun" <theo.lebrun@bootlin.com>]

LSO is runtime-detected using the PBUF_LSO field inside register DCFG6.
Allow disabling that feature if it is broken by using bp->caps coming
from match data.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
---
 drivers/net/ethernet/cadence/macb.h      | 1 +
 drivers/net/ethernet/cadence/macb_main.c | 7 +++++--
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/cadence/macb.h b/drivers/net/ethernet/cadence/macb.h
index 93e8dd092313..05bfa9bd4782 100644
--- a/drivers/net/ethernet/cadence/macb.h
+++ b/drivers/net/ethernet/cadence/macb.h
@@ -778,6 +778,7 @@
 #define MACB_CAPS_DMA_64B			BIT(21)
 #define MACB_CAPS_DMA_PTP			BIT(22)
 #define MACB_CAPS_RSC				BIT(23)
+#define MACB_CAPS_NO_LSO			BIT(24)
 
 /* LSO settings */
 #define MACB_LSO_UFO_ENABLE			0x01
diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index be3d0c2313a1..8b688a6cb2f9 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -4564,8 +4564,11 @@ static int macb_init(struct platform_device *pdev)
 	/* Set features */
 	dev->hw_features = NETIF_F_SG;
 
-	/* Check LSO capability */
-	if (GEM_BFEXT(PBUF_LSO, gem_readl(bp, DCFG6)))
+	/* Check LSO capability; runtime detection can be overridden by a cap
+	 * flag if the hardware is known to be buggy
+	 */
+	if (!(bp->caps & MACB_CAPS_NO_LSO) &&
+	    GEM_BFEXT(PBUF_LSO, gem_readl(bp, DCFG6)))
 		dev->hw_features |= MACB_NETIF_LSO;
 
 	/* Checksum offload is only available on gem with packet buffer */

-- 
2.51.1