[PATCH net-next v2 14/18] 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
designcfg_debug6/GEM_DCFG6. Allow disabling that feature if it is
broken by using struct macb_config->caps.

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 | 6 ++++--
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/cadence/macb.h b/drivers/net/ethernet/cadence/macb.h
index d42c81cf441ce435cad38e2dfd779b0e6a141bf3..e5de6549861965e2823044d81b6abc20d2b27ceb 100644
--- a/drivers/net/ethernet/cadence/macb.h
+++ b/drivers/net/ethernet/cadence/macb.h
@@ -736,6 +736,7 @@
 #define MACB_CAPS_NEED_TSUCLK			BIT(10)
 #define MACB_CAPS_QUEUE_DISABLE			BIT(11)
 #define MACB_CAPS_RSC_CAPABLE			BIT(12)
+#define MACB_CAPS_NO_LSO			BIT(13)
 #define MACB_CAPS_PCS				BIT(24)
 #define MACB_CAPS_HIGH_SPEED			BIT(25)
 #define MACB_CAPS_CLK_HW_CHG			BIT(26)
diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index 34223dad2d01ae4bcefc0823c868a67f59435638..f9a3a5caebcafe3d9197a3bc7681b64734d7ac93 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -4346,8 +4346,10 @@ 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 */

-- 
2.50.0