[PATCH v1 2/3] net: bcmgenet: use optional max DMA burst size property

[matthias . bgg]

From: Matthias Brugger <mbrugger@xxxxxxxx>

Depending on the HW, the maximal usable DMA burst size can vary.
If not set accordingly a timeout in the transmit queue happens and no
package can be sent. Read to optional max-burst-sz property, if not
present, fallback to the standard value.

Signed-off-by: Matthias Brugger <mbrugger@xxxxxxxx>
---

 drivers/net/ethernet/broadcom/genet/bcmgenet.c | 13 +++++++++++--
 drivers/net/ethernet/broadcom/genet/bcmgenet.h |  1 +
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/genet/bcmgenet.c b/drivers/net/ethernet/broadcom/genet/bcmgenet.c
index 12cb77ef1081..a7bb822a6d83 100644
--- a/drivers/net/ethernet/broadcom/genet/bcmgenet.c
+++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.c
@@ -2576,7 +2576,8 @@ static int bcmgenet_init_dma(struct bcmgenet_priv *priv)
 	}
 
 	/* Init rDma */
-	bcmgenet_rdma_writel(priv, DMA_MAX_BURST_LENGTH, DMA_SCB_BURST_SIZE);
+	bcmgenet_rdma_writel(priv, priv->dma_max_burst_length,
+			     DMA_SCB_BURST_SIZE);
 
 	/* Initialize Rx queues */
 	ret = bcmgenet_init_rx_queues(priv->dev);
@@ -2589,7 +2590,8 @@ static int bcmgenet_init_dma(struct bcmgenet_priv *priv)
 	}
 
 	/* Init tDma */
-	bcmgenet_tdma_writel(priv, DMA_MAX_BURST_LENGTH, DMA_SCB_BURST_SIZE);
+	bcmgenet_tdma_writel(priv, priv->dma_max_burst_length,
+			     DMA_SCB_BURST_SIZE);
 
 	/* Initialize Tx queues */
 	bcmgenet_init_tx_queues(priv->dev);
@@ -3522,6 +3524,13 @@ static int bcmgenet_probe(struct platform_device *pdev)
 
 	clk_prepare_enable(priv->clk);
 
+	if (dn) {
+		of_property_read_u32(dn, "dma-burst-sz",
+				     &priv->dma_max_burst_length);
+	} else {
+		priv->dma_max_burst_length = DMA_MAX_BURST_LENGTH;
+	}
+
 	bcmgenet_set_hw_params(priv);
 
 	/* Mii wait queue */
diff --git a/drivers/net/ethernet/broadcom/genet/bcmgenet.h b/drivers/net/ethernet/broadcom/genet/bcmgenet.h
index 4a8fc03d82fd..897f356eb376 100644
--- a/drivers/net/ethernet/broadcom/genet/bcmgenet.h
+++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.h
@@ -663,6 +663,7 @@ struct bcmgenet_priv {
 	bool crc_fwd_en;
 
 	unsigned int dma_rx_chk_bit;
+	unsigned int dma_max_burst_length;
 
 	u32 msg_enable;
 
-- 
2.23.0