[PATCH 4/7] net: stmmac: Parse FIFO sizes from feature registers

[Thierry Reding]

From: Thierry Reding <treding@xxxxxxxxxx>

New version of this core encode the FIFO sizes in one of the feature
registers. Use these sizes as default, but still allow device tree to
override them for backwards compatibility.

Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
---
 drivers/net/ethernet/stmicro/stmmac/common.h      | 3 +++
 drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c  | 2 ++
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 3 +++
 3 files changed, 8 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/common.h b/drivers/net/ethernet/stmicro/stmmac/common.h
index 144fe84e8a53..6ac653845d82 100644
--- a/drivers/net/ethernet/stmicro/stmmac/common.h
+++ b/drivers/net/ethernet/stmicro/stmmac/common.h
@@ -324,6 +324,9 @@ struct dma_features {
 	unsigned int number_tx_queues;
 	/* Alternate (enhanced) DESC mode */
 	unsigned int enh_desc;
+	/* TX and RX FIFO sizes */
+	unsigned int tx_fifo_size;
+	unsigned int rx_fifo_size;
 };
 
 /* GMAC TX FIFO is 8K, Rx FIFO is 16K */
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c b/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c
index 377d1b44d4f2..8d249f3b34c8 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c
@@ -296,6 +296,8 @@ static void dwmac4_get_hw_feature(void __iomem *ioaddr,
 	hw_cap = readl(ioaddr + GMAC_HW_FEATURE1);
 	dma_cap->av = (hw_cap & GMAC_HW_FEAT_AVSEL) >> 20;
 	dma_cap->tsoen = (hw_cap & GMAC_HW_TSOEN) >> 18;
+	dma_cap->tx_fifo_size = 128 << ((hw_cap >> 6) & 0x1f);
+	dma_cap->rx_fifo_size = 128 << ((hw_cap >> 0) & 0x1f);
 	/* MAC HW feature2 */
 	hw_cap = readl(ioaddr + GMAC_HW_FEATURE2);
 	/* TX and RX number of channels */
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index d7387919bdb6..291e34f0ca94 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -1281,6 +1281,9 @@ static void stmmac_dma_operation_mode(struct stmmac_priv *priv)
 {
 	int rxfifosz = priv->plat->rx_fifo_size;
 
+	if (rxfifosz == 0)
+		rxfifosz = priv->dma_cap.rx_fifo_size;
+
 	if (priv->plat->force_thresh_dma_mode)
 		priv->hw->dma->dma_mode(priv->ioaddr, tc, tc, rxfifosz);
 	else if (priv->plat->force_sf_dma_mode || priv->plat->tx_coe) {
-- 
2.11.1