[PATCH 07/14] net: dwc_eth_qos: Allow platform to override tx/rx_fifo_sz

[Sumit Garg]

The GMAC controller on QCS404 SoC (support added by upcoming patch) fails
to work with maximum tx/rx_fifo_sz supported by the hardware (16K). So
allow platforms to override FIFO size using corresponding DT node
properties.

Signed-off-by: Sumit Garg <sumit.garg at linaro.org>
---
 drivers/net/dwc_eth_qos.c | 19 +++++++++++++------
 drivers/net/dwc_eth_qos.h |  1 +
 2 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/drivers/net/dwc_eth_qos.c b/drivers/net/dwc_eth_qos.c
index 753a912607..65b8556be2 100644
--- a/drivers/net/dwc_eth_qos.c
+++ b/drivers/net/dwc_eth_qos.c
@@ -852,12 +852,19 @@ static int eqos_start(struct udevice *dev)
 	rx_fifo_sz = (val >> EQOS_MAC_HW_FEATURE1_RXFIFOSIZE_SHIFT) &
 		EQOS_MAC_HW_FEATURE1_RXFIFOSIZE_MASK;
 
-	/*
-	 * r/tx_fifo_sz is encoded as log2(n / 128). Undo that by shifting.
-	 * r/tqs is encoded as (n / 256) - 1.
-	 */
-	tqs = (128 << tx_fifo_sz) / 256 - 1;
-	rqs = (128 << rx_fifo_sz) / 256 - 1;
+	/* r/tx_fifo_sz is encoded as log2(n / 128). Undo that by shifting */
+	tx_fifo_sz = 128 << tx_fifo_sz;
+	rx_fifo_sz = 128 << rx_fifo_sz;
+
+	/* Allow platform to override TX/RX fifo size */
+	if (eqos->tx_fifo_sz)
+		tx_fifo_sz = eqos->tx_fifo_sz;
+	if (eqos->rx_fifo_sz)
+		rx_fifo_sz = eqos->rx_fifo_sz;
+
+	/* r/tqs is encoded as (n / 256) - 1 */
+	tqs = tx_fifo_sz / 256 - 1;
+	rqs = rx_fifo_sz / 256 - 1;
 
 	clrsetbits_le32(&eqos->mtl_regs->txq0_operation_mode,
 			EQOS_MTL_TXQ0_OPERATION_MODE_TQS_MASK <<
diff --git a/drivers/net/dwc_eth_qos.h b/drivers/net/dwc_eth_qos.h
index 8fccd6f057..466a792de7 100644
--- a/drivers/net/dwc_eth_qos.h
+++ b/drivers/net/dwc_eth_qos.h
@@ -276,6 +276,7 @@ struct eqos_priv {
 	bool started;
 	bool reg_access_ok;
 	bool clk_ck_enabled;
+	unsigned int tx_fifo_sz, rx_fifo_sz;
 };
 
 void eqos_inval_desc_generic(void *desc);
-- 
2.34.1