[U-Boot] [PATCH] net/macb: increase RX buffer size for GEM

[Ramon Fried]

Macb Ethernet controller requires a RX buffer of 128 bytes. It is
highly sub-optimal for Gigabit-capable GEM that is able to use
a bigger DMA buffer. Change this constant and associated macros
with data stored in the private structure.
RX DMA buffer size has to be multiple of 64 bytes as indicated in
DMA Configuration Register specification.

Signed-off-by: Ramon Fried <rfried.dev at gmail.com>
---
 drivers/net/macb.c | 29 +++++++++++++++++++++--------
 1 file changed, 21 insertions(+), 8 deletions(-)

diff --git a/drivers/net/macb.c b/drivers/net/macb.c
index c072f99d8f..8eb6977fa9 100644
--- a/drivers/net/macb.c
+++ b/drivers/net/macb.c
@@ -45,10 +45,16 @@
 
 DECLARE_GLOBAL_DATA_PTR;
 
-#define MACB_RX_BUFFER_SIZE		4096
-#define MACB_RX_RING_SIZE		(MACB_RX_BUFFER_SIZE / 128)
+/* These buffer sizes must be power of 2 and divisible
+ * by RX_BUFFER_MULTIPLE
+ */
+#define MACB_RX_BUFFER_SIZE		128
+#define GEM_RX_BUFFER_SIZE		2048
 #define RX_BUFFER_MULTIPLE		64
+
+#define MACB_RX_RING_SIZE		32
 #define MACB_TX_RING_SIZE		16
+
 #define MACB_TX_TIMEOUT		1000
 #define MACB_AUTONEG_TIMEOUT	5000000
 
@@ -95,6 +101,7 @@ struct macb_device {
 	void			*tx_buffer;
 	struct macb_dma_desc	*rx_ring;
 	struct macb_dma_desc	*tx_ring;
+	size_t			rx_buffer_size;
 
 	unsigned long		rx_buffer_dma;
 	unsigned long		rx_ring_dma;
@@ -395,15 +402,16 @@ static int _macb_recv(struct macb_device *macb, uchar **packetp)
 		}
 
 		if (status & MACB_BIT(RX_EOF)) {
-			buffer = macb->rx_buffer + 128 * macb->rx_tail;
+			buffer = macb->rx_buffer +
+				macb->rx_buffer_size * macb->rx_tail;
 			length = status & RXBUF_FRMLEN_MASK;
 
 			macb_invalidate_rx_buffer(macb);
 			if (macb->wrapped) {
 				unsigned int headlen, taillen;
 
-				headlen = 128 * (MACB_RX_RING_SIZE
-						 - macb->rx_tail);
+				headlen = macb->rx_buffer_size *
+					(MACB_RX_RING_SIZE - macb->rx_tail);
 				taillen = length - headlen;
 				memcpy((void *)net_rx_packets[0],
 				       buffer, headlen);
@@ -701,7 +709,7 @@ static void gmac_configure_dma(struct macb_device *macb)
 	u32 buffer_size;
 	u32 dmacfg;
 
-	buffer_size = 128 / RX_BUFFER_MULTIPLE;
+	buffer_size = macb->rx_buffer_size / RX_BUFFER_MULTIPLE;
 	dmacfg = gem_readl(macb, DMACFG) & ~GEM_BF(RXBS, -1L);
 	dmacfg |= GEM_BF(RXBS, buffer_size);
 
@@ -746,7 +754,7 @@ static int _macb_init(struct macb_device *macb, const char *name)
 			paddr |= MACB_BIT(RX_WRAP);
 		macb->rx_ring[i].addr = paddr;
 		macb->rx_ring[i].ctrl = 0;
-		paddr += 128;
+		paddr += macb->rx_buffer_size;
 	}
 	macb_flush_ring_desc(macb, RX);
 	macb_flush_rx_buffer(macb);
@@ -957,8 +965,13 @@ static void _macb_eth_initialize(struct macb_device *macb)
 	int id = 0;	/* This is not used by functions we call */
 	u32 ncfgr;
 
+	if (macb_is_gem(macb))
+		macb->rx_buffer_size = GEM_RX_BUFFER_SIZE;
+	else
+		macb->rx_buffer_size = MACB_RX_BUFFER_SIZE;
+
 	/* TODO: we need check the rx/tx_ring_dma is dcache line aligned */
-	macb->rx_buffer = dma_alloc_coherent(MACB_RX_BUFFER_SIZE,
+	macb->rx_buffer = dma_alloc_coherent(macb->rx_buffer_size * MACB_RX_RING_SIZE,
 					     &macb->rx_buffer_dma);
 	macb->rx_ring = dma_alloc_coherent(MACB_RX_DMA_DESC_SIZE,
 					   &macb->rx_ring_dma);
-- 
2.22.0