[U-Boot] [PATCH v2 4/4] macb: allow GEM to have configurable receive buffer size

[Dave Aldridge <fovsoft@gmail.com>]

GEM has configurable receive buffer sizes so requires this to be
programmed up.

Signed-off-by: Dave Aldridge <fovsoft@gmail.com>
---
 drivers/net/macb.c |   19 +++++++++++++++++++
 drivers/net/macb.h |    5 +++++
 2 files changed, 24 insertions(+), 0 deletions(-)

diff --git a/drivers/net/macb.c b/drivers/net/macb.c
index 36f0a0f..de52c09 100644
--- a/drivers/net/macb.c
+++ b/drivers/net/macb.c
@@ -436,6 +436,23 @@ static int macb_phy_init(struct macb_device *macb)
 	}
 }
 
+/*
+ * Configure the receive DMA engine to use the correct receive buffer size.
+ * This is a configurable parameter for GEM.
+ */
+static void macb_configure_dma(struct macb_device *macb)
+{
+	u32 dmacfg;
+	u32 rx_ring_buf_size = CONFIG_SYS_MACB_RX_BUFFER_SIZE /
+			       CONFIG_SYS_MACB_RX_RING_SIZE;
+
+	if (macb->is_gem) {
+		dmacfg = gem_readl(macb, DMACFG) & ~GEM_BF(RXBS, -1L);
+		dmacfg |= GEM_BF(RXBS, rx_ring_buf_size / 64);
+		gem_writel(macb, DMACFG, dmacfg);
+	}
+}
+
 static int macb_init(struct eth_device *netdev, bd_t *bd)
 {
 	struct macb_device *macb = to_macb(netdev);
@@ -465,6 +482,8 @@ static int macb_init(struct eth_device *netdev, bd_t *bd)
 	}
 	macb->rx_tail = macb->tx_head = macb->tx_tail = 0;
 
+	macb_configure_dma(macb);
+
 	macb_writel(macb, RBQP, macb->rx_ring_dma);
 	macb_writel(macb, TBQP, macb->tx_ring_dma);
 
diff --git a/drivers/net/macb.h b/drivers/net/macb.h
index c0759cf..e0fbd46 100644
--- a/drivers/net/macb.h
+++ b/drivers/net/macb.h
@@ -76,6 +76,7 @@
 /* GEM register offsets. */
 #define GEM_NCFGR				0x0004
 #define GEM_USRIO				0x000c
+#define GEM_DMACFG				0x0010
 #define GEM_HRB					0x0080
 #define GEM_HRT					0x0084
 #define GEM_SA1B				0x0088
@@ -165,6 +166,10 @@
 #define GEM_DBW64				1
 #define GEM_DBW128				2
 
+/* Bitfields in DMACFG. */
+#define GEM_RXBS_OFFSET				16
+#define GEM_RXBS_SIZE				8
+
 /* Bitfields in NSR */
 #define MACB_NSR_LINK_OFFSET			0
 #define MACB_NSR_LINK_SIZE			1
-- 
1.7.3.4