net/macb: increase RX buffer size for GEM

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: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/cadence/macb.c b/drivers/net/ethernet/cadence/macb.c
index 4465e27ba9d1303e82bb431a34f68d078b0e051f..aab7bb22b1d0b1d101e762df9a66ec1ff9676f83 100644 (file)
--- a/drivers/net/ethernet/cadence/macb.c
+++ b/drivers/net/ethernet/cadence/macb.c
@@ -32,7 +32,9 @@
 
 #include "macb.h"
 
-#define RX_BUFFER_SIZE         128
+#define MACB_RX_BUFFER_SIZE    128
+#define GEM_RX_BUFFER_SIZE     2048
+#define RX_BUFFER_MULTIPLE     64  /* bytes */
 #define RX_RING_SIZE           512 /* must be power of 2 */
 #define RX_RING_BYTES          (sizeof(struct macb_dma_desc) * RX_RING_SIZE)
 
@@ -92,7 +94,7 @@ static struct macb_dma_desc *macb_rx_desc(struct macb *bp, unsigned int index)
 
 static void *macb_rx_buffer(struct macb *bp, unsigned int index)
 {
-       return bp->rx_buffers + RX_BUFFER_SIZE * macb_rx_ring_wrap(index);
+       return bp->rx_buffers + bp->rx_buffer_size * macb_rx_ring_wrap(index);
 }
 
 void macb_set_hwaddr(struct macb *bp)
@@ -575,7 +577,7 @@ static int macb_rx_frame(struct macb *bp, unsigned int first_frag,
        skb_put(skb, len);
 
        for (frag = first_frag; ; frag++) {
-               unsigned int frag_len = RX_BUFFER_SIZE;
+               unsigned int frag_len = bp->rx_buffer_size;
 
                if (offset + frag_len > len) {
                        BUG_ON(frag != last_frag);
@@ -583,7 +585,7 @@ static int macb_rx_frame(struct macb *bp, unsigned int first_frag,
                }
                skb_copy_to_linear_data_offset(skb, offset,
                                macb_rx_buffer(bp, frag), frag_len);
-               offset += RX_BUFFER_SIZE;
+               offset += bp->rx_buffer_size;
                desc = macb_rx_desc(bp, frag);
                desc->addr &= ~MACB_BIT(RX_USED);
 
@@ -870,6 +872,30 @@ static int macb_start_xmit(struct sk_buff *skb, struct net_device *dev)
        return NETDEV_TX_OK;
 }
 
+static void macb_init_rx_buffer_size(struct macb *bp)
+{
+       if (!macb_is_gem(bp)) {
+               bp->rx_buffer_size = MACB_RX_BUFFER_SIZE;
+       } else {
+               bp->rx_buffer_size = GEM_RX_BUFFER_SIZE;
+
+               if (bp->rx_buffer_size > PAGE_SIZE) {
+                       netdev_warn(bp->dev,
+                                   "RX buffer cannot be bigger than PAGE_SIZE, shrinking\n");
+                       bp->rx_buffer_size = PAGE_SIZE;
+               }
+               if (bp->rx_buffer_size % RX_BUFFER_MULTIPLE) {
+                       netdev_warn(bp->dev,
+                                   "RX buffer must be multiple of %d bytes, shrinking\n",
+                                   RX_BUFFER_MULTIPLE);
+                       bp->rx_buffer_size =
+                               rounddown(bp->rx_buffer_size, RX_BUFFER_MULTIPLE);
+               }
+               bp->rx_buffer_size = max(RX_BUFFER_MULTIPLE, GEM_RX_BUFFER_SIZE);
+       }
+}
+
+
 static void macb_free_consistent(struct macb *bp)
 {
        if (bp->tx_skb) {
@@ -888,7 +914,7 @@ static void macb_free_consistent(struct macb *bp)
        }
        if (bp->rx_buffers) {
                dma_free_coherent(&bp->pdev->dev,
-                                 RX_RING_SIZE * RX_BUFFER_SIZE,
+                                 RX_RING_SIZE * bp->rx_buffer_size,
                                  bp->rx_buffers, bp->rx_buffers_dma);
                bp->rx_buffers = NULL;
        }
@@ -921,7 +947,7 @@ static int macb_alloc_consistent(struct macb *bp)
                   "Allocated TX ring of %d bytes at %08lx (mapped %p)\n",
                   size, (unsigned long)bp->tx_ring_dma, bp->tx_ring);
 
-       size = RX_RING_SIZE * RX_BUFFER_SIZE;
+       size = RX_RING_SIZE * bp->rx_buffer_size;
        bp->rx_buffers = dma_alloc_coherent(&bp->pdev->dev, size,
                                            &bp->rx_buffers_dma, GFP_KERNEL);
        if (!bp->rx_buffers)
@@ -946,7 +972,7 @@ static void macb_init_rings(struct macb *bp)
        for (i = 0; i < RX_RING_SIZE; i++) {
                bp->rx_ring[i].addr = addr;
                bp->rx_ring[i].ctrl = 0;
-               addr += RX_BUFFER_SIZE;
+               addr += bp->rx_buffer_size;
        }
        bp->rx_ring[RX_RING_SIZE - 1].addr |= MACB_BIT(RX_WRAP);
 
@@ -1056,7 +1082,7 @@ static void macb_configure_dma(struct macb *bp)
 
        if (macb_is_gem(bp)) {
                dmacfg = gem_readl(bp, DMACFG) & ~GEM_BF(RXBS, -1L);
-               dmacfg |= GEM_BF(RXBS, RX_BUFFER_SIZE / 64);
+               dmacfg |= GEM_BF(RXBS, bp->rx_buffer_size / RX_BUFFER_MULTIPLE);
                dmacfg |= GEM_BF(FBLDO, 16);
                dmacfg |= GEM_BIT(TXPBMS) | GEM_BF(RXBMS, -1L);
                dmacfg &= ~GEM_BIT(ENDIA);
@@ -1244,6 +1270,9 @@ static int macb_open(struct net_device *dev)
        if (!bp->phy_dev)
                return -EAGAIN;
 
+       /* RX buffers initialization */
+       macb_init_rx_buffer_size(bp);
+
        err = macb_alloc_consistent(bp);
        if (err) {
                netdev_err(dev, "Unable to allocate DMA memory (error %d)\n",

diff --git a/drivers/net/ethernet/cadence/macb.h b/drivers/net/ethernet/cadence/macb.h
index 548c0ecae8697e5ffb0006819f7670b9fba813f8..9b5e19f8b61dbd7ecf65137bab3968763845ec9d 100644 (file)
--- a/drivers/net/ethernet/cadence/macb.h
+++ b/drivers/net/ethernet/cadence/macb.h
@@ -551,6 +551,7 @@ struct macb {
        unsigned int            rx_tail;
        struct macb_dma_desc    *rx_ring;
        void                    *rx_buffers;
+       size_t                  rx_buffer_size;
 
        unsigned int            tx_head, tx_tail;
        struct macb_dma_desc    *tx_ring;