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 4465e27..aab7bb2 100644
--- 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 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 @@
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 @@
}
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 @@
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 @@
}
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 @@
"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 @@
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 @@
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 @@
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 548c0ec..9b5e19f 100644
--- a/drivers/net/ethernet/cadence/macb.h
+++ b/drivers/net/ethernet/cadence/macb.h
@@ -551,6 +551,7 @@
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;