[U-Boot] [PATCH v2 04/18] pcnet: add cache flushing & invalidation

[Paul Burton]

Ensure that the view of memory from the CPU & the ethernet controller is
coherent at the various points where they exchange data. This prevents
stale data from being transmitted or received, and prevents the driver
from getting stuck waiting for the ethernet controller to update
descriptors when in reality it has but the old values are being read
from cache.

Signed-off-by: Paul Burton <paul.burton at imgtec.com>
---
Changes in v2:
  - rebase atop master
---
 drivers/net/pcnet.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/net/pcnet.c b/drivers/net/pcnet.c
index 843a6fc..7b87660 100644
--- a/drivers/net/pcnet.c
+++ b/drivers/net/pcnet.c
@@ -364,6 +364,7 @@ static int pcnet_init(struct eth_device *dev, bd_t *bis)
 					       RX_RING_LEN_BITS);
 	lp->init_block.rx_ring = PCI_TO_MEM_LE(dev, lp->rx_ring);
 	lp->init_block.tx_ring = PCI_TO_MEM_LE(dev, lp->tx_ring);
+	flush_dcache_range((unsigned long)lp, (unsigned long)&lp->rx_buf);
 
 	PCNET_DEBUG1("\ntlen_rlen=0x%x rx_ring=0x%x tx_ring=0x%x\n",
 		     lp->init_block.tlen_rlen,
@@ -407,8 +408,13 @@ static int pcnet_send(struct eth_device *dev, void *packet, int pkt_len)
 	PCNET_DEBUG2("Tx%d: %d bytes from 0x%p ", lp->cur_tx, pkt_len,
 		     packet);
 
+	flush_dcache_range((unsigned long)packet,
+			   (unsigned long)packet + pkt_len);
+
 	/* Wait for completion by testing the OWN bit */
 	for (i = 1000; i > 0; i--) {
+		invalidate_dcache_range((unsigned long)entry,
+					(unsigned long)entry + sizeof(*entry));
 		status = le16_to_cpu(entry->status);
 		if ((status & 0x8000) == 0)
 			break;
@@ -431,6 +437,8 @@ static int pcnet_send(struct eth_device *dev, void *packet, int pkt_len)
 	entry->misc = 0x00000000;
 	entry->base = PCI_TO_MEM_LE(dev, packet);
 	entry->status = cpu_to_le16(status);
+	flush_dcache_range((unsigned long)entry,
+			   (unsigned long)entry + sizeof(*entry));
 
 	/* Trigger an immediate send poll. */
 	pcnet_write_csr(dev, 0, 0x0008);
@@ -451,6 +459,8 @@ static int pcnet_recv (struct eth_device *dev)
 
 	while (1) {
 		entry = &lp->rx_ring[lp->cur_rx];
+		invalidate_dcache_range((unsigned long)entry,
+					(unsigned long)entry + sizeof(*entry));
 		/*
 		 * If we own the next entry, it's a new packet. Send it up.
 		 */
@@ -479,6 +489,10 @@ static int pcnet_recv (struct eth_device *dev)
 				printf("%s: Rx%d: invalid packet length %d\n",
 				       dev->name, lp->cur_rx, pkt_len);
 			} else {
+				invalidate_dcache_range(
+					(unsigned long)lp->rx_buf[lp->cur_rx],
+					(unsigned long)lp->rx_buf[lp->cur_rx] +
+					pkt_len);
 				NetReceive(lp->rx_buf[lp->cur_rx], pkt_len);
 				PCNET_DEBUG2("Rx%d: %d bytes from 0x%p\n",
 					     lp->cur_rx, pkt_len,
@@ -486,6 +500,8 @@ static int pcnet_recv (struct eth_device *dev)
 			}
 		}
 		entry->status |= cpu_to_le16(0x8000);
+		flush_dcache_range((unsigned long)entry,
+				   (unsigned long)entry + sizeof(*entry));
 
 		if (++lp->cur_rx >= RX_RING_SIZE)
 			lp->cur_rx = 0;
-- 
1.8.4.1