commit 36f7a411c3c4c3ff33755877c0a6067c4ac3a2a9
author Michal Simek <michal.simek@xilinx.com> Thu Dec 10 16:31:38 2015 +0100
committer Michal Simek <michal.simek@xilinx.com> Wed Jan 27 15:55:52 2016 +0100
tree 50b0a96ada382804f761d5bcfaa91f4c89ebdebe
parent 90e89bff620b1fd897ca0dc08882f78da290c210

net: emaclite: Use indirect access in emaclite_recv

When IP is configured with pong buffers, IP is receiving packets to ping
and then to pong buffer and than ping again.
The original logic in the driver remains there that when ping buffer is
free, pong buffer is checked too and return if both are free.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>

drivers/net/xilinx_emaclite.c

diff --git a/drivers/net/xilinx_emaclite.c b/drivers/net/xilinx_emaclite.c
index e97ce2c..800345b 100644
--- a/drivers/net/xilinx_emaclite.c
+++ b/drivers/net/xilinx_emaclite.c
@@ -17,15 +17,12 @@
 #include <miiphy.h>
 #include <fdtdec.h>
 #include <asm-generic/errno.h>
+#include <linux/kernel.h>
 
 #undef DEBUG
 
 #define ENET_ADDR_LENGTH	6
-
-/* EmacLite constants */
-#define XEL_BUFFER_OFFSET	0x0800	/* Next buffer's offset */
-#define XEL_RSR_OFFSET		0x17FC	/* Rx status */
-#define XEL_RXBUFF_OFFSET	0x1000	/* Receive Buffer */
+#define ETH_FCS_LEN		4 /* Octets in the FCS */
 
 /* Xmit complete */
 #define XEL_TSR_XMIT_BUSY_MASK		0x00000001UL
@@ -86,7 +83,7 @@
 };
 
 struct xemaclite {
-	u32 nextrxbuffertouse;	/* Next RX buffer to read from */
+	bool use_rx_pong_buffer_next;	/* Next RX buffer to read from */
 	u32 txpp;		/* TX ping pong buffer */
 	u32 rxpp;		/* RX ping pong buffer */
 	int phyaddr;
@@ -453,63 +450,87 @@
 
 static int emaclite_recv(struct eth_device *dev)
 {
-	u32 length;
-	u32 reg;
-	u32 baseaddress;
+	u32 length, first_read, reg, attempt = 0;
+	void *addr, *ack;
 	struct xemaclite *emaclite = dev->priv;
+	struct emaclite_regs *regs = emaclite->regs;
+	struct ethernet_hdr *eth;
+	struct ip_udp_hdr *ip;
 
-	baseaddress = dev->iobase + emaclite->nextrxbuffertouse;
-	reg = in_be32 (baseaddress + XEL_RSR_OFFSET);
-	debug("Testing data at address 0x%x\n", baseaddress);
-	if ((reg & XEL_RSR_RECV_DONE_MASK) == XEL_RSR_RECV_DONE_MASK) {
-		if (emaclite->rxpp)
-			emaclite->nextrxbuffertouse ^= XEL_BUFFER_OFFSET;
-	} else {
+try_again:
+	if (!emaclite->use_rx_pong_buffer_next) {
+		reg = in_be32(&regs->rx_ping_rsr);
+		debug("Testing data at rx_ping\n");
+		if ((reg & XEL_RSR_RECV_DONE_MASK) == XEL_RSR_RECV_DONE_MASK) {
+			debug("Data found in rx_ping buffer\n");
+			addr = &regs->rx_ping;
+			ack = &regs->rx_ping_rsr;
+		} else {
+			debug("Data not found in rx_ping buffer\n");
+			/* Pong buffer is not available - return immediately */
+			if (!emaclite->rxpp)
+				return -1;
 
-		if (!emaclite->rxpp) {
-			debug("No data was available - address 0x%x\n",
-								baseaddress);
-			return 0;
+			/* Try pong buffer if this is first attempt */
+			if (attempt++)
+				return -1;
+			emaclite->use_rx_pong_buffer_next =
+					!emaclite->use_rx_pong_buffer_next;
+			goto try_again;
+		}
+	} else {
+		reg = in_be32(&regs->rx_pong_rsr);
+		debug("Testing data at rx_pong\n");
+		if ((reg & XEL_RSR_RECV_DONE_MASK) == XEL_RSR_RECV_DONE_MASK) {
+			debug("Data found in rx_pong buffer\n");
+			addr = &regs->rx_pong;
+			ack = &regs->rx_pong_rsr;
 		} else {
-			baseaddress ^= XEL_BUFFER_OFFSET;
-			reg = in_be32 (baseaddress + XEL_RSR_OFFSET);
-			if ((reg & XEL_RSR_RECV_DONE_MASK) !=
-						XEL_RSR_RECV_DONE_MASK) {
-				debug("No data was available - address 0x%x\n",
-						baseaddress);
-				return 0;
-			}
+			debug("Data not found in rx_pong buffer\n");
+			/* Try ping buffer if this is first attempt */
+			if (attempt++)
+				return -1;
+			emaclite->use_rx_pong_buffer_next =
+					!emaclite->use_rx_pong_buffer_next;
+			goto try_again;
 		}
 	}
-	/* Get the length of the frame that arrived */
-	switch(((ntohl(in_be32 (baseaddress + XEL_RXBUFF_OFFSET + 0xC))) &
-			0xFFFF0000 ) >> 16) {
-		case 0x806:
-			length = 42 + 20; /* FIXME size of ARP */
-			debug("ARP Packet\n");
-			break;
-		case 0x800:
-			length = 14 + 14 +
-			(((ntohl(in_be32 (baseaddress + XEL_RXBUFF_OFFSET +
-						0x10))) & 0xFFFF0000) >> 16);
-			/* FIXME size of IP packet */
-			debug ("IP Packet\n");
-			break;
-		default:
-			debug("Other Packet\n");
-			length = PKTSIZE;
-			break;
+
+	/* Read all bytes for ARP packet with 32bit alignment - 48bytes  */
+	first_read = ALIGN(ETHER_HDR_SIZE + ARP_HDR_SIZE + ETH_FCS_LEN, 4);
+	xemaclite_alignedread(addr, etherrxbuff, first_read);
+
+	/* Detect real packet size */
+	eth = (struct ethernet_hdr *)etherrxbuff;
+	switch (ntohs(eth->et_protlen)) {
+	case PROT_ARP:
+		length = first_read;
+		debug("ARP Packet %x\n", length);
+		break;
+	case PROT_IP:
+		ip = (struct ip_udp_hdr *)(etherrxbuff + ETHER_HDR_SIZE);
+		length = ntohs(ip->ip_len);
+		length += ETHER_HDR_SIZE + ETH_FCS_LEN;
+		debug("IP Packet %x\n", length);
+		break;
+	default:
+		debug("Other Packet\n");
+		length = PKTSIZE;
+		break;
 	}
 
-	xemaclite_alignedread((u32 *) (baseaddress + XEL_RXBUFF_OFFSET),
-			etherrxbuff, length);
+	/* Read the rest of the packet which is longer then first read */
+	if (length != first_read)
+		xemaclite_alignedread(addr + first_read,
+				      etherrxbuff + first_read,
+				      length - first_read);
 
 	/* Acknowledge the frame */
-	reg = in_be32 (baseaddress + XEL_RSR_OFFSET);
+	reg = in_be32(ack);
 	reg &= ~XEL_RSR_RECV_DONE_MASK;
-	out_be32 (baseaddress + XEL_RSR_OFFSET, reg);
+	out_be32(ack, reg);
 
-	debug("Packet receive from 0x%x, length %dB\n", baseaddress, length);
+	debug("Packet receive from 0x%p, length %dB\n", addr, length);
 	net_process_received_packet((uchar *)etherrxbuff, length);
 	return length;