[PATCH 10/12] net: ks8851: Receive one packet per recv call

[Marek Vasut <marex@denx.de>]

Instead of reading out the entire FIFO and possibly overwriting U-Boot
memory, read out one packet per recv call, pass it to U-Boot network
stack, and repeat. It is however necessary to cache RXFC value, because
reading that one out clears it.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Eugen Hristev <eugen.hristev@microchip.com>
Cc: Joe Hershberger <joe.hershberger@ni.com>
---
 drivers/net/ks8851_mll.c | 65 ++++++++++++++++++++++------------------
 1 file changed, 36 insertions(+), 29 deletions(-)

diff --git a/drivers/net/ks8851_mll.c b/drivers/net/ks8851_mll.c
index d70f0a4dc2..5a566d1c66 100644
--- a/drivers/net/ks8851_mll.c
+++ b/drivers/net/ks8851_mll.c
@@ -30,6 +30,7 @@ struct ks_net {
 	phys_addr_t		iobase;
 	int			bus_width;
 	u16			sharedbus;
+	u16			rxfc;
 	u8			extra_byte;
 };
 
@@ -223,33 +224,31 @@ static inline void ks_read_qmu(struct ks_net *ks, u16 *buf, u32 len)
 	ks_wrreg16(ks, KS_RXQCR, RXQCR_CMD_CNTL);
 }
 
-static void ks_rcv(struct ks_net *ks, uchar **pv_data)
+static int ks_rcv(struct ks_net *ks, uchar *data)
 {
-	unsigned int frame_cnt;
 	u16 sts, len;
-	int i;
-
-	frame_cnt = ks_rdreg16(ks, KS_RXFCTR) >> 8;
-
-	/* read all header information */
-	for (i = 0; i < frame_cnt; i++) {
-		/* Checking Received packet status */
-		sts = ks_rdreg16(ks, KS_RXFHSR);
-		/* Get packet len from hardware */
-		len = ks_rdreg16(ks, KS_RXFHBCR);
-
-		if ((sts & RXFSHR_RXFV) && len && (len < RX_BUF_SIZE)) {
-			/* read data block including CRC 4 bytes */
-			ks_read_qmu(ks, (u16 *)(*pv_data), len);
-
-			/* net_rx_packets buffer size is ok (*pv_data) */
-			net_process_received_packet(*pv_data, len);
-			pv_data++;
-		} else {
-			ks_wrreg16(ks, KS_RXQCR, RXQCR_CMD_CNTL | RXQCR_RRXEF);
-			printf(DRIVERNAME ": bad packet\n");
-		}
+
+	if (!ks->rxfc)
+		ks->rxfc = ks_rdreg16(ks, KS_RXFCTR) >> 8;
+
+	if (!ks->rxfc)
+		return 0;
+
+	/* Checking Received packet status */
+	sts = ks_rdreg16(ks, KS_RXFHSR);
+	/* Get packet len from hardware */
+	len = ks_rdreg16(ks, KS_RXFHBCR);
+
+	if ((sts & RXFSHR_RXFV) && len && (len < RX_BUF_SIZE)) {
+		/* read data block including CRC 4 bytes */
+		ks_read_qmu(ks, (u16 *)data, len);
+		ks->rxfc--;
+		return len - 4;
 	}
+
+	ks_wrreg16(ks, KS_RXQCR, RXQCR_CMD_CNTL | RXQCR_RRXEF);
+	printf(DRIVERNAME ": bad packet\n");
+	return 0;
 }
 
 /*
@@ -405,6 +404,8 @@ static int ks8851_mll_init_common(struct ks_net *ks)
 	/* Configure the PHY, initialize the link state */
 	ks8851_mll_phy_configure(ks);
 
+	ks->rxfc = 0;
+
 	/* Turn on Tx + Rx */
 	ks8851_mll_enable(ks);
 
@@ -464,16 +465,17 @@ static void ks8851_mll_halt_common(struct ks_net *ks)
  * needs to be enough to prevent a packet being discarded while
  * we are processing the previous one.
  */
-static int ks8851_mll_recv_common(struct ks_net *ks, uchar **data)
+static int ks8851_mll_recv_common(struct ks_net *ks, uchar *data)
 {
 	u16 status;
+	int ret = 0;
 
 	status = ks_rdreg16(ks, KS_ISR);
 
 	ks_wrreg16(ks, KS_ISR, status);
 
-	if (status & IRQ_RXI)
-		ks_rcv(ks, data);
+	if (ks->rxfc || (status & IRQ_RXI))
+		ret = ks_rcv(ks, data);
 
 	if (status & IRQ_LDI) {
 		u16 pmecr = ks_rdreg16(ks, KS_PMECR);
@@ -482,7 +484,7 @@ static int ks8851_mll_recv_common(struct ks_net *ks, uchar **data)
 		ks_wrreg16(ks, KS_PMECR, pmecr | PMECR_WKEVT_LINK);
 	}
 
-	return 0;
+	return ret;
 }
 
 static void ks8851_mll_write_hwaddr_common(struct ks_net *ks, u8 enetaddr[6])
@@ -522,8 +524,13 @@ static int ks8851_mll_send(struct eth_device *dev, void *packet, int length)
 static int ks8851_mll_recv(struct eth_device *dev)
 {
 	struct ks_net *ks = container_of(dev, struct ks_net, dev);
+	int ret;
+
+	ret = ks8851_mll_recv_common(ks, net_rx_packets[0]);
+	if (ret)
+		net_process_received_packet(net_rx_packets[0], ret);
 
-	return ks8851_mll_recv_common(ks, (uchar **)net_rx_packets);
+	return ret;
 }
 
 static int ks8851_mll_write_hwaddr(struct eth_device *dev)
-- 
2.25.1