From: Marek Vasut <marex@denx.de>
Date: Mon, 25 Apr 2022 18:28:05 +0000 (+0200)
Subject: net: dm9000: Correctly handle empty FIFO
X-Git-Url: http://git.dujemihanovic.xyz/?a=commitdiff_plain;h=ecd8b0371386eb0b1826f5d067a3086ad5184a85;p=u-boot.git

net: dm9000: Correctly handle empty FIFO

Assign packet pointer only in case the MAC reports anything in the FIFO.
In case the MAC indicates empty FIFO, return 0 to pass that information
to the network stack.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Joe Hershberger <joe.hershberger@ni.com>
Cc: Ramon Fried <rfried.dev@gmail.com>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>
---

diff --git a/drivers/net/dm9000x.c b/drivers/net/dm9000x.c
index 78ce536d4a..07733df533 100644
--- a/drivers/net/dm9000x.c
+++ b/drivers/net/dm9000x.c
@@ -666,10 +666,10 @@ static int dm9000_recv(struct udevice *dev, int flags, uchar **packetp)
 	int ret;
 
 	ret = dm9000_recv_common(db, data);
-	if (ret)
+	if (ret > 0)
 		*packetp = (void *)data;
 
-	return ret ? ret : -EAGAIN;
+	return ret >= 0 ? ret : -EAGAIN;
 }
 
 static int dm9000_write_hwaddr(struct udevice *dev)