[PATCH v5 18/20] net-lwip: add TFTP_BLOCKSIZE

[Jerome Forissier]

Add support for setting the TFTP block size. The default value (1468)
is fine for Ethernet and allows a better throughput than the TFTP
default (512), if the server supports the blksize option of course.

I tested this change with qemu_arm64_lwip_defconfig. The throughput is
now 875 KiB/s vs. 313 KiB/s before. That is still a low number, but I
think we can't expect more without implementing the windowsize option.

Signed-off-by: Jerome Forissier <jerome.forissier at linaro.org>
---
 net/Kconfig     | 20 ++++++++++----------
 net/lwip/tftp.c |  2 ++
 2 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/net/Kconfig b/net/Kconfig
index 952690d677d..7e5406bb923 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -69,16 +69,6 @@ config SYS_FAULT_ECHO_LINK_DOWN
 	  this option is active, then CONFIG_SYS_FAULT_MII_ADDR also needs to
 	  be configured.
 
-config TFTP_BLOCKSIZE
-	int "TFTP block size"
-	default 1468
-	help
-	  Default TFTP block size.
-	  The MTU is typically 1500 for ethernet, so a TFTP block of
-	  1468 (MTU minus eth.hdrs) provides a good throughput with
-	  almost-MTU block sizes.
-	  You can also activate CONFIG_IP_DEFRAG to set a larger block.
-
 config TFTP_PORT
 	bool "Set TFTP UDP source/destination ports via the environment"
 	help
@@ -263,4 +253,14 @@ config SYS_RX_ETH_BUFFER
 	  since all buffers can be full shortly after enabling the interface on
 	  high Ethernet traffic.
 
+config TFTP_BLOCKSIZE
+	int "TFTP block size"
+	default 1468
+	help
+	  Default TFTP block size.
+	  The MTU is typically 1500 for ethernet, so a TFTP block of
+	  1468 (MTU minus eth.hdrs) provides a good throughput with
+	  almost-MTU block sizes.
+	  You can also activate CONFIG_IP_DEFRAG to set a larger block.
+
 endif   # if NET || NET_LWIP
diff --git a/net/lwip/tftp.c b/net/lwip/tftp.c
index 78de0bd0dba..1fe948c84ec 100644
--- a/net/lwip/tftp.c
+++ b/net/lwip/tftp.c
@@ -136,6 +136,8 @@ static int tftp_loop(struct udevice *udev, ulong addr, char *fname,
 	if (!(err == ERR_OK || err == ERR_USE))
 		log_err("tftp_init_client err: %d\n", err);
 
+	tftp_client_set_blksize(CONFIG_TFTP_BLOCKSIZE);
+
 	ctx.start_time = get_timer(0);
 	err = tftp_get(&ctx, &srvip, srvport, fname, TFTP_MODE_OCTET);
 	/* might return different errors, like routing problems */
-- 
2.40.1