X-Git-Url: http://git.openwrt.org/?a=blobdiff_plain;f=target%2Flinux%2Fbrcm2708%2Fpatches-4.19%2F950-0434-smsc95xx-dynamically-fix-up-TX-buffer-alignment-with.patch;fp=target%2Flinux%2Fbrcm2708%2Fpatches-4.19%2F950-0434-smsc95xx-dynamically-fix-up-TX-buffer-alignment-with.patch;h=6891ec28a0e0e5ee13e64cbf779ffbdc1cc9d7c7;hb=67dcc43f3a22dc3a7ac07a7065971b426feeb043;hp=0000000000000000000000000000000000000000;hpb=47a93a810f78adce5a130d287f82b28e9b54313c;p=openwrt%2Fopenwrt.git

diff --git a/target/linux/brcm2708/patches-4.19/950-0434-smsc95xx-dynamically-fix-up-TX-buffer-alignment-with.patch b/target/linux/brcm2708/patches-4.19/950-0434-smsc95xx-dynamically-fix-up-TX-buffer-alignment-with.patch
new file mode 100644
index 0000000000..6891ec28a0
--- /dev/null
+++ b/target/linux/brcm2708/patches-4.19/950-0434-smsc95xx-dynamically-fix-up-TX-buffer-alignment-with.patch
@@ -0,0 +1,62 @@
+From 26c79197da4b2911e10c600d79839a82a43a06ff Mon Sep 17 00:00:00 2001
+From: P33M <p33m@github.com>
+Date: Wed, 1 May 2019 17:04:32 +0100
+Subject: [PATCH] smsc95xx: dynamically fix up TX buffer alignment with
+ padding bytes
+
+dwc_otg requires a 32-bit aligned buffer start address, otherwise
+expensive bounce buffers are used. The LAN951x hardware can skip up to
+3 bytes between the TX header and the start of frame data, which can
+be used to force alignment of the URB passed to dwc_otg.
+
+As found in https://github.com/raspberrypi/linux/issues/2924
+---
+ drivers/net/usb/smsc95xx.c | 12 +++++++-----
+ drivers/net/usb/smsc95xx.h |  2 +-
+ 2 files changed, 8 insertions(+), 6 deletions(-)
+
+--- a/drivers/net/usb/smsc95xx.c
++++ b/drivers/net/usb/smsc95xx.c
+@@ -2082,7 +2082,9 @@ static struct sk_buff *smsc95xx_tx_fixup
+ 					 struct sk_buff *skb, gfp_t flags)
+ {
+ 	bool csum = skb->ip_summed == CHECKSUM_PARTIAL;
+-	int overhead = csum ? SMSC95XX_TX_OVERHEAD_CSUM : SMSC95XX_TX_OVERHEAD;
++	unsigned int align_bytes = -((uintptr_t)skb->data) & 0x3;
++	int overhead = csum ? SMSC95XX_TX_OVERHEAD_CSUM + align_bytes
++				: SMSC95XX_TX_OVERHEAD + align_bytes;
+ 	u32 tx_cmd_a, tx_cmd_b;
+ 
+ 	/* We do not advertise SG, so skbs should be already linearized */
+@@ -2116,16 +2118,16 @@ static struct sk_buff *smsc95xx_tx_fixup
+ 		}
+ 	}
+ 
+-	skb_push(skb, 4);
+-	tx_cmd_b = (u32)(skb->len - 4);
++	skb_push(skb, 4 + align_bytes);
++	tx_cmd_b = (u32)(skb->len - 4 - align_bytes);
+ 	if (csum)
+ 		tx_cmd_b |= TX_CMD_B_CSUM_ENABLE;
+ 	cpu_to_le32s(&tx_cmd_b);
+ 	memcpy(skb->data, &tx_cmd_b, 4);
+ 
+ 	skb_push(skb, 4);
+-	tx_cmd_a = (u32)(skb->len - 8) | TX_CMD_A_FIRST_SEG_ |
+-		TX_CMD_A_LAST_SEG_;
++	tx_cmd_a = (u32)(skb->len - 8 - align_bytes) | TX_CMD_A_FIRST_SEG_ |
++		(align_bytes << 16) | TX_CMD_A_LAST_SEG_;
+ 	cpu_to_le32s(&tx_cmd_a);
+ 	memcpy(skb->data, &tx_cmd_a, 4);
+ 
+--- a/drivers/net/usb/smsc95xx.h
++++ b/drivers/net/usb/smsc95xx.h
+@@ -21,7 +21,7 @@
+ #define _SMSC95XX_H
+ 
+ /* Tx command words */
+-#define TX_CMD_A_DATA_OFFSET_	(0x001F0000)	/* Data Start Offset */
++#define TX_CMD_A_DATA_OFFSET_	(0x00030000)	/* Data Start Offset */
+ #define TX_CMD_A_FIRST_SEG_	(0x00002000)	/* First Segment */
+ #define TX_CMD_A_LAST_SEG_	(0x00001000)	/* Last Segment */
+ #define TX_CMD_A_BUF_SIZE_	(0x000007FF)	/* Buffer Size */