diff options
Diffstat (limited to 'target/linux/brcm2708/patches-4.19/950-0434-smsc95xx-dynamically-fix-up-TX-buffer-alignment-with.patch')
| -rw-r--r-- | target/linux/brcm2708/patches-4.19/950-0434-smsc95xx-dynamically-fix-up-TX-buffer-alignment-with.patch | 62 |
1 files changed, 62 insertions, 0 deletions
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 */ |