From 393e0b4f178ec7fce1141dacc3304e3607a92ee9 Mon Sep 17 00:00:00 2001 From: Suraj Gupta Date: Fri, 27 Mar 2026 13:02:37 +0530 Subject: [PATCH 1/2] net: xilinx: axienet: Correct BD length masks to match AXIDMA IP spec The XAXIDMA_BD_CTRL_LENGTH_MASK and XAXIDMA_BD_STS_ACTUAL_LEN_MASK macros were defined as 0x007FFFFF (23 bits), but the AXI DMA IP product guide (PG021) specifies the buffer length field as bits 25:0 (26 bits). Update both masks to match the IP documentation. In practice this had no functional impact, since Ethernet frames are far smaller than 2^23 bytes and the extra bits were always zero, but the masks should still reflect the hardware specification. Fixes: 8a3b7a252dca ("drivers/net/ethernet/xilinx: added Xilinx AXI Ethernet driver") Signed-off-by: Suraj Gupta Reviewed-by: Sean Anderson Link: https://patch.msgid.link/20260327073238.134948-2-suraj.gupta2@amd.com Signed-off-by: Paolo Abeni --- drivers/net/ethernet/xilinx/xilinx_axienet.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet.h b/drivers/net/ethernet/xilinx/xilinx_axienet.h index 5ff742103beb..fcd3aaef27fc 100644 --- a/drivers/net/ethernet/xilinx/xilinx_axienet.h +++ b/drivers/net/ethernet/xilinx/xilinx_axienet.h @@ -105,7 +105,7 @@ #define XAXIDMA_BD_HAS_DRE_MASK 0xF00 /* Whether has DRE mask */ #define XAXIDMA_BD_WORDLEN_MASK 0xFF /* Whether has DRE mask */ -#define XAXIDMA_BD_CTRL_LENGTH_MASK 0x007FFFFF /* Requested len */ +#define XAXIDMA_BD_CTRL_LENGTH_MASK GENMASK(25, 0) /* Requested len */ #define XAXIDMA_BD_CTRL_TXSOF_MASK 0x08000000 /* First tx packet */ #define XAXIDMA_BD_CTRL_TXEOF_MASK 0x04000000 /* Last tx packet */ #define XAXIDMA_BD_CTRL_ALL_MASK 0x0C000000 /* All control bits */ @@ -130,7 +130,7 @@ #define XAXIDMA_BD_CTRL_TXEOF_MASK 0x04000000 /* Last tx packet */ #define XAXIDMA_BD_CTRL_ALL_MASK 0x0C000000 /* All control bits */ -#define XAXIDMA_BD_STS_ACTUAL_LEN_MASK 0x007FFFFF /* Actual len */ +#define XAXIDMA_BD_STS_ACTUAL_LEN_MASK GENMASK(25, 0) /* Actual len */ #define XAXIDMA_BD_STS_COMPLETE_MASK 0x80000000 /* Completed */ #define XAXIDMA_BD_STS_DEC_ERR_MASK 0x40000000 /* Decode error */ #define XAXIDMA_BD_STS_SLV_ERR_MASK 0x20000000 /* Slave error */ From d1978d03e86785872871bff9c2623174b10740de Mon Sep 17 00:00:00 2001 From: Suraj Gupta Date: Fri, 27 Mar 2026 13:02:38 +0530 Subject: [PATCH 2/2] net: xilinx: axienet: Fix BQL accounting for multi-BD TX packets When a TX packet spans multiple buffer descriptors (scatter-gather), axienet_free_tx_chain sums the per-BD actual length from descriptor status into a caller-provided accumulator. That sum is reset on each NAPI poll. If the BDs for a single packet complete across different polls, the earlier bytes are lost and never credited to BQL. This causes BQL to think bytes are permanently in-flight, eventually stalling the TX queue. The SKB pointer is stored only on the last BD of a packet. When that BD completes, use skb->len for the byte count instead of summing per-BD status lengths. This matches netdev_sent_queue(), which debits skb->len, and naturally survives across polls because no partial packet contributes to the accumulator. Fixes: c900e49d58eb ("net: xilinx: axienet: Implement BQL") Signed-off-by: Suraj Gupta Reviewed-by: Sean Anderson Link: https://patch.msgid.link/20260327073238.134948-3-suraj.gupta2@amd.com Signed-off-by: Paolo Abeni --- drivers/net/ethernet/xilinx/xilinx_axienet_main.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c index b06e4c37ff61..263c4b67fd5a 100644 --- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c +++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c @@ -770,8 +770,8 @@ static int axienet_device_reset(struct net_device *ndev) * @first_bd: Index of first descriptor to clean up * @nr_bds: Max number of descriptors to clean up * @force: Whether to clean descriptors even if not complete - * @sizep: Pointer to a u32 filled with the total sum of all bytes - * in all cleaned-up descriptors. Ignored if NULL. + * @sizep: Pointer to a u32 accumulating the total byte count of + * completed packets (using skb->len). Ignored if NULL. * @budget: NAPI budget (use 0 when not called from NAPI poll) * * Would either be called after a successful transmit operation, or after @@ -805,6 +805,8 @@ static int axienet_free_tx_chain(struct axienet_local *lp, u32 first_bd, DMA_TO_DEVICE); if (cur_p->skb && (status & XAXIDMA_BD_STS_COMPLETE_MASK)) { + if (sizep) + *sizep += cur_p->skb->len; napi_consume_skb(cur_p->skb, budget); packets++; } @@ -818,9 +820,6 @@ static int axienet_free_tx_chain(struct axienet_local *lp, u32 first_bd, wmb(); cur_p->cntrl = 0; cur_p->status = 0; - - if (sizep) - *sizep += status & XAXIDMA_BD_STS_ACTUAL_LEN_MASK; } if (!force) {