From b38c55320bf85a84a4f04803c57b261fc87e9b4b Mon Sep 17 00:00:00 2001 From: Dimitri Daskalakis Date: Tue, 24 Mar 2026 12:51:22 -0700 Subject: [PATCH 1/2] eth: fbnic: Account for page fragments when updating BDQ tail FBNIC supports fixed size buffers of 4K. When PAGE_SIZE > 4K, we fragment the page across multiple descriptors (FBNIC_BD_FRAG_COUNT). When refilling the BDQ, the correct number of entries are populated, but tail was only incremented by one. So on a system with 64K pages, HW would get one descriptor refilled for every 16 we populate. Additionally, we program the ring size in the HW when enabling the BDQ. This was not accounting for page fragments, so on systems with 64K pages, the HW used 1/16th of the ring. Fixes: 0cb4c0a13723 ("eth: fbnic: Implement Rx queue alloc/start/stop/free") Signed-off-by: Dimitri Daskalakis Link: https://patch.msgid.link/20260324195123.3486219-2-dimitri.daskalakis1@gmail.com Signed-off-by: Jakub Kicinski --- drivers/net/ethernet/meta/fbnic/fbnic_txrx.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_txrx.c b/drivers/net/ethernet/meta/fbnic/fbnic_txrx.c index 9fb91d4f3971..9cd85a0d0c3a 100644 --- a/drivers/net/ethernet/meta/fbnic/fbnic_txrx.c +++ b/drivers/net/ethernet/meta/fbnic/fbnic_txrx.c @@ -927,7 +927,7 @@ static void fbnic_fill_bdq(struct fbnic_ring *bdq) /* Force DMA writes to flush before writing to tail */ dma_wmb(); - writel(i, bdq->doorbell); + writel(i * FBNIC_BD_FRAG_COUNT, bdq->doorbell); } } @@ -2564,7 +2564,7 @@ static void fbnic_enable_bdq(struct fbnic_ring *hpq, struct fbnic_ring *ppq) hpq->tail = 0; hpq->head = 0; - log_size = fls(hpq->size_mask); + log_size = fls(hpq->size_mask) + ilog2(FBNIC_BD_FRAG_COUNT); /* Store descriptor ring address and size */ fbnic_ring_wr32(hpq, FBNIC_QUEUE_BDQ_HPQ_BAL, lower_32_bits(hpq->dma)); @@ -2576,7 +2576,7 @@ static void fbnic_enable_bdq(struct fbnic_ring *hpq, struct fbnic_ring *ppq) if (!ppq->size_mask) goto write_ctl; - log_size = fls(ppq->size_mask); + log_size = fls(ppq->size_mask) + ilog2(FBNIC_BD_FRAG_COUNT); /* Add enabling of PPQ to BDQ control */ bdq_ctl |= FBNIC_QUEUE_BDQ_CTL_PPQ_ENABLE; From f3567dd428b264b3f06f881e5e85a738c7c910df Mon Sep 17 00:00:00 2001 From: Dimitri Daskalakis Date: Tue, 24 Mar 2026 12:51:23 -0700 Subject: [PATCH 2/2] eth: fbnic: Fix debugfs output for BDQ's with page frags The rings size_mask represents the number of pages, so we need to determine the number of page frags when dumping the descriptors. Fixes: df04373b0dab ("eth fbnic: Add debugfs hooks for tx/rx rings") Signed-off-by: Dimitri Daskalakis Link: https://patch.msgid.link/20260324195123.3486219-3-dimitri.daskalakis1@gmail.com Signed-off-by: Jakub Kicinski --- drivers/net/ethernet/meta/fbnic/fbnic_debugfs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_debugfs.c b/drivers/net/ethernet/meta/fbnic/fbnic_debugfs.c index 08270db2dee8..3c4563c8f403 100644 --- a/drivers/net/ethernet/meta/fbnic/fbnic_debugfs.c +++ b/drivers/net/ethernet/meta/fbnic/fbnic_debugfs.c @@ -197,7 +197,7 @@ static int fbnic_dbg_bdq_desc_seq_show(struct seq_file *s, void *v) return 0; } - for (i = 0; i <= ring->size_mask; i++) { + for (i = 0; i < (ring->size_mask + 1) * FBNIC_BD_FRAG_COUNT; i++) { u64 bd = le64_to_cpu(ring->desc[i]); seq_printf(s, "%04x %#04llx %#014llx\n", i,