From 88289d56cb28af9d10d8b79232979e744ea1e47f Mon Sep 17 00:00:00 2001 From: Marc St-Amand Date: Wed, 9 Feb 2022 15:13:25 +0530 Subject: net: macb: Align the dma and coherent dma masks [ Upstream commit 37f7860602b5b2d99fc7465f6407f403f5941988 ] Single page and coherent memory blocks can use different DMA masks when the macb accesses physical memory directly. The kernel is clever enough to allocate pages that fit into the requested address width. When using the ARM SMMU, the DMA mask must be the same for single pages and big coherent memory blocks. Otherwise the translation tables turn into one big mess. [ 74.959909] macb ff0e0000.ethernet eth0: DMA bus error: HRESP not OK [ 74.959989] arm-smmu fd800000.smmu: Unhandled context fault: fsr=0x402, iova=0x3165687460, fsynr=0x20001, cbfrsynra=0x877, cb=1 [ 75.173939] macb ff0e0000.ethernet eth0: DMA bus error: HRESP not OK [ 75.173955] arm-smmu fd800000.smmu: Unhandled context fault: fsr=0x402, iova=0x3165687460, fsynr=0x20001, cbfrsynra=0x877, cb=1 Since using the same DMA mask does not hurt direct 1:1 physical memory mappings, this commit always aligns DMA and coherent masks. Signed-off-by: Marc St-Amand Signed-off-by: Harini Katakam Acked-by: Nicolas Ferre Tested-by: Conor Dooley Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/net/ethernet/cadence/macb_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/net/ethernet/cadence/macb_main.c') diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c index d13fb1d31821..d71c11a6282e 100644 --- a/drivers/net/ethernet/cadence/macb_main.c +++ b/drivers/net/ethernet/cadence/macb_main.c @@ -4739,7 +4739,7 @@ static int macb_probe(struct platform_device *pdev) #ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT if (GEM_BFEXT(DAW64, gem_readl(bp, DCFG6))) { - dma_set_mask(&pdev->dev, DMA_BIT_MASK(44)); + dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(44)); bp->hw_dma_cap |= HW_DMA_CAP_64B; } #endif -- cgit v1.2.3 From b5e792187f507db877bf45b645927f4f0ff8cb55 Mon Sep 17 00:00:00 2001 From: Robert Hancock Date: Thu, 3 Mar 2022 12:10:27 -0600 Subject: net: macb: Fix lost RX packet wakeup race in NAPI receive commit 0bf476fc3624e3a72af4ba7340d430a91c18cd67 upstream. There is an oddity in the way the RSR register flags propagate to the ISR register (and the actual interrupt output) on this hardware: it appears that RSR register bits only result in ISR being asserted if the interrupt was actually enabled at the time, so enabling interrupts with RSR bits already set doesn't trigger an interrupt to be raised. There was already a partial fix for this race in the macb_poll function where it checked for RSR bits being set and re-triggered NAPI receive. However, there was a still a race window between checking RSR and actually enabling interrupts, where a lost wakeup could happen. It's necessary to check again after enabling interrupts to see if RSR was set just prior to the interrupt being enabled, and re-trigger receive in that case. This issue was noticed in a point-to-point UDP request-response protocol which periodically saw timeouts or abnormally high response times due to received packets not being processed in a timely fashion. In many applications, more packets arriving, including TCP retransmissions, would cause the original packet to be processed, thus masking the issue. Fixes: 02f7a34f34e3 ("net: macb: Re-enable RX interrupt only when RX is done") Cc: stable@vger.kernel.org Co-developed-by: Scott McNutt Signed-off-by: Scott McNutt Signed-off-by: Robert Hancock Tested-by: Claudiu Beznea Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/ethernet/cadence/macb_main.c | 25 ++++++++++++++++++++++++- 1 file changed, 24 insertions(+), 1 deletion(-) (limited to 'drivers/net/ethernet/cadence/macb_main.c') diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c index d71c11a6282e..9705c49655ad 100644 --- a/drivers/net/ethernet/cadence/macb_main.c +++ b/drivers/net/ethernet/cadence/macb_main.c @@ -1606,7 +1606,14 @@ static int macb_poll(struct napi_struct *napi, int budget) if (work_done < budget) { napi_complete_done(napi, work_done); - /* Packets received while interrupts were disabled */ + /* RSR bits only seem to propagate to raise interrupts when + * interrupts are enabled at the time, so if bits are already + * set due to packets received while interrupts were disabled, + * they will not cause another interrupt to be generated when + * interrupts are re-enabled. + * Check for this case here. This has been seen to happen + * around 30% of the time under heavy network load. + */ status = macb_readl(bp, RSR); if (status) { if (bp->caps & MACB_CAPS_ISR_CLEAR_ON_WRITE) @@ -1614,6 +1621,22 @@ static int macb_poll(struct napi_struct *napi, int budget) napi_reschedule(napi); } else { queue_writel(queue, IER, bp->rx_intr_mask); + + /* In rare cases, packets could have been received in + * the window between the check above and re-enabling + * interrupts. Therefore, a double-check is required + * to avoid losing a wakeup. This can potentially race + * with the interrupt handler doing the same actions + * if an interrupt is raised just after enabling them, + * but this should be harmless. + */ + status = macb_readl(bp, RSR); + if (unlikely(status)) { + queue_writel(queue, IDR, bp->rx_intr_mask); + if (bp->caps & MACB_CAPS_ISR_CLEAR_ON_WRITE) + queue_writel(queue, ISR, MACB_BIT(RCOMP)); + napi_schedule(napi); + } } } -- cgit v1.2.3 From 123a52eb610d6cbf8ec49b1df831efc685334601 Mon Sep 17 00:00:00 2001 From: Tomas Melin Date: Thu, 7 Apr 2022 19:16:59 +0300 Subject: net: macb: Restart tx only if queue pointer is lagging [ Upstream commit 5ad7f18cd82cee8e773d40cc7a1465a526f2615c ] commit 4298388574da ("net: macb: restart tx after tx used bit read") added support for restarting transmission. Restarting tx does not work in case controller asserts TXUBR interrupt and TQBP is already at the end of the tx queue. In that situation, restarting tx will immediately cause assertion of another TXUBR interrupt. The driver will end up in an infinite interrupt loop which it cannot break out of. For cases where TQBP is at the end of the tx queue, instead only clear TX_USED interrupt. As more data gets pushed to the queue, transmission will resume. This issue was observed on a Xilinx Zynq-7000 based board. During stress test of the network interface, driver would get stuck on interrupt loop within seconds or minutes causing CPU to stall. Signed-off-by: Tomas Melin Tested-by: Claudiu Beznea Reviewed-by: Claudiu Beznea Link: https://lore.kernel.org/r/20220407161659.14532-1-tomas.melin@vaisala.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/net/ethernet/cadence/macb_main.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'drivers/net/ethernet/cadence/macb_main.c') diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c index 9705c49655ad..217c1a0f8940 100644 --- a/drivers/net/ethernet/cadence/macb_main.c +++ b/drivers/net/ethernet/cadence/macb_main.c @@ -1689,6 +1689,7 @@ static void macb_tx_restart(struct macb_queue *queue) unsigned int head = queue->tx_head; unsigned int tail = queue->tx_tail; struct macb *bp = queue->bp; + unsigned int head_idx, tbqp; if (bp->caps & MACB_CAPS_ISR_CLEAR_ON_WRITE) queue_writel(queue, ISR, MACB_BIT(TXUBR)); @@ -1696,6 +1697,13 @@ static void macb_tx_restart(struct macb_queue *queue) if (head == tail) return; + tbqp = queue_readl(queue, TBQP) / macb_dma_desc_get_size(bp); + tbqp = macb_adj_dma_desc_idx(bp, macb_tx_ring_wrap(bp, tbqp)); + head_idx = macb_adj_dma_desc_idx(bp, macb_tx_ring_wrap(bp, head)); + + if (tbqp == head_idx) + return; + macb_writel(bp, NCR, macb_readl(bp, NCR) | MACB_BIT(TSTART)); } -- cgit v1.2.3