Re: [PATCH net] net:ethernet: mtk_wed: setup WDMA_RING_TX(0) for non-DBDC MT7986
From: Paolo Abeni <pabeni@redhat.com>
Date: 2026-07-06 10:11:03
Also in:
linux-mediatek
From: AI Reviewer <redacted> This is an AI-generated review of your patch. The human sending this email has considered the AI review valid, or at least plausible. Full review at: https://sashiko.dev/ --- net:ethernet: mtk_wed: setup WDMA_RING_TX(0) for non-DBDC MT7986 This commit updates mtk_wed_start() to configure WDMA_RING_TX(0) on non-DBDC MT7986 devices. It adds a call to mtk_wed_wdma_tx_ring_setup() for v2 hardware if the descriptor is not yet set up.
quoted hunk ↗ jump to hunk
diff --git a/drivers/net/ethernet/mediatek/mtk_wed.c b/drivers/net/ethernet/mediatek/mtk_wed.c index 10d9beaae3721..2420557f6c966 100644 --- a/drivers/net/ethernet/mediatek/mtk_wed.c +++ b/drivers/net/ethernet/mediatek/mtk_wed.c@@ -2334,6 +2334,10 @@ mtk_wed_start(struct mtk_wed_device *dev, u32 irq_mask) if (!dev->rx_wdma[i].desc) mtk_wed_wdma_rx_ring_setup(dev, i, 16, false);
[Severity: High] This isn't a bug introduced by this patch, but does this loop need to check the return value of mtk_wed_wdma_rx_ring_setup()? If mtk_wed_wdma_rx_ring_setup() returns -ENOMEM, the hardware registers are not programmed, but mtk_wed_start() continues execution and enables DMA. Could this lead to hardware DMA using an uninitialized ring base address?
+ if (mtk_wed_is_v2(dev->hw)) + if (!dev->tx_wdma[0].desc) + mtk_wed_wdma_tx_ring_setup(dev, 0, MTK_WED_WDMA_RING_SIZE, false);
[Severity: High] Are there similar error handling concerns with this new call to mtk_wed_wdma_tx_ring_setup()? Like the RX path, if dma_alloc_coherent() fails inside this setup function, it returns -ENOMEM without programming the hardware registers. Since mtk_wed_start() doesn't check this return value, it will proceed to enable hardware DMA, which might attempt to use an uninitialized DMA address. [Severity: High] Does the check for !dev->tx_wdma[0].desc prevent necessary hardware initialization after a warm reset? When the WLAN driver triggers a hardware reset, the WED hardware registers are cleared, and mtk_wed_start() is called again. Because dev->tx_wdma[0].desc was allocated during the initial start, the guard will evaluate to false, skipping the hardware register reprogramming for tx_wdma[0]. Will the hardware DMA end up using a zeroed ring base address after a reset?
+
if (dev->wlan.hw_rro) {
for (i = 0; i < MTK_WED_RX_PAGE_QUEUES; i++) {
u32 addr = MTK_WED_RRO_MSDU_PG_CTRL0(i) +-- This is an AI-generated review.