git: 3f6c1e731376 - main - mgb: Propagate DMA setup errors and use the requested channel

The branch main has been updated by kbowling:

URL: https://cgit.FreeBSD.org/src/commit/?id=3f6c1e731376ffaf8612e7e196119acabbf357e4

commit 3f6c1e731376ffaf8612e7e196119acabbf357e4
Author:     Kevin Bowling <kbowling@FreeBSD.org>
AuthorDate: 2026-09-17 03:07:54 +0000
Commit:     Kevin Bowling <kbowling@FreeBSD.org>
CommitDate: 2026-09-17 06:14:18 +0000

    mgb: Propagate DMA setup errors and use the requested channel
    
    Check the receive DMA and frame transfer setup results that were
    previously discarded. Return EINVAL for invalid ring/writeback addresses
    rather than reporting success, and stop initialization through
    iflib_init_failed() when a ring could not be configured.
    
    Use the transmit queue count for transmit initialization and the supplied
    channel index for DMA operations. The driver currently allocates one
    queue in each direction, so those index/count corrections are latent.
    
    MFC after:      2 weeks
    Sponsored by:   BBOX.io
---
 sys/dev/mgb/if_mgb.c | 25 +++++++++++++++++++------
 1 file changed, 19 insertions(+), 6 deletions(-)

diff --git a/sys/dev/mgb/if_mgb.c b/sys/dev/mgb/if_mgb.c
index 409f34167df0..53a69f480784 100644
--- a/sys/dev/mgb/if_mgb.c
+++ b/sys/dev/mgb/if_mgb.c
@@ -601,7 +601,12 @@ mgb_init(if_ctx_t ctx)
 	miid = device_get_softc(sc->miibus);
 	device_printf(sc->dev, "running init ...\n");
 
-	mgb_dma_init(sc);
+	error = mgb_dma_init(sc);
+	if (error != 0) {
+		device_printf(sc->dev, "DMA initialization failed: %d\n", error);
+		iflib_init_failed(ctx);
+		return;
+	}
 
 	/* XXX: Turn off perfect filtering, turn on (broad|multi|uni)cast rx */
 	CSR_CLEAR_REG(sc, MGB_RFE_CTL, MGB_RFE_ALLOW_PERFECT_FILTER);
@@ -1235,7 +1240,7 @@ mgb_dma_init(struct mgb_softc *sc)
 		if ((error = mgb_dma_rx_ring_init(sc, ch)))
 			goto fail;
 
-	for (ch = 0; ch < scctx->isc_nrxqsets; ch++)
+	for (ch = 0; ch < scctx->isc_ntxqsets; ch++)
 		if ((error = mgb_dma_tx_ring_init(sc, ch)))
 			goto fail;
 
@@ -1250,13 +1255,18 @@ mgb_dma_rx_ring_init(struct mgb_softc *sc, int channel)
 	int ring_config, error = 0;
 
 	rdata = &sc->rx_ring_data;
-	mgb_dmac_control(sc, MGB_DMAC_RX_START, 0, DMAC_RESET);
+	error = mgb_dmac_control(sc, MGB_DMAC_RX_START, channel, DMAC_RESET);
+	if (error != 0) {
+		device_printf(sc->dev, "Failed to reset RX DMAC.\n");
+		goto fail;
+	}
 	KASSERT(MGB_DMAC_STATE_IS_INITIAL(sc, MGB_DMAC_RX_START, channel),
 	    ("Trying to init channels when not in init state\n"));
 
 	/* write ring address */
 	if (rdata->ring_bus_addr == 0) {
 		device_printf(sc->dev, "Invalid ring bus addr.\n");
+		error = EINVAL;
 		goto fail;
 	}
 
@@ -1268,6 +1278,7 @@ mgb_dma_rx_ring_init(struct mgb_softc *sc, int channel)
 	/* write head pointer writeback address */
 	if (rdata->head_wb_bus_addr == 0) {
 		device_printf(sc->dev, "Invalid head wb bus addr.\n");
+		error = EINVAL;
 		goto fail;
 	}
 	CSR_WRITE_REG(sc, MGB_DMA_RX_HEAD_WB_H(channel),
@@ -1290,17 +1301,17 @@ mgb_dma_rx_ring_init(struct mgb_softc *sc, int channel)
 
 	rdata->last_head = CSR_READ_REG(sc, MGB_DMA_RX_HEAD(channel));
 
-	mgb_fct_control(sc, MGB_FCT_RX_CTL, channel, FCT_RESET);
+	error = mgb_fct_control(sc, MGB_FCT_RX_CTL, channel, FCT_RESET);
 	if (error != 0) {
 		device_printf(sc->dev, "Failed to reset RX FCT.\n");
 		goto fail;
 	}
-	mgb_fct_control(sc, MGB_FCT_RX_CTL, channel, FCT_ENABLE);
+	error = mgb_fct_control(sc, MGB_FCT_RX_CTL, channel, FCT_ENABLE);
 	if (error != 0) {
 		device_printf(sc->dev, "Failed to enable RX FCT.\n");
 		goto fail;
 	}
-	mgb_dmac_control(sc, MGB_DMAC_RX_START, channel, DMAC_START);
+	error = mgb_dmac_control(sc, MGB_DMAC_RX_START, channel, DMAC_START);
 	if (error != 0)
 		device_printf(sc->dev, "Failed to start RX DMAC.\n");
 fail:
@@ -1334,6 +1345,7 @@ mgb_dma_tx_ring_init(struct mgb_softc *sc, int channel)
 	/* write ring address */
 	if (rdata->ring_bus_addr == 0) {
 		device_printf(sc->dev, "Invalid ring bus addr.\n");
+		error = EINVAL;
 		goto fail;
 	}
 	CSR_WRITE_REG(sc, MGB_DMA_TX_BASE_H(channel),
@@ -1354,6 +1366,7 @@ mgb_dma_tx_ring_init(struct mgb_softc *sc, int channel)
 	/* write head pointer writeback address */
 	if (rdata->head_wb_bus_addr == 0) {
 		device_printf(sc->dev, "Invalid head wb bus addr.\n");
+		error = EINVAL;
 		goto fail;
 	}
 	CSR_WRITE_REG(sc, MGB_DMA_TX_HEAD_WB_H(channel),