From: Alexander Bluhm <bluhm@openbsd.org>
Subject: bge 64 bit dma
To: tech@openbsd.org
Date: Fri, 27 Feb 2026 23:47:57 +0100

Hi,

Brad sent me this diff.  I have tested it on

bge0 at pci12 dev 0 function 0 "Broadcom BCM5720" rev 0x00, BCM5720 A0 (0x5720000): msi, address 04:32:01:f1:4e:7c

and Hrvoje here

bge1 at pci14 dev 0 function 1 "Broadcom BCM5720" rev 0x00, BCM5720 A0 (0x5720000), APE firmware NCSI 1.5.61.0: msi, address d0:94:66:5b:66:0e

Is that enough test coverage to enable 64 bit dma for bge(4)?

bluhm

Index: dev/pci/if_bge.c
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/dev/pci/if_bge.c,v
diff -u -p -r1.408 if_bge.c
--- dev/pci/if_bge.c	15 Jul 2025 13:40:02 -0000	1.408
+++ dev/pci/if_bge.c	27 Feb 2026 22:37:33 -0000
@@ -1285,7 +1285,8 @@ bge_init_rx_ring_std(struct bge_softc *s
 
 	for (i = 0; i < BGE_STD_RX_RING_CNT; i++) {
 		if (bus_dmamap_create(sc->bge_dmatag, sc->bge_rx_std_len, 1,
-		    sc->bge_rx_std_len, 0, BUS_DMA_NOWAIT | BUS_DMA_ALLOCNOW,
+		    sc->bge_rx_std_len, 0,
+		    BUS_DMA_NOWAIT | BUS_DMA_ALLOCNOW | sc->bge_dmaflags,
 		    &sc->bge_cdata.bge_rx_std_map[i]) != 0) {
 			printf("%s: unable to create dmamap for slot %d\n",
 			    sc->bge_dev.dv_xname, i);
@@ -1411,7 +1412,7 @@ bge_init_rx_ring_jumbo(struct bge_softc 
 
 	for (i = 0; i < BGE_JUMBO_RX_RING_CNT; i++) {
 		if (bus_dmamap_create(sc->bge_dmatag, BGE_JLEN, 4, BGE_JLEN, 0,
-		    BUS_DMA_NOWAIT | BUS_DMA_ALLOCNOW,
+		    BUS_DMA_NOWAIT | BUS_DMA_ALLOCNOW | sc->bge_dmaflags,
 		    &sc->bge_cdata.bge_rx_jumbo_map[i]) != 0) {
 			printf("%s: unable to create dmamap for slot %d\n",
 			    sc->bge_dev.dv_xname, i);
@@ -1560,7 +1561,8 @@ bge_init_tx_ring(struct bge_softc *sc)
 
 	for (i = 0; i < BGE_TX_RING_CNT; i++) {
 		if (bus_dmamap_create(sc->bge_dmatag, txmaxsegsz,
-		    BGE_NTXSEG, txsegsz, 0, BUS_DMA_NOWAIT, &sc->bge_txdma[i]))
+		    BGE_NTXSEG, txsegsz, 0, BUS_DMA_NOWAIT | sc->bge_dmaflags,
+		    &sc->bge_txdma[i]))
 			return (ENOBUFS);
 	}
 
@@ -2906,6 +2908,8 @@ bge_attach(struct device *parent, struct
 	    BGE_ASICREV(sc->bge_chipid) == BGE_ASICREV_BCM57780)
 		sc->bge_flags |= BGE_CPMU_PRESENT;
 
+	sc->bge_dmaflags = (sc->bge_flags & BGE_PCIE) ? BUS_DMA_64BIT : 0;
+
 	if (pci_get_capability(pa->pa_pc, pa->pa_tag, PCI_CAP_MSI,
 	    &sc->bge_msicap, NULL)) {
 		if (bge_can_use_msi(sc) == 0)
@@ -3000,7 +3004,7 @@ bge_attach(struct device *parent, struct
 	DPRINTFN(5, ("bus_dmamem_alloc\n"));
 	if (bus_dmamem_alloc(sc->bge_dmatag, sizeof(struct bge_ring_data),
 	    PAGE_SIZE, 0, &sc->bge_ring_seg, 1, &sc->bge_ring_nseg,
-	    BUS_DMA_NOWAIT)) {
+	    BUS_DMA_NOWAIT | sc->bge_dmaflags)) {
 		printf(": can't alloc rx buffers\n");
 		goto fail_2;
 	}
@@ -3015,7 +3019,7 @@ bge_attach(struct device *parent, struct
 	DPRINTFN(5, ("bus_dmamap_create\n"));
 	if (bus_dmamap_create(sc->bge_dmatag, sizeof(struct bge_ring_data), 1,
 	    sizeof(struct bge_ring_data), 0,
-	    BUS_DMA_NOWAIT, &sc->bge_ring_map)) {
+	    BUS_DMA_NOWAIT | sc->bge_dmaflags, &sc->bge_ring_map)) {
 		printf(": can't create dma map\n");
 		goto fail_4;
 	}
Index: dev/pci/if_bgereg.h
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/dev/pci/if_bgereg.h,v
diff -u -p -r1.136 if_bgereg.h
--- dev/pci/if_bgereg.h	4 Jul 2023 10:22:39 -0000	1.136
+++ dev/pci/if_bgereg.h	27 Feb 2026 22:37:33 -0000
@@ -2942,6 +2942,7 @@ struct bge_softc {
 	u_int32_t		bge_rx_overruns;
 	u_int32_t		bge_tx_collisions;
 	bus_dmamap_t		bge_txdma[BGE_TX_RING_CNT];
+	int			bge_dmaflags;
 
 	struct mutex		bge_kstat_mtx;
 	struct kstat		*bge_kstat;