On 10/6/23 1:06 PM, Emmanuel Vadot wrote:
The branch main has been updated by manu:
URL:
https://cgit.FreeBSD.org/src/commit/?id=38cbdae33b7c3f772845c06f52b86c0ddeab6a17
commit 38cbdae33b7c3f772845c06f52b86c0ddeab6a17
Author: Emmanuel Vadot <[email protected]>
AuthorDate: 2023-10-06 16:04:49 +0000
Commit: Emmanuel Vadot <[email protected]>
CommitDate: 2023-10-06 17:05:45 +0000
dwc: Rewrite barrier part
We only need a barrier after writing the OWN bit so everything is
coherent for the DMA engine.
---
sys/dev/dwc/dwc1000_dma.c | 3 ---
1 file changed, 3 deletions(-)
diff --git a/sys/dev/dwc/dwc1000_dma.c b/sys/dev/dwc/dwc1000_dma.c
index f6baa0bd3e45..4f8ae088305a 100644
--- a/sys/dev/dwc/dwc1000_dma.c
+++ b/sys/dev/dwc/dwc1000_dma.c
@@ -216,7 +216,6 @@ txdesc_setup(struct dwc_softc *sc, int idx, bus_addr_t
paddr,
sc->txdesc_ring[idx].addr1 = (uint32_t)(paddr);
sc->txdesc_ring[idx].desc0 = desc0;
sc->txdesc_ring[idx].desc1 = desc1;
- wmb();
sc->txdesc_ring[idx].desc0 |= TDESC0_OWN;
wmb();
}
@@ -237,7 +236,6 @@ rxdesc_setup(struct dwc_softc *sc, int idx, bus_addr_t
paddr)
sc->rxdesc_ring[idx].desc1 = ERDESC1_RCH |
MIN(MCLBYTES, ERDESC1_RBS1_MASK);
- wmb();
sc->rxdesc_ring[idx].desc0 = RDESC0_OWN;
wmb();
return (nidx);
@@ -524,7 +522,6 @@ dma1000_rxfinish_locked(struct dwc_softc *sc)
m = dwc_rxfinish_one(sc, desc, sc->rxbuf_map + idx);
if (m == NULL) {
- wmb();
desc->desc0 = RDESC0_OWN;
wmb();
} else {
Hmm, are you sure? I suspect you removed the wrong barrier here. You want the
other writes to update other fields in the desc to post before the write that
sets TDESC0_OWN. The barrier after TDESC0_OWN is useless, but the one you
removed
is probably the one that matters. In particular you don't want TDESC0_OWN to be
set when other writes (e.g. setting desc1) are not yet visible.
--
John Baldwin
