Add memory barriers (fence instructions) so the data wrotten by hardware

to physical address now can be read by VA.

This fixes operation on Rocket Core (FPGA).

Sponsored by:	DARPA, AFRL
Sponsored by:	HEIF5

1 files changed, 7 insertions, 3 deletions

diff --git a/sys/riscv/htif/htif_block.c b/sys/riscv/htif/htif_block.c
index c9d2ffc..a31de1c 100644
--- a/sys/riscv/htif/htif_block.c
+++ b/sys/riscv/htif/htif_block.c
@@ -115,6 +115,7 @@ htif_blk_intr(void *arg, uint64_t entry)
 	data = HTIF_DEV_DATA(entry);
 
 	if (sc->curtag == data) {
+		wmb();
 		sc->cmd_done = 1;
 		wakeup(&sc->intr_chan);
 	} else {
@@ -198,6 +199,7 @@ htif_blk_task(void *arg)
 {
 	struct htif_blk_request req __aligned(HTIF_ALIGN);
 	struct htif_blk_softc *sc;
+	uint64_t req_paddr;
 	struct bio *bp;
 	uint64_t paddr;
 	uint64_t cmd;
@@ -217,11 +219,13 @@ htif_blk_task(void *arg)
 		if (bp->bio_cmd == BIO_READ || bp->bio_cmd == BIO_WRITE) {
 			HTIF_BLK_LOCK(sc);
 
+			rmb();
 			req.offset = (bp->bio_pblkno * sc->disk->d_sectorsize);
 			req.size = bp->bio_bcount;
 			paddr = vtophys(bp->bio_data);
 			KASSERT(paddr != 0, ("paddr is 0"));
 			req.addr = paddr;
+			sc->curtag++;
 			req.tag = sc->curtag;
 
 			cmd = sc->index;
@@ -230,9 +234,9 @@ htif_blk_task(void *arg)
 				cmd |= (HTIF_CMD_READ << HTIF_CMD_SHIFT);
 			else
 				cmd |= (HTIF_CMD_WRITE << HTIF_CMD_SHIFT);
-			paddr = vtophys(&req);
-			KASSERT(paddr != 0, ("paddr is 0"));
-			cmd |= paddr;
+			req_paddr = vtophys(&req);
+			KASSERT(req_paddr != 0, ("req_paddr is 0"));
+			cmd |= req_paddr;
 
 			sc->cmd_done = 0;
 			htif_command(cmd);