 @@ -1,14 +1,14 @@
-/*	$NetBSD: ahcisata_core.c,v 1.30 2010/11/13 13:52:00 uebayasi Exp $	*/
+/*	$NetBSD: ahcisata_core.c,v 1.31 2011/01/10 11:18:14 tsutsui Exp $	*/
 /*
  * Copyright (c) 2006 Manuel Bouyer.
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
+ *
 @@ -16,27 +16,27 @@
  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
  */
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: ahcisata_core.c,v 1.30 2010/11/13 13:52:00 uebayasi Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ahcisata_core.c,v 1.31 2011/01/10 11:18:14 tsutsui Exp $");
 #include <sys/types.h>
 #include <sys/malloc.h>
 #include <sys/param.h>
 #include <sys/kernel.h>
 #include <sys/systm.h>
 #include <sys/disklabel.h>
 #include <sys/proc.h>
 #include <sys/buf.h>
 #include <dev/ata/atareg.h>
 #include <dev/ata/satavar.h>
 #include <dev/ata/satareg.h>
 @@ -759,27 +759,28 @@ ahci_cmd_start(struct ata_channel *chp,
 	AHCIDEBUG_PRINT(("ahci_cmd_start CI 0x%x\n",
 	    AHCI_READ(sc, AHCI_P_CI(chp->ch_channel))), DEBUG_XFERS);
 	cmd_tbl = achp->ahcic_cmd_tbl[slot];
 	AHCIDEBUG_PRINT(("%s port %d tbl %p\n", AHCINAME(sc), chp->ch_channel,
 	      cmd_tbl), DEBUG_XFERS);
 	satafis_rhd_construct_cmd(ata_c, cmd_tbl->cmdt_cfis);
 	cmd_h = &achp->ahcic_cmdh[slot];
 	AHCIDEBUG_PRINT(("%s port %d header %p\n", AHCINAME(sc),
 	    chp->ch_channel, cmd_h), DEBUG_XFERS);
 	if (ahci_dma_setup(chp, slot,
-	    (ata_c->flags & (AT_READ|AT_WRITE)) ? ata_c->data : NULL,
+	    (ata_c->flags & (AT_READ|AT_WRITE) && ata_c->bcount > 0) ?
 	    ata_c->data : NULL,
 	    ata_c->bcount,
 	    (ata_c->flags & AT_READ) ? BUS_DMA_READ : BUS_DMA_WRITE)) {
 		ata_c->flags |= AT_DF;
 		ahci_cmd_complete(chp, xfer, slot);
 		return;
+	}
 	cmd_h->cmdh_flags = htole16(
 	    ((ata_c->flags & AT_WRITE) ? AHCI_CMDH_F_WR : 0) |
 	    RHD_FISLEN / 4);
 	cmd_h->cmdh_prdbc = 0;
 	AHCI_CMDH_SYNC(sc, achp, slot,
 	    BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
 @@ -894,27 +895,27 @@ ahci_cmd_done(struct ata_channel *chp, s
+{
 	struct ahci_softc *sc = (struct ahci_softc *)chp->ch_atac;
 	struct ahci_channel *achp = (struct ahci_channel *)chp;
 	struct ata_command *ata_c = xfer->c_cmd;
 	uint16_t *idwordbuf;
 	int i;
 	AHCIDEBUG_PRINT(("ahci_cmd_done channel %d\n", chp->ch_channel),
 	    DEBUG_FUNCS);
 	/* this comamnd is not active any more */
 	achp->ahcic_cmds_active &= ~(1 << slot);
-	if (ata_c->flags & (AT_READ|AT_WRITE)) {
+	if (ata_c->flags & (AT_READ|AT_WRITE) && ata_c->bcount > 0) {
 		bus_dmamap_sync(sc->sc_dmat, achp->ahcic_datad[slot], 0,
 		    achp->ahcic_datad[slot]->dm_mapsize,
 		    (ata_c->flags & AT_READ) ? BUS_DMASYNC_POSTREAD :
 		    BUS_DMASYNC_POSTWRITE);
 		bus_dmamap_unload(sc->sc_dmat, achp->ahcic_datad[slot]);
+	}
 	AHCI_CMDH_SYNC(sc, achp, slot,
 	    BUS_DMASYNC_POSTREAD | BUS_DMASYNC_POSTWRITE);
 	/* ata(4) expects IDENTIFY data to be in host endianess */
 	if (ata_c->r_command == WDCC_IDENTIFY ||
 	    ata_c->r_command == ATAPI_IDENTIFY_DEVICE) {