hyperv: Add helpers for busdma(9) operation

MFC after:	1 week
Sponsored by:	Microsoft OSTC
Differential Revision:	https://reviews.freebsd.org/D6443

1 files changed, 98 insertions, 0 deletions

diff --git a/sys/dev/hyperv/vmbus/hyperv_busdma.c b/sys/dev/hyperv/vmbus/hyperv_busdma.c
new file mode 100644
index 0000000..07f4e74
--- /dev/null
+++ b/sys/dev/hyperv/vmbus/hyperv_busdma.c
@@ -0,0 +1,98 @@
+/*-
+ * Copyright (c) 2016 Microsoft Corp.
+ * All rights reserved.
+ *
+ * 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 unmodified, 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * 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>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/bus.h>
+
+#include <machine/bus.h>
+
+#include <dev/hyperv/include/hyperv_busdma.h>
+
+#define HYPERV_DMA_WAITMASK	(BUS_DMA_WAITOK | BUS_DMA_NOWAIT)
+
+void
+hyperv_dma_map_paddr(void *arg, bus_dma_segment_t *segs, int nseg, int error)
+{
+	bus_addr_t *paddr = arg;
+
+	if (error)
+		return;
+
+	KASSERT(nseg == 1, ("too many segments %d!", nseg));
+	*paddr = segs->ds_addr;
+}
+
+void *
+hyperv_dmamem_alloc(bus_dma_tag_t parent_dtag, bus_size_t alignment,
+    bus_addr_t boundary, bus_size_t size, struct hyperv_dma *dma, int flags)
+{
+	void *ret;
+	int error;
+
+	error = bus_dma_tag_create(parent_dtag, /* parent */
+	    alignment,		/* alignment */
+	    boundary,		/* boundary */
+	    BUS_SPACE_MAXADDR,	/* lowaddr */
+	    BUS_SPACE_MAXADDR,	/* highaddr */
+	    NULL, NULL,		/* filter, filterarg */
+	    size,		/* maxsize */
+	    1,			/* nsegments */
+	    size,		/* maxsegsize */
+	    0,			/* flags */
+	    NULL,		/* lockfunc */
+	    NULL,		/* lockfuncarg */
+	    &dma->hv_dtag);
+	if (error)
+		return NULL;
+
+	error = bus_dmamem_alloc(dma->hv_dtag, &ret,
+	    (flags & HYPERV_DMA_WAITMASK) | BUS_DMA_COHERENT, &dma->hv_dmap);
+	if (error) {
+		bus_dma_tag_destroy(dma->hv_dtag);
+		return NULL;
+	}
+
+	error = bus_dmamap_load(dma->hv_dtag, dma->hv_dmap, ret, size,
+	    hyperv_dma_map_paddr, &dma->hv_paddr, BUS_DMA_NOWAIT);
+	if (error) {
+		bus_dmamem_free(dma->hv_dtag, ret, dma->hv_dmap);
+		bus_dma_tag_destroy(dma->hv_dtag);
+		return NULL;
+	}
+	return ret;
+}
+
+void
+hyperv_dmamem_free(struct hyperv_dma *dma, void *ptr)
+{
+	bus_dmamap_unload(dma->hv_dtag, dma->hv_dmap);
+	bus_dmamem_free(dma->hv_dtag, ptr, dma->hv_dmap);
+	bus_dma_tag_destroy(dma->hv_dtag);
+}