dma_alloc() and dma_free(). This is a thin shim on top of a bag of

pools, sized by powers of 2, which are constrained to dma memory.
ok matthew tedu thib

4 files changed, 90 insertions, 3 deletions

diff --git a/sys/conf/files b/sys/conf/files
index c3ac3f56cac..6187472e38f 100644
--- a/sys/conf/files
+++ b/sys/conf/files
@@ -1,4 +1,4 @@
-#	$OpenBSD: files,v 1.496 2010/07/05 23:10:16 tedu Exp $
+#	$OpenBSD: files,v 1.497 2010/07/13 16:47:03 deraadt Exp $
 #	$NetBSD: files,v 1.87 1996/05/19 17:17:50 jonathan Exp $
 
 #	@(#)files.newconf	7.5 (Berkeley) 5/10/93
@@ -731,6 +731,7 @@ file kern/subr_evcount.c
 file kern/subr_extent.c
 file kern/subr_log.c
 file kern/subr_pool.c
+file kern/dma_alloc.c
 file kern/subr_prf.c
 file kern/subr_prof.c
 file kern/subr_userconf.c		boot_config
diff --git a/sys/kern/dma_alloc.c b/sys/kern/dma_alloc.c
new file mode 100644
index 00000000000..7c61f906ffd
--- /dev/null
+++ b/sys/kern/dma_alloc.c
@@ -0,0 +1,76 @@
+/*	$OpenBSD: dma_alloc.c,v 1.1 2010/07/13 16:47:03 deraadt Exp $	 */
+/*
+ * Copyright (c) 2010 Theo de Raadt <deraadt@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/param.h>
+#include <sys/pool.h>
+#include <uvm/uvm.h>
+
+static __inline int	 dma_alloc_index(size_t size);
+
+#define DMA_BUCKET_OFFSET 4
+static char dmanames[PAGE_SHIFT - DMA_BUCKET_OFFSET][8];
+struct pool dmapools[PAGE_SHIFT - DMA_BUCKET_OFFSET];
+
+void
+dma_alloc_init(void)
+{
+	int i;
+
+	for (i = 0; i < nitems(dmapools); i++) {
+		snprintf(dmanames[i], sizeof(dmanames[0]), "dma%d",
+		    1 << (i + DMA_BUCKET_OFFSET));
+		pool_init(&dmapools[i], 1 << (i + DMA_BUCKET_OFFSET), 0, 0, 0,
+		    dmanames[i], NULL);
+		pool_set_constraints(&dmapools[i], &dma_constraint, 1);
+		/* XXX need pool_setlowat(&dmapools[i], dmalowat); */
+	}
+}
+
+static __inline int
+dma_alloc_index(size_t sz)
+{
+	int b;
+
+	for (b = 0; b < nitems(dmapools); b++)
+		if (sz <= (1 << (b + DMA_BUCKET_OFFSET)))
+			return (b);
+#ifdef DEBUG
+	printf("dma_alloc/free: object %d too large\n", sz)
+#endif
+	return (-1);
+}
+
+void *
+dma_alloc(size_t size, int prflags)
+{
+	int pi = dma_alloc_index(size);
+
+	if (pi == -1)
+		return (NULL);
+	return pool_get(&dmapools[pi], prflags);
+}
+
+
+void
+dma_free(void *m, size_t size)
+{
+	int pi = dma_alloc_index(size);
+
+	if (pi == -1)
+		return;
+	pool_put(&dmapools[pi], m);
+}
diff --git a/sys/sys/pool.h b/sys/sys/pool.h
index e49d075d407..b1a471ad20c 100644
--- a/sys/sys/pool.h
+++ b/sys/sys/pool.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pool.h,v 1.34 2010/06/27 03:03:48 thib Exp $	*/
+/*	$OpenBSD: pool.h,v 1.35 2010/07/13 16:47:02 deraadt Exp $	*/
 /*	$NetBSD: pool.h,v 1.27 2001/06/06 22:00:17 rafal Exp $	*/
 
 /*-
@@ -170,6 +170,11 @@ int		pool_chk(struct pool *, const char *);
 void		pool_walk(struct pool *, int, int (*)(const char *, ...),
 		    void (*)(void *, int, int (*)(const char *, ...)));
 #endif
+
+/* the allocator for dma-able memory is a thin layer on top of pool  */
+void			 dma_alloc_init(void);
+void			*dma_alloc(size_t size, int flags);
+void			 dma_free(void *m, size_t size);
 #endif /* _KERNEL */
 
 #endif /* _SYS_POOL_H_ */
diff --git a/sys/uvm/uvm_init.c b/sys/uvm/uvm_init.c
index 69502ec87b3..68ea0330b14 100644
--- a/sys/uvm/uvm_init.c
+++ b/sys/uvm/uvm_init.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uvm_init.c,v 1.25 2009/08/06 15:28:14 oga Exp $	*/
+/*	$OpenBSD: uvm_init.c,v 1.26 2010/07/13 16:47:03 deraadt Exp $	*/
 /*	$NetBSD: uvm_init.c,v 1.14 2000/06/27 17:29:23 mrg Exp $	*/
 
 /*
@@ -126,6 +126,11 @@ uvm_init(void)
 	kmeminit();
 
 	/*
+	 * step 6.5: init the dma allocator, which is backed by pools.
+	 */
+	dma_alloc_init();
+
+	/*
 	 * step 7: init all pagers and the pager_map.
 	 */