Add a `prefetch threshold' member to the bus_dma_tag_t, so that

eventually we can determine whether or not to allocate a spill
page on a per-mapping basis.

From NetBSD

ok martin@

4 files changed, 26 insertions, 4 deletions

diff --git a/sys/arch/alpha/pci/apecs_dma.c b/sys/arch/alpha/pci/apecs_dma.c
index a4ba8c61253..979081ea0e9 100644
--- a/sys/arch/alpha/pci/apecs_dma.c
+++ b/sys/arch/alpha/pci/apecs_dma.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: apecs_dma.c,v 1.4 2006/03/20 01:00:58 martin Exp $ */
+/* $OpenBSD: apecs_dma.c,v 1.5 2006/04/04 21:20:40 brad Exp $ */
 /* $NetBSD: apecs_dma.c,v 1.13 2000/06/29 08:58:45 mrg Exp $ */
 
 /*-
@@ -87,6 +87,9 @@ void	apecs_bus_dmamap_unload_sgmap(bus_dma_tag_t, bus_dmamap_t);
 #define	APECS_SGMAP_MAPPED_BASE	(8*1024*1024)
 #define	APECS_SGMAP_MAPPED_SIZE	(8*1024*1024)
 
+/* APECS has a 256-byte out-bound DMA prefetch threshold. */
+#define	APECS_SGMAP_PFTHRESH	256
+
 /*
  * Macro to flush APECS scatter/gather TLB.
  */
@@ -140,6 +143,7 @@ apecs_dma_init(acp)
 	t->_next_window = NULL;
 	t->_boundary = 0;
 	t->_sgmap = &acp->ac_sgmap;
+	t->_pfthresh = APECS_SGMAP_PFTHRESH;
 	t->_get_tag = apecs_dma_get_tag;
 	t->_dmamap_create = alpha_sgmap_dmamap_create;
 	t->_dmamap_destroy = alpha_sgmap_dmamap_destroy;
diff --git a/sys/arch/alpha/pci/cia_dma.c b/sys/arch/alpha/pci/cia_dma.c
index 37394c9e799..5cc6c2a3fb4 100644
--- a/sys/arch/alpha/pci/cia_dma.c
+++ b/sys/arch/alpha/pci/cia_dma.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: cia_dma.c,v 1.6 2006/03/20 01:00:58 martin Exp $ */
+/* $OpenBSD: cia_dma.c,v 1.7 2006/04/04 21:20:40 brad Exp $ */
 /* $NetBSD: cia_dma.c,v 1.16 2000/06/29 08:58:46 mrg Exp $ */
 
 /*-
@@ -90,6 +90,9 @@ void	cia_bus_dmamap_unload_sgmap(bus_dma_tag_t, bus_dmamap_t);
 #define	CIA_SGMAP_MAPPED_BASE	(8*1024*1024)
 #define	CIA_SGMAP_MAPPED_SIZE	(8*1024*1024)
 
+/* ALCOR/ALGOR2/PYXIS have a 256-byte out-bound DMA prefetch threshold. */
+#define	CIA_SGMAP_PFTHRESH	256
+
 void	cia_tlb_invalidate(void);
 void	cia_broken_pyxis_tlb_invalidate(void);
 
@@ -144,6 +147,7 @@ cia_dma_init(ccp)
 	t->_next_window = NULL;
 	t->_boundary = 0;
 	t->_sgmap = &ccp->cc_sgmap;
+	t->_pfthresh = CIA_SGMAP_PFTHRESH;
 	t->_get_tag = cia_dma_get_tag;
 	t->_dmamap_create = alpha_sgmap_dmamap_create;
 	t->_dmamap_destroy = alpha_sgmap_dmamap_destroy;
diff --git a/sys/arch/alpha/pci/lca_dma.c b/sys/arch/alpha/pci/lca_dma.c
index a6c4f293f4c..8655bc90210 100644
--- a/sys/arch/alpha/pci/lca_dma.c
+++ b/sys/arch/alpha/pci/lca_dma.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: lca_dma.c,v 1.6 2006/03/20 01:00:58 martin Exp $	*/
+/*	$OpenBSD: lca_dma.c,v 1.7 2006/04/04 21:20:40 brad Exp $	*/
 /* $NetBSD: lca_dma.c,v 1.13 2000/06/29 08:58:47 mrg Exp $ */
 
 /*-
@@ -88,6 +88,12 @@ void	lca_bus_dmamap_unload_sgmap(bus_dma_tag_t, bus_dmamap_t);
 #define	LCA_SGMAP_MAPPED_SIZE	(8*1024*1024)
 
 /*
+ * The LCA doesn't have a DMA prefetch threshold.  However, it is known
+ * to lose if we don't allocate a spill page.  So initialize it to 256.
+ */
+#define	LCA_SGMAP_PFTHRESH	256
+
+/*
  * Macro to flush LCA scatter/gather TLB.
  */
 #define	LCA_TLB_INVALIDATE() \
@@ -139,6 +145,7 @@ lca_dma_init(lcp)
 	t->_next_window = NULL;
 	t->_boundary = 0;
 	t->_sgmap = &lcp->lc_sgmap;
+	t->_pfthresh = LCA_SGMAP_PFTHRESH;
 	t->_get_tag = lca_dma_get_tag;
 	t->_dmamap_create = alpha_sgmap_dmamap_create;
 
diff --git a/sys/arch/alpha/pci/tsp_dma.c b/sys/arch/alpha/pci/tsp_dma.c
index 339daaf9648..ef8fb593a68 100644
--- a/sys/arch/alpha/pci/tsp_dma.c
+++ b/sys/arch/alpha/pci/tsp_dma.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: tsp_dma.c,v 1.4 2006/03/20 01:00:58 martin Exp $ */
+/* $OpenBSD: tsp_dma.c,v 1.5 2006/04/04 21:20:40 brad Exp $ */
 /* $NetBSD: tsp_dma.c,v 1.1 1999/06/29 06:46:47 ross Exp $ */
 
 /*-
@@ -111,6 +111,12 @@ void	tsp_bus_dmamap_unload_sgmap(bus_dma_tag_t, bus_dmamap_t);
 
 void	tsp_tlb_invalidate(struct tsp_config *);
 
+/*
+ * XXX Need to figure out what this is, if any.  Initialize it to
+ * XXX something that should be safe.
+ */
+#define	TSP_SGMAP_PFTHRESH	256
+
 void
 tsp_dma_init(pcp)
 	struct tsp_config *pcp;
@@ -179,6 +185,7 @@ tsp_dma_init(pcp)
 	t->_next_window = NULL;
 	t->_boundary = 0;
 	t->_sgmap = &pcp->pc_sgmap;
+	t->_pfthresh = TSP_SGMAP_PFTHRESH;
 	t->_get_tag = tsp_dma_get_tag;
 	t->_dmamap_create = alpha_sgmap_dmamap_create;
 	t->_dmamap_destroy = alpha_sgmap_dmamap_destroy;