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@

7 files changed, 41 insertions, 7 deletions

diff --git a/sys/arch/alpha/include/bus.h b/sys/arch/alpha/include/bus.h
index ce668936a65..c18f5f16afc 100644
--- a/sys/arch/alpha/include/bus.h
+++ b/sys/arch/alpha/include/bus.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: bus.h,v 1.21 2006/04/04 21:18:43 brad Exp $	*/
+/*	$OpenBSD: bus.h,v 1.22 2006/04/04 21:20:40 brad Exp $	*/
 /*	$NetBSD: bus.h,v 1.10 1996/12/02 22:19:32 cgd Exp $	*/
 
 /*
@@ -531,6 +531,16 @@ struct alpha_bus_dma_tag {
 	struct alpha_sgmap *_sgmap;
 
 	/*
+	 * The SGMAP MMU implements a prefetch FIFO to keep data
+	 * moving down the pipe, when doing host->bus DMA writes.
+	 * The threshold (distance until the next page) used to
+	 * trigger the prefetch is differnet on different chipsets,
+	 * and we need to know what it is in order to know whether
+	 * or not to allocate a spill page.
+	 */
+	bus_size_t _pfthresh;
+
+	/*
 	 * Internal-use only utility methods.  NOT TO BE USED BY
 	 * MACHINE-INDEPENDENT CODE!
 	 */
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;
diff --git a/sys/arch/alpha/tc/tc_dma.c b/sys/arch/alpha/tc/tc_dma.c
index 5de443eaaa5..a22b10b765f 100644
--- a/sys/arch/alpha/tc/tc_dma.c
+++ b/sys/arch/alpha/tc/tc_dma.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: tc_dma.c,v 1.1 2002/05/02 22:56:06 miod Exp $ */
+/* $OpenBSD: tc_dma.c,v 1.2 2006/04/04 21:20:40 brad Exp $ */
 /* $NetBSD: tc_dma.c,v 1.10 2001/07/19 06:40:02 thorpej Exp $ */
 
 /*-
@@ -54,6 +54,7 @@ struct alpha_bus_dma_tag tc_dmat_direct = {
 	NULL,				/* _next_window */
 	0,				/* _boundary */
 	NULL,				/* _sgmap */
+	0,				/* _pfthresh */
 	NULL,				/* _get_tag */
 	_bus_dmamap_create,
 	_bus_dmamap_destroy,
diff --git a/sys/arch/alpha/tc/tc_dma_3000_500.c b/sys/arch/alpha/tc/tc_dma_3000_500.c
index 49732d62ec9..51faf6d9262 100644
--- a/sys/arch/alpha/tc/tc_dma_3000_500.c
+++ b/sys/arch/alpha/tc/tc_dma_3000_500.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: tc_dma_3000_500.c,v 1.1 2002/05/02 22:56:06 miod Exp $ */
+/* $OpenBSD: tc_dma_3000_500.c,v 1.2 2006/04/04 21:20:40 brad Exp $ */
 /* $NetBSD: tc_dma_3000_500.c,v 1.13 2001/07/19 06:40:03 thorpej Exp $ */
 
 /*-
@@ -61,6 +61,7 @@ struct alpha_bus_dma_tag tc_dmat_sgmap = {
 	NULL,				/* _next_window */
 	0,				/* _boundary */
 	NULL,				/* _sgmap */
+	0,				/* _pfthresh */
 	NULL,				/* _get_tag */
 	tc_bus_dmamap_create_sgmap,
 	tc_bus_dmamap_destroy_sgmap,