Extent sgi bus_dma to cope with different views of memory: non-contiguous

for the cpu, contiguous from different bases for devices. This allows
memory above 256MB to be used with bus_dma (and we had really been lucky
with the first few large-memory builds).
Information about memory accesses taken from Linux.

2 files changed, 33 insertions, 3 deletions

diff --git a/sys/arch/sgi/localbus/crimebus.h b/sys/arch/sgi/localbus/crimebus.h
index 8eb35227c9b..67f7f7b4719 100644
--- a/sys/arch/sgi/localbus/crimebus.h
+++ b/sys/arch/sgi/localbus/crimebus.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: crimebus.h,v 1.5 2007/05/03 19:34:00 miod Exp $	*/
+/*	$OpenBSD: crimebus.h,v 1.6 2007/06/21 20:17:12 miod Exp $	*/
 
 /*
  * Copyright (c) 2003-2004 Opsycon AB (www.opsycon.se).
@@ -100,6 +100,9 @@
 #define  CRIME_MEM_BANK_128MB	   0x100
 #define CRIME_MAX_BANKS		 8
 
+#define	CRIME_MEMORY_OFFSET	0x40000000	/* 1GB */
+#define	CRIME_MEMORY_MASK	0x3fffffff
+
 #define	CRIME_MEM_ERROR_STAT	 0x0250
 #define	CRIME_MEM_ERROR_ADDR	 0x0258
 
diff --git a/sys/arch/sgi/localbus/macebus.c b/sys/arch/sgi/localbus/macebus.c
index 93e50b71b8e..555275d380d 100644
--- a/sys/arch/sgi/localbus/macebus.c
+++ b/sys/arch/sgi/localbus/macebus.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: macebus.c,v 1.24 2007/06/20 20:47:34 miod Exp $ */
+/*	$OpenBSD: macebus.c,v 1.25 2007/06/21 20:17:12 miod Exp $ */
 
 /*
  * Copyright (c) 2000-2004 Opsycon AB  (www.opsycon.se)
@@ -69,6 +69,9 @@ void macebus_do_pending_int(int);
 intrmask_t macebus_iointr(intrmask_t, struct trap_frame *);
 intrmask_t macebus_aux(intrmask_t, struct trap_frame *);
 
+bus_addr_t macebus_pa_to_device(paddr_t);
+paddr_t	macebus_device_to_pa(bus_addr_t);
+
 int maceticks;		/* Time tracker for special events */
 
 struct cfattach macebus_ca = {
@@ -121,7 +124,9 @@ struct machine_bus_dma_tag mace_bus_dma_tag = {
 	_dmamem_map,
 	_dmamem_unmap,
 	_dmamem_mmap,
-	NULL
+	macebus_pa_to_device,
+	macebus_device_to_pa,
+	CRIME_MEMORY_MASK
 };
 
 /*
@@ -430,6 +435,28 @@ mace_space_region(bus_space_tag_t t, bus_space_handle_t bsh,
 }
 
 /*
+ * Macebus bus_dma helpers.
+ * Mace accesses memory contiguously at 0x40000000 onwards.
+ */
+
+bus_addr_t
+macebus_pa_to_device(paddr_t pa)
+{
+	return (pa | CRIME_MEMORY_OFFSET);
+}
+
+paddr_t
+macebus_device_to_pa(bus_addr_t addr)
+{
+	paddr_t pa = (paddr_t)addr & CRIME_MEMORY_MASK;
+
+	if (pa >= 256 * 1024 * 1024)
+		pa |= CRIME_MEMORY_OFFSET;
+
+	return (pa);
+}
+
+/*
  *  Macebus interrupt handler driver.
  */