svn commit: r207951 - projects/altix/sys/kern

Marcel Moolenaar marcel at FreeBSD.org
Wed May 12 04:42:36 UTC 2010


Author: marcel
Date: Wed May 12 04:42:36 2010
New Revision: 207951
URL: http://svn.freebsd.org/changeset/base/207951

Log:
  The Altix needs busdma work because 1) there's no memory where devices
  can get to, unless they are truly 64-bit and 2) there's an I/O MMU that
  we need to use.
  
  Bootstrap an MI implementation from the amd64 MD version. I have this
  gut feeling we can have 90% or more of busdma implemented by MI code.

Added:
     - copied unchanged from r207950, projects/altix/sys/amd64/amd64/busdma_machdep.c
Directory Properties:
  projects/altix/sys/kern/subr_busdma.c   (props changed)

Copied: projects/altix/sys/kern/subr_busdma.c (from r207950, projects/altix/sys/amd64/amd64/busdma_machdep.c)
==============================================================================
--- /dev/null	00:00:00 1970	(empty, because file is newly added)
+++ projects/altix/sys/kern/subr_busdma.c	Wed May 12 04:42:36 2010	(r207951, copy of r207950, projects/altix/sys/amd64/amd64/busdma_machdep.c)
@@ -0,0 +1,1205 @@
+/*-
+ * Copyright (c) 1997, 1998 Justin T. Gibbs.
+ * 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, this list of conditions, and the following disclaimer,
+ *    without modification, immediately at the beginning of the file.
+ * 2. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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/malloc.h>
+#include <sys/bus.h>
+#include <sys/interrupt.h>
+#include <sys/kernel.h>
+#include <sys/ktr.h>
+#include <sys/lock.h>
+#include <sys/proc.h>
+#include <sys/mutex.h>
+#include <sys/mbuf.h>
+#include <sys/uio.h>
+#include <sys/sysctl.h>
+
+#include <vm/vm.h>
+#include <vm/vm_page.h>
+#include <vm/vm_map.h>
+
+#include <machine/atomic.h>
+#include <machine/bus.h>
+#include <machine/md_var.h>
+#include <machine/specialreg.h>
+
+#define MAX_BPAGES 8192
+
+struct bounce_zone;
+
+struct bus_dma_tag {
+	bus_dma_tag_t	  parent;
+	bus_size_t	  alignment;
+	bus_size_t	  boundary;
+	bus_addr_t	  lowaddr;
+	bus_addr_t	  highaddr;
+	bus_dma_filter_t *filter;
+	void		 *filterarg;
+	bus_size_t	  maxsize;
+	u_int		  nsegments;
+	bus_size_t	  maxsegsz;
+	int		  flags;
+	int		  ref_count;
+	int		  map_count;
+	bus_dma_lock_t	 *lockfunc;
+	void		 *lockfuncarg;
+	bus_dma_segment_t *segments;
+	struct bounce_zone *bounce_zone;
+};
+
+struct bounce_page {
+	vm_offset_t	vaddr;		/* kva of bounce buffer */
+	bus_addr_t	busaddr;	/* Physical address */
+	vm_offset_t	datavaddr;	/* kva of client data */
+	bus_size_t	datacount;	/* client data count */
+	STAILQ_ENTRY(bounce_page) links;
+};
+
+int busdma_swi_pending;
+
+struct bounce_zone {
+	STAILQ_ENTRY(bounce_zone) links;
+	STAILQ_HEAD(bp_list, bounce_page) bounce_page_list;
+	int		total_bpages;
+	int		free_bpages;
+	int		reserved_bpages;
+	int		active_bpages;
+	int		total_bounced;
+	int		total_deferred;
+	int		map_count;
+	bus_size_t	alignment;
+	bus_addr_t	lowaddr;
+	char		zoneid[8];
+	char		lowaddrid[20];
+	struct sysctl_ctx_list sysctl_tree;
+	struct sysctl_oid *sysctl_tree_top;
+};
+
+static struct mtx bounce_lock;
+static int total_bpages;
+static int busdma_zonecount;
+static STAILQ_HEAD(, bounce_zone) bounce_zone_list;
+
+SYSCTL_NODE(_hw, OID_AUTO, busdma, CTLFLAG_RD, 0, "Busdma parameters");
+SYSCTL_INT(_hw_busdma, OID_AUTO, total_bpages, CTLFLAG_RD, &total_bpages, 0,
+	   "Total bounce pages");
+
+struct bus_dmamap {
+	struct bp_list	       bpages;
+	int		       pagesneeded;
+	int		       pagesreserved;
+	bus_dma_tag_t	       dmat;
+	void		      *buf;		/* unmapped buffer pointer */
+	bus_size_t	       buflen;		/* unmapped buffer length */
+	bus_dmamap_callback_t *callback;
+	void		      *callback_arg;
+	STAILQ_ENTRY(bus_dmamap) links;
+};
+
+static STAILQ_HEAD(, bus_dmamap) bounce_map_waitinglist;
+static STAILQ_HEAD(, bus_dmamap) bounce_map_callbacklist;
+static struct bus_dmamap nobounce_dmamap;
+
+static void init_bounce_pages(void *dummy);
+static int alloc_bounce_zone(bus_dma_tag_t dmat);
+static int alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages);
+static int reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map,
+				int commit);
+static bus_addr_t add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map,
+				   vm_offset_t vaddr, bus_size_t size);
+static void free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage);
+static __inline int run_filter(bus_dma_tag_t dmat, bus_addr_t paddr);
+
+/*
+ * Return true if a match is made.
+ *
+ * To find a match walk the chain of bus_dma_tag_t's looking for 'paddr'.
+ *
+ * If paddr is within the bounds of the dma tag then call the filter callback
+ * to check for a match, if there is no filter callback then assume a match.
+ */
+static __inline int
+run_filter(bus_dma_tag_t dmat, bus_addr_t paddr)
+{
+	int retval;
+
+	retval = 0;
+
+	do {
+		if (((paddr > dmat->lowaddr && paddr <= dmat->highaddr)
+		 || ((paddr & (dmat->alignment - 1)) != 0))
+		 && (dmat->filter == NULL
+		  || (*dmat->filter)(dmat->filterarg, paddr) != 0))
+			retval = 1;
+
+		dmat = dmat->parent;		
+	} while (retval == 0 && dmat != NULL);
+	return (retval);
+}
+
+/*
+ * Convenience function for manipulating driver locks from busdma (during
+ * busdma_swi, for example).  Drivers that don't provide their own locks
+ * should specify &Giant to dmat->lockfuncarg.  Drivers that use their own
+ * non-mutex locking scheme don't have to use this at all.
+ */
+void
+busdma_lock_mutex(void *arg, bus_dma_lock_op_t op)
+{
+	struct mtx *dmtx;
+
+	dmtx = (struct mtx *)arg;
+	switch (op) {
+	case BUS_DMA_LOCK:
+		mtx_lock(dmtx);
+		break;
+	case BUS_DMA_UNLOCK:
+		mtx_unlock(dmtx);
+		break;
+	default:
+		panic("Unknown operation 0x%x for busdma_lock_mutex!", op);
+	}
+}
+
+/*
+ * dflt_lock should never get called.  It gets put into the dma tag when
+ * lockfunc == NULL, which is only valid if the maps that are associated
+ * with the tag are meant to never be defered.
+ * XXX Should have a way to identify which driver is responsible here.
+ */
+static void
+dflt_lock(void *arg, bus_dma_lock_op_t op)
+{
+	panic("driver error: busdma dflt_lock called");
+}
+
+#define BUS_DMA_COULD_BOUNCE	BUS_DMA_BUS3
+#define BUS_DMA_MIN_ALLOC_COMP	BUS_DMA_BUS4
+/*
+ * Allocate a device specific dma_tag.
+ */
+int
+bus_dma_tag_create(bus_dma_tag_t parent, bus_size_t alignment,
+		   bus_size_t boundary, bus_addr_t lowaddr,
+		   bus_addr_t highaddr, bus_dma_filter_t *filter,
+		   void *filterarg, bus_size_t maxsize, int nsegments,
+		   bus_size_t maxsegsz, int flags, bus_dma_lock_t *lockfunc,
+		   void *lockfuncarg, bus_dma_tag_t *dmat)
+{
+	bus_dma_tag_t newtag;
+	int error = 0;
+
+	/* Basic sanity checking */
+	if (boundary != 0 && boundary < maxsegsz)
+		maxsegsz = boundary;
+
+	if (maxsegsz == 0) {
+		return (EINVAL);
+	}
+
+	/* Return a NULL tag on failure */
+	*dmat = NULL;
+
+	newtag = (bus_dma_tag_t)malloc(sizeof(*newtag), M_DEVBUF,
+	    M_ZERO | M_NOWAIT);
+	if (newtag == NULL) {
+		CTR4(KTR_BUSDMA, "%s returned tag %p tag flags 0x%x error %d",
+		    __func__, newtag, 0, error);
+		return (ENOMEM);
+	}
+
+	newtag->parent = parent;
+	newtag->alignment = alignment;
+	newtag->boundary = boundary;
+	newtag->lowaddr = trunc_page((vm_paddr_t)lowaddr) + (PAGE_SIZE - 1);
+	newtag->highaddr = trunc_page((vm_paddr_t)highaddr) + (PAGE_SIZE - 1);
+	newtag->filter = filter;
+	newtag->filterarg = filterarg;
+	newtag->maxsize = maxsize;
+	newtag->nsegments = nsegments;
+	newtag->maxsegsz = maxsegsz;
+	newtag->flags = flags;
+	newtag->ref_count = 1; /* Count ourself */
+	newtag->map_count = 0;
+	if (lockfunc != NULL) {
+		newtag->lockfunc = lockfunc;
+		newtag->lockfuncarg = lockfuncarg;
+	} else {
+		newtag->lockfunc = dflt_lock;
+		newtag->lockfuncarg = NULL;
+	}
+	newtag->segments = NULL;
+
+	/* Take into account any restrictions imposed by our parent tag */
+	if (parent != NULL) {
+		newtag->lowaddr = MIN(parent->lowaddr, newtag->lowaddr);
+		newtag->highaddr = MAX(parent->highaddr, newtag->highaddr);
+		if (newtag->boundary == 0)
+			newtag->boundary = parent->boundary;
+		else if (parent->boundary != 0)
+			newtag->boundary = MIN(parent->boundary,
+					       newtag->boundary);
+		if (newtag->filter == NULL) {
+			/*
+			 * Short circuit looking at our parent directly
+			 * since we have encapsulated all of its information
+			 */
+			newtag->filter = parent->filter;
+			newtag->filterarg = parent->filterarg;
+			newtag->parent = parent->parent;
+		}
+		if (newtag->parent != NULL)
+			atomic_add_int(&parent->ref_count, 1);
+	}
+
+	if (newtag->lowaddr < ptoa((vm_paddr_t)Maxmem)
+	 || newtag->alignment > 1)
+		newtag->flags |= BUS_DMA_COULD_BOUNCE;
+
+	if (((newtag->flags & BUS_DMA_COULD_BOUNCE) != 0) &&
+	    (flags & BUS_DMA_ALLOCNOW) != 0) {
+		struct bounce_zone *bz;
+
+		/* Must bounce */
+
+		if ((error = alloc_bounce_zone(newtag)) != 0) {
+			free(newtag, M_DEVBUF);
+			return (error);
+		}
+		bz = newtag->bounce_zone;
+
+		if (ptoa(bz->total_bpages) < maxsize) {
+			int pages;
+
+			pages = atop(maxsize) - bz->total_bpages;
+
+			/* Add pages to our bounce pool */
+			if (alloc_bounce_pages(newtag, pages) < pages)
+				error = ENOMEM;
+		}
+		/* Performed initial allocation */
+		newtag->flags |= BUS_DMA_MIN_ALLOC_COMP;
+	}
+	
+	if (error != 0) {
+		free(newtag, M_DEVBUF);
+	} else {
+		*dmat = newtag;
+	}
+	CTR4(KTR_BUSDMA, "%s returned tag %p tag flags 0x%x error %d",
+	    __func__, newtag, (newtag != NULL ? newtag->flags : 0), error);
+	return (error);
+}
+
+int
+bus_dma_tag_destroy(bus_dma_tag_t dmat)
+{
+	bus_dma_tag_t dmat_copy;
+	int error;
+
+	error = 0;
+	dmat_copy = dmat;
+
+	if (dmat != NULL) {
+
+		if (dmat->map_count != 0) {
+			error = EBUSY;
+			goto out;
+		}
+
+		while (dmat != NULL) {
+			bus_dma_tag_t parent;
+
+			parent = dmat->parent;
+			atomic_subtract_int(&dmat->ref_count, 1);
+			if (dmat->ref_count == 0) {
+				if (dmat->segments != NULL)
+					free(dmat->segments, M_DEVBUF);
+				free(dmat, M_DEVBUF);
+				/*
+				 * Last reference count, so
+				 * release our reference
+				 * count on our parent.
+				 */
+				dmat = parent;
+			} else
+				dmat = NULL;
+		}
+	}
+out:
+	CTR3(KTR_BUSDMA, "%s tag %p error %d", __func__, dmat_copy, error);
+	return (error);
+}
+
+/*
+ * Allocate a handle for mapping from kva/uva/physical
+ * address space into bus device space.
+ */
+int
+bus_dmamap_create(bus_dma_tag_t dmat, int flags, bus_dmamap_t *mapp)
+{
+	int error;
+
+	error = 0;
+
+	if (dmat->segments == NULL) {
+		dmat->segments = (bus_dma_segment_t *)malloc(
+		    sizeof(bus_dma_segment_t) * dmat->nsegments, M_DEVBUF,
+		    M_NOWAIT);
+		if (dmat->segments == NULL) {
+			CTR3(KTR_BUSDMA, "%s: tag %p error %d",
+			    __func__, dmat, ENOMEM);
+			return (ENOMEM);
+		}
+	}
+
+	/*
+	 * Bouncing might be required if the driver asks for an active
+	 * exclusion region, a data alignment that is stricter than 1, and/or
+	 * an active address boundary.
+	 */
+	if (dmat->flags & BUS_DMA_COULD_BOUNCE) {
+
+		/* Must bounce */
+		struct bounce_zone *bz;
+		int maxpages;
+
+		if (dmat->bounce_zone == NULL) {
+			if ((error = alloc_bounce_zone(dmat)) != 0)
+				return (error);
+		}
+		bz = dmat->bounce_zone;
+
+		*mapp = (bus_dmamap_t)malloc(sizeof(**mapp), M_DEVBUF,
+					     M_NOWAIT | M_ZERO);
+		if (*mapp == NULL) {
+			CTR3(KTR_BUSDMA, "%s: tag %p error %d",
+			    __func__, dmat, ENOMEM);
+			return (ENOMEM);
+		}
+
+		/* Initialize the new map */
+		STAILQ_INIT(&((*mapp)->bpages));
+
+		/*
+		 * Attempt to add pages to our pool on a per-instance
+		 * basis up to a sane limit.
+		 */
+		if (dmat->alignment > 1)
+			maxpages = MAX_BPAGES;
+		else
+			maxpages = MIN(MAX_BPAGES, Maxmem -atop(dmat->lowaddr));
+		if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0
+		 || (bz->map_count > 0 && bz->total_bpages < maxpages)) {
+			int pages;
+
+			pages = MAX(atop(dmat->maxsize), 1);
+			pages = MIN(maxpages - bz->total_bpages, pages);
+			pages = MAX(pages, 1);
+			if (alloc_bounce_pages(dmat, pages) < pages)
+				error = ENOMEM;
+
+			if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0) {
+				if (error == 0)
+					dmat->flags |= BUS_DMA_MIN_ALLOC_COMP;
+			} else {
+				error = 0;
+			}
+		}
+		bz->map_count++;
+	} else {
+		*mapp = NULL;
+	}
+	if (error == 0)
+		dmat->map_count++;
+	CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
+	    __func__, dmat, dmat->flags, error);
+	return (error);
+}
+
+/*
+ * Destroy a handle for mapping from kva/uva/physical
+ * address space into bus device space.
+ */
+int
+bus_dmamap_destroy(bus_dma_tag_t dmat, bus_dmamap_t map)
+{
+	if (map != NULL && map != &nobounce_dmamap) {
+		if (STAILQ_FIRST(&map->bpages) != NULL) {
+			CTR3(KTR_BUSDMA, "%s: tag %p error %d",
+			    __func__, dmat, EBUSY);
+			return (EBUSY);
+		}
+		if (dmat->bounce_zone)
+			dmat->bounce_zone->map_count--;
+		free(map, M_DEVBUF);
+	}
+	dmat->map_count--;
+	CTR2(KTR_BUSDMA, "%s: tag %p error 0", __func__, dmat);
+	return (0);
+}
+
+
+/*
+ * Allocate a piece of memory that can be efficiently mapped into
+ * bus device space based on the constraints lited in the dma tag.
+ * A dmamap to for use with dmamap_load is also allocated.
+ */
+int
+bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
+		 bus_dmamap_t *mapp)
+{
+	int mflags;
+
+	if (flags & BUS_DMA_NOWAIT)
+		mflags = M_NOWAIT;
+	else
+		mflags = M_WAITOK;
+
+	/* If we succeed, no mapping/bouncing will be required */
+	*mapp = NULL;
+
+	if (dmat->segments == NULL) {
+		dmat->segments = (bus_dma_segment_t *)malloc(
+		    sizeof(bus_dma_segment_t) * dmat->nsegments, M_DEVBUF,
+		    mflags);
+		if (dmat->segments == NULL) {
+			CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
+			    __func__, dmat, dmat->flags, ENOMEM);
+			return (ENOMEM);
+		}
+	}
+	if (flags & BUS_DMA_ZERO)
+		mflags |= M_ZERO;
+
+	/* 
+	 * XXX:
+	 * (dmat->alignment < dmat->maxsize) is just a quick hack; the exact
+	 * alignment guarantees of malloc need to be nailed down, and the
+	 * code below should be rewritten to take that into account.
+	 *
+	 * In the meantime, we'll warn the user if malloc gets it wrong.
+	 */
+	if ((dmat->maxsize <= PAGE_SIZE) &&
+	   (dmat->alignment < dmat->maxsize) &&
+	    dmat->lowaddr >= ptoa((vm_paddr_t)Maxmem)) {
+		*vaddr = malloc(dmat->maxsize, M_DEVBUF, mflags);
+	} else {
+		/*
+		 * XXX Use Contigmalloc until it is merged into this facility
+		 *     and handles multi-seg allocations.  Nobody is doing
+		 *     multi-seg allocations yet though.
+		 * XXX Certain AGP hardware does.
+		 */
+		*vaddr = contigmalloc(dmat->maxsize, M_DEVBUF, mflags,
+		    0ul, dmat->lowaddr, dmat->alignment? dmat->alignment : 1ul,
+		    dmat->boundary);
+	}
+	if (*vaddr == NULL) {
+		CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
+		    __func__, dmat, dmat->flags, ENOMEM);
+		return (ENOMEM);
+	} else if ((uintptr_t)*vaddr & (dmat->alignment - 1)) {
+		printf("bus_dmamem_alloc failed to align memory properly.\n");
+	}
+	if (flags & BUS_DMA_NOCACHE)
+		pmap_change_attr((vm_offset_t)*vaddr, dmat->maxsize,
+		    PAT_UNCACHEABLE);
+	CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
+	    __func__, dmat, dmat->flags, 0);
+	return (0);
+}
+
+/*
+ * Free a piece of memory and it's allociated dmamap, that was allocated
+ * via bus_dmamem_alloc.  Make the same choice for free/contigfree.
+ */
+void
+bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
+{
+	/*
+	 * dmamem does not need to be bounced, so the map should be
+	 * NULL
+	 */
+	if (map != NULL)
+		panic("bus_dmamem_free: Invalid map freed\n");
+	pmap_change_attr((vm_offset_t)vaddr, dmat->maxsize, PAT_WRITE_BACK);
+	if ((dmat->maxsize <= PAGE_SIZE) &&
+	   (dmat->alignment < dmat->maxsize) &&
+	    dmat->lowaddr >= ptoa((vm_paddr_t)Maxmem))
+		free(vaddr, M_DEVBUF);
+	else {
+		contigfree(vaddr, dmat->maxsize, M_DEVBUF);
+	}
+	CTR3(KTR_BUSDMA, "%s: tag %p flags 0x%x", __func__, dmat, dmat->flags);
+}
+
+/*
+ * Utility function to load a linear buffer.  lastaddrp holds state
+ * between invocations (for multiple-buffer loads).  segp contains
+ * the starting segment on entrace, and the ending segment on exit.
+ * first indicates if this is the first invocation of this function.
+ */
+static __inline int
+_bus_dmamap_load_buffer(bus_dma_tag_t dmat,
+    			bus_dmamap_t map,
+			void *buf, bus_size_t buflen,
+			pmap_t pmap,
+			int flags,
+			bus_addr_t *lastaddrp,
+			bus_dma_segment_t *segs,
+			int *segp,
+			int first)
+{
+	bus_size_t sgsize;
+	bus_addr_t curaddr, lastaddr, baddr, bmask;
+	vm_offset_t vaddr;
+	bus_addr_t paddr;
+	int seg;
+
+	if (map == NULL)
+		map = &nobounce_dmamap;
+
+	if ((map != &nobounce_dmamap && map->pagesneeded == 0) 
+	 && ((dmat->flags & BUS_DMA_COULD_BOUNCE) != 0)) {
+		vm_offset_t	vendaddr;
+
+		CTR4(KTR_BUSDMA, "lowaddr= %d Maxmem= %d, boundary= %d, "
+		    "alignment= %d", dmat->lowaddr, ptoa((vm_paddr_t)Maxmem),
+		    dmat->boundary, dmat->alignment);
+		CTR3(KTR_BUSDMA, "map= %p, nobouncemap= %p, pagesneeded= %d",
+		    map, &nobounce_dmamap, map->pagesneeded);
+		/*
+		 * Count the number of bounce pages
+		 * needed in order to complete this transfer
+		 */
+		vaddr = (vm_offset_t)buf;
+		vendaddr = (vm_offset_t)buf + buflen;
+
+		while (vaddr < vendaddr) {
+			bus_size_t sg_len;
+
+			sg_len = PAGE_SIZE - ((vm_offset_t)vaddr & PAGE_MASK);
+			if (pmap)
+				paddr = pmap_extract(pmap, vaddr);
+			else
+				paddr = pmap_kextract(vaddr);
+			if (run_filter(dmat, paddr) != 0) {
+				sg_len = roundup2(sg_len, dmat->alignment);
+				map->pagesneeded++;
+			}
+			vaddr += sg_len;
+		}
+		CTR1(KTR_BUSDMA, "pagesneeded= %d\n", map->pagesneeded);
+	}
+
+	/* Reserve Necessary Bounce Pages */
+	if (map->pagesneeded != 0) {
+		mtx_lock(&bounce_lock);
+		if (flags & BUS_DMA_NOWAIT) {
+			if (reserve_bounce_pages(dmat, map, 0) != 0) {
+				mtx_unlock(&bounce_lock);
+				return (ENOMEM);
+			}
+		} else {
+			if (reserve_bounce_pages(dmat, map, 1) != 0) {
+				/* Queue us for resources */
+				map->dmat = dmat;
+				map->buf = buf;
+				map->buflen = buflen;
+				STAILQ_INSERT_TAIL(&bounce_map_waitinglist,
+				    map, links);
+				mtx_unlock(&bounce_lock);
+				return (EINPROGRESS);
+			}
+		}
+		mtx_unlock(&bounce_lock);
+	}
+
+	vaddr = (vm_offset_t)buf;
+	lastaddr = *lastaddrp;
+	bmask = ~(dmat->boundary - 1);
+
+	for (seg = *segp; buflen > 0 ; ) {
+		bus_size_t max_sgsize;
+
+		/*
+		 * Get the physical address for this segment.
+		 */
+		if (pmap)
+			curaddr = pmap_extract(pmap, vaddr);
+		else
+			curaddr = pmap_kextract(vaddr);
+
+		/*
+		 * Compute the segment size, and adjust counts.
+		 */
+		max_sgsize = MIN(buflen, dmat->maxsegsz);
+		sgsize = PAGE_SIZE - ((vm_offset_t)curaddr & PAGE_MASK);
+		if (map->pagesneeded != 0 && run_filter(dmat, curaddr)) {
+			sgsize = roundup2(sgsize, dmat->alignment);
+			sgsize = MIN(sgsize, max_sgsize);
+			curaddr = add_bounce_page(dmat, map, vaddr, sgsize);
+		} else {
+			sgsize = MIN(sgsize, max_sgsize);
+		}
+
+		/*
+		 * Make sure we don't cross any boundaries.
+		 */
+		if (dmat->boundary > 0) {
+			baddr = (curaddr + dmat->boundary) & bmask;
+			if (sgsize > (baddr - curaddr))
+				sgsize = (baddr - curaddr);
+		}
+
+		/*
+		 * Insert chunk into a segment, coalescing with
+		 * previous segment if possible.
+		 */
+		if (first) {
+			segs[seg].ds_addr = curaddr;
+			segs[seg].ds_len = sgsize;
+			first = 0;
+		} else {
+			if (curaddr == lastaddr &&
+			    (segs[seg].ds_len + sgsize) <= dmat->maxsegsz &&
+			    (dmat->boundary == 0 ||
+			     (segs[seg].ds_addr & bmask) == (curaddr & bmask)))
+				segs[seg].ds_len += sgsize;
+			else {
+				if (++seg >= dmat->nsegments)
+					break;
+				segs[seg].ds_addr = curaddr;
+				segs[seg].ds_len = sgsize;
+			}
+		}
+
+		lastaddr = curaddr + sgsize;
+		vaddr += sgsize;
+		buflen -= sgsize;
+	}
+
+	*segp = seg;
+	*lastaddrp = lastaddr;
+
+	/*
+	 * Did we fit?
+	 */
+	return (buflen != 0 ? EFBIG : 0); /* XXX better return value here? */
+}
+
+/*
+ * Map the buffer buf into bus space using the dmamap map.
+ */
+int
+bus_dmamap_load(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
+		bus_size_t buflen, bus_dmamap_callback_t *callback,
+		void *callback_arg, int flags)
+{
+	bus_addr_t		lastaddr = 0;
+	int			error, nsegs = 0;
+
+	if (map != NULL) {
+		flags |= BUS_DMA_WAITOK;
+		map->callback = callback;
+		map->callback_arg = callback_arg;
+	}
+
+	error = _bus_dmamap_load_buffer(dmat, map, buf, buflen, NULL, flags,
+	     &lastaddr, dmat->segments, &nsegs, 1);
+
+	CTR5(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d nsegs %d",
+	    __func__, dmat, dmat->flags, error, nsegs + 1);
+
+	if (error == EINPROGRESS) {
+		return (error);
+	}
+
+	if (error)
+		(*callback)(callback_arg, dmat->segments, 0, error);
+	else
+		(*callback)(callback_arg, dmat->segments, nsegs + 1, 0);
+
+	/*
+	 * Return ENOMEM to the caller so that it can pass it up the stack.
+	 * This error only happens when NOWAIT is set, so deferal is disabled.
+	 */
+	if (error == ENOMEM)
+		return (error);
+
+	return (0);
+}
+
+
+/*
+ * Like _bus_dmamap_load(), but for mbufs.
+ */
+int
+bus_dmamap_load_mbuf(bus_dma_tag_t dmat, bus_dmamap_t map,
+		     struct mbuf *m0,
+		     bus_dmamap_callback2_t *callback, void *callback_arg,
+		     int flags)
+{
+	int nsegs, error;
+
+	M_ASSERTPKTHDR(m0);
+
+	flags |= BUS_DMA_NOWAIT;
+	nsegs = 0;
+	error = 0;
+	if (m0->m_pkthdr.len <= dmat->maxsize) {
+		int first = 1;
+		bus_addr_t lastaddr = 0;
+		struct mbuf *m;
+
+		for (m = m0; m != NULL && error == 0; m = m->m_next) {
+			if (m->m_len > 0) {
+				error = _bus_dmamap_load_buffer(dmat, map,
+						m->m_data, m->m_len,
+						NULL, flags, &lastaddr,
+						dmat->segments, &nsegs, first);
+				first = 0;
+			}
+		}
+	} else {
+		error = EINVAL;
+	}
+
+	if (error) {
+		/* force "no valid mappings" in callback */
+		(*callback)(callback_arg, dmat->segments, 0, 0, error);
+	} else {
+		(*callback)(callback_arg, dmat->segments,
+			    nsegs+1, m0->m_pkthdr.len, error);
+	}
+	CTR5(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d nsegs %d",
+	    __func__, dmat, dmat->flags, error, nsegs + 1);
+	return (error);
+}
+
+int
+bus_dmamap_load_mbuf_sg(bus_dma_tag_t dmat, bus_dmamap_t map,
+			struct mbuf *m0, bus_dma_segment_t *segs, int *nsegs,
+			int flags)
+{
+	int error;
+
+	M_ASSERTPKTHDR(m0);
+
+	flags |= BUS_DMA_NOWAIT;
+	*nsegs = 0;
+	error = 0;
+	if (m0->m_pkthdr.len <= dmat->maxsize) {
+		int first = 1;
+		bus_addr_t lastaddr = 0;
+		struct mbuf *m;
+
+		for (m = m0; m != NULL && error == 0; m = m->m_next) {
+			if (m->m_len > 0) {
+				error = _bus_dmamap_load_buffer(dmat, map,
+						m->m_data, m->m_len,
+						NULL, flags, &lastaddr,
+						segs, nsegs, first);
+				first = 0;
+			}
+		}
+	} else {
+		error = EINVAL;
+	}
+
+	/* XXX FIXME: Having to increment nsegs is really annoying */
+	++*nsegs;
+	CTR5(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d nsegs %d",
+	    __func__, dmat, dmat->flags, error, *nsegs);
+	return (error);
+}
+
+/*
+ * Like _bus_dmamap_load(), but for uios.
+ */
+int
+bus_dmamap_load_uio(bus_dma_tag_t dmat, bus_dmamap_t map,
+		    struct uio *uio,
+		    bus_dmamap_callback2_t *callback, void *callback_arg,
+		    int flags)
+{
+	bus_addr_t lastaddr = 0;
+	int nsegs, error, first, i;
+	bus_size_t resid;
+	struct iovec *iov;
+	pmap_t pmap;
+
+	flags |= BUS_DMA_NOWAIT;
+	resid = uio->uio_resid;
+	iov = uio->uio_iov;
+
+	if (uio->uio_segflg == UIO_USERSPACE) {
+		KASSERT(uio->uio_td != NULL,
+			("bus_dmamap_load_uio: USERSPACE but no proc"));
+		pmap = vmspace_pmap(uio->uio_td->td_proc->p_vmspace);
+	} else
+		pmap = NULL;
+
+	nsegs = 0;
+	error = 0;
+	first = 1;
+	for (i = 0; i < uio->uio_iovcnt && resid != 0 && !error; i++) {
+		/*
+		 * Now at the first iovec to load.  Load each iovec
+		 * until we have exhausted the residual count.
+		 */
+		bus_size_t minlen =
+			resid < iov[i].iov_len ? resid : iov[i].iov_len;
+		caddr_t addr = (caddr_t) iov[i].iov_base;
+
+		if (minlen > 0) {
+			error = _bus_dmamap_load_buffer(dmat, map,
+					addr, minlen, pmap, flags, &lastaddr,
+					dmat->segments, &nsegs, first);
+			first = 0;
+
+			resid -= minlen;
+		}
+	}
+
+	if (error) {
+		/* force "no valid mappings" in callback */
+		(*callback)(callback_arg, dmat->segments, 0, 0, error);
+	} else {
+		(*callback)(callback_arg, dmat->segments,
+			    nsegs+1, uio->uio_resid, error);
+	}
+	CTR5(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d nsegs %d",
+	    __func__, dmat, dmat->flags, error, nsegs + 1);
+	return (error);
+}
+
+/*
+ * Release the mapping held by map.
+ */
+void
+_bus_dmamap_unload(bus_dma_tag_t dmat, bus_dmamap_t map)
+{
+	struct bounce_page *bpage;
+
+	while ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
+		STAILQ_REMOVE_HEAD(&map->bpages, links);
+		free_bounce_page(dmat, bpage);
+	}
+}
+
+void
+_bus_dmamap_sync(bus_dma_tag_t dmat, bus_dmamap_t map, bus_dmasync_op_t op)
+{
+	struct bounce_page *bpage;
+
+	if ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
+		/*
+		 * Handle data bouncing.  We might also
+		 * want to add support for invalidating
+		 * the caches on broken hardware
+		 */
+		CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x op 0x%x "
+		    "performing bounce", __func__, op, dmat, dmat->flags);
+
+		if (op & BUS_DMASYNC_PREWRITE) {
+			while (bpage != NULL) {
+				bcopy((void *)bpage->datavaddr,
+				      (void *)bpage->vaddr,
+				      bpage->datacount);
+				bpage = STAILQ_NEXT(bpage, links);
+			}
+			dmat->bounce_zone->total_bounced++;
+		}
+
+		if (op & BUS_DMASYNC_POSTREAD) {
+			while (bpage != NULL) {
+				bcopy((void *)bpage->vaddr,
+				      (void *)bpage->datavaddr,
+				      bpage->datacount);
+				bpage = STAILQ_NEXT(bpage, links);
+			}
+			dmat->bounce_zone->total_bounced++;
+		}
+	}
+}
+
+static void
+init_bounce_pages(void *dummy __unused)
+{
+
+	total_bpages = 0;
+	STAILQ_INIT(&bounce_zone_list);
+	STAILQ_INIT(&bounce_map_waitinglist);
+	STAILQ_INIT(&bounce_map_callbacklist);
+	mtx_init(&bounce_lock, "bounce pages lock", NULL, MTX_DEF);
+}
+SYSINIT(bpages, SI_SUB_LOCK, SI_ORDER_ANY, init_bounce_pages, NULL);
+
+static struct sysctl_ctx_list *
+busdma_sysctl_tree(struct bounce_zone *bz)
+{
+	return (&bz->sysctl_tree);
+}
+
+static struct sysctl_oid *
+busdma_sysctl_tree_top(struct bounce_zone *bz)
+{
+	return (bz->sysctl_tree_top);
+}
+
+static int
+alloc_bounce_zone(bus_dma_tag_t dmat)
+{
+	struct bounce_zone *bz;
+
+	/* Check to see if we already have a suitable zone */
+	STAILQ_FOREACH(bz, &bounce_zone_list, links) {
+		if ((dmat->alignment <= bz->alignment)
+		 && (dmat->lowaddr >= bz->lowaddr)) {
+			dmat->bounce_zone = bz;
+			return (0);
+		}
+	}
+
+	if ((bz = (struct bounce_zone *)malloc(sizeof(*bz), M_DEVBUF,
+	    M_NOWAIT | M_ZERO)) == NULL)
+		return (ENOMEM);
+
+	STAILQ_INIT(&bz->bounce_page_list);

*** DIFF OUTPUT TRUNCATED AT 1000 LINES ***


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