freebsd-skq/sys/sparc64/sparc64/iommu.c

/*-
 * Copyright (c) 1999, 2000 Matthew R. Green
 * Copyright (c) 2001-2003 Thomas Moestl
 * 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.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. 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 ``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 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.
 */
/*-
 * Copyright (c) 1998 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Paul Kranenburg.
 *
 * 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.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *        This product includes software developed by the NetBSD
 *        Foundation, Inc. and its contributors.
 * 4. Neither the name of The NetBSD Foundation nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */
/*-
 * Copyright (c) 1992, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This software was developed by the Computer Systems Engineering group
 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
 * contributed to Berkeley.
 *
 * 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.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 *
 *	from: NetBSD: sbus.c,v 1.13 1999/05/23 07:24:02 mrg Exp
 *	from: @(#)sbus.c	8.1 (Berkeley) 6/11/93
 *	from: NetBSD: iommu.c,v 1.42 2001/08/06 22:02:58 eeh Exp
 *
 * $FreeBSD$
 */

/*
 * UltraSPARC IOMMU support; used by both the sbus and pci code.
 * Currently, the IOTSBs are synchronized, because determining the bus the map
 * is to be loaded for is not possible with the current busdma code.
 * The code is structured so that the IOMMUs can be easily divorced when that
 * is fixed.
 *
 * TODO:
 * - As soon as there is a newbus way to get a parent dma tag, divorce the
 *   IOTSBs.
 * - Support sub-page boundaries.
 * - Fix alignment handling for small allocations (the possible page offset
 *   of malloc()ed memory is not handled at all). Revise interaction of
 *   alignment with the load_mbuf and load_uio functions.
 * - Handle lowaddr and highaddr in some way, and try to work out a way
 *   for filter callbacks to work. Currently, only lowaddr is honored
 *   in that no addresses above it are considered at all.
 * - Implement BUS_DMA_ALLOCNOW in bus_dma_tag_create as far as possible.
 * - Check the possible return values and callback error arguments;
 *   the callback currently gets called in error conditions where it should
 *   not be.
 * - When running out of DVMA space, return EINPROGRESS in the non-
 *   BUS_DMA_NOWAIT case and delay the callback until sufficient space
 *   becomes available.
 * - Use the streaming cache unless BUS_DMA_COHERENT is specified; do not
 *   flush the streaming cache when coherent mappings are synced.
 * - Add bounce buffers to support machines with more than 16GB of RAM.
 */

#include "opt_iommu.h"

#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/uio.h>

#include <vm/vm.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>

#include <machine/bus.h>
#include <machine/bus_private.h>
#include <machine/iommureg.h>
#include <machine/pmap.h>
#include <machine/resource.h>

#include <sys/rman.h>

#include <machine/iommuvar.h>

/*
 * Tuning constants.
 */
#define	IOMMU_MAX_PRE		(32 * 1024)
#define	IOMMU_MAX_PRE_SEG	3

/* Threshold for using the streaming buffer. */
#define	IOMMU_STREAM_THRESH	128

MALLOC_DEFINE(M_IOMMU, "dvmamem", "IOMMU DVMA Buffers");

static	int iommu_strbuf_flush_sync(struct iommu_state *);
#ifdef IOMMU_DIAG
static 	void iommu_diag(struct iommu_state *, vm_offset_t va);
#endif

/*
 * Protects iommu_maplruq, dm_reslist of all maps on the queue and all
 * iommu states as long as the TSBs are synchronized.
 */
struct mtx iommu_mtx;

/*
 * The following 4 variables need to be moved to the per-IOMMU state once
 * the IOTSBs are divorced.
 * LRU queue handling for lazy resource allocation.
 */
static TAILQ_HEAD(iommu_maplruq_head, bus_dmamap) iommu_maplruq =
   TAILQ_HEAD_INITIALIZER(iommu_maplruq);

/* DVMA space rman. */
static struct rman iommu_dvma_rman;

/* Virtual and physical address of the TSB. */
static u_int64_t *iommu_tsb;
static vm_offset_t iommu_ptsb;

/* List of all IOMMUs. */
static STAILQ_HEAD(, iommu_state) iommu_insts =
   STAILQ_HEAD_INITIALIZER(iommu_insts);

/*
 * Helpers. Some of these take unused iommu states as parameters, to ease the
 * transition to divorced TSBs.
 */
#define	IOMMU_READ8(is, reg, off) 					\
	bus_space_read_8((is)->is_bustag, (is)->is_bushandle, 		\
	    (is)->reg + (off))
#define	IOMMU_WRITE8(is, reg, off, v)					\
	bus_space_write_8((is)->is_bustag, (is)->is_bushandle, 		\
	    (is)->reg + (off), (v))

#define	IOMMU_HAS_SB(is)						\
	((is)->is_sb[0] != 0 || (is)->is_sb[1] != 0)

/*
 * Always overallocate one page; this is needed to handle alignment of the
 * buffer, so it makes sense using a lazy allocation scheme.
 */
#define	IOMMU_SIZE_ROUNDUP(sz)						\
	(round_io_page(sz) + IO_PAGE_SIZE)

#define	IOMMU_SET_TTE(is, va, tte)					\
	(iommu_tsb[IOTSBSLOT(va)] = (tte))
#define	IOMMU_GET_TTE(is, va)						\
	iommu_tsb[IOTSBSLOT(va)]

/* Resource helpers */
#define	IOMMU_RES_START(res)						\
	((bus_addr_t)rman_get_start(res) << IO_PAGE_SHIFT)
#define	IOMMU_RES_END(res)						\
	((bus_addr_t)(rman_get_end(res) + 1) << IO_PAGE_SHIFT)
#define	IOMMU_RES_SIZE(res)						\
	((bus_size_t)rman_get_size(res) << IO_PAGE_SHIFT)

/* Helpers for struct bus_dmamap_res */
#define	BDR_START(r)	IOMMU_RES_START((r)->dr_res)
#define	BDR_END(r)	IOMMU_RES_END((r)->dr_res)
#define	BDR_SIZE(r)	IOMMU_RES_SIZE((r)->dr_res)

/* Locking macros. */
#define	IS_LOCK(is)	mtx_lock(&iommu_mtx)
#define	IS_LOCK_ASSERT(is)	mtx_assert(&iommu_mtx, MA_OWNED)
#define	IS_UNLOCK(is)	mtx_unlock(&iommu_mtx)


/* Flush a page from the TLB. No locking required, since this is atomic. */
static __inline void
iommu_tlb_flush(struct iommu_state *is, bus_addr_t va)
{
	struct iommu_state *it;

	/*
	 * Since the TSB is shared for now, the TLBs of all IOMMUs
	 * need to be flushed.
	 */
	STAILQ_FOREACH(it, &iommu_insts, is_link)
		IOMMU_WRITE8(it, is_iommu, IMR_FLUSH, va);
}

/*
 * Flush a page from the streaming buffer. No locking required, since this is
 * atomic.
 */
static __inline void
iommu_strbuf_flushpg(struct iommu_state *is, bus_addr_t va)
{
	int i;

	for (i = 0; i < 2; i++) {
		if (is->is_sb[i] != 0)
			IOMMU_WRITE8(is, is_sb[i], ISR_PGFLUSH, va);
	}
}

/*
 * Flush an address from the streaming buffer(s); this is an asynchronous
 * operation. To make sure that it has completed, iommu_strbuf_sync() needs
 * to be called. No locking required.
 */
static __inline void
iommu_strbuf_flush(struct iommu_state *is, bus_addr_t va)
{
	struct iommu_state *it;

	/*
	 * Need to flush the streaming buffers of all IOMMUs, we cannot
	 * determine which one was used for the transaction.
	 */
	STAILQ_FOREACH(it, &iommu_insts, is_link)
		iommu_strbuf_flushpg(it, va);
}

/* Synchronize all outstanding flush operations. */
static __inline void
iommu_strbuf_sync(struct iommu_state *is)
{
	struct iommu_state *it;

	IS_LOCK_ASSERT(is);
	/*
	 * Need to sync the streaming buffers of all IOMMUs, we cannot
	 * determine which one was used for the transaction.
	 */
	STAILQ_FOREACH(it, &iommu_insts, is_link)
		iommu_strbuf_flush_sync(it);
}

/* LRU queue handling for lazy resource allocation. */
static __inline void
iommu_map_insq(struct iommu_state *is, bus_dmamap_t map)
{

	IS_LOCK_ASSERT(is);
	if (!SLIST_EMPTY(&map->dm_reslist)) {
		if (map->dm_onq)
			TAILQ_REMOVE(&iommu_maplruq, map, dm_maplruq);
		TAILQ_INSERT_TAIL(&iommu_maplruq, map, dm_maplruq);
		map->dm_onq = 1;
	}
}

static __inline void
iommu_map_remq(struct iommu_state *is, bus_dmamap_t map)
{

	IS_LOCK_ASSERT(is);
	if (map->dm_onq)
		TAILQ_REMOVE(&iommu_maplruq, map, dm_maplruq);
	map->dm_onq = 0;
}

/*
 * initialise the UltraSPARC IOMMU (SBus or PCI):
 *	- allocate and setup the iotsb.
 *	- enable the IOMMU
 *	- initialise the streaming buffers (if they exist)
 *	- create a private DVMA map.
 */
void
iommu_init(char *name, struct iommu_state *is, int tsbsize, u_int32_t iovabase,
    int resvpg)
{
	struct iommu_state *first;
	vm_size_t size;
	vm_offset_t offs;
	u_int64_t end;
	int i;

	/*
	 * Setup the iommu.
	 *
	 * The sun4u iommu is part of the SBUS or PCI controller so we
	 * will deal with it here..
	 *
	 * The IOMMU address space always ends at 0xffffe000, but the starting
	 * address depends on the size of the map.  The map size is 1024 * 2 ^
	 * is->is_tsbsize entries, where each entry is 8 bytes.  The start of
	 * the map can be calculated by (0xffffe000 << (8 + is->is_tsbsize)).
	 */
	is->is_cr = (tsbsize << IOMMUCR_TSBSZ_SHIFT) | IOMMUCR_EN;
	is->is_tsbsize = tsbsize;
	is->is_dvmabase = iovabase;
	if (iovabase == -1)
		is->is_dvmabase = IOTSB_VSTART(is->is_tsbsize);

	size = IOTSB_BASESZ << is->is_tsbsize;
	printf("%s: DVMA map: %#lx to %#lx\n", name,
	    is->is_dvmabase, is->is_dvmabase +
	    (size << (IO_PAGE_SHIFT - IOTTE_SHIFT)) - 1);

	if (STAILQ_EMPTY(&iommu_insts)) {
		/*
		 * First IOMMU to be registered; set up resource mamangement
		 * and allocate TSB memory.
		 */
		mtx_init(&iommu_mtx, "iommu", NULL, MTX_DEF);
		end = is->is_dvmabase + (size << (IO_PAGE_SHIFT - IOTTE_SHIFT));
		iommu_dvma_rman.rm_type = RMAN_ARRAY;
		iommu_dvma_rman.rm_descr = "DVMA Memory";
		if (rman_init(&iommu_dvma_rman) != 0 ||
		    rman_manage_region(&iommu_dvma_rman,
		    (is->is_dvmabase >> IO_PAGE_SHIFT) + resvpg,
		    (end >> IO_PAGE_SHIFT) - 1) != 0)
			panic("iommu_init: can't initialize dvma rman");
		/*
		 * Allocate memory for I/O page tables.  They need to be
		 * physically contiguous.
		 */
		iommu_tsb = contigmalloc(size, M_DEVBUF, M_NOWAIT, 0, ~0UL,
		    PAGE_SIZE, 0);
		if (iommu_tsb == 0)
			panic("iommu_init: contigmalloc failed");
		iommu_ptsb = pmap_kextract((vm_offset_t)iommu_tsb);
		bzero(iommu_tsb, size);
	} else {
		/*
		 * Not the first IOMMU; just check that the parameters match
		 * those of the first one.
		 */
		first = STAILQ_FIRST(&iommu_insts);
		if (is->is_tsbsize != first->is_tsbsize ||
		    is->is_dvmabase != first->is_dvmabase) {
			panic("iommu_init: secondary IOMMU state does not "
			    "match primary");
		}
	}
	STAILQ_INSERT_TAIL(&iommu_insts, is, is_link);

	/*
	 * Initialize streaming buffer, if it is there.
	 */
	if (IOMMU_HAS_SB(is)) {
		/*
		 * Find two 64-byte blocks in is_flush that are aligned on
		 * a 64-byte boundary for flushing.
		 */
		offs = roundup2((vm_offset_t)is->is_flush,
		    STRBUF_FLUSHSYNC_NBYTES);
		for (i = 0; i < 2; i++, offs += STRBUF_FLUSHSYNC_NBYTES) {
			is->is_flushva[i] = (int64_t *)offs;
			is->is_flushpa[i] = pmap_kextract(offs);
		}
	}

	/*
	 * Now actually start up the IOMMU.
	 */
	iommu_reset(is);
}

/*
 * Streaming buffers don't exist on the UltraSPARC IIi; we should have
 * detected that already and disabled them.  If not, we will notice that
 * they aren't there when the STRBUF_EN bit does not remain.
 */
void
iommu_reset(struct iommu_state *is)
{
	int i;

	IOMMU_WRITE8(is, is_iommu, IMR_TSB, iommu_ptsb);
	/* Enable IOMMU in diagnostic mode */
	IOMMU_WRITE8(is, is_iommu, IMR_CTL, is->is_cr | IOMMUCR_DE);

	for (i = 0; i < 2; i++) {
		if (is->is_sb[i] != 0) {
			/* Enable diagnostics mode? */
			IOMMU_WRITE8(is, is_sb[i], ISR_CTL, STRBUF_EN);

			/* No streaming buffers? Disable them */
			if (IOMMU_READ8(is, is_sb[i], ISR_CTL) == 0)
				is->is_sb[i] = 0;
		}
	}
}

/*
 * Enter a mapping into the TSB. No locking required, since each TSB slot is
 * uniquely assigned to a single map.
 */
static void
iommu_enter(struct iommu_state *is, vm_offset_t va, vm_paddr_t pa,
    int stream, int flags)
{
	int64_t tte;

	KASSERT(va >= is->is_dvmabase,
	    ("iommu_enter: va %#lx not in DVMA space", va));
	KASSERT(pa < IOMMU_MAXADDR,
	    ("iommu_enter: XXX: physical address too large (%#lx)", pa));

	tte = MAKEIOTTE(pa, !(flags & BUS_DMA_NOWRITE),
	    !(flags & BUS_DMA_NOCACHE), stream);

	IOMMU_SET_TTE(is, va, tte);
	iommu_tlb_flush(is, va);
#ifdef IOMMU_DIAG
	IS_LOCK(is);
	iommu_diag(is, va);
	IS_UNLOCK(is);
#endif
}

/*
 * Remove mappings created by iommu_enter. Flush the streaming buffer, but do
 * not synchronize it. Returns whether a streaming buffer flush was performed.
 */
static int
iommu_remove(struct iommu_state *is, vm_offset_t va, vm_size_t len)
{
	int streamed = 0;

#ifdef IOMMU_DIAG
	iommu_diag(is, va);
#endif

	KASSERT(va >= is->is_dvmabase,
	    ("iommu_remove: va 0x%lx not in DVMA space", (u_long)va));
	KASSERT(va + len >= va,
	    ("iommu_remove: va 0x%lx + len 0x%lx wraps", (long)va, (long)len));

	va = trunc_io_page(va);
	while (len > 0) {
		if ((IOMMU_GET_TTE(is, va) & IOTTE_STREAM) != 0) {
			streamed = 1;
			iommu_strbuf_flush(is, va);
		}
		len -= ulmin(len, IO_PAGE_SIZE);
		IOMMU_SET_TTE(is, va, 0);
		iommu_tlb_flush(is, va);
		va += IO_PAGE_SIZE;
	}
	return (streamed);
}

/* Decode an IOMMU fault for host bridge error handlers. */
void
iommu_decode_fault(struct iommu_state *is, vm_offset_t phys)
{
	bus_addr_t va;
	long idx;

	idx = phys - iommu_ptsb;
	if (phys < iommu_ptsb ||
	    idx > (PAGE_SIZE << is->is_tsbsize))
		return;
	va = is->is_dvmabase +
	    (((bus_addr_t)idx >> IOTTE_SHIFT) << IO_PAGE_SHIFT);
	printf("IOMMU fault virtual address %#lx\n", (u_long)va);
}

/*
 * A barrier operation which makes sure that all previous streaming buffer
 * flushes complete before it returns.
 */
static int
iommu_strbuf_flush_sync(struct iommu_state *is)
{
	struct timeval cur, end;
	int i;

	IS_LOCK_ASSERT(is);
	if (!IOMMU_HAS_SB(is))
		return (0);

	/*
	 * Streaming buffer flushes:
	 *
	 *   1 Tell strbuf to flush by storing va to strbuf_pgflush.  If
	 *     we're not on a cache line boundary (64-bits):
	 *   2 Store 0 in flag
	 *   3 Store pointer to flag in flushsync
	 *   4 wait till flushsync becomes 0x1
	 *
	 * If it takes more than .5 sec, something
	 * went wrong.
	 */
	*is->is_flushva[0] = 1;
	*is->is_flushva[1] = 1;
	membar(StoreStore);
	for (i = 0; i < 2; i++) {
		if (is->is_sb[i] != 0) {
			*is->is_flushva[i] = 0;
			IOMMU_WRITE8(is, is_sb[i], ISR_FLUSHSYNC,
			    is->is_flushpa[i]);
		}
	}

	microuptime(&cur);
	end.tv_sec = 0;
	/*
	 * 0.5s is the recommended timeout from the U2S manual. The actual
	 * time required should be smaller by at least a factor of 1000.
	 * We have no choice but to busy-wait.
	 */
	end.tv_usec = 500000;
	timevaladd(&end, &cur);

	while ((!*is->is_flushva[0] || !*is->is_flushva[1]) &&
	    timevalcmp(&cur, &end, <=))
		microuptime(&cur);

	if (!*is->is_flushva[0] || !*is->is_flushva[1]) {
		panic("iommu_strbuf_flush_done: flush timeout %ld, %ld at %#lx",
		    *is->is_flushva[0], *is->is_flushva[1], is->is_flushpa[0]);
	}

	return (1);
}

/* Determine whether we may enable streaming on a mapping. */
static __inline int
iommu_use_streaming(struct iommu_state *is, bus_dmamap_t map, bus_size_t size)
{

	/*
	 * This cannot be enabled yet, as many driver are still missing
	 * bus_dmamap_sync() calls. As soon as there is a BUS_DMA_STREAMING
	 * flag, this should be reenabled conditionally on it.
	 */
#ifdef notyet
	return (size >= IOMMU_STREAM_THRESH && IOMMU_HAS_SB(is) &&
	    (map->dm_flags & DMF_COHERENT) == 0);
#else
	return (0);
#endif
}

/*
 * Allocate DVMA virtual memory for a map. The map may not be on a queue, so
 * that it can be freely modified.
 */
static int
iommu_dvma_valloc(bus_dma_tag_t t, struct iommu_state *is, bus_dmamap_t map,
    bus_size_t size)
{
	struct resource *res;
	struct bus_dmamap_res *bdr;
	bus_size_t align, sgsize;

	KASSERT(!map->dm_onq, ("iommu_dvma_valloc: map on queue!"));
	if ((bdr = malloc(sizeof(*bdr), M_IOMMU, M_NOWAIT)) == NULL)
		return (EAGAIN);
	/*
	 * If a boundary is specified, a map cannot be larger than it; however
	 * we do not clip currently, as that does not play well with the lazy
	 * allocation code.
	 * Alignment to a page boundary is always enforced.
	 */
	align = (t->dt_alignment + IO_PAGE_MASK) >> IO_PAGE_SHIFT;
	sgsize = round_io_page(size) >> IO_PAGE_SHIFT;
	if (t->dt_boundary > 0 && t->dt_boundary < IO_PAGE_SIZE)
		panic("iommu_dvmamap_load: illegal boundary specified");
	res = rman_reserve_resource_bound(&iommu_dvma_rman, 0L,
	    t->dt_lowaddr >> IO_PAGE_SHIFT, sgsize,
	    t->dt_boundary >> IO_PAGE_SHIFT,
	    RF_ACTIVE | rman_make_alignment_flags(align), NULL);
	if (res == NULL) {
		free(bdr, M_IOMMU);
		return (ENOMEM);
	}

	bdr->dr_res = res;
	bdr->dr_used = 0;
	SLIST_INSERT_HEAD(&map->dm_reslist, bdr, dr_link);
	return (0);
}

/* Unload the map and mark all resources as unused, but do not free them. */
static void
iommu_dvmamap_vunload(struct iommu_state *is, bus_dmamap_t map)
{
	struct bus_dmamap_res *r;
	int streamed = 0;

	IS_LOCK_ASSERT(is);	/* for iommu_strbuf_sync() below. */
	SLIST_FOREACH(r, &map->dm_reslist, dr_link) {
		streamed |= iommu_remove(is, BDR_START(r), r->dr_used);
		r->dr_used = 0;
	}
	if (streamed)
		iommu_strbuf_sync(is);
}

/* Free a DVMA virtual memory resource. */
static __inline void
iommu_dvma_vfree_res(bus_dmamap_t map, struct bus_dmamap_res *r)
{

	KASSERT(r->dr_used == 0, ("iommu_dvma_vfree_res: resource busy!"));
	if (r->dr_res != NULL && rman_release_resource(r->dr_res) != 0)
		printf("warning: DVMA space lost\n");
	SLIST_REMOVE(&map->dm_reslist, r, bus_dmamap_res, dr_link);
	free(r, M_IOMMU);
}

/* Free all DVMA virtual memory for a map. */
static void
iommu_dvma_vfree(struct iommu_state *is, bus_dmamap_t map)
{

	IS_LOCK(is);
	iommu_map_remq(is, map);
	iommu_dvmamap_vunload(is, map);
	IS_UNLOCK(is);
	while (!SLIST_EMPTY(&map->dm_reslist))
		iommu_dvma_vfree_res(map, SLIST_FIRST(&map->dm_reslist));
}

/* Prune a map, freeing all unused DVMA resources. */
static bus_size_t
iommu_dvma_vprune(struct iommu_state *is, bus_dmamap_t map)
{
	struct bus_dmamap_res *r, *n;
	bus_size_t freed = 0;

	IS_LOCK_ASSERT(is);
	for (r = SLIST_FIRST(&map->dm_reslist); r != NULL; r = n) {
		n = SLIST_NEXT(r, dr_link);
		if (r->dr_used == 0) {
			freed += BDR_SIZE(r);
			iommu_dvma_vfree_res(map, r);
		}
	}
	if (SLIST_EMPTY(&map->dm_reslist))
		iommu_map_remq(is, map);
	return (freed);
}

/*
 * Try to find a suitably-sized (and if requested, -aligned) slab of DVMA
 * memory with IO page offset voffs.
 */
static bus_addr_t
iommu_dvma_vfindseg(bus_dmamap_t map, vm_offset_t voffs, bus_size_t size,
    bus_addr_t amask)
{
	struct bus_dmamap_res *r;
	bus_addr_t dvmaddr, dvmend;

	KASSERT(!map->dm_onq, ("iommu_dvma_vfindseg: map on queue!"));
	SLIST_FOREACH(r, &map->dm_reslist, dr_link) {
		dvmaddr = round_io_page(BDR_START(r) + r->dr_used);
		/* Alignment can only work with voffs == 0. */
		dvmaddr = (dvmaddr + amask) & ~amask;
		dvmaddr += voffs;
		dvmend = dvmaddr + size;
		if (dvmend <= BDR_END(r)) {
			r->dr_used = dvmend - BDR_START(r);
			return (dvmaddr);
		}
	}
	return (0);
}

/*
 * Try to find or allocate a slab of DVMA space; see above.
 */
static int
iommu_dvma_vallocseg(bus_dma_tag_t dt, struct iommu_state *is, bus_dmamap_t map,
    vm_offset_t voffs, bus_size_t size, bus_addr_t amask, bus_addr_t *addr)
{
	bus_dmamap_t tm, last;
	bus_addr_t dvmaddr, freed;
	int error, complete = 0;

	dvmaddr = iommu_dvma_vfindseg(map, voffs, size, amask);

	/* Need to allocate. */
	if (dvmaddr == 0) {
		while ((error = iommu_dvma_valloc(dt, is, map,
			voffs + size)) == ENOMEM && !complete) {
			/*
			 * Free the allocated DVMA of a few maps until
			 * the required size is reached. This is an
			 * approximation to not have to call the allocation
			 * function too often; most likely one free run
			 * will not suffice if not one map was large enough
			 * itself due to fragmentation.
			 */
			IS_LOCK(is);
			freed = 0;
			last = TAILQ_LAST(&iommu_maplruq, iommu_maplruq_head);
			do {
				tm = TAILQ_FIRST(&iommu_maplruq);
				complete = tm == last;
				if (tm == NULL)
					break;
				freed += iommu_dvma_vprune(is, tm);
				/* Move to the end. */
				iommu_map_insq(is, tm);
			} while (freed < size && !complete);
			IS_UNLOCK(is);
		}
		if (error != 0)
			return (error);
		dvmaddr = iommu_dvma_vfindseg(map, voffs, size, amask);
		KASSERT(dvmaddr != 0,
		    ("iommu_dvma_vallocseg: allocation failed unexpectedly!"));
	}
	*addr = dvmaddr;
	return (0);
}

static int
iommu_dvmamem_alloc(bus_dma_tag_t dt, void **vaddr, int flags,
    bus_dmamap_t *mapp)
{
	struct iommu_state *is = dt->dt_cookie;
	int error, mflags;

	/*
	 * XXX: This will break for 32 bit transfers on machines with more than
	 * 16G (1 << 34 bytes) of memory.
	 */
	if ((error = sparc64_dma_alloc_map(dt, mapp)) != 0)
		return (error);

	if ((flags & BUS_DMA_NOWAIT) != 0)
		mflags = M_NOWAIT;
	else
		mflags = M_WAITOK;
	if ((flags & BUS_DMA_ZERO) != 0)
		mflags |= M_ZERO;

	if ((*vaddr = malloc(dt->dt_maxsize, M_IOMMU, mflags)) == NULL) {
		error = ENOMEM;
		sparc64_dma_free_map(dt, *mapp);
		return (error);
	}
	if ((flags & BUS_DMA_COHERENT) != 0)
		(*mapp)->dm_flags |= DMF_COHERENT;
	/*
	 * Try to preallocate DVMA space. If this fails, it is retried at load
	 * time.
	 */
	iommu_dvma_valloc(dt, is, *mapp, IOMMU_SIZE_ROUNDUP(dt->dt_maxsize));
	IS_LOCK(is);
	iommu_map_insq(is, *mapp);
	IS_UNLOCK(is);
	return (0);
}

static void
iommu_dvmamem_free(bus_dma_tag_t dt, void *vaddr, bus_dmamap_t map)
{
	struct iommu_state *is = dt->dt_cookie;

	iommu_dvma_vfree(is, map);
	sparc64_dma_free_map(dt, map);
	free(vaddr, M_IOMMU);
}

static int
iommu_dvmamap_create(bus_dma_tag_t dt, int flags, bus_dmamap_t *mapp)
{
	struct iommu_state *is = dt->dt_cookie;
	bus_size_t totsz, presz, currsz;
	int error, i, maxpre;

	if ((error = sparc64_dma_alloc_map(dt, mapp)) != 0)
		return (error);
	if ((flags & BUS_DMA_COHERENT) != 0)
		(*mapp)->dm_flags |= DMF_COHERENT;
	/*
	 * Preallocate DVMA space; if this fails now, it is retried at load
	 * time. Through bus_dmamap_load_mbuf() and bus_dmamap_load_uio(), it
	 * is possible to have multiple discontiguous segments in a single map,
	 * which is handled by allocating additional resources, instead of
	 * increasing the size, to avoid fragmentation.
	 * Clamp preallocation to IOMMU_MAX_PRE. In some situations we can
	 * handle more; that case is handled by reallocating at map load time.
	 */
	totsz = ulmin(IOMMU_SIZE_ROUNDUP(dt->dt_maxsize), IOMMU_MAX_PRE); 
	error = iommu_dvma_valloc(dt, is, *mapp, totsz);
	if (error != 0)
		return (0);
	/*
	 * Try to be smart about preallocating some additional segments if
	 * needed.
	 */
	maxpre = imin(dt->dt_nsegments, IOMMU_MAX_PRE_SEG);
	presz = dt->dt_maxsize / maxpre;
	KASSERT(presz != 0, ("iommu_dvmamap_create: bogus preallocation size "
	    ", nsegments = %d, maxpre = %d, maxsize = %lu", dt->dt_nsegments,
	    maxpre, dt->dt_maxsize));
	for (i = 1; i < maxpre && totsz < IOMMU_MAX_PRE; i++) {
		currsz = round_io_page(ulmin(presz, IOMMU_MAX_PRE - totsz));
		error = iommu_dvma_valloc(dt, is, *mapp, currsz);
		if (error != 0)
			break;
		totsz += currsz;
	}
	IS_LOCK(is);
	iommu_map_insq(is, *mapp);
	IS_UNLOCK(is);
	return (0);
}

static int
iommu_dvmamap_destroy(bus_dma_tag_t dt, bus_dmamap_t map)
{
	struct iommu_state *is = dt->dt_cookie;

	iommu_dvma_vfree(is, map);
	sparc64_dma_free_map(dt, map);
	return (0);
}

/*
 * IOMMU DVMA operations, common to SBUS and PCI.
 */
static int
iommu_dvmamap_load_buffer(bus_dma_tag_t dt, struct iommu_state *is,
    bus_dmamap_t map, void *buf, bus_size_t buflen, struct thread *td,
    int flags, bus_dma_segment_t *segs, int *segp, int align)
{
	bus_addr_t amask, dvmaddr;
	bus_size_t sgsize, esize;
	vm_offset_t vaddr, voffs;
	vm_paddr_t curaddr;
	int error, sgcnt, firstpg, stream;
	pmap_t pmap = NULL;

	KASSERT(buflen != 0, ("iommu_dvmamap_load_buffer: buflen == 0!"));
	if (buflen > dt->dt_maxsize)
		return (EINVAL);

	if (td != NULL)
		pmap = vmspace_pmap(td->td_proc->p_vmspace);

	vaddr = (vm_offset_t)buf;
	voffs = vaddr & IO_PAGE_MASK;
	amask = align ? dt->dt_alignment - 1 : 0;

	/* Try to find a slab that is large enough. */
	error = iommu_dvma_vallocseg(dt, is, map, voffs, buflen, amask,
	    &dvmaddr);
	if (error != 0)
		return (error);

	sgcnt = *segp;
	firstpg = 1;
	stream = iommu_use_streaming(is, map, buflen);
	for (; buflen > 0; ) {
		/*
		 * Get the physical address for this page.
		 */
		if (pmap != NULL)
			curaddr = pmap_extract(pmap, vaddr);
		else
			curaddr = pmap_kextract(vaddr);

		/*
		 * Compute the segment size, and adjust counts.
		 */
		sgsize = IO_PAGE_SIZE - ((u_long)vaddr & IO_PAGE_MASK);
		if (buflen < sgsize)
			sgsize = buflen;

		buflen -= sgsize;
		vaddr += sgsize;

		iommu_enter(is, trunc_io_page(dvmaddr), trunc_io_page(curaddr),
		    stream, flags);

		/*
		 * Chop the chunk up into segments of at most maxsegsz, but try
		 * to fill each segment as well as possible.
		 */
		if (!firstpg) {
			esize = ulmin(sgsize,
			    dt->dt_maxsegsz - segs[sgcnt].ds_len);
			segs[sgcnt].ds_len += esize;
			sgsize -= esize;
			dvmaddr += esize;
		}
		while (sgsize > 0) {
			sgcnt++;
			if (sgcnt >= dt->dt_nsegments)
				return (EFBIG);
			/*
			 * No extra alignment here - the common practice in the
			 * busdma code seems to be that only the first segment
			 * needs to satisfy the alignment constraints (and that
			 * only for bus_dmamem_alloc()ed maps). It is assumed
			 * that such tags have maxsegsize >= maxsize.
			 */
			esize = ulmin(sgsize, dt->dt_maxsegsz);
			segs[sgcnt].ds_addr = dvmaddr;
			segs[sgcnt].ds_len = esize;
			sgsize -= esize;
			dvmaddr += esize;
		}

		firstpg = 0;
	}
	*segp = sgcnt;
	return (0);
}

static int
iommu_dvmamap_load(bus_dma_tag_t dt, bus_dmamap_t map, void *buf,
    bus_size_t buflen, bus_dmamap_callback_t *cb, void *cba,
    int flags)
{
	struct iommu_state *is = dt->dt_cookie;
	int error, seg = -1;

	if ((map->dm_flags & DMF_LOADED) != 0) {
#ifdef DIAGNOSTIC
		printf("iommu_dvmamap_load: map still in use\n");
#endif
		bus_dmamap_unload(dt, map);
	}

	/*
	 * Make sure that the map is not on a queue so that the resource list
	 * may be safely accessed and modified without needing the lock to
	 * cover the whole operation.
	 */
	IS_LOCK(is);
	iommu_map_remq(is, map);
	IS_UNLOCK(is);

	error = iommu_dvmamap_load_buffer(dt, is, map, buf, buflen, NULL,
	    flags, dt->dt_segments, &seg, 1);

	IS_LOCK(is);
	iommu_map_insq(is, map);
	if (error != 0) {
		iommu_dvmamap_vunload(is, map);
		IS_UNLOCK(is);
		(*cb)(cba, dt->dt_segments, 0, error);
	} else {
		IS_UNLOCK(is);
		map->dm_flags |= DMF_LOADED;
		(*cb)(cba, dt->dt_segments, seg + 1, 0);
	}

	return (error);
}

static int
iommu_dvmamap_load_mbuf(bus_dma_tag_t dt, bus_dmamap_t map, struct mbuf *m0,
    bus_dmamap_callback2_t *cb, void *cba, int flags)
{
	struct iommu_state *is = dt->dt_cookie;
	struct mbuf *m;
	int error = 0, first = 1, nsegs = -1;

	M_ASSERTPKTHDR(m0);

	if ((map->dm_flags & DMF_LOADED) != 0) {
#ifdef DIAGNOSTIC
		printf("iommu_dvmamap_load_mbuf: map still in use\n");
#endif
		bus_dmamap_unload(dt, map);
	}

	IS_LOCK(is);
	iommu_map_remq(is, map);
	IS_UNLOCK(is);

	if (m0->m_pkthdr.len <= dt->dt_maxsize) {
		for (m = m0; m != NULL && error == 0; m = m->m_next) {
			if (m->m_len == 0)
				continue;
			error = iommu_dvmamap_load_buffer(dt, is, map,
			    m->m_data, m->m_len, NULL, flags, dt->dt_segments,
			    &nsegs, first);
			first = 0;
		}
	} else
		error = EINVAL;

	IS_LOCK(is);
	iommu_map_insq(is, map);
	if (error != 0) {
		iommu_dvmamap_vunload(is, map);
		IS_UNLOCK(is);
		/* force "no valid mappings" in callback */
		(*cb)(cba, dt->dt_segments, 0, 0, error);
	} else {
		IS_UNLOCK(is);
		map->dm_flags |= DMF_LOADED;
		(*cb)(cba, dt->dt_segments, nsegs + 1, m0->m_pkthdr.len, 0);
	}
	return (error);
}

static int
iommu_dvmamap_load_mbuf_sg(bus_dma_tag_t dt, bus_dmamap_t map, struct mbuf *m0,
    bus_dma_segment_t *segs, int *nsegs, int flags)
{
	struct iommu_state *is = dt->dt_cookie;
	struct mbuf *m;
	int error = 0, first = 1;

	M_ASSERTPKTHDR(m0);

	*nsegs = -1;
	if ((map->dm_flags & DMF_LOADED) != 0) {
#ifdef DIAGNOSTIC
		printf("iommu_dvmamap_load_mbuf: map still in use\n");
#endif
		bus_dmamap_unload(dt, map);
	}

	IS_LOCK(is);
	iommu_map_remq(is, map);
	IS_UNLOCK(is);

	if (m0->m_pkthdr.len <= dt->dt_maxsize) {
		for (m = m0; m != NULL && error == 0; m = m->m_next) {
			if (m->m_len == 0)
				continue;
			error = iommu_dvmamap_load_buffer(dt, is, map,
			    m->m_data, m->m_len, NULL, flags, segs,
			    nsegs, first);
			first = 0;
		}
	} else
		error = EINVAL;

	IS_LOCK(is);
	iommu_map_insq(is, map);
	if (error != 0) {
		iommu_dvmamap_vunload(is, map);
	} else {
		map->dm_flags |= DMF_LOADED;
		++*nsegs;
	}
	IS_UNLOCK(is);
	return (error);
}

static int
iommu_dvmamap_load_uio(bus_dma_tag_t dt, bus_dmamap_t map, struct uio *uio,
    bus_dmamap_callback2_t *cb,  void *cba, int flags)
{
	struct iommu_state *is = dt->dt_cookie;
	struct iovec *iov;
	struct thread *td = NULL;
	bus_size_t minlen, resid;
	int nsegs = -1, error = 0, first = 1, i;

	if ((map->dm_flags & DMF_LOADED) != 0) {
#ifdef DIAGNOSTIC
		printf("iommu_dvmamap_load_uio: map still in use\n");
#endif
		bus_dmamap_unload(dt, map);
	}

	IS_LOCK(is);
	iommu_map_remq(is, map);
	IS_UNLOCK(is);

	resid = uio->uio_resid;
	iov = uio->uio_iov;

	if (uio->uio_segflg == UIO_USERSPACE) {
		td = uio->uio_td;
		KASSERT(td != NULL,
		    ("%s: USERSPACE but no proc", __func__));
	}

	for (i = 0; i < uio->uio_iovcnt && resid != 0 && error == 0; i++) {
		/*
		 * Now at the first iovec to load.  Load each iovec
		 * until we have exhausted the residual count.
		 */
		minlen = resid < iov[i].iov_len ? resid : iov[i].iov_len;
		if (minlen == 0)
			continue;

		error = iommu_dvmamap_load_buffer(dt, is, map,
		    iov[i].iov_base, minlen, td, flags, dt->dt_segments, 
		    &nsegs, first);
		first = 0;

		resid -= minlen;
	}

	IS_LOCK(is);
	iommu_map_insq(is, map);
	if (error) {
		iommu_dvmamap_vunload(is, map);
		IS_UNLOCK(is);
		/* force "no valid mappings" in callback */
		(*cb)(cba, dt->dt_segments, 0, 0, error);
	} else {
		IS_UNLOCK(is);
		map->dm_flags |= DMF_LOADED;
		(*cb)(cba, dt->dt_segments, nsegs + 1, uio->uio_resid, 0);
	}
	return (error);
}

static void
iommu_dvmamap_unload(bus_dma_tag_t dt, bus_dmamap_t map)
{
	struct iommu_state *is = dt->dt_cookie;

	if ((map->dm_flags & DMF_LOADED) == 0)
		return;
	IS_LOCK(is);
	iommu_dvmamap_vunload(is, map);
	iommu_map_insq(is, map);
	IS_UNLOCK(is);
	map->dm_flags &= ~DMF_LOADED;
}

static void
iommu_dvmamap_sync(bus_dma_tag_t dt, bus_dmamap_t map, bus_dmasync_op_t op)
{
	struct iommu_state *is = dt->dt_cookie;
	struct bus_dmamap_res *r;
	vm_offset_t va;
	vm_size_t len;
	int streamed = 0;

	if ((map->dm_flags & DMF_LOADED) == 0)
		return;
	/* XXX This is probably bogus. */
	if ((op & BUS_DMASYNC_PREREAD) != 0)
		membar(Sync);
	if (IOMMU_HAS_SB(is) &&
	    ((op & BUS_DMASYNC_POSTREAD) != 0 ||
	     (op & BUS_DMASYNC_PREWRITE) != 0)) {
		IS_LOCK(is);
		SLIST_FOREACH(r, &map->dm_reslist, dr_link) {
			va = (vm_offset_t)BDR_START(r);
			len = r->dr_used;
			/* if we have a streaming buffer, flush it here first */
			while (len > 0) {
				if ((IOMMU_GET_TTE(is, va) & IOTTE_STREAM) != 0) {
					streamed = 1;
					iommu_strbuf_flush(is, va);
				}
				len -= ulmin(len, IO_PAGE_SIZE);
				va += IO_PAGE_SIZE;
			}
		}
		if (streamed)
			iommu_strbuf_sync(is);
		IS_UNLOCK(is);
	}
	if ((op & BUS_DMASYNC_PREWRITE) != 0)
		membar(Sync);
}

#ifdef IOMMU_DIAG

/*
 * Perform an IOMMU diagnostic access and print the tag belonging to va.
 */
static void
iommu_diag(struct iommu_state *is, vm_offset_t va)
{
	int i;
	u_int64_t tag, data;

	IS_LOCK_ASSERT(is);
	IOMMU_WRITE8(is, is_dva, 0, trunc_io_page(va));
	membar(StoreStore | StoreLoad);
	printf("iommu_diag: tte entry %#lx", IOMMU_GET_TTE(is, va));
	if (is->is_dtcmp != 0) {
		printf(", tag compare register is %#lx\n",
		    IOMMU_READ8(is, is_dtcmp, 0));
	} else
		printf("\n");
	for (i = 0; i < 16; i++) {
		tag = IOMMU_READ8(is, is_dtag, i * 8);
		data = IOMMU_READ8(is, is_ddram, i * 8);
		printf("iommu_diag: tag %d: %#lx, vpn %#lx, err %lx; "
		    "data %#lx, pa %#lx, v %d, c %d\n", i,
		    tag, (tag & IOMMU_DTAG_VPNMASK) << IOMMU_DTAG_VPNSHIFT,
		    (tag & IOMMU_DTAG_ERRMASK) >> IOMMU_DTAG_ERRSHIFT, data,
		    (data & IOMMU_DDATA_PGMASK) << IOMMU_DDATA_PGSHIFT,
		    (data & IOMMU_DDATA_V) != 0, (data & IOMMU_DDATA_C) != 0);
	}
}

#endif /* IOMMU_DIAG */

struct bus_dma_methods iommu_dma_methods = {
	iommu_dvmamap_create,
	iommu_dvmamap_destroy,
	iommu_dvmamap_load,
	iommu_dvmamap_load_mbuf,
	iommu_dvmamap_load_mbuf_sg,
	iommu_dvmamap_load_uio,
	iommu_dvmamap_unload,
	iommu_dvmamap_sync,
	iommu_dvmamem_alloc,
	iommu_dvmamem_free,
};