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      1 /*	$NetBSD: iommu.c,v 1.102 2023/12/01 05:22:01 thorpej Exp $ */
      2 
      3 /*
      4  * Copyright (c) 1996
      5  * 	The President and Fellows of Harvard College. All rights reserved.
      6  * Copyright (c) 1995 	Paul Kranenburg
      7  *
      8  * Redistribution and use in source and binary forms, with or without
      9  * modification, are permitted provided that the following conditions
     10  * are met:
     11  * 1. Redistributions of source code must retain the above copyright
     12  *    notice, this list of conditions and the following disclaimer.
     13  * 2. Redistributions in binary form must reproduce the above copyright
     14  *    notice, this list of conditions and the following disclaimer in the
     15  *    documentation and/or other materials provided with the distribution.
     16  * 3. All advertising materials mentioning features or use of this software
     17  *    must display the following acknowledgement:
     18  *	This product includes software developed by Aaron Brown and
     19  *	Harvard University.
     20  *	This product includes software developed by Paul Kranenburg.
     21  * 4. Neither the name of the University nor the names of its contributors
     22  *    may be used to endorse or promote products derived from this software
     23  *    without specific prior written permission.
     24  *
     25  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     27  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     28  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     29  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     30  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     31  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     32  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     33  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     34  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     35  * SUCH DAMAGE.
     36  *
     37  */
     38 
     39 #include <sys/cdefs.h>
     40 __KERNEL_RCSID(0, "$NetBSD: iommu.c,v 1.102 2023/12/01 05:22:01 thorpej Exp $");
     41 
     42 #include "opt_sparc_arch.h"
     43 
     44 #include <sys/param.h>
     45 #include <sys/malloc.h>
     46 #include <sys/queue.h>
     47 #include <sys/systm.h>
     48 #include <sys/device.h>
     49 #include <sys/proc.h>
     50 #include <sys/vmem.h>
     51 
     52 #include <uvm/uvm.h>
     53 
     54 #define _SPARC_BUS_DMA_PRIVATE
     55 #include <sys/bus.h>
     56 #include <machine/autoconf.h>
     57 #include <machine/ctlreg.h>
     58 #include <sparc/sparc/asm.h>
     59 #include <sparc/sparc/vaddrs.h>
     60 #include <sparc/sparc/cpuvar.h>
     61 #include <sparc/sparc/iommureg.h>
     62 #include <sparc/sparc/iommuvar.h>
     63 
     64 struct iommu_softc {
     65 	struct iommureg	*sc_reg;
     66 	u_int		sc_pagesize;
     67 	u_int		sc_range;
     68 	bus_addr_t	sc_dvmabase;
     69 	iopte_t		*sc_ptes;
     70 	int		sc_cachecoherent;
     71 /*
     72  * Note: operations on the extent map are being protected with
     73  * splhigh(), since we cannot predict at which interrupt priority
     74  * our clients will run.
     75  */
     76 	struct sparc_bus_dma_tag sc_dmatag;
     77 	vmem_t *sc_dvmamap;
     78 };
     79 
     80 /* autoconfiguration driver */
     81 int	iommu_print(void *, const char *);
     82 void	iommu_attach(device_t, device_t, void *);
     83 int	iommu_match(device_t, cfdata_t, void *);
     84 
     85 #if defined(SUN4M)
     86 static void iommu_copy_prom_entries(struct iommu_softc *);
     87 #endif
     88 
     89 CFATTACH_DECL_NEW(iommu, sizeof(struct iommu_softc),
     90     iommu_match, iommu_attach, NULL, NULL);
     91 
     92 /* IOMMU DMA map functions */
     93 int	iommu_dmamap_create(bus_dma_tag_t, bus_size_t, int, bus_size_t,
     94 			bus_size_t, int, bus_dmamap_t *);
     95 int	iommu_dmamap_load(bus_dma_tag_t, bus_dmamap_t, void *,
     96 			bus_size_t, struct proc *, int);
     97 int	iommu_dmamap_load_mbuf(bus_dma_tag_t, bus_dmamap_t,
     98 			struct mbuf *, int);
     99 int	iommu_dmamap_load_uio(bus_dma_tag_t, bus_dmamap_t,
    100 			struct uio *, int);
    101 int	iommu_dmamap_load_raw(bus_dma_tag_t, bus_dmamap_t,
    102 			bus_dma_segment_t *, int, bus_size_t, int);
    103 void	iommu_dmamap_unload(bus_dma_tag_t, bus_dmamap_t);
    104 void	iommu_dmamap_sync(bus_dma_tag_t, bus_dmamap_t, bus_addr_t,
    105 			bus_size_t, int);
    106 
    107 int	iommu_dmamem_map(bus_dma_tag_t, bus_dma_segment_t *,
    108 			int, size_t, void **, int);
    109 void	iommu_dmamem_unmap(bus_dma_tag_t, void *, size_t);
    110 paddr_t	iommu_dmamem_mmap(bus_dma_tag_t, bus_dma_segment_t *,
    111 			int, off_t, int, int);
    112 int	iommu_dvma_alloc(struct iommu_softc *, bus_dmamap_t, vaddr_t,
    113 			 bus_size_t, int, bus_addr_t *, bus_size_t *);
    114 
    115 /*
    116  * Print the location of some iommu-attached device (called just
    117  * before attaching that device).  If `iommu' is not NULL, the
    118  * device was found but not configured; print the iommu as well.
    119  * Return UNCONF (config_find ignores this if the device was configured).
    120  */
    121 int
    122 iommu_print(void *args, const char *iommu)
    123 {
    124 	struct iommu_attach_args *ia = args;
    125 
    126 	if (iommu)
    127 		aprint_normal("%s at %s", ia->iom_name, iommu);
    128 	return (UNCONF);
    129 }
    130 
    131 int
    132 iommu_match(device_t parent, cfdata_t cf, void *aux)
    133 {
    134 	struct mainbus_attach_args *ma = aux;
    135 
    136 	if (CPU_ISSUN4 || CPU_ISSUN4C)
    137 		return (0);
    138 	return (strcmp(cf->cf_name, ma->ma_name) == 0);
    139 }
    140 
    141 /*
    142  * Attach the iommu.
    143  */
    144 void
    145 iommu_attach(device_t parent, device_t self, void *aux)
    146 {
    147 #if defined(SUN4M)
    148 	struct iommu_softc *sc = device_private(self);
    149 	struct mainbus_attach_args *ma = aux;
    150 	struct sparc_bus_dma_tag *dmat = &sc->sc_dmatag;
    151 	bus_space_handle_t bh;
    152 	int node;
    153 	int js1_implicit_iommu;
    154 	int i, s;
    155 	u_int iopte_table_pa;
    156 	struct pglist mlist;
    157 	u_int size;
    158 	struct vm_page *m;
    159 	vaddr_t va;
    160 
    161 	dmat->_cookie = sc;
    162 	dmat->_dmamap_create = iommu_dmamap_create;
    163 	dmat->_dmamap_destroy = _bus_dmamap_destroy;
    164 	dmat->_dmamap_load = iommu_dmamap_load;
    165 	dmat->_dmamap_load_mbuf = iommu_dmamap_load_mbuf;
    166 	dmat->_dmamap_load_uio = iommu_dmamap_load_uio;
    167 	dmat->_dmamap_load_raw = iommu_dmamap_load_raw;
    168 	dmat->_dmamap_unload = iommu_dmamap_unload;
    169 	dmat->_dmamap_sync = iommu_dmamap_sync;
    170 
    171 	dmat->_dmamem_alloc = _bus_dmamem_alloc;
    172 	dmat->_dmamem_free = _bus_dmamem_free;
    173 	dmat->_dmamem_map = iommu_dmamem_map;
    174 	dmat->_dmamem_unmap = _bus_dmamem_unmap;
    175 	dmat->_dmamem_mmap = iommu_dmamem_mmap;
    176 
    177 	/*
    178 	 * JS1/OF device tree does not have an iommu node and sbus
    179 	 * node is directly under root.  mainbus_attach detects this
    180 	 * and calls us with sbus node instead so that we can attach
    181 	 * implicit iommu and attach that sbus node under it.
    182 	 */
    183 	node = ma->ma_node;
    184 	if (strcmp(prom_getpropstring(node, "name"), "sbus") == 0)
    185 		js1_implicit_iommu = 1;
    186 	else
    187 		js1_implicit_iommu = 0;
    188 
    189 	/*
    190 	 * Map registers into our space. The PROM may have done this
    191 	 * already, but I feel better if we have our own copy. Plus, the
    192 	 * prom doesn't map the entire register set.
    193 	 *
    194 	 * XXX struct iommureg is bigger than ra->ra_len; what are the
    195 	 *     other fields for?
    196 	 */
    197 	if (bus_space_map(ma->ma_bustag, ma->ma_paddr,
    198 			  sizeof(struct iommureg), 0, &bh) != 0) {
    199 		printf("iommu_attach: cannot map registers\n");
    200 		return;
    201 	}
    202 	sc->sc_reg = (struct iommureg *)bh;
    203 
    204 	sc->sc_cachecoherent = js1_implicit_iommu ? 0
    205 				: node_has_property(node, "cache-coherence?");
    206 	if (CACHEINFO.c_enabled == 0) /* XXX - is this correct? */
    207 		sc->sc_cachecoherent = 0;
    208 
    209 	sc->sc_pagesize = js1_implicit_iommu ? PAGE_SIZE
    210 				: prom_getpropint(node, "page-size", PAGE_SIZE),
    211 
    212 	/*
    213 	 * Allocate memory for I/O pagetables.
    214 	 * This takes 64K of contiguous physical memory to map 64M of
    215 	 * DVMA space (starting at IOMMU_DVMA_BASE).
    216 	 * The table must be aligned on a (-IOMMU_DVMA_BASE/pagesize)
    217 	 * boundary (i.e. 64K for 64M of DVMA space).
    218 	 */
    219 
    220 	size = ((0 - IOMMU_DVMA_BASE) / sc->sc_pagesize) * sizeof(iopte_t);
    221 	if (uvm_pglistalloc(size, vm_first_phys, vm_first_phys+vm_num_phys,
    222 			    size, 0, &mlist, 1, 0) != 0)
    223 		panic("iommu_attach: no memory");
    224 
    225 	va = uvm_km_alloc(kernel_map, size, 0, UVM_KMF_VAONLY);
    226 	if (va == 0)
    227 		panic("iommu_attach: no memory");
    228 
    229 	sc->sc_ptes = (iopte_t *)va;
    230 
    231 	m = TAILQ_FIRST(&mlist);
    232 	iopte_table_pa = VM_PAGE_TO_PHYS(m);
    233 
    234 	/* Map the pages */
    235 	for (; m != NULL; m = TAILQ_NEXT(m,pageq.queue)) {
    236 		paddr_t pa = VM_PAGE_TO_PHYS(m);
    237 		pmap_kenter_pa(va, pa | PMAP_NC,
    238 		    VM_PROT_READ | VM_PROT_WRITE, 0);
    239 		va += PAGE_SIZE;
    240 	}
    241 	pmap_update(pmap_kernel());
    242 
    243 	/*
    244 	 * Copy entries from current IOMMU table.
    245 	 * XXX - Why do we need to do this?
    246 	 */
    247 	iommu_copy_prom_entries(sc);
    248 
    249 	/*
    250 	 * Now we can install our new pagetable into the IOMMU
    251 	 */
    252 	sc->sc_range = 0 - IOMMU_DVMA_BASE;
    253 	sc->sc_dvmabase = IOMMU_DVMA_BASE;
    254 
    255 	/* calculate log2(sc->sc_range/16MB) */
    256 	i = ffs(sc->sc_range/(1 << 24)) - 1;
    257 	if ((1 << i) != (sc->sc_range/(1 << 24)))
    258 		panic("iommu: bad range: %d", i);
    259 
    260 	s = splhigh();
    261 	IOMMU_FLUSHALL(sc);
    262 
    263 	/* Load range and physical address of PTEs */
    264 	sc->sc_reg->io_cr = (sc->sc_reg->io_cr & ~IOMMU_CTL_RANGE) |
    265 			  (i << IOMMU_CTL_RANGESHFT) | IOMMU_CTL_ME;
    266 	sc->sc_reg->io_bar = (iopte_table_pa >> 4) & IOMMU_BAR_IBA;
    267 
    268 	IOMMU_FLUSHALL(sc);
    269 	splx(s);
    270 
    271 	printf(": version 0x%x/0x%x, page-size %d, range %dMB\n",
    272 		(sc->sc_reg->io_cr & IOMMU_CTL_VER) >> 24,
    273 		(sc->sc_reg->io_cr & IOMMU_CTL_IMPL) >> 28,
    274 		sc->sc_pagesize,
    275 		sc->sc_range >> 20);
    276 
    277 	sc->sc_dvmamap = vmem_create("iommudvma",
    278 				     IOMMU_DVMA_BASE,
    279 				     IOMMU_DVMA_END - IOMMU_DVMA_BASE,
    280 				     PAGE_SIZE,		/* quantum */
    281 				     NULL,		/* importfn */
    282 				     NULL,		/* releasefn */
    283 				     NULL,		/* source */
    284 				     0,			/* qcache_max */
    285 				     VM_SLEEP,
    286 				     IPL_VM);
    287 
    288 	devhandle_t selfh = device_handle(self);
    289 
    290 	/*
    291 	 * If we are attaching implicit iommu on JS1/OF we do not have
    292 	 * an iommu node to traverse, instead mainbus_attach passed us
    293 	 * sbus node in ma.ma_node.  Attach it as the only iommu child.
    294 	 */
    295 	if (js1_implicit_iommu) {
    296 		struct iommu_attach_args ia;
    297 		struct openprom_addr sbus_iommu_reg = { 0, 0x10001000, 0x28 };
    298 
    299 		memset(&ia, 0, sizeof ia);
    300 
    301 		/* Propagate BUS & DMA tags */
    302 		ia.iom_bustag = ma->ma_bustag;
    303 		ia.iom_dmatag = &sc->sc_dmatag;
    304 
    305 		ia.iom_name = "sbus";
    306 		ia.iom_node = node;
    307 		ia.iom_reg = &sbus_iommu_reg;
    308 		ia.iom_nreg = 1;
    309 
    310 		config_found(self, (void *)&ia, iommu_print,
    311 		    CFARGS(.devhandle = prom_node_to_devhandle(selfh, node)));
    312 		return;
    313 	}
    314 
    315 	/*
    316 	 * Loop through ROM children (expect Sbus among them).
    317 	 */
    318 	for (node = firstchild(node); node; node = nextsibling(node)) {
    319 		struct iommu_attach_args ia;
    320 
    321 		memset(&ia, 0, sizeof ia);
    322 		ia.iom_name = prom_getpropstring(node, "name");
    323 
    324 		/* Propagate BUS & DMA tags */
    325 		ia.iom_bustag = ma->ma_bustag;
    326 		ia.iom_dmatag = &sc->sc_dmatag;
    327 
    328 		ia.iom_node = node;
    329 
    330 		ia.iom_reg = NULL;
    331 		prom_getprop(node, "reg", sizeof(struct openprom_addr),
    332 			&ia.iom_nreg, &ia.iom_reg);
    333 
    334 		config_found(self, (void *)&ia, iommu_print,
    335 		    CFARGS(.devhandle = prom_node_to_devhandle(selfh, node)));
    336 		if (ia.iom_reg != NULL)
    337 			free(ia.iom_reg, M_DEVBUF);
    338 	}
    339 #endif
    340 }
    341 
    342 #if defined(SUN4M)
    343 static void
    344 iommu_copy_prom_entries(struct iommu_softc *sc)
    345 {
    346 	u_int pbase, pa;
    347 	u_int range;
    348 	iopte_t *tpte_p;
    349 	u_int pagesz = sc->sc_pagesize;
    350 	int use_ac = (cpuinfo.cpu_impl == 4 && cpuinfo.mxcc);
    351 	u_int mmupcr_save;
    352 
    353 	/*
    354 	 * We read in the original table using MMU bypass and copy all
    355 	 * of its entries to the appropriate place in our new table,
    356 	 * even if the sizes are different.
    357 	 * This is pretty easy since we know DVMA ends at 0xffffffff.
    358 	 */
    359 
    360 	range = (1 << 24) <<
    361 	    ((sc->sc_reg->io_cr & IOMMU_CTL_RANGE) >> IOMMU_CTL_RANGESHFT);
    362 
    363 	pbase = (sc->sc_reg->io_bar & IOMMU_BAR_IBA) <<
    364 			(14 - IOMMU_BAR_IBASHFT);
    365 
    366 	if (use_ac) {
    367 		/*
    368 		 * Set MMU AC bit so we'll still read from the cache
    369 		 * in by-pass mode.
    370 		 */
    371 		mmupcr_save = lda(SRMMU_PCR, ASI_SRMMU);
    372 		sta(SRMMU_PCR, ASI_SRMMU, mmupcr_save | VIKING_PCR_AC);
    373 	} else
    374 		mmupcr_save = 0; /* XXX - avoid GCC `uninitialized' warning */
    375 
    376 	/* Flush entire IOMMU TLB before messing with the in-memory tables */
    377 	IOMMU_FLUSHALL(sc);
    378 
    379 	/*
    380 	 * tpte_p = top of our PTE table
    381 	 * pa     = top of current PTE table
    382 	 * Then work downwards and copy entries until we hit the bottom
    383 	 * of either table.
    384 	 */
    385 	for (tpte_p = &sc->sc_ptes[((0 - IOMMU_DVMA_BASE)/pagesz) - 1],
    386 	     pa = (u_int)pbase + (range/pagesz - 1)*sizeof(iopte_t);
    387 	     tpte_p >= &sc->sc_ptes[0] && pa >= (u_int)pbase;
    388 	     tpte_p--, pa -= sizeof(iopte_t)) {
    389 
    390 		*tpte_p = lda(pa, ASI_BYPASS);
    391 	}
    392 
    393 	if (use_ac) {
    394 		/* restore mmu after bug-avoidance */
    395 		sta(SRMMU_PCR, ASI_SRMMU, mmupcr_save);
    396 	}
    397 }
    398 #endif
    399 
    400 static void
    401 iommu_enter(struct iommu_softc *sc, bus_addr_t dva, paddr_t pa)
    402 {
    403 	int pte;
    404 
    405 	/* This routine relies on the fact that sc->sc_pagesize == PAGE_SIZE */
    406 
    407 #ifdef DIAGNOSTIC
    408 	if (dva < sc->sc_dvmabase)
    409 		panic("iommu_enter: dva 0x%lx not in DVMA space", (long)dva);
    410 #endif
    411 
    412 	pte = atop(pa) << IOPTE_PPNSHFT;
    413 	pte &= IOPTE_PPN;
    414 	pte |= IOPTE_V | IOPTE_W | (sc->sc_cachecoherent ? IOPTE_C : 0);
    415 	sc->sc_ptes[atop(dva - sc->sc_dvmabase)] = pte;
    416 	IOMMU_FLUSHPAGE(sc, dva);
    417 }
    418 
    419 /*
    420  * iommu_remove: removes mappings created by iommu_enter
    421  */
    422 static void
    423 iommu_remove(struct iommu_softc *sc, bus_addr_t dva, bus_size_t len)
    424 {
    425 	u_int pagesz = sc->sc_pagesize;
    426 	bus_addr_t base = sc->sc_dvmabase;
    427 
    428 #ifdef DEBUG
    429 	if (dva < base)
    430 		panic("iommu_remove: va 0x%lx not in DVMA space", (long)dva);
    431 #endif
    432 
    433 	while ((long)len > 0) {
    434 #ifdef notyet
    435 #ifdef DEBUG
    436 		if ((sc->sc_ptes[atop(dva - base)] & IOPTE_V) == 0)
    437 			panic("iommu_remove: clearing invalid pte at dva 0x%lx",
    438 			      (long)dva);
    439 #endif
    440 #endif
    441 		sc->sc_ptes[atop(dva - base)] = 0;
    442 		IOMMU_FLUSHPAGE(sc, dva);
    443 		len -= pagesz;
    444 		dva += pagesz;
    445 	}
    446 }
    447 
    448 #if 0	/* These registers aren't there??? */
    449 void
    450 iommu_error(void)
    451 {
    452 	struct iommu_softc *sc = X;
    453 	struct iommureg *iop = sc->sc_reg;
    454 
    455 	printf("iommu: afsr 0x%x, afar 0x%x\n", iop->io_afsr, iop->io_afar);
    456 	printf("iommu: mfsr 0x%x, mfar 0x%x\n", iop->io_mfsr, iop->io_mfar);
    457 }
    458 
    459 int
    460 iommu_alloc(u_int va, u_int len)
    461 {
    462 	struct iommu_softc *sc = X;
    463 	int off, tva, iovaddr, pte;
    464 	paddr_t pa;
    465 
    466 	off = (int)va & PGOFSET;
    467 	len = round_page(len + off);
    468 	va -= off;
    469 
    470 if ((int)sc->sc_dvmacur + len > 0)
    471 	sc->sc_dvmacur = sc->sc_dvmabase;
    472 
    473 	iovaddr = tva = sc->sc_dvmacur;
    474 	sc->sc_dvmacur += len;
    475 	while (len) {
    476 		(void) pmap_extract(pmap_kernel(), va, &pa);
    477 
    478 #define IOMMU_PPNSHIFT	8
    479 #define IOMMU_V		0x00000002
    480 #define IOMMU_W		0x00000004
    481 
    482 		pte = atop(pa) << IOMMU_PPNSHIFT;
    483 		pte |= IOMMU_V | IOMMU_W;
    484 		sta(sc->sc_ptes + atop(tva - sc->sc_dvmabase), ASI_BYPASS, pte);
    485 		sc->sc_reg->io_flushpage = tva;
    486 		len -= PAGE_SIZE;
    487 		va += PAGE_SIZE;
    488 		tva += PAGE_SIZE;
    489 	}
    490 	return iovaddr + off;
    491 }
    492 #endif
    493 
    494 
    495 /*
    496  * IOMMU DMA map functions.
    497  */
    498 int
    499 iommu_dmamap_create(bus_dma_tag_t t, bus_size_t size, int nsegments,
    500 		    bus_size_t maxsegsz, bus_size_t boundary, int flags,
    501 		    bus_dmamap_t *dmamp)
    502 {
    503 	bus_dmamap_t map;
    504 	int error;
    505 
    506 	if ((error = _bus_dmamap_create(t, size, nsegments, maxsegsz,
    507 					boundary, flags, &map)) != 0)
    508 		return (error);
    509 
    510 	if ((flags & BUS_DMA_24BIT) != 0) {
    511 		/* Limit this map to the range usable by `24-bit' devices */
    512 		map->_dm_ex_start = D24_DVMA_BASE;
    513 		map->_dm_ex_end = D24_DVMA_END - 1;
    514 	} else {
    515 		/* Enable allocations from the entire map */
    516 		map->_dm_ex_start = VMEM_ADDR_MIN;
    517 		map->_dm_ex_end = VMEM_ADDR_MAX;
    518 	}
    519 
    520 	*dmamp = map;
    521 	return (0);
    522 }
    523 
    524 /*
    525  * Internal routine to allocate space in the IOMMU map.
    526  */
    527 int
    528 iommu_dvma_alloc(struct iommu_softc *sc, bus_dmamap_t map,
    529 		 vaddr_t va, bus_size_t len, int flags,
    530 		 bus_addr_t *dvap, bus_size_t *sgsizep)
    531 {
    532 	bus_size_t sgsize;
    533 	u_long align, voff;
    534 	vmem_addr_t dvaddr;
    535 	int error;
    536 	int pagesz = PAGE_SIZE;
    537 
    538 	/*
    539 	 * Remember page offset, then truncate the buffer address to
    540 	 * a page boundary.
    541 	 */
    542 	voff = va & (pagesz - 1);
    543 	va &= -pagesz;
    544 
    545 	if (len > map->_dm_size)
    546 		return (EINVAL);
    547 
    548 	sgsize = (len + voff + pagesz - 1) & -pagesz;
    549 	align = dvma_cachealign ? dvma_cachealign : map->_dm_align;
    550 
    551 	const vm_flag_t vmflags = VM_BESTFIT |
    552 	    ((flags & BUS_DMA_NOWAIT) ? VM_NOSLEEP : VM_SLEEP);
    553 
    554 	error = vmem_xalloc(sc->sc_dvmamap, sgsize,
    555 			    align,			/* alignment */
    556 			    va & (align-1),		/* phase */
    557 			    map->_dm_boundary,		/* nocross */
    558 			    map->_dm_ex_start,		/* minaddr */
    559 			    map->_dm_ex_end,		/* maxaddr */
    560 			    vmflags,
    561 			    &dvaddr);
    562 
    563 	*dvap = (bus_addr_t)dvaddr;
    564 	*sgsizep = sgsize;
    565 	return (error);
    566 }
    567 
    568 /*
    569  * Prepare buffer for DMA transfer.
    570  */
    571 int
    572 iommu_dmamap_load(bus_dma_tag_t t, bus_dmamap_t map,
    573 		  void *buf, bus_size_t buflen,
    574 		  struct proc *p, int flags)
    575 {
    576 	struct iommu_softc *sc = t->_cookie;
    577 	bus_size_t sgsize;
    578 	bus_addr_t dva;
    579 	vaddr_t va = (vaddr_t)buf;
    580 	int pagesz = PAGE_SIZE;
    581 	pmap_t pmap;
    582 	int error;
    583 
    584 	/*
    585 	 * Make sure that on error condition we return "no valid mappings".
    586 	 */
    587 	map->dm_nsegs = 0;
    588 
    589 	/* Allocate IOMMU resources */
    590 	if ((error = iommu_dvma_alloc(sc, map, va, buflen, flags,
    591 					&dva, &sgsize)) != 0)
    592 		return (error);
    593 
    594 	if ((sc->sc_cachecoherent == 0) ||
    595 	    (curcpu()->cacheinfo.ec_totalsize == 0))
    596 		cache_flush(buf, buflen); /* XXX - move to bus_dma_sync? */
    597 
    598 	/*
    599 	 * We always use just one segment.
    600 	 */
    601 	map->dm_mapsize = buflen;
    602 	map->dm_nsegs = 1;
    603 	map->dm_segs[0].ds_addr = dva + (va & (pagesz - 1));
    604 	map->dm_segs[0].ds_len = buflen;
    605 	map->dm_segs[0]._ds_sgsize = sgsize;
    606 
    607 	if (p != NULL)
    608 		pmap = p->p_vmspace->vm_map.pmap;
    609 	else
    610 		pmap = pmap_kernel();
    611 
    612 	for (; sgsize != 0; ) {
    613 		paddr_t pa;
    614 		/*
    615 		 * Get the physical address for this page.
    616 		 */
    617 		if (!pmap_extract(pmap, va, &pa)) {
    618 			iommu_dmamap_unload(t, map);
    619 			return (EFAULT);
    620 		}
    621 
    622 		iommu_enter(sc, dva, pa);
    623 
    624 		dva += pagesz;
    625 		va += pagesz;
    626 		sgsize -= pagesz;
    627 	}
    628 
    629 	return (0);
    630 }
    631 
    632 /*
    633  * Like _bus_dmamap_load(), but for mbufs.
    634  */
    635 int
    636 iommu_dmamap_load_mbuf(bus_dma_tag_t t, bus_dmamap_t map,
    637 		       struct mbuf *m, int flags)
    638 {
    639 
    640 	panic("_bus_dmamap_load_mbuf: not implemented");
    641 }
    642 
    643 /*
    644  * Like _bus_dmamap_load(), but for uios.
    645  */
    646 int
    647 iommu_dmamap_load_uio(bus_dma_tag_t t, bus_dmamap_t map,
    648 		      struct uio *uio, int flags)
    649 {
    650 
    651 	panic("_bus_dmamap_load_uio: not implemented");
    652 }
    653 
    654 /*
    655  * Like _bus_dmamap_load(), but for raw memory allocated with
    656  * bus_dmamem_alloc().
    657  */
    658 int
    659 iommu_dmamap_load_raw(bus_dma_tag_t t, bus_dmamap_t map,
    660 		      bus_dma_segment_t *segs, int nsegs, bus_size_t size,
    661 		      int flags)
    662 {
    663 	struct iommu_softc *sc = t->_cookie;
    664 	struct vm_page *m;
    665 	paddr_t pa;
    666 	bus_addr_t dva;
    667 	bus_size_t sgsize;
    668 	struct pglist *mlist;
    669 	int pagesz = PAGE_SIZE;
    670 	int error;
    671 
    672 	map->dm_nsegs = 0;
    673 
    674 	/* Allocate IOMMU resources */
    675 	if ((error = iommu_dvma_alloc(sc, map, segs[0]._ds_va, size,
    676 				      flags, &dva, &sgsize)) != 0)
    677 		return (error);
    678 
    679 	/*
    680 	 * Note DVMA address in case bus_dmamem_map() is called later.
    681 	 * It can then insure cache coherency by choosing a KVA that
    682 	 * is aligned to `ds_addr'.
    683 	 */
    684 	segs[0].ds_addr = dva;
    685 	segs[0].ds_len = size;
    686 
    687 	map->dm_segs[0].ds_addr = dva;
    688 	map->dm_segs[0].ds_len = size;
    689 	map->dm_segs[0]._ds_sgsize = sgsize;
    690 
    691 	/* Map physical pages into IOMMU */
    692 	mlist = segs[0]._ds_mlist;
    693 	for (m = TAILQ_FIRST(mlist); m != NULL; m = TAILQ_NEXT(m,pageq.queue)) {
    694 		if (sgsize == 0)
    695 			panic("iommu_dmamap_load_raw: size botch");
    696 		pa = VM_PAGE_TO_PHYS(m);
    697 		iommu_enter(sc, dva, pa);
    698 		dva += pagesz;
    699 		sgsize -= pagesz;
    700 	}
    701 
    702 	map->dm_nsegs = 1;
    703 	map->dm_mapsize = size;
    704 
    705 	return (0);
    706 }
    707 
    708 /*
    709  * Unload an IOMMU DMA map.
    710  */
    711 void
    712 iommu_dmamap_unload(bus_dma_tag_t t, bus_dmamap_t map)
    713 {
    714 	struct iommu_softc *sc = t->_cookie;
    715 	bus_dma_segment_t *segs = map->dm_segs;
    716 	int nsegs = map->dm_nsegs;
    717 	bus_addr_t dva;
    718 	bus_size_t len;
    719 	int i;
    720 
    721 	for (i = 0; i < nsegs; i++) {
    722 		dva = segs[i].ds_addr & -PAGE_SIZE;
    723 		len = segs[i]._ds_sgsize;
    724 
    725 		iommu_remove(sc, dva, len);
    726 		vmem_xfree(sc->sc_dvmamap, dva, len);
    727 	}
    728 
    729 	/* Mark the mappings as invalid. */
    730 	map->dm_mapsize = 0;
    731 	map->dm_nsegs = 0;
    732 }
    733 
    734 /*
    735  * DMA map synchronization.
    736  */
    737 void
    738 iommu_dmamap_sync(bus_dma_tag_t t, bus_dmamap_t map,
    739 		  bus_addr_t offset, bus_size_t len, int ops)
    740 {
    741 
    742 	/*
    743 	 * XXX Should flush CPU write buffers.
    744 	 */
    745 }
    746 
    747 /*
    748  * Map DMA-safe memory.
    749  */
    750 int
    751 iommu_dmamem_map(bus_dma_tag_t t, bus_dma_segment_t *segs, int nsegs,
    752 		 size_t size, void **kvap, int flags)
    753 {
    754 	struct iommu_softc *sc = t->_cookie;
    755 	struct vm_page *m;
    756 	vaddr_t va;
    757 	bus_addr_t addr;
    758 	struct pglist *mlist;
    759 	int cbit;
    760 	u_long align;
    761 	int pagesz = PAGE_SIZE;
    762 
    763 	if (nsegs != 1)
    764 		panic("iommu_dmamem_map: nsegs = %d", nsegs);
    765 
    766 	cbit = sc->sc_cachecoherent ? 0 : PMAP_NC;
    767 	align = dvma_cachealign ? dvma_cachealign : pagesz;
    768 
    769 	size = round_page(size);
    770 
    771 	/*
    772 	 * In case the segment has already been loaded by
    773 	 * iommu_dmamap_load_raw(), find a region of kernel virtual
    774 	 * addresses that can accommodate our alignment requirements.
    775 	 */
    776 	va = _bus_dma_valloc_skewed(size, 0, align,
    777 				    segs[0].ds_addr & (align - 1));
    778 	if (va == 0)
    779 		return (ENOMEM);
    780 
    781 	segs[0]._ds_va = va;
    782 	*kvap = (void *)va;
    783 
    784 	/*
    785 	 * Map the pages allocated in _bus_dmamem_alloc() to the
    786 	 * kernel virtual address space.
    787 	 */
    788 	mlist = segs[0]._ds_mlist;
    789 	for (m = TAILQ_FIRST(mlist); m != NULL; m = TAILQ_NEXT(m,pageq.queue)) {
    790 
    791 		if (size == 0)
    792 			panic("iommu_dmamem_map: size botch");
    793 
    794 		addr = VM_PAGE_TO_PHYS(m);
    795 		pmap_kenter_pa(va, addr | cbit,
    796 		    VM_PROT_READ | VM_PROT_WRITE, 0);
    797 #if 0
    798 			if (flags & BUS_DMA_COHERENT)
    799 				/* XXX */;
    800 #endif
    801 		va += pagesz;
    802 		size -= pagesz;
    803 	}
    804 	pmap_update(pmap_kernel());
    805 
    806 	return (0);
    807 }
    808 
    809 void
    810 iommu_dmamem_unmap(bus_dma_tag_t t, void *kva, size_t size)
    811 {
    812 
    813 #ifdef DIAGNOSTIC
    814 	if ((u_long)kva & PAGE_MASK)
    815 		panic("iommu_dmamem_unmap");
    816 #endif
    817 
    818 	size = round_page(size);
    819 	pmap_kremove((vaddr_t)kva, size);
    820 	pmap_update(pmap_kernel());
    821 	uvm_unmap(kernel_map, (vaddr_t)kva, (vaddr_t)kva + size);
    822 }
    823 
    824 
    825 /*
    826  * mmap(2)'ing DMA-safe memory.
    827  */
    828 paddr_t
    829 iommu_dmamem_mmap(bus_dma_tag_t t, bus_dma_segment_t *segs, int nsegs,
    830 		  off_t off, int prot, int flags)
    831 {
    832 
    833 	panic("_bus_dmamem_mmap: not implemented");
    834 }
    835