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agp_amd.c revision 1.3.2.4
      1  1.3.2.4  nathanw /*	$NetBSD: agp_amd.c,v 1.3.2.4 2001/10/22 20:41:23 nathanw Exp $	*/
      2  1.3.2.2  nathanw 
      3  1.3.2.2  nathanw /*-
      4  1.3.2.2  nathanw  * Copyright (c) 2000 Doug Rabson
      5  1.3.2.2  nathanw  * All rights reserved.
      6  1.3.2.2  nathanw  *
      7  1.3.2.2  nathanw  * Redistribution and use in source and binary forms, with or without
      8  1.3.2.2  nathanw  * modification, are permitted provided that the following conditions
      9  1.3.2.2  nathanw  * are met:
     10  1.3.2.2  nathanw  * 1. Redistributions of source code must retain the above copyright
     11  1.3.2.2  nathanw  *    notice, this list of conditions and the following disclaimer.
     12  1.3.2.2  nathanw  * 2. Redistributions in binary form must reproduce the above copyright
     13  1.3.2.2  nathanw  *    notice, this list of conditions and the following disclaimer in the
     14  1.3.2.2  nathanw  *    documentation and/or other materials provided with the distribution.
     15  1.3.2.2  nathanw  *
     16  1.3.2.2  nathanw  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     17  1.3.2.2  nathanw  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     18  1.3.2.2  nathanw  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     19  1.3.2.2  nathanw  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     20  1.3.2.2  nathanw  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     21  1.3.2.2  nathanw  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     22  1.3.2.2  nathanw  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     23  1.3.2.2  nathanw  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     24  1.3.2.2  nathanw  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     25  1.3.2.2  nathanw  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  1.3.2.2  nathanw  * SUCH DAMAGE.
     27  1.3.2.2  nathanw  *
     28  1.3.2.2  nathanw  *	$FreeBSD: src/sys/pci/agp_amd.c,v 1.6 2001/07/05 21:28:46 jhb Exp $
     29  1.3.2.2  nathanw  */
     30  1.3.2.2  nathanw 
     31  1.3.2.2  nathanw #include <sys/param.h>
     32  1.3.2.2  nathanw #include <sys/systm.h>
     33  1.3.2.2  nathanw #include <sys/malloc.h>
     34  1.3.2.2  nathanw #include <sys/kernel.h>
     35  1.3.2.2  nathanw #include <sys/lock.h>
     36  1.3.2.2  nathanw #include <sys/proc.h>
     37  1.3.2.2  nathanw #include <sys/conf.h>
     38  1.3.2.2  nathanw #include <sys/device.h>
     39  1.3.2.2  nathanw #include <sys/agpio.h>
     40  1.3.2.2  nathanw 
     41  1.3.2.2  nathanw #include <uvm/uvm_extern.h>
     42  1.3.2.2  nathanw 
     43  1.3.2.2  nathanw #include <dev/pci/pcivar.h>
     44  1.3.2.2  nathanw #include <dev/pci/pcireg.h>
     45  1.3.2.2  nathanw #include <dev/pci/agpvar.h>
     46  1.3.2.2  nathanw #include <dev/pci/agpreg.h>
     47  1.3.2.2  nathanw 
     48  1.3.2.2  nathanw #include <dev/pci/pcidevs.h>
     49  1.3.2.2  nathanw 
     50  1.3.2.2  nathanw #define READ2(off)	bus_space_read_2(asc->iot, asc->ioh, off)
     51  1.3.2.2  nathanw #define READ4(off)	bus_space_read_4(asc->iot, asc->ioh, off)
     52  1.3.2.2  nathanw #define WRITE2(off,v)	bus_space_write_2(asc->iot, asc->ioh, off, v)
     53  1.3.2.2  nathanw #define WRITE4(off,v)	bus_space_write_4(asc->iot, asc->ioh, off, v)
     54  1.3.2.2  nathanw 
     55  1.3.2.2  nathanw struct agp_amd_gatt {
     56  1.3.2.2  nathanw 	bus_dmamap_t	ag_dmamap;
     57  1.3.2.2  nathanw 	bus_dma_segment_t ag_dmaseg;
     58  1.3.2.2  nathanw 	int		ag_nseg;
     59  1.3.2.2  nathanw 	u_int32_t	ag_entries;
     60  1.3.2.2  nathanw 	u_int32_t      *ag_vdir;	/* virtual address of page dir */
     61  1.3.2.2  nathanw 	bus_addr_t	ag_pdir;	/* bus address of page dir */
     62  1.3.2.2  nathanw 	u_int32_t      *ag_virtual;	/* virtual address of gatt */
     63  1.3.2.2  nathanw 	bus_addr_t	ag_physical;	/* bus address of gatt */
     64  1.3.2.2  nathanw 	size_t		ag_size;
     65  1.3.2.2  nathanw };
     66  1.3.2.2  nathanw 
     67  1.3.2.2  nathanw struct agp_amd_softc {
     68  1.3.2.2  nathanw 	u_int32_t	initial_aperture; /* aperture size at startup */
     69  1.3.2.2  nathanw 	struct agp_amd_gatt *gatt;
     70  1.3.2.2  nathanw 	bus_space_handle_t ioh;
     71  1.3.2.2  nathanw 	bus_space_tag_t iot;
     72  1.3.2.2  nathanw };
     73  1.3.2.2  nathanw 
     74  1.3.2.2  nathanw static u_int32_t agp_amd_get_aperture(struct agp_softc *);
     75  1.3.2.2  nathanw static int agp_amd_set_aperture(struct agp_softc *, u_int32_t);
     76  1.3.2.2  nathanw static int agp_amd_bind_page(struct agp_softc *, off_t, bus_addr_t);
     77  1.3.2.2  nathanw static int agp_amd_unbind_page(struct agp_softc *, off_t);
     78  1.3.2.2  nathanw static void agp_amd_flush_tlb(struct agp_softc *);
     79  1.3.2.2  nathanw 
     80  1.3.2.2  nathanw 
     81  1.3.2.2  nathanw struct agp_methods agp_amd_methods = {
     82  1.3.2.2  nathanw 	agp_amd_get_aperture,
     83  1.3.2.2  nathanw 	agp_amd_set_aperture,
     84  1.3.2.2  nathanw 	agp_amd_bind_page,
     85  1.3.2.2  nathanw 	agp_amd_unbind_page,
     86  1.3.2.2  nathanw 	agp_amd_flush_tlb,
     87  1.3.2.2  nathanw 	agp_generic_enable,
     88  1.3.2.2  nathanw 	agp_generic_alloc_memory,
     89  1.3.2.2  nathanw 	agp_generic_free_memory,
     90  1.3.2.2  nathanw 	agp_generic_bind_memory,
     91  1.3.2.2  nathanw 	agp_generic_unbind_memory,
     92  1.3.2.2  nathanw };
     93  1.3.2.2  nathanw 
     94  1.3.2.2  nathanw 
     95  1.3.2.2  nathanw static struct agp_amd_gatt *
     96  1.3.2.2  nathanw agp_amd_alloc_gatt(struct agp_softc *sc)
     97  1.3.2.2  nathanw {
     98  1.3.2.2  nathanw 	u_int32_t apsize = AGP_GET_APERTURE(sc);
     99  1.3.2.2  nathanw 	u_int32_t entries = apsize >> AGP_PAGE_SHIFT;
    100  1.3.2.2  nathanw 	struct agp_amd_gatt *gatt;
    101  1.3.2.2  nathanw 	int i, npages;
    102  1.3.2.3  nathanw 	caddr_t vdir;
    103  1.3.2.2  nathanw 
    104  1.3.2.2  nathanw 	gatt = malloc(sizeof(struct agp_amd_gatt), M_AGP, M_NOWAIT);
    105  1.3.2.2  nathanw 	if (!gatt)
    106  1.3.2.2  nathanw 		return 0;
    107  1.3.2.2  nathanw 
    108  1.3.2.2  nathanw 	if (agp_alloc_dmamem(sc->as_dmat,
    109  1.3.2.2  nathanw 	    AGP_PAGE_SIZE + entries * sizeof(u_int32_t), 0,
    110  1.3.2.4  nathanw 	    &gatt->ag_dmamap, &vdir, &gatt->ag_pdir,
    111  1.3.2.2  nathanw 	    &gatt->ag_dmaseg, 1, &gatt->ag_nseg) != 0) {
    112  1.3.2.2  nathanw 		printf("failed to allocate GATT\n");
    113  1.3.2.4  nathanw 		free(gatt, M_AGP);
    114  1.3.2.2  nathanw 		return NULL;
    115  1.3.2.2  nathanw 	}
    116  1.3.2.2  nathanw 
    117  1.3.2.3  nathanw 	gatt->ag_vdir = (u_int32_t *)vdir;
    118  1.3.2.2  nathanw 	gatt->ag_entries = entries;
    119  1.3.2.3  nathanw 	gatt->ag_virtual = (u_int32_t *)(vdir + AGP_PAGE_SIZE);
    120  1.3.2.2  nathanw 	gatt->ag_physical = gatt->ag_pdir + AGP_PAGE_SIZE;
    121  1.3.2.2  nathanw 	gatt->ag_size = AGP_PAGE_SIZE + entries * sizeof(u_int32_t);
    122  1.3.2.2  nathanw 
    123  1.3.2.2  nathanw 	memset(gatt->ag_vdir, 0, AGP_PAGE_SIZE);
    124  1.3.2.2  nathanw 	memset(gatt->ag_virtual, 0, entries * sizeof(u_int32_t));
    125  1.3.2.2  nathanw 
    126  1.3.2.2  nathanw 	/*
    127  1.3.2.2  nathanw 	 * Map the pages of the GATT into the page directory.
    128  1.3.2.2  nathanw 	 */
    129  1.3.2.2  nathanw 	npages = ((entries * sizeof(u_int32_t) + AGP_PAGE_SIZE - 1)
    130  1.3.2.2  nathanw 		  >> AGP_PAGE_SHIFT);
    131  1.3.2.2  nathanw 
    132  1.3.2.2  nathanw 	for (i = 0; i < npages; i++)
    133  1.3.2.2  nathanw 		gatt->ag_vdir[i] = (gatt->ag_physical + i * AGP_PAGE_SIZE) | 1;
    134  1.3.2.2  nathanw 
    135  1.3.2.2  nathanw 	/*
    136  1.3.2.2  nathanw 	 * Make sure the chipset can see everything.
    137  1.3.2.2  nathanw 	 */
    138  1.3.2.2  nathanw 	agp_flush_cache();
    139  1.3.2.2  nathanw 
    140  1.3.2.2  nathanw 	return gatt;
    141  1.3.2.2  nathanw }
    142  1.3.2.2  nathanw 
    143  1.3.2.2  nathanw #if 0
    144  1.3.2.2  nathanw static void
    145  1.3.2.2  nathanw agp_amd_free_gatt(struct agp_softc *sc, struct agp_amd_gatt *gatt)
    146  1.3.2.2  nathanw {
    147  1.3.2.2  nathanw 	agp_free_dmamem(sc->as_dmat, gatt->ag_size,
    148  1.3.2.2  nathanw 	    gatt->ag_dmamap, (caddr_t)gatt->ag_virtual, &gatt->ag_dmaseg,
    149  1.3.2.2  nathanw 	    gatt->ag_nseg);
    150  1.3.2.2  nathanw 	free(gatt, M_AGP);
    151  1.3.2.2  nathanw }
    152  1.3.2.2  nathanw #endif
    153  1.3.2.2  nathanw 
    154  1.3.2.2  nathanw int
    155  1.3.2.2  nathanw agp_amd_match(const struct pci_attach_args *pa)
    156  1.3.2.2  nathanw {
    157  1.3.2.2  nathanw 
    158  1.3.2.2  nathanw 	switch (PCI_PRODUCT(pa->pa_id)) {
    159  1.3.2.2  nathanw 	case PCI_PRODUCT_AMD_SC751_SC:
    160  1.3.2.3  nathanw 	case PCI_PRODUCT_AMD_SC762_NB:
    161  1.3.2.2  nathanw 		return 1;
    162  1.3.2.2  nathanw 	}
    163  1.3.2.2  nathanw 
    164  1.3.2.2  nathanw 	return 0;
    165  1.3.2.2  nathanw }
    166  1.3.2.2  nathanw 
    167  1.3.2.2  nathanw int
    168  1.3.2.2  nathanw agp_amd_attach(struct device *parent, struct device *self, void *aux)
    169  1.3.2.2  nathanw {
    170  1.3.2.2  nathanw 	struct agp_softc *sc = (void *)self;
    171  1.3.2.2  nathanw 	struct agp_amd_softc *asc;
    172  1.3.2.2  nathanw 	struct pci_attach_args *pa = aux;
    173  1.3.2.2  nathanw 	struct agp_amd_gatt *gatt;
    174  1.3.2.2  nathanw 	pcireg_t reg;
    175  1.3.2.2  nathanw 	int error;
    176  1.3.2.2  nathanw 
    177  1.3.2.2  nathanw 	asc = malloc(sizeof *asc, M_AGP, M_NOWAIT);
    178  1.3.2.2  nathanw 	if (asc == NULL) {
    179  1.3.2.2  nathanw 		printf(": can't allocate softc\n");
    180  1.3.2.2  nathanw 		/* agp_generic_detach(sc) */
    181  1.3.2.2  nathanw 		return ENOMEM;
    182  1.3.2.2  nathanw 	}
    183  1.3.2.2  nathanw 	memset(asc, 0, sizeof *asc);
    184  1.3.2.2  nathanw 
    185  1.3.2.2  nathanw 	error = pci_mapreg_map(pa, AGP_AMD751_REGISTERS, PCI_MAPREG_TYPE_MEM, 0,
    186  1.3.2.2  nathanw 	    &asc->iot, &asc->ioh, NULL, NULL);
    187  1.3.2.2  nathanw 	if (error != 0) {
    188  1.3.2.2  nathanw 		printf(": can't map AGP registers\n");
    189  1.3.2.2  nathanw 		agp_generic_detach(sc);
    190  1.3.2.2  nathanw 		return error;
    191  1.3.2.2  nathanw 	}
    192  1.3.2.2  nathanw 
    193  1.3.2.2  nathanw 	if (agp_map_aperture(pa, sc) != 0) {
    194  1.3.2.2  nathanw 		printf(": can't map aperture\n");
    195  1.3.2.2  nathanw 		agp_generic_detach(sc);
    196  1.3.2.2  nathanw 		free(asc, M_AGP);
    197  1.3.2.2  nathanw 		return ENXIO;
    198  1.3.2.2  nathanw 	}
    199  1.3.2.2  nathanw 	pci_get_capability(pa->pa_pc, pa->pa_tag, PCI_CAP_AGP, &sc->as_capoff,
    200  1.3.2.2  nathanw 	    NULL);
    201  1.3.2.2  nathanw 	sc->as_methods = &agp_amd_methods;
    202  1.3.2.2  nathanw 	sc->as_chipc = asc;
    203  1.3.2.2  nathanw 	asc->initial_aperture = AGP_GET_APERTURE(sc);
    204  1.3.2.2  nathanw 
    205  1.3.2.2  nathanw 	for (;;) {
    206  1.3.2.2  nathanw 		gatt = agp_amd_alloc_gatt(sc);
    207  1.3.2.2  nathanw 		if (gatt)
    208  1.3.2.2  nathanw 			break;
    209  1.3.2.2  nathanw 
    210  1.3.2.2  nathanw 		/*
    211  1.3.2.2  nathanw 		 * Probably contigmalloc failure. Try reducing the
    212  1.3.2.2  nathanw 		 * aperture so that the gatt size reduces.
    213  1.3.2.2  nathanw 		 */
    214  1.3.2.2  nathanw 		if (AGP_SET_APERTURE(sc, AGP_GET_APERTURE(sc) / 2)) {
    215  1.3.2.2  nathanw 			printf(": can't set aperture\n");
    216  1.3.2.2  nathanw 			return ENOMEM;
    217  1.3.2.2  nathanw 		}
    218  1.3.2.2  nathanw 	}
    219  1.3.2.2  nathanw 	asc->gatt = gatt;
    220  1.3.2.2  nathanw 
    221  1.3.2.2  nathanw 	/* Install the gatt. */
    222  1.3.2.2  nathanw 	WRITE4(AGP_AMD751_ATTBASE, gatt->ag_physical);
    223  1.3.2.2  nathanw 
    224  1.3.2.2  nathanw 	/* Enable synchronisation between host and agp. */
    225  1.3.2.2  nathanw 	reg = pci_conf_read(pa->pa_pc, pa->pa_tag, AGP_AMD751_MODECTRL);
    226  1.3.2.2  nathanw 	reg &= ~0x00ff00ff;
    227  1.3.2.2  nathanw 	reg |= (AGP_AMD751_MODECTRL_SYNEN) | (AGP_AMD751_MODECTRL2_GPDCE << 16);
    228  1.3.2.2  nathanw 	pci_conf_write(pa->pa_pc, pa->pa_tag, AGP_AMD751_MODECTRL, reg);
    229  1.3.2.2  nathanw 	/* Enable the TLB and flush */
    230  1.3.2.2  nathanw 	WRITE2(AGP_AMD751_STATUS,
    231  1.3.2.2  nathanw 	       READ2(AGP_AMD751_STATUS) | AGP_AMD751_STATUS_GCE);
    232  1.3.2.2  nathanw 	AGP_FLUSH_TLB(sc);
    233  1.3.2.2  nathanw 
    234  1.3.2.2  nathanw 	return 0;
    235  1.3.2.2  nathanw }
    236  1.3.2.2  nathanw 
    237  1.3.2.2  nathanw #if 0
    238  1.3.2.2  nathanw static int
    239  1.3.2.2  nathanw agp_amd_detach(struct agp_softc *sc)
    240  1.3.2.2  nathanw {
    241  1.3.2.2  nathanw 	pcireg_t reg;
    242  1.3.2.2  nathanw 	struct agp_amd_softc *asc = sc->as_chipc;
    243  1.3.2.2  nathanw 
    244  1.3.2.2  nathanw 	/* Disable the TLB.. */
    245  1.3.2.2  nathanw 	WRITE2(AGP_AMD751_STATUS,
    246  1.3.2.2  nathanw 	       READ2(AGP_AMD751_STATUS) & ~AGP_AMD751_STATUS_GCE);
    247  1.3.2.2  nathanw 
    248  1.3.2.2  nathanw 	/* Disable host-agp sync */
    249  1.3.2.2  nathanw 	reg = pci_conf_read(sc->as_pc, sc->as_tag, AGP_AMD751_MODECTRL);
    250  1.3.2.2  nathanw 	reg &= 0xffffff00;
    251  1.3.2.2  nathanw 	pci_conf_write(sc->as_pc, sc->as_tag, AGP_AMD751_MODECTRL, reg);
    252  1.3.2.2  nathanw 
    253  1.3.2.2  nathanw 	/* Clear the GATT base */
    254  1.3.2.2  nathanw 	WRITE4(AGP_AMD751_ATTBASE, 0);
    255  1.3.2.2  nathanw 
    256  1.3.2.2  nathanw 	/* Put the aperture back the way it started. */
    257  1.3.2.2  nathanw 	AGP_SET_APERTURE(sc, asc->initial_aperture);
    258  1.3.2.2  nathanw 
    259  1.3.2.2  nathanw 	agp_amd_free_gatt(sc, asc->gatt);
    260  1.3.2.2  nathanw 
    261  1.3.2.2  nathanw 	/* XXXfvdl no pci_mapreg_unmap */
    262  1.3.2.2  nathanw 
    263  1.3.2.2  nathanw 	return 0;
    264  1.3.2.2  nathanw }
    265  1.3.2.2  nathanw #endif
    266  1.3.2.2  nathanw 
    267  1.3.2.2  nathanw static u_int32_t
    268  1.3.2.2  nathanw agp_amd_get_aperture(struct agp_softc *sc)
    269  1.3.2.2  nathanw {
    270  1.3.2.2  nathanw 	int vas;
    271  1.3.2.2  nathanw 
    272  1.3.2.2  nathanw 	vas = (pci_conf_read(sc->as_pc, sc->as_tag, AGP_AMD751_APCTRL) & 0x06);
    273  1.3.2.2  nathanw 	vas >>= 1;
    274  1.3.2.2  nathanw 	/*
    275  1.3.2.2  nathanw 	 * The aperture size is equal to 32M<<vas.
    276  1.3.2.2  nathanw 	 */
    277  1.3.2.2  nathanw 	return (32*1024*1024) << vas;
    278  1.3.2.2  nathanw }
    279  1.3.2.2  nathanw 
    280  1.3.2.2  nathanw static int
    281  1.3.2.2  nathanw agp_amd_set_aperture(struct agp_softc *sc, u_int32_t aperture)
    282  1.3.2.2  nathanw {
    283  1.3.2.2  nathanw 	int vas;
    284  1.3.2.2  nathanw 	pcireg_t reg;
    285  1.3.2.2  nathanw 
    286  1.3.2.2  nathanw 	/*
    287  1.3.2.2  nathanw 	 * Check for a power of two and make sure its within the
    288  1.3.2.2  nathanw 	 * programmable range.
    289  1.3.2.2  nathanw 	 */
    290  1.3.2.2  nathanw 	if (aperture & (aperture - 1)
    291  1.3.2.2  nathanw 	    || aperture < 32*1024*1024
    292  1.3.2.2  nathanw 	    || aperture > 2U*1024*1024*1024)
    293  1.3.2.2  nathanw 		return EINVAL;
    294  1.3.2.2  nathanw 
    295  1.3.2.2  nathanw 	vas = ffs(aperture / 32*1024*1024) - 1;
    296  1.3.2.2  nathanw 
    297  1.3.2.2  nathanw 	reg = pci_conf_read(sc->as_pc, sc->as_tag, AGP_AMD751_APCTRL);
    298  1.3.2.2  nathanw 	reg = (reg & ~0x06) | (vas << 1);
    299  1.3.2.2  nathanw 	pci_conf_write(sc->as_pc, sc->as_tag, AGP_AMD751_APCTRL, reg);
    300  1.3.2.2  nathanw 
    301  1.3.2.2  nathanw 	return 0;
    302  1.3.2.2  nathanw }
    303  1.3.2.2  nathanw 
    304  1.3.2.2  nathanw static int
    305  1.3.2.2  nathanw agp_amd_bind_page(struct agp_softc *sc, off_t offset, bus_addr_t physical)
    306  1.3.2.2  nathanw {
    307  1.3.2.2  nathanw 	struct agp_amd_softc *asc = sc->as_chipc;
    308  1.3.2.2  nathanw 
    309  1.3.2.2  nathanw 	if (offset < 0 || offset >= (asc->gatt->ag_entries << AGP_PAGE_SHIFT))
    310  1.3.2.2  nathanw 		return EINVAL;
    311  1.3.2.2  nathanw 
    312  1.3.2.2  nathanw 	asc->gatt->ag_virtual[offset >> AGP_PAGE_SHIFT] = physical | 1;
    313  1.3.2.2  nathanw 	return 0;
    314  1.3.2.2  nathanw }
    315  1.3.2.2  nathanw 
    316  1.3.2.2  nathanw static int
    317  1.3.2.2  nathanw agp_amd_unbind_page(struct agp_softc *sc, off_t offset)
    318  1.3.2.2  nathanw {
    319  1.3.2.2  nathanw 	struct agp_amd_softc *asc = sc->as_chipc;
    320  1.3.2.2  nathanw 
    321  1.3.2.2  nathanw 	if (offset < 0 || offset >= (asc->gatt->ag_entries << AGP_PAGE_SHIFT))
    322  1.3.2.2  nathanw 		return EINVAL;
    323  1.3.2.2  nathanw 
    324  1.3.2.2  nathanw 	asc->gatt->ag_virtual[offset >> AGP_PAGE_SHIFT] = 0;
    325  1.3.2.2  nathanw 	return 0;
    326  1.3.2.2  nathanw }
    327  1.3.2.2  nathanw 
    328  1.3.2.2  nathanw static void
    329  1.3.2.2  nathanw agp_amd_flush_tlb(struct agp_softc *sc)
    330  1.3.2.2  nathanw {
    331  1.3.2.2  nathanw 	struct agp_amd_softc *asc = sc->as_chipc;
    332  1.3.2.2  nathanw 
    333  1.3.2.2  nathanw 	/* Set the cache invalidate bit and wait for the chipset to clear */
    334  1.3.2.2  nathanw 	WRITE4(AGP_AMD751_TLBCTRL, 1);
    335  1.3.2.2  nathanw 	do {
    336  1.3.2.2  nathanw 		DELAY(1);
    337  1.3.2.2  nathanw 	} while (READ4(AGP_AMD751_TLBCTRL));
    338  1.3.2.2  nathanw }
    339