dvma.c revision 1.8
1/* $NetBSD: dvma.c,v 1.8 1998/01/22 22:20:37 gwr Exp $ */ 2 3/*- 4 * Copyright (c) 1996 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Gordon W. Ross and Jeremy Cooper. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the NetBSD 21 * Foundation, Inc. and its contributors. 22 * 4. Neither the name of The NetBSD Foundation nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39/* 40 * DVMA (Direct Virtual Memory Access - like DMA) 41 * 42 * In the Sun3 architecture, memory cycles initiated by secondary bus 43 * masters (DVMA devices) passed through the same MMU that governed CPU 44 * accesses. All DVMA devices were wired in such a way so that an offset 45 * was added to the addresses they issued, causing them to access virtual 46 * memory starting at address 0x0FF00000 - the offset. The task of 47 * enabling a DVMA device to access main memory only involved creating 48 * valid mapping in the MMU that translated these high addresses into the 49 * appropriate physical addresses. 50 * 51 * The Sun3x presents a challenge to programming DVMA because the MMU is no 52 * longer shared by both secondary bus masters and the CPU. The MC68030's 53 * built-in MMU serves only to manage virtual memory accesses initiated by 54 * the CPU. Secondary bus master bus accesses pass through a different MMU, 55 * aptly named the 'I/O Mapper'. To enable every device driver that uses 56 * DVMA to understand that these two address spaces are disconnected would 57 * require a tremendous amount of code re-writing. To avoid this, we will 58 * ensure that the I/O Mapper and the MC68030 MMU are programmed together, 59 * so that DVMA mappings are consistent in both the CPU virtual address 60 * space and secondary bus master address space - creating an environment 61 * just like the Sun3 system. 62 * 63 * The maximum address space that any DVMA device in the Sun3x architecture 64 * is capable of addressing is 24 bits wide (16 Megabytes.) We can alias 65 * all of the mappings that exist in the I/O mapper by duplicating them in 66 * a specially reserved section of the CPU's virtual address space, 16 67 * Megabytes in size. Whenever a DVMA buffer is allocated, the allocation 68 * code will enter in a mapping both in the MC68030 MMU page tables and the 69 * I/O mapper. 70 * 71 * The address returned by the allocation routine is a virtual address that 72 * the requesting driver must use to access the buffer. It is up to the 73 * device driver to convert this virtual address into the appropriate slave 74 * address that its device should issue to access the buffer. (There will be 75 * routines that assist the driver in doing so.) 76 */ 77#include <sys/param.h> 78#include <sys/systm.h> 79#include <sys/device.h> 80#include <sys/proc.h> 81#include <sys/malloc.h> 82#include <sys/map.h> 83#include <sys/buf.h> 84#include <sys/vnode.h> 85#include <sys/user.h> 86#include <sys/core.h> 87#include <sys/exec.h> 88 89#include <vm/vm.h> 90#include <vm/vm_kern.h> 91#include <vm/vm_map.h> 92 93#include <machine/autoconf.h> 94#include <machine/cpu.h> 95#include <machine/enable.h> 96#include <machine/pmap.h> 97#include <machine/dvma.h> 98#include <machine/machdep.h> 99 100#include "iommu.h" 101 102/* 103 * Use a resource map to manage DVMA scratch-memory pages. 104 */ 105 106/* Number of slots in dvmamap. */ 107int dvma_max_segs = btoc(DVMA_MAP_SIZE); 108struct map *dvmamap; 109 110void 111dvma_init() 112{ 113 114 /* 115 * Create the resource map for DVMA pages. 116 */ 117 dvmamap = malloc((sizeof(struct map) * dvma_max_segs), 118 M_DEVBUF, M_WAITOK); 119 120 rminit(dvmamap, btoc(DVMA_MAP_AVAIL), btoc(DVMA_MAP_BASE), 121 "dvmamap", dvma_max_segs); 122 123 /* 124 * Enable DVMA in the System Enable register. 125 * Note: This is only necessary for VME slave accesses. 126 * On-board devices are always capable of DVMA. 127 */ 128 *enable_reg |= ENA_SDVMA; 129} 130 131 132/* 133 * Given a DVMA address, return the physical address that 134 * would be used by some OTHER bus-master besides the CPU. 135 * (Examples: on-board ie/le, VME xy board). 136 */ 137u_long 138dvma_kvtopa(kva, bustype) 139 void * kva; 140 int bustype; 141{ 142 u_long addr, mask; 143 144 addr = (u_long)kva; 145 if ((addr & DVMA_MAP_BASE) != DVMA_MAP_BASE) 146 panic("dvma_kvtopa: bad dmva addr=0x%x\n", addr); 147 148 switch (bustype) { 149 case BUS_OBIO: 150 case BUS_OBMEM: 151 mask = DVMA_OBIO_SLAVE_MASK; 152 break; 153 default: /* VME bus device. */ 154 mask = DVMA_VME_SLAVE_MASK; 155 break; 156 } 157 158 return(addr & mask); 159} 160 161 162/* 163 * Map a range [va, va+len] of wired virtual addresses in the given map 164 * to a kernel address in DVMA space. 165 */ 166void * 167dvma_mapin(kmem_va, len, canwait) 168 void * kmem_va; 169 int len, canwait; 170{ 171 void * dvma_addr; 172 vm_offset_t kva, tva; 173 register int npf, s; 174 register vm_offset_t pa; 175 long off, pn; 176 177 kva = (u_long)kmem_va; 178#ifdef DIAGNOSTIC 179 /* 180 * Addresses below VM_MIN_KERNEL_ADDRESS are not part of the kernel 181 * map and should not participate in DVMA. 182 */ 183 if (kva < VM_MIN_KERNEL_ADDRESS) 184 panic("dvma_mapin: bad kva"); 185#endif 186 187 /* 188 * Calculate the offset of the data buffer from a page boundary. 189 */ 190 off = (int)kva & PGOFSET; 191 kva -= off; /* Truncate starting address to nearest page. */ 192 len = round_page(len + off); /* Round the buffer length to pages. */ 193 npf = btoc(len); /* Determine the number of pages to be mapped. */ 194 195 s = splimp(); 196 for (;;) { 197 /* 198 * Try to allocate DVMA space of the appropriate size 199 * in which to do a transfer. 200 */ 201 pn = rmalloc(dvmamap, npf); 202 203 if (pn != 0) 204 break; 205 if (canwait) { 206 (void)tsleep(dvmamap, PRIBIO+1, "physio", 0); 207 continue; 208 } 209 splx(s); 210 return NULL; 211 } 212 splx(s); 213 214 215 /* 216 * Tva is the starting page to which the data buffer will be double 217 * mapped. Dvma_addr is the starting address of the buffer within 218 * that page and is the return value of the function. 219 */ 220 tva = ctob(pn); 221 dvma_addr = (void *) (tva + off); 222 223 for (;npf--; kva += NBPG, tva += NBPG) { 224 /* 225 * Retrieve the physical address of each page in the buffer 226 * and enter mappings into the I/O MMU so they may be seen 227 * by external bus masters and into the special DVMA space 228 * in the MC68030 MMU so they may be seen by the CPU. 229 */ 230 pa = pmap_extract(pmap_kernel(), kva); 231#ifdef DEBUG 232 if (pa == 0) 233 panic("dvma_mapin: null page frame"); 234#endif DEBUG 235 236 iommu_enter((tva & IOMMU_VA_MASK), pa); 237 pmap_enter(pmap_kernel(), tva, pa | PMAP_NC, 238 VM_PROT_READ|VM_PROT_WRITE, 1); 239 } 240 241 return (dvma_addr); 242} 243 244/* 245 * Remove double map of `va' in DVMA space at `kva'. 246 * 247 * TODO - This function might be the perfect place to handle the 248 * synchronization between the DVMA cache and central RAM 249 * on the 3/470. 250 */ 251void 252dvma_mapout(dvma_addr, len) 253 void * dvma_addr; 254 int len; 255{ 256 u_long kva; 257 int s, off; 258 259 kva = (u_long)dvma_addr; 260 off = (int)kva & PGOFSET; 261 kva -= off; 262 len = round_page(len + off); 263 264 iommu_remove((kva & IOMMU_VA_MASK), len); 265 266 /* 267 * XXX - don't call pmap_remove() with DVMA space yet. 268 * XXX It cannot (currently) handle the removal 269 * XXX of address ranges which do not participate in the 270 * XXX PV system by virtue of their _virtual_ addresses. 271 * XXX DVMA is one of these special address spaces. 272 */ 273#ifdef DVMA_ON_PVLIST 274 pmap_remove(pmap_kernel(), kva, kva + len); 275#endif /* DVMA_ON_PVLIST */ 276 277 s = splimp(); 278 rmfree(dvmamap, btoc(len), btoc(kva)); 279 wakeup(dvmamap); 280 splx(s); 281} 282 283/* 284 * Allocate actual memory pages in DVMA space. 285 * (For sun3 compatibility - the ie driver.) 286 */ 287void * 288dvma_malloc(bytes) 289 size_t bytes; 290{ 291 void *new_mem, *dvma_mem; 292 vm_size_t new_size; 293 294 if (!bytes) 295 return NULL; 296 new_size = m68k_round_page(bytes); 297 new_mem = (void*)kmem_alloc(kernel_map, new_size); 298 if (!new_mem) 299 return NULL; 300 dvma_mem = dvma_mapin(new_mem, new_size, 1); 301 return (dvma_mem); 302} 303