1 /* $NetBSD: dvma.c,v 1.23 2001/09/11 20:37:13 chs 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 78 #include <sys/param.h> 79 #include <sys/systm.h> 80 #include <sys/device.h> 81 #include <sys/proc.h> 82 #include <sys/malloc.h> 83 #include <sys/map.h> 84 #include <sys/buf.h> 85 #include <sys/vnode.h> 86 #include <sys/user.h> 87 #include <sys/core.h> 88 #include <sys/exec.h> 89 90 #include <uvm/uvm_extern.h> 91 92 #include <machine/autoconf.h> 93 #include <machine/cpu.h> 94 #include <machine/dvma.h> 95 #include <machine/pmap.h> 96 97 #include <sun3/sun3/machdep.h> 98 99 #include <sun3/sun3x/enable.h> 100 #include <sun3/sun3x/iommu.h> 101 102 /* 103 * Use a resource map to manage DVMA scratch-memory pages. 104 * Note: SunOS says last three pages are reserved (PROM?) 105 * Note: need a separate map (sub-map?) for last 1MB for 106 * use by VME slave interface. 107 */ 108 109 /* Number of slots in dvmamap. */ 110 int dvma_max_segs = btoc(DVMA_MAP_SIZE); 111 struct map *dvmamap; 112 113 void 114 dvma_init() 115 { 116 117 /* 118 * Create the resource map for DVMA pages. 119 */ 120 dvmamap = malloc((sizeof(struct map) * dvma_max_segs), 121 M_DEVBUF, M_WAITOK); 122 123 rminit(dvmamap, btoc(DVMA_MAP_AVAIL), btoc(DVMA_MAP_BASE), 124 "dvmamap", dvma_max_segs); 125 126 /* 127 * Enable DVMA in the System Enable register. 128 * Note: This is only necessary for VME slave accesses. 129 * On-board devices are always capable of DVMA. 130 */ 131 *enable_reg |= ENA_SDVMA; 132 } 133 134 135 /* 136 * Given a DVMA address, return the physical address that 137 * would be used by some OTHER bus-master besides the CPU. 138 * (Examples: on-board ie/le, VME xy board). 139 */ 140 u_long 141 dvma_kvtopa(kva, bustype) 142 void * kva; 143 int bustype; 144 { 145 u_long addr, mask; 146 147 addr = (u_long)kva; 148 if ((addr & DVMA_MAP_BASE) != DVMA_MAP_BASE) 149 panic("dvma_kvtopa: bad dmva addr=0x%lx\n", addr); 150 151 switch (bustype) { 152 case BUS_OBIO: 153 case BUS_OBMEM: 154 mask = DVMA_OBIO_SLAVE_MASK; 155 break; 156 default: /* VME bus device. */ 157 mask = DVMA_VME_SLAVE_MASK; 158 break; 159 } 160 161 return(addr & mask); 162 } 163 164 165 /* 166 * Map a range [va, va+len] of wired virtual addresses in the given map 167 * to a kernel address in DVMA space. 168 */ 169 void * 170 dvma_mapin(kmem_va, len, canwait) 171 void * kmem_va; 172 int len, canwait; 173 { 174 void * dvma_addr; 175 vaddr_t kva, tva; 176 int npf, s; 177 paddr_t pa; 178 long off, pn; 179 boolean_t rv; 180 181 kva = (vaddr_t)kmem_va; 182 #ifdef DIAGNOSTIC 183 /* 184 * Addresses below VM_MIN_KERNEL_ADDRESS are not part of the kernel 185 * map and should not participate in DVMA. 186 */ 187 if (kva < VM_MIN_KERNEL_ADDRESS) 188 panic("dvma_mapin: bad kva"); 189 #endif 190 191 /* 192 * Calculate the offset of the data buffer from a page boundary. 193 */ 194 off = kva & PGOFSET; 195 kva -= off; /* Truncate starting address to nearest page. */ 196 len = round_page(len + off); /* Round the buffer length to pages. */ 197 npf = btoc(len); /* Determine the number of pages to be mapped. */ 198 199 s = splvm(); 200 for (;;) { 201 /* 202 * Try to allocate DVMA space of the appropriate size 203 * in which to do a transfer. 204 */ 205 pn = rmalloc(dvmamap, npf); 206 207 if (pn != 0) 208 break; 209 if (canwait) { 210 (void)tsleep(dvmamap, PRIBIO+1, "physio", 0); 211 continue; 212 } 213 splx(s); 214 return NULL; 215 } 216 splx(s); 217 218 219 /* 220 * Tva is the starting page to which the data buffer will be double 221 * mapped. Dvma_addr is the starting address of the buffer within 222 * that page and is the return value of the function. 223 */ 224 tva = ctob(pn); 225 dvma_addr = (void *) (tva + off); 226 227 for (;npf--; kva += NBPG, tva += NBPG) { 228 /* 229 * Retrieve the physical address of each page in the buffer 230 * and enter mappings into the I/O MMU so they may be seen 231 * by external bus masters and into the special DVMA space 232 * in the MC68030 MMU so they may be seen by the CPU. 233 */ 234 rv = pmap_extract(pmap_kernel(), kva, &pa); 235 #ifdef DEBUG 236 if (rv == FALSE) 237 panic("dvma_mapin: null page frame"); 238 #endif /* DEBUG */ 239 240 iommu_enter((tva & IOMMU_VA_MASK), pa); 241 pmap_kenter_pa(tva, pa | PMAP_NC, VM_PROT_READ | VM_PROT_WRITE); 242 } 243 pmap_update(pmap_kernel()); 244 245 return (dvma_addr); 246 } 247 248 /* 249 * Remove double map of `va' in DVMA space at `kva'. 250 * 251 * TODO - This function might be the perfect place to handle the 252 * synchronization between the DVMA cache and central RAM 253 * on the 3/470. 254 */ 255 void 256 dvma_mapout(dvma_addr, len) 257 void * dvma_addr; 258 int len; 259 { 260 u_long kva; 261 int s, off; 262 263 kva = (u_long)dvma_addr; 264 off = (int)kva & PGOFSET; 265 kva -= off; 266 len = round_page(len + off); 267 268 iommu_remove((kva & IOMMU_VA_MASK), len); 269 pmap_kremove(kva, len); 270 pmap_update(pmap_kernel()); 271 272 s = splvm(); 273 rmfree(dvmamap, btoc(len), btoc(kva)); 274 wakeup(dvmamap); 275 splx(s); 276 } 277 278 /* 279 * Allocate actual memory pages in DVMA space. 280 * (For sun3 compatibility - the ie driver.) 281 */ 282 void * 283 dvma_malloc(bytes) 284 size_t bytes; 285 { 286 void *new_mem, *dvma_mem; 287 vsize_t new_size; 288 289 if (!bytes) 290 return NULL; 291 new_size = m68k_round_page(bytes); 292 new_mem = (void*)uvm_km_alloc(kernel_map, new_size); 293 if (!new_mem) 294 return NULL; 295 dvma_mem = dvma_mapin(new_mem, new_size, 1); 296 return (dvma_mem); 297 } 298 299 /* 300 * Free pages from dvma_malloc() 301 */ 302 void 303 dvma_free(addr, size) 304 void *addr; 305 size_t size; 306 { 307 vsize_t sz = m68k_round_page(size); 308 309 dvma_mapout(addr, sz); 310 /* XXX: need kmem address to free it... 311 Oh well, we never call this anyway. */ 312 } 313