1 /* $NetBSD: dvma.c,v 1.46 2024/09/08 09:36:49 rillig 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 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /* 33 * DVMA (Direct Virtual Memory Access - like DMA) 34 * 35 * In the Sun3 architecture, memory cycles initiated by secondary bus 36 * masters (DVMA devices) passed through the same MMU that governed CPU 37 * accesses. All DVMA devices were wired in such a way so that an offset 38 * was added to the addresses they issued, causing them to access virtual 39 * memory starting at address 0x0FF00000 - the offset. The task of 40 * enabling a DVMA device to access main memory only involved creating 41 * valid mapping in the MMU that translated these high addresses into the 42 * appropriate physical addresses. 43 * 44 * The Sun3x presents a challenge to programming DVMA because the MMU is no 45 * longer shared by both secondary bus masters and the CPU. The MC68030's 46 * built-in MMU serves only to manage virtual memory accesses initiated by 47 * the CPU. Secondary bus master bus accesses pass through a different MMU, 48 * aptly named the 'I/O Mapper'. To enable every device driver that uses 49 * DVMA to understand that these two address spaces are disconnected would 50 * require a tremendous amount of code re-writing. To avoid this, we will 51 * ensure that the I/O Mapper and the MC68030 MMU are programmed together, 52 * so that DVMA mappings are consistent in both the CPU virtual address 53 * space and secondary bus master address space - creating an environment 54 * just like the Sun3 system. 55 * 56 * The maximum address space that any DVMA device in the Sun3x architecture 57 * is capable of addressing is 24 bits wide (16 Megabytes.) We can alias 58 * all of the mappings that exist in the I/O mapper by duplicating them in 59 * a specially reserved section of the CPU's virtual address space, 16 60 * Megabytes in size. Whenever a DVMA buffer is allocated, the allocation 61 * code will enter in a mapping both in the MC68030 MMU page tables and the 62 * I/O mapper. 63 * 64 * The address returned by the allocation routine is a virtual address that 65 * the requesting driver must use to access the buffer. It is up to the 66 * device driver to convert this virtual address into the appropriate slave 67 * address that its device should issue to access the buffer. (There will be 68 * routines that assist the driver in doing so.) 69 */ 70 71 #include <sys/cdefs.h> 72 __KERNEL_RCSID(0, "$NetBSD: dvma.c,v 1.46 2024/09/08 09:36:49 rillig Exp $"); 73 74 #include <sys/param.h> 75 #include <sys/systm.h> 76 #include <sys/device.h> 77 #include <sys/proc.h> 78 #include <sys/vmem.h> 79 #include <sys/buf.h> 80 #include <sys/vnode.h> 81 #include <sys/core.h> 82 #include <sys/exec.h> 83 84 #include <uvm/uvm_extern.h> 85 86 #define _SUN68K_BUS_DMA_PRIVATE 87 #include <machine/autoconf.h> 88 #include <machine/bus.h> 89 #include <machine/cpu.h> 90 #include <machine/dvma.h> 91 #include <machine/pmap.h> 92 93 #include <sun3/sun3/machdep.h> 94 95 #include <sun3/sun3x/enable.h> 96 #include <sun3/sun3x/iommu.h> 97 98 /* 99 * Use a vmem arena to manage DVMA scratch-memory pages. 100 * Note: SunOS says last three pages are reserved (PROM?) 101 * Note: need a separate map (sub-map?) for last 1MB for 102 * use by VME slave interface. 103 */ 104 vmem_t *dvma_arena; 105 106 void 107 dvma_init(void) 108 { 109 110 /* 111 * Create the vmem arena for DVMA pages. 112 */ 113 dvma_arena = vmem_create("dvma", DVMA_MAP_BASE, DVMA_MAP_AVAIL, 114 PAGE_SIZE, /* quantum */ 115 NULL, /* importfn */ 116 NULL, /* releasefn */ 117 NULL, /* source */ 118 0, /* qcache_max */ 119 VM_SLEEP, 120 IPL_VM); 121 122 /* 123 * Enable DVMA in the System Enable register. 124 * Note: This is only necessary for VME slave accesses. 125 * On-board devices are always capable of DVMA. 126 */ 127 *enable_reg |= ENA_SDVMA; 128 } 129 130 131 /* 132 * Given a DVMA address, return the physical address that 133 * would be used by some OTHER bus-master besides the CPU. 134 * (Examples: on-board ie/le, VME xy board). 135 */ 136 u_long 137 dvma_kvtopa(void *kva, int bustype) 138 { 139 u_long addr, mask; 140 141 addr = (u_long)kva; 142 if ((addr & DVMA_MAP_BASE) != DVMA_MAP_BASE) 143 panic("dvma_kvtopa: bad dmva addr=0x%lx", addr); 144 145 switch (bustype) { 146 case BUS_OBIO: 147 case BUS_OBMEM: 148 mask = DVMA_OBIO_SLAVE_MASK; 149 break; 150 default: /* VME bus device. */ 151 mask = DVMA_VME_SLAVE_MASK; 152 break; 153 } 154 155 return addr & mask; 156 } 157 158 159 /* 160 * Map a range [va, va+len] of wired virtual addresses in the given map 161 * to a kernel address in DVMA space. 162 */ 163 void * 164 dvma_mapin(void *kmem_va, int len, int canwait) 165 { 166 void *dvma_addr; 167 vaddr_t kva; 168 vmem_addr_t tva; 169 int npf, error; 170 paddr_t pa; 171 long off; 172 bool rv __debugused; 173 174 kva = (vaddr_t)kmem_va; 175 KASSERT(kva >= VM_MIN_KERNEL_ADDRESS); 176 177 /* 178 * Calculate the offset of the data buffer from a page boundary. 179 */ 180 off = kva & PGOFSET; 181 kva -= off; /* Truncate starting address to nearest page. */ 182 len = round_page(len + off); /* Round the buffer length to pages. */ 183 npf = btoc(len); /* Determine the number of pages to be mapped. */ 184 185 /* 186 * Try to allocate DVMA space of the appropriate size 187 * in which to do a transfer. 188 */ 189 const vm_flag_t vmflags = VM_INSTANTFIT | 190 (canwait ? VM_SLEEP : VM_NOSLEEP); 191 192 error = vmem_xalloc(dvma_arena, len, 193 0, /* alignment */ 194 0, /* phase */ 195 0, /* nocross */ 196 VMEM_ADDR_MIN, /* minaddr */ 197 VMEM_ADDR_MAX, /* maxaddr */ 198 vmflags, 199 &tva); 200 if (error) 201 return NULL; 202 203 /* 204 * Tva is the starting page to which the data buffer will be double 205 * mapped. Dvma_addr is the starting address of the buffer within 206 * that page and is the return value of the function. 207 */ 208 dvma_addr = (void *)(tva + off); 209 210 for (; npf--; kva += PAGE_SIZE, tva += PAGE_SIZE) { 211 /* 212 * Retrieve the physical address of each page in the buffer 213 * and enter mappings into the I/O MMU so they may be seen 214 * by external bus masters and into the special DVMA space 215 * in the MC68030 MMU so they may be seen by the CPU. 216 */ 217 rv = pmap_extract(pmap_kernel(), kva, &pa); 218 #ifdef DEBUG 219 if (rv == false) 220 panic("dvma_mapin: null page frame"); 221 #endif /* DEBUG */ 222 223 iommu_enter((tva & IOMMU_VA_MASK), pa); 224 pmap_kenter_pa(tva, 225 pa | PMAP_NC, VM_PROT_READ | VM_PROT_WRITE, 0); 226 } 227 pmap_update(pmap_kernel()); 228 229 return dvma_addr; 230 } 231 232 /* 233 * Remove double map of `va' in DVMA space at `kva'. 234 * 235 * TODO - This function might be the perfect place to handle the 236 * synchronization between the DVMA cache and central RAM 237 * on the 3/470. 238 */ 239 void 240 dvma_mapout(void *dvma_addr, int len) 241 { 242 u_long kva; 243 int off; 244 245 kva = (u_long)dvma_addr; 246 off = (int)kva & PGOFSET; 247 kva -= off; 248 len = round_page(len + off); 249 250 iommu_remove((kva & IOMMU_VA_MASK), len); 251 pmap_kremove(kva, len); 252 pmap_update(pmap_kernel()); 253 254 vmem_xfree(dvma_arena, kva, len); 255 } 256 257 /* 258 * Allocate actual memory pages in DVMA space. 259 * (For sun3 compatibility - the ie driver.) 260 */ 261 void * 262 dvma_malloc(size_t bytes) 263 { 264 void *new_mem, *dvma_mem; 265 vsize_t new_size; 266 267 if (bytes == 0) 268 return NULL; 269 new_size = m68k_round_page(bytes); 270 new_mem = (void *)uvm_km_alloc(kernel_map, new_size, 0, UVM_KMF_WIRED); 271 if (new_mem == 0) 272 return NULL; 273 dvma_mem = dvma_mapin(new_mem, new_size, 1); 274 return dvma_mem; 275 } 276 277 /* 278 * Free pages from dvma_malloc() 279 */ 280 void 281 dvma_free(void *addr, size_t size) 282 { 283 vsize_t sz = m68k_round_page(size); 284 285 dvma_mapout(addr, sz); 286 /* XXX: need kmem address to free it... 287 Oh well, we never call this anyway. */ 288 } 289 290 int 291 _bus_dmamap_load_raw(bus_dma_tag_t t, bus_dmamap_t map, bus_dma_segment_t *segs, 292 int nsegs, bus_size_t size, int flags) 293 { 294 295 panic("_bus_dmamap_load_raw(): not implemented yet."); 296 } 297 298 int 299 _bus_dmamap_load(bus_dma_tag_t t, bus_dmamap_t map, void *buf, 300 bus_size_t buflen, struct proc *p, int flags) 301 { 302 vaddr_t kva; 303 vmem_addr_t dva; 304 vsize_t off, sgsize; 305 paddr_t pa; 306 pmap_t pmap; 307 int error, rv __diagused; 308 309 /* 310 * Make sure that on error condition we return "no valid mappings". 311 */ 312 map->dm_nsegs = 0; 313 map->dm_mapsize = 0; 314 315 if (buflen > map->_dm_size) 316 return EINVAL; 317 318 kva = (vaddr_t)buf; 319 off = kva & PGOFSET; 320 sgsize = round_page(off + buflen); 321 322 /* Try to allocate DVMA space. */ 323 const vm_flag_t vmflags = VM_INSTANTFIT | 324 ((flags & BUS_DMA_NOWAIT) ? VM_NOSLEEP : VM_SLEEP); 325 326 error = vmem_xalloc(dvma_arena, sgsize, 327 0, /* alignment */ 328 0, /* phase */ 329 0, /* nocross */ 330 VMEM_ADDR_MIN, /* minaddr */ 331 VMEM_ADDR_MAX, /* maxaddr */ 332 vmflags, 333 &dva); 334 if (error) 335 return ENOMEM; 336 337 /* Fill in the segment. */ 338 map->dm_segs[0].ds_addr = dva + off; 339 map->dm_segs[0].ds_len = buflen; 340 map->dm_segs[0]._ds_va = dva; 341 map->dm_segs[0]._ds_sgsize = sgsize; 342 343 /* 344 * Now map the DVMA addresses we allocated to point to the 345 * pages of the caller's buffer. 346 */ 347 if (p != NULL) 348 pmap = p->p_vmspace->vm_map.pmap; 349 else 350 pmap = pmap_kernel(); 351 352 while (sgsize > 0) { 353 rv = pmap_extract(pmap, kva, &pa); 354 #ifdef DIAGNOSTIC 355 if (rv == false) 356 panic("%s: unmapped VA", __func__); 357 #endif 358 iommu_enter((dva & IOMMU_VA_MASK), pa); 359 pmap_kenter_pa(dva, 360 pa | PMAP_NC, VM_PROT_READ | VM_PROT_WRITE, 0); 361 kva += PAGE_SIZE; 362 dva += PAGE_SIZE; 363 sgsize -= PAGE_SIZE; 364 } 365 366 map->dm_nsegs = 1; 367 map->dm_mapsize = map->dm_segs[0].ds_len; 368 369 return 0; 370 } 371 372 void 373 _bus_dmamap_unload(bus_dma_tag_t t, bus_dmamap_t map) 374 { 375 bus_dma_segment_t *segs; 376 vaddr_t dva; 377 vsize_t sgsize; 378 379 #ifdef DIAGNOSTIC 380 if (map->dm_nsegs != 1) 381 panic("%s: invalid nsegs = %d", __func__, map->dm_nsegs); 382 #endif 383 384 segs = map->dm_segs; 385 dva = segs[0]._ds_va & ~PGOFSET; 386 sgsize = segs[0]._ds_sgsize; 387 388 /* Unmap the DVMA addresses. */ 389 iommu_remove((dva & IOMMU_VA_MASK), sgsize); 390 pmap_kremove(dva, sgsize); 391 pmap_update(pmap_kernel()); 392 393 /* Free the DVMA addresses. */ 394 vmem_xfree(dvma_arena, dva, sgsize); 395 396 /* Mark the mappings as invalid. */ 397 map->dm_mapsize = 0; 398 map->dm_nsegs = 0; 399 } 400
Indexes created Sat Sep 20 22:09:52 GMT 2025