1 /* $NetBSD: dvma.c,v 1.25 2002/09/27 15:36:57 provos 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/extent.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 an extent 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 struct extent *dvma_extent; 111 112 void 113 dvma_init() 114 { 115 116 /* 117 * Create the extent map for DVMA pages. 118 */ 119 dvma_extent = extent_create("dvma", DVMA_MAP_BASE, 120 DVMA_MAP_BASE + (DVMA_MAP_AVAIL - 1), M_DEVBUF, 121 NULL, 0, EX_NOCOALESCE|EX_NOWAIT); 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 */ 137 u_long 138 dvma_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%lx", 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 */ 166 void * 167 dvma_mapin(kmem_va, len, canwait) 168 void * kmem_va; 169 int len, canwait; 170 { 171 void * dvma_addr; 172 vaddr_t kva, tva; 173 int npf, s, error; 174 paddr_t pa; 175 long off; 176 boolean_t rv; 177 178 kva = (vaddr_t)kmem_va; 179 #ifdef DIAGNOSTIC 180 /* 181 * Addresses below VM_MIN_KERNEL_ADDRESS are not part of the kernel 182 * map and should not participate in DVMA. 183 */ 184 if (kva < VM_MIN_KERNEL_ADDRESS) 185 panic("dvma_mapin: bad kva"); 186 #endif 187 188 /* 189 * Calculate the offset of the data buffer from a page boundary. 190 */ 191 off = kva & PGOFSET; 192 kva -= off; /* Truncate starting address to nearest page. */ 193 len = round_page(len + off); /* Round the buffer length to pages. */ 194 npf = btoc(len); /* Determine the number of pages to be mapped. */ 195 196 /* 197 * Try to allocate DVMA space of the appropriate size 198 * in which to do a transfer. 199 */ 200 s = splvm(); 201 error = extent_alloc(dvma_extent, len, PAGE_SIZE, 0, 202 EX_FAST | EX_NOWAIT | (canwait ? EX_WAITSPACE : 0), &tva); 203 splx(s); 204 if (error) 205 return (NULL); 206 207 /* 208 * Tva is the starting page to which the data buffer will be double 209 * mapped. Dvma_addr is the starting address of the buffer within 210 * that page and is the return value of the function. 211 */ 212 dvma_addr = (void *) (tva + off); 213 214 for (;npf--; kva += NBPG, tva += NBPG) { 215 /* 216 * Retrieve the physical address of each page in the buffer 217 * and enter mappings into the I/O MMU so they may be seen 218 * by external bus masters and into the special DVMA space 219 * in the MC68030 MMU so they may be seen by the CPU. 220 */ 221 rv = pmap_extract(pmap_kernel(), kva, &pa); 222 #ifdef DEBUG 223 if (rv == FALSE) 224 panic("dvma_mapin: null page frame"); 225 #endif /* DEBUG */ 226 227 iommu_enter((tva & IOMMU_VA_MASK), pa); 228 pmap_kenter_pa(tva, pa | PMAP_NC, VM_PROT_READ | VM_PROT_WRITE); 229 } 230 pmap_update(pmap_kernel()); 231 232 return (dvma_addr); 233 } 234 235 /* 236 * Remove double map of `va' in DVMA space at `kva'. 237 * 238 * TODO - This function might be the perfect place to handle the 239 * synchronization between the DVMA cache and central RAM 240 * on the 3/470. 241 */ 242 void 243 dvma_mapout(dvma_addr, len) 244 void *dvma_addr; 245 int len; 246 { 247 u_long kva; 248 int s, off; 249 250 kva = (u_long)dvma_addr; 251 off = (int)kva & PGOFSET; 252 kva -= off; 253 len = round_page(len + off); 254 255 iommu_remove((kva & IOMMU_VA_MASK), len); 256 pmap_kremove(kva, len); 257 pmap_update(pmap_kernel()); 258 259 s = splvm(); 260 if (extent_free(dvma_extent, kva, len, EX_NOWAIT | EX_MALLOCOK)) 261 panic("dvma_mapout: unable to free region: 0x%lx,0x%x", 262 kva, len); 263 splx(s); 264 } 265 266 /* 267 * Allocate actual memory pages in DVMA space. 268 * (For sun3 compatibility - the ie driver.) 269 */ 270 void * 271 dvma_malloc(bytes) 272 size_t bytes; 273 { 274 void *new_mem, *dvma_mem; 275 vsize_t new_size; 276 277 if (!bytes) 278 return NULL; 279 new_size = m68k_round_page(bytes); 280 new_mem = (void*)uvm_km_alloc(kernel_map, new_size); 281 if (!new_mem) 282 return NULL; 283 dvma_mem = dvma_mapin(new_mem, new_size, 1); 284 return (dvma_mem); 285 } 286 287 /* 288 * Free pages from dvma_malloc() 289 */ 290 void 291 dvma_free(addr, size) 292 void *addr; 293 size_t size; 294 { 295 vsize_t sz = m68k_round_page(size); 296 297 dvma_mapout(addr, sz); 298 /* XXX: need kmem address to free it... 299 Oh well, we never call this anyway. */ 300 } 301