1 /* $NetBSD: dvma.c,v 1.30 2005/12/11 12:19:27 christos 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/cdefs.h> 79 __KERNEL_RCSID(0, "$NetBSD: dvma.c,v 1.30 2005/12/11 12:19:27 christos Exp $"); 80 81 #include <sys/param.h> 82 #include <sys/systm.h> 83 #include <sys/device.h> 84 #include <sys/proc.h> 85 #include <sys/malloc.h> 86 #include <sys/extent.h> 87 #include <sys/buf.h> 88 #include <sys/vnode.h> 89 #include <sys/user.h> 90 #include <sys/core.h> 91 #include <sys/exec.h> 92 93 #include <uvm/uvm_extern.h> 94 95 #include <machine/autoconf.h> 96 #include <machine/cpu.h> 97 #include <machine/dvma.h> 98 #include <machine/pmap.h> 99 100 #include <sun3/sun3/machdep.h> 101 102 #include <sun3/sun3x/enable.h> 103 #include <sun3/sun3x/iommu.h> 104 105 /* 106 * Use an extent map to manage DVMA scratch-memory pages. 107 * Note: SunOS says last three pages are reserved (PROM?) 108 * Note: need a separate map (sub-map?) for last 1MB for 109 * use by VME slave interface. 110 */ 111 112 /* Number of slots in dvmamap. */ 113 struct extent *dvma_extent; 114 115 void 116 dvma_init(void) 117 { 118 119 /* 120 * Create the extent map for DVMA pages. 121 */ 122 dvma_extent = extent_create("dvma", DVMA_MAP_BASE, 123 DVMA_MAP_BASE + (DVMA_MAP_AVAIL - 1), M_DEVBUF, 124 NULL, 0, EX_NOCOALESCE|EX_NOWAIT); 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(void *kva, int bustype) 142 { 143 u_long addr, mask; 144 145 addr = (u_long)kva; 146 if ((addr & DVMA_MAP_BASE) != DVMA_MAP_BASE) 147 panic("dvma_kvtopa: bad dmva addr=0x%lx", addr); 148 149 switch (bustype) { 150 case BUS_OBIO: 151 case BUS_OBMEM: 152 mask = DVMA_OBIO_SLAVE_MASK; 153 break; 154 default: /* VME bus device. */ 155 mask = DVMA_VME_SLAVE_MASK; 156 break; 157 } 158 159 return(addr & mask); 160 } 161 162 163 /* 164 * Map a range [va, va+len] of wired virtual addresses in the given map 165 * to a kernel address in DVMA space. 166 */ 167 void * 168 dvma_mapin(void *kmem_va, int len, int canwait) 169 { 170 void * dvma_addr; 171 vaddr_t kva, tva; 172 int npf, s, error; 173 paddr_t pa; 174 long off; 175 boolean_t rv; 176 177 kva = (vaddr_t)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 = 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 /* 196 * Try to allocate DVMA space of the appropriate size 197 * in which to do a transfer. 198 */ 199 s = splvm(); 200 error = extent_alloc(dvma_extent, len, PAGE_SIZE, 0, 201 EX_FAST | EX_NOWAIT | (canwait ? EX_WAITSPACE : 0), &tva); 202 splx(s); 203 if (error) 204 return (NULL); 205 206 /* 207 * Tva is the starting page to which the data buffer will be double 208 * mapped. Dvma_addr is the starting address of the buffer within 209 * that page and is the return value of the function. 210 */ 211 dvma_addr = (void *) (tva + off); 212 213 for (;npf--; kva += PAGE_SIZE, tva += PAGE_SIZE) { 214 /* 215 * Retrieve the physical address of each page in the buffer 216 * and enter mappings into the I/O MMU so they may be seen 217 * by external bus masters and into the special DVMA space 218 * in the MC68030 MMU so they may be seen by the CPU. 219 */ 220 rv = pmap_extract(pmap_kernel(), kva, &pa); 221 #ifdef DEBUG 222 if (rv == FALSE) 223 panic("dvma_mapin: null page frame"); 224 #endif /* DEBUG */ 225 226 iommu_enter((tva & IOMMU_VA_MASK), pa); 227 pmap_kenter_pa(tva, pa | PMAP_NC, VM_PROT_READ | VM_PROT_WRITE); 228 } 229 pmap_update(pmap_kernel()); 230 231 return (dvma_addr); 232 } 233 234 /* 235 * Remove double map of `va' in DVMA space at `kva'. 236 * 237 * TODO - This function might be the perfect place to handle the 238 * synchronization between the DVMA cache and central RAM 239 * on the 3/470. 240 */ 241 void 242 dvma_mapout(void *dvma_addr, int len) 243 { 244 u_long kva; 245 int s, off; 246 247 kva = (u_long)dvma_addr; 248 off = (int)kva & PGOFSET; 249 kva -= off; 250 len = round_page(len + off); 251 252 iommu_remove((kva & IOMMU_VA_MASK), len); 253 pmap_kremove(kva, len); 254 pmap_update(pmap_kernel()); 255 256 s = splvm(); 257 if (extent_free(dvma_extent, kva, len, EX_NOWAIT | EX_MALLOCOK)) 258 panic("dvma_mapout: unable to free region: 0x%lx,0x%x", 259 kva, len); 260 splx(s); 261 } 262 263 /* 264 * Allocate actual memory pages in DVMA space. 265 * (For sun3 compatibility - the ie driver.) 266 */ 267 void * 268 dvma_malloc(size_t bytes) 269 { 270 void *new_mem, *dvma_mem; 271 vsize_t new_size; 272 273 if (!bytes) 274 return NULL; 275 new_size = m68k_round_page(bytes); 276 new_mem = (void*)uvm_km_alloc(kernel_map, new_size, 0, UVM_KMF_WIRED); 277 if (!new_mem) 278 return NULL; 279 dvma_mem = dvma_mapin(new_mem, new_size, 1); 280 return (dvma_mem); 281 } 282 283 /* 284 * Free pages from dvma_malloc() 285 */ 286 void 287 dvma_free(void *addr, size_t size) 288 { 289 vsize_t sz = m68k_round_page(size); 290 291 dvma_mapout(addr, sz); 292 /* XXX: need kmem address to free it... 293 Oh well, we never call this anyway. */ 294 } 295