dma.c revision 1.8
1 /* $NetBSD: dma.c,v 1.8 1996/06/18 11:10:11 leo Exp $ */ 2 3 /* 4 * Copyright (c) 1995 Leo Weppelman. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by Leo Weppelman. 18 * 4. The name of the author may not be used to endorse or promote products 19 * derived from this software without specific prior written permission 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 26 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 30 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33 /* 34 * This file contains special code dealing with the DMA interface 35 * on the Atari ST. 36 * 37 * The DMA circuitry requires some special treatment for the peripheral 38 * devices which make use of the ST's DMA feature (the hard disk and the 39 * floppy drive). 40 * All devices using DMA need mutually exclusive access and can follow some 41 * standard pattern which will be provided in this file. 42 * 43 * The file contains the following entry points: 44 * 45 * st_dmagrab: ensure exclusive access to the DMA circuitry 46 * st_dmafree: free exclusive access to the DMA circuitry 47 * st_dmawanted: somebody is queued waiting for DMA-access 48 * dmaint: DMA interrupt routine, switches to the current driver 49 * st_dmaaddr_set: specify 24 bit RAM address 50 * st_dmaaddr_get: get address of last DMA-op 51 * st_dmacomm: program DMA, flush FIFO first 52 */ 53 54 #include <sys/param.h> 55 #include <sys/systm.h> 56 #include <sys/kernel.h> 57 #include <sys/queue.h> 58 #include <machine/cpu.h> 59 #include <machine/iomap.h> 60 #include <machine/dma.h> 61 62 #define NDMA_DEV 10 /* Max 2 floppy's, 8 hard-disks */ 63 typedef struct dma_entry { 64 TAILQ_ENTRY(dma_entry) entries; /* List pointers */ 65 void (*call_func)(void *); /* Call when lock granted */ 66 void (*int_func)(void *); /* Call on DMA interrupt */ 67 void *softc; /* Arg. to int_func */ 68 int *lock_stat; /* status of DMA lock */ 69 } DMA_ENTRY; 70 71 /* 72 * Preallocated entries. An allocator seem an overkill here. 73 */ 74 static DMA_ENTRY dmatable[NDMA_DEV]; /* preallocated entries */ 75 76 /* 77 * Heads of free and active lists: 78 */ 79 static TAILQ_HEAD(freehead, dma_entry) dma_free; 80 static TAILQ_HEAD(acthead, dma_entry) dma_active; 81 82 static int must_init = 1; /* Must initialize */ 83 84 void cdmaint __P((int)); 85 86 long sr; /* sr at time of interrupt */ 87 static void init_queues __P((void)); 88 89 static void 90 init_queues() 91 { 92 int i; 93 94 TAILQ_INIT(&dma_free); 95 TAILQ_INIT(&dma_active); 96 97 for(i = 0; i < NDMA_DEV; i++) 98 TAILQ_INSERT_HEAD(&dma_free, &dmatable[i], entries); 99 } 100 101 int 102 st_dmagrab(int_func, call_func, softc, lock_stat, rcaller) 103 dma_farg int_func; 104 dma_farg call_func; 105 void *softc; 106 int *lock_stat; 107 int rcaller; 108 { 109 int sps; 110 DMA_ENTRY *req; 111 112 if(must_init) { 113 init_queues(); 114 must_init = 0; 115 } 116 *lock_stat = DMA_LOCK_REQ; 117 118 sps = splhigh(); 119 120 /* 121 * Create a request... 122 */ 123 if(dma_free.tqh_first == NULL) 124 panic("st_dmagrab: Too many outstanding requests\n"); 125 req = dma_free.tqh_first; 126 TAILQ_REMOVE(&dma_free, dma_free.tqh_first, entries); 127 req->call_func = call_func; 128 req->int_func = int_func; 129 req->softc = softc; 130 req->lock_stat = lock_stat; 131 TAILQ_INSERT_TAIL(&dma_active, req, entries); 132 133 if(dma_active.tqh_first != req) { 134 splx(sps); 135 return(0); 136 } 137 splx(sps); 138 139 /* 140 * We're at the head of the queue, ergo: we got the lock. 141 */ 142 *lock_stat = DMA_LOCK_GRANT; 143 144 if(rcaller) { 145 /* 146 * Just return to caller immediately without going 147 * through 'call_func' first. 148 */ 149 return(1); 150 } 151 152 (*call_func)(softc); /* Call followup function */ 153 return(0); 154 } 155 156 void 157 st_dmafree(softc, lock_stat) 158 void *softc; 159 int *lock_stat; 160 { 161 int sps; 162 DMA_ENTRY *req; 163 164 sps = splhigh(); 165 166 /* 167 * Some validity checks first. 168 */ 169 if((req = dma_active.tqh_first) == NULL) 170 panic("st_dmafree: empty active queue\n"); 171 if(req->softc != softc) 172 printf("Caller of st_dmafree is not lock-owner!\n"); 173 174 /* 175 * Clear lock status, move request from active to free queue. 176 */ 177 *lock_stat = 0; 178 TAILQ_REMOVE(&dma_active, req, entries); 179 TAILQ_INSERT_HEAD(&dma_free, req, entries); 180 181 if((req = dma_active.tqh_first) != NULL) { 182 /* 183 * Call next request through softint handler. This avoids 184 * spl-conflicts. 185 */ 186 *req->lock_stat = DMA_LOCK_GRANT; 187 add_sicallback((si_farg)req->call_func, req->softc, 0); 188 } 189 splx(sps); 190 return; 191 } 192 193 int 194 st_dmawanted() 195 { 196 return(dma_active.tqh_first->entries.tqe_next != NULL); 197 } 198 199 void 200 cdmaint(sr) 201 int sr; /* sr at time of interrupt */ 202 { 203 dma_farg int_func; 204 void *softc; 205 206 if(dma_active.tqh_first != NULL) { 207 int_func = dma_active.tqh_first->int_func; 208 softc = dma_active.tqh_first->softc; 209 210 if(!BASEPRI(sr)) 211 add_sicallback((si_farg)int_func, softc, 0); 212 else { 213 spl1(); 214 (*int_func)(softc); 215 } 216 } 217 else printf("DMA interrupt discarded\n"); 218 } 219 220 /* 221 * Setup address for DMA-transfer. 222 * Note: The order _is_ important! 223 */ 224 void 225 st_dmaaddr_set(address) 226 caddr_t address; 227 { 228 register u_long ad = (u_long)address; 229 230 DMA->dma_addr[AD_LOW ] = (ad ) & 0xff; 231 DMA->dma_addr[AD_MID ] = (ad >> 8) & 0xff; 232 DMA->dma_addr[AD_HIGH] = (ad >>16) & 0xff; 233 } 234 235 /* 236 * Get address from DMA unit. 237 */ 238 u_long 239 st_dmaaddr_get() 240 { 241 register u_long ad = 0; 242 243 ad = (DMA->dma_addr[AD_LOW ] & 0xff); 244 ad |= (DMA->dma_addr[AD_MID ] & 0xff) << 8; 245 ad |= (DMA->dma_addr[AD_HIGH] & 0xff) <<16; 246 return(ad); 247 } 248 249 /* 250 * Program the DMA-controller to transfer 'nblk' blocks of 512 bytes. 251 * The DMA_WRBIT trick flushes the FIFO before doing DMA. 252 */ 253 void 254 st_dmacomm(mode, nblk) 255 int mode, nblk; 256 { 257 DMA->dma_mode = mode; 258 DMA->dma_mode = mode ^ DMA_WRBIT; 259 DMA->dma_mode = mode; 260 DMA->dma_data = nblk; 261 delay(2); /* Needed for Falcon */ 262 DMA->dma_mode = DMA_SCREG | (mode & DMA_WRBIT); 263 } 264
Indexes created Tue Sep 30 20:09:53 GMT 2025