dma.c revision 1.7
1 /* $NetBSD: dma.c,v 1.7 1996/04/19 20:35:46 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 static int sched_soft = 0; /* callback scheduled */ 76 77 /* 78 * Heads of free and active lists: 79 */ 80 static TAILQ_HEAD(freehead, dma_entry) dma_free; 81 static TAILQ_HEAD(acthead, dma_entry) dma_active; 82 83 static int must_init = 1; /* Must initialize */ 84 85 void cdmaint __P((int)); 86 87 long sr; /* sr at time of interrupt */ 88 static void cdmasoft __P((void *, void *)); 89 static void init_queues __P((void)); 90 91 static void 92 init_queues() 93 { 94 int i; 95 96 TAILQ_INIT(&dma_free); 97 TAILQ_INIT(&dma_active); 98 99 for(i = 0; i < NDMA_DEV; i++) 100 TAILQ_INSERT_HEAD(&dma_free, &dmatable[i], entries); 101 } 102 103 int 104 st_dmagrab(int_func, call_func, softc, lock_stat, rcaller) 105 dma_farg int_func; 106 dma_farg call_func; 107 void *softc; 108 int *lock_stat; 109 int rcaller; 110 { 111 int sps; 112 DMA_ENTRY *req; 113 114 if(must_init) { 115 init_queues(); 116 must_init = 0; 117 } 118 *lock_stat = DMA_LOCK_REQ; 119 120 sps = splhigh(); 121 122 /* 123 * Create a request... 124 */ 125 if(dma_free.tqh_first == NULL) 126 panic("st_dmagrab: Too many outstanding requests\n"); 127 req = dma_free.tqh_first; 128 TAILQ_REMOVE(&dma_free, dma_free.tqh_first, entries); 129 req->call_func = call_func; 130 req->int_func = int_func; 131 req->softc = softc; 132 req->lock_stat = lock_stat; 133 TAILQ_INSERT_TAIL(&dma_active, req, entries); 134 135 if(dma_active.tqh_first != req) { 136 splx(sps); 137 return(0); 138 } 139 splx(sps); 140 141 /* 142 * We're at the head of the queue, ergo: we got the lock. 143 */ 144 *lock_stat = DMA_LOCK_GRANT; 145 146 if(rcaller) { 147 /* 148 * Just return to caller immediately without going 149 * through 'call_func' first. 150 */ 151 return(1); 152 } 153 154 (*call_func)(softc); /* Call followup function */ 155 return(0); 156 } 157 158 void 159 st_dmafree(softc, lock_stat) 160 void *softc; 161 int *lock_stat; 162 { 163 int sps; 164 DMA_ENTRY *req; 165 166 sps = splhigh(); 167 168 /* 169 * Some validity checks first. 170 */ 171 if((req = dma_active.tqh_first) == NULL) 172 panic("st_dmafree: empty active queue\n"); 173 if(req->softc != softc) 174 printf("Caller of st_dmafree is not lock-owner!\n"); 175 176 /* 177 * Clear lock status, move request from active to free queue. 178 */ 179 *lock_stat = 0; 180 TAILQ_REMOVE(&dma_active, req, entries); 181 TAILQ_INSERT_HEAD(&dma_free, req, entries); 182 183 if((req = dma_active.tqh_first) != NULL) { 184 /* 185 * Call next request through softint handler. This avoids 186 * spl-conflicts. 187 */ 188 *req->lock_stat = DMA_LOCK_GRANT; 189 add_sicallback((si_farg)req->call_func, req->softc, 0); 190 } 191 splx(sps); 192 return; 193 } 194 195 int 196 st_dmawanted() 197 { 198 return(dma_active.tqh_first->entries.tqe_next != NULL); 199 } 200 201 void 202 cdmaint(sr) 203 int sr; /* sr at time of interrupt */ 204 { 205 if(dma_active.tqh_first != NULL) { 206 if(!BASEPRI(sr)) { 207 if(!sched_soft++) 208 add_sicallback(cdmasoft, 0, 0); 209 } 210 else { 211 spl1(); 212 cdmasoft(NULL, NULL); 213 } 214 } 215 else printf("DMA interrupt discarded\n"); 216 } 217 218 static void 219 cdmasoft(arg1, arg2) 220 void *arg1, *arg2; 221 { 222 int s; 223 dma_farg int_func; 224 void *softc; 225 226 /* 227 * Prevent a race condition here. DMA might be freed while 228 * the callback was pending! 229 */ 230 s = splhigh(); 231 sched_soft = 0; 232 if(dma_active.tqh_first != NULL) { 233 int_func = dma_active.tqh_first->int_func; 234 softc = dma_active.tqh_first->softc; 235 } 236 else int_func = softc = NULL; 237 splx(s); 238 239 if(int_func != NULL) 240 (*int_func)(softc); 241 } 242 243 /* 244 * Setup address for DMA-transfer. 245 * Note: The order _is_ important! 246 */ 247 void 248 st_dmaaddr_set(address) 249 caddr_t address; 250 { 251 register u_long ad = (u_long)address; 252 253 DMA->dma_addr[AD_LOW ] = (ad ) & 0xff; 254 DMA->dma_addr[AD_MID ] = (ad >> 8) & 0xff; 255 DMA->dma_addr[AD_HIGH] = (ad >>16) & 0xff; 256 } 257 258 /* 259 * Get address from DMA unit. 260 */ 261 u_long 262 st_dmaaddr_get() 263 { 264 register u_long ad = 0; 265 266 ad = (DMA->dma_addr[AD_LOW ] & 0xff); 267 ad |= (DMA->dma_addr[AD_MID ] & 0xff) << 8; 268 ad |= (DMA->dma_addr[AD_HIGH] & 0xff) <<16; 269 return(ad); 270 } 271 272 /* 273 * Program the DMA-controller to transfer 'nblk' blocks of 512 bytes. 274 * The DMA_WRBIT trick flushes the FIFO before doing DMA. 275 */ 276 void 277 st_dmacomm(mode, nblk) 278 int mode, nblk; 279 { 280 DMA->dma_mode = mode; 281 DMA->dma_mode = mode ^ DMA_WRBIT; 282 DMA->dma_mode = mode; 283 DMA->dma_data = nblk; 284 delay(2); /* Needed for Falcon */ 285 DMA->dma_mode = DMA_SCREG | (mode & DMA_WRBIT); 286 } 287
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