dma.c revision 1.13
1 /* $NetBSD: dma.c,v 1.13 1997/01/12 15:44:45 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 59 #include <machine/cpu.h> 60 #include <machine/iomap.h> 61 #include <machine/dma.h> 62 63 #include <atari/atari/intr.h> 64 65 #define NDMA_DEV 10 /* Max 2 floppy's, 8 hard-disks */ 66 typedef struct dma_entry { 67 TAILQ_ENTRY(dma_entry) entries; /* List pointers */ 68 void (*call_func)(void *); /* Call when lock granted */ 69 void (*int_func)(void *); /* Call on DMA interrupt */ 70 void *softc; /* Arg. to int_func */ 71 int *lock_stat; /* status of DMA lock */ 72 } DMA_ENTRY; 73 74 /* 75 * Preallocated entries. An allocator seem an overkill here. 76 */ 77 static DMA_ENTRY dmatable[NDMA_DEV]; /* preallocated entries */ 78 79 /* 80 * Heads of free and active lists: 81 */ 82 static TAILQ_HEAD(freehead, dma_entry) dma_free; 83 static TAILQ_HEAD(acthead, dma_entry) dma_active; 84 85 static int must_init = 1; /* Must initialize */ 86 87 int cdmaint __P((void *, int)); 88 89 static void st_dma_init __P((void)); 90 91 static void 92 st_dma_init() 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 if (intr_establish(7, USER_VEC, 0, cdmaint, NULL) == NULL) 103 panic("st_dma_init: Can't establish interrupt\n"); 104 } 105 106 int 107 st_dmagrab(int_func, call_func, softc, lock_stat, rcaller) 108 dma_farg int_func; 109 dma_farg call_func; 110 void *softc; 111 int *lock_stat; 112 int rcaller; 113 { 114 int sps; 115 DMA_ENTRY *req; 116 117 if(must_init) { 118 st_dma_init(); 119 must_init = 0; 120 } 121 *lock_stat = DMA_LOCK_REQ; 122 123 sps = splhigh(); 124 125 /* 126 * Create a request... 127 */ 128 if(dma_free.tqh_first == NULL) 129 panic("st_dmagrab: Too many outstanding requests\n"); 130 req = dma_free.tqh_first; 131 TAILQ_REMOVE(&dma_free, dma_free.tqh_first, entries); 132 req->call_func = call_func; 133 req->int_func = int_func; 134 req->softc = softc; 135 req->lock_stat = lock_stat; 136 TAILQ_INSERT_TAIL(&dma_active, req, entries); 137 138 if(dma_active.tqh_first != req) { 139 splx(sps); 140 return(0); 141 } 142 splx(sps); 143 144 /* 145 * We're at the head of the queue, ergo: we got the lock. 146 */ 147 *lock_stat = DMA_LOCK_GRANT; 148 149 if(rcaller) { 150 /* 151 * Just return to caller immediately without going 152 * through 'call_func' first. 153 */ 154 return(1); 155 } 156 157 (*call_func)(softc); /* Call followup function */ 158 return(0); 159 } 160 161 void 162 st_dmafree(softc, lock_stat) 163 void *softc; 164 int *lock_stat; 165 { 166 int sps; 167 DMA_ENTRY *req; 168 169 sps = splhigh(); 170 171 /* 172 * Some validity checks first. 173 */ 174 if((req = dma_active.tqh_first) == NULL) 175 panic("st_dmafree: empty active queue\n"); 176 if(req->softc != softc) 177 printf("Caller of st_dmafree is not lock-owner!\n"); 178 179 /* 180 * Clear lock status, move request from active to free queue. 181 */ 182 *lock_stat = 0; 183 TAILQ_REMOVE(&dma_active, req, entries); 184 TAILQ_INSERT_HEAD(&dma_free, req, entries); 185 186 if((req = dma_active.tqh_first) != NULL) { 187 /* 188 * Call next request through softint handler. This avoids 189 * spl-conflicts. 190 */ 191 *req->lock_stat = DMA_LOCK_GRANT; 192 add_sicallback((si_farg)req->call_func, req->softc, 0); 193 } 194 splx(sps); 195 return; 196 } 197 198 int 199 st_dmawanted() 200 { 201 return(dma_active.tqh_first->entries.tqe_next != NULL); 202 } 203 204 int 205 cdmaint(unused, sr) 206 void *unused; 207 int sr; /* sr at time of interrupt */ 208 { 209 dma_farg int_func; 210 void *softc; 211 212 if(dma_active.tqh_first != NULL) { 213 /* 214 * Due to the logic of the ST-DMA chip, it is not possible to 215 * check for stray interrupts here... 216 */ 217 int_func = dma_active.tqh_first->int_func; 218 softc = dma_active.tqh_first->softc; 219 220 if(!BASEPRI(sr)) 221 add_sicallback((si_farg)int_func, softc, 0); 222 else { 223 spl1(); 224 (*int_func)(softc); 225 spl0(); 226 } 227 return 1; 228 } 229 return 0; 230 } 231 232 /* 233 * Setup address for DMA-transfer. 234 * Note: The order _is_ important! 235 */ 236 void 237 st_dmaaddr_set(address) 238 caddr_t address; 239 { 240 register u_long ad = (u_long)address; 241 242 DMA->dma_addr[AD_LOW ] = (ad ) & 0xff; 243 DMA->dma_addr[AD_MID ] = (ad >> 8) & 0xff; 244 DMA->dma_addr[AD_HIGH] = (ad >>16) & 0xff; 245 } 246 247 /* 248 * Get address from DMA unit. 249 */ 250 u_long 251 st_dmaaddr_get() 252 { 253 register u_long ad = 0; 254 255 ad = (DMA->dma_addr[AD_LOW ] & 0xff); 256 ad |= (DMA->dma_addr[AD_MID ] & 0xff) << 8; 257 ad |= (DMA->dma_addr[AD_HIGH] & 0xff) <<16; 258 return(ad); 259 } 260 261 /* 262 * Program the DMA-controller to transfer 'nblk' blocks of 512 bytes. 263 * The DMA_WRBIT trick flushes the FIFO before doing DMA. 264 */ 265 void 266 st_dmacomm(mode, nblk) 267 int mode, nblk; 268 { 269 DMA->dma_mode = mode; 270 DMA->dma_mode = mode ^ DMA_WRBIT; 271 DMA->dma_mode = mode; 272 DMA->dma_data = nblk; 273 delay(2); /* Needed for Falcon */ 274 DMA->dma_mode = DMA_SCREG | (mode & DMA_WRBIT); 275 } 276
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