dma.c revision 1.3
1 /* $NetBSD: dma.c,v 1.3 1995/04/30 12:04:48 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: specify 24 bit RAM address 50 * st_dmacomm: program DMA, flush FIFO first 51 */ 52 53 #include <sys/param.h> 54 #include <sys/systm.h> 55 #include <sys/kernel.h> 56 #include <sys/queue.h> 57 #include <machine/cpu.h> 58 #include <machine/iomap.h> 59 #include <machine/dma.h> 60 61 #define NDMA_DEV 10 /* Max 2 floppy's, 8 hard-disks */ 62 typedef struct dma_entry { 63 TAILQ_ENTRY(dma_entry) entries; /* List pointers */ 64 void (*call_func)(); /* Call when lock granted */ 65 void (*int_func)(); /* Call on DMA interrupt */ 66 void *softc; /* Arg. to int_func */ 67 int *lock_stat; /* status of DMA lock */ 68 } DMA_ENTRY; 69 70 /* 71 * Preallocated entries. An allocator seem an overkill here. 72 */ 73 static DMA_ENTRY dmatable[NDMA_DEV]; /* preallocated entries */ 74 static int sched_soft = 0; /* callback scheduled */ 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 static void cdmasoft __P((void)); 85 static void init_queues __P((void)); 86 87 static void init_queues() 88 { 89 int i; 90 91 TAILQ_INIT(&dma_free); 92 TAILQ_INIT(&dma_active); 93 94 for(i = 0; i < NDMA_DEV; i++) 95 TAILQ_INSERT_HEAD(&dma_free, &dmatable[i], entries); 96 } 97 98 int st_dmagrab(int_func, call_func, softc, lock_stat, rcaller) 99 void (*int_func)(); 100 void (*call_func)(); 101 void *softc; 102 int *lock_stat; 103 int rcaller; 104 { 105 int sps; 106 DMA_ENTRY *req; 107 108 if(must_init) { 109 init_queues(); 110 must_init = 0; 111 } 112 *lock_stat = DMA_LOCK_REQ; 113 114 sps = splhigh(); 115 116 /* 117 * Create a request... 118 */ 119 if(dma_free.tqh_first == NULL) 120 panic("st_dmagrab: Too many outstanding requests\n"); 121 req = dma_free.tqh_first; 122 TAILQ_REMOVE(&dma_free, dma_free.tqh_first, entries); 123 req->call_func = call_func; 124 req->int_func = int_func; 125 req->softc = softc; 126 req->lock_stat = lock_stat; 127 TAILQ_INSERT_TAIL(&dma_active, req, entries); 128 129 if(dma_active.tqh_first != req) { 130 splx(sps); 131 return(0); 132 } 133 splx(sps); 134 135 /* 136 * We're at the head of the queue, ergo: we got the lock. 137 */ 138 *lock_stat = DMA_LOCK_GRANT; 139 140 if(rcaller) { 141 /* 142 * Just return to caller immediately without going 143 * through 'call_func' first. 144 */ 145 return(1); 146 } 147 148 (*call_func)(softc); /* Call followup function */ 149 return(0); 150 } 151 152 void 153 st_dmafree(softc, lock_stat) 154 void *softc; 155 int *lock_stat; 156 { 157 int sps; 158 DMA_ENTRY *req; 159 160 sps = splhigh(); 161 162 /* 163 * Some validity checks first. 164 */ 165 if((req = dma_active.tqh_first) == NULL) 166 panic("st_dmafree: empty active queue\n"); 167 if(req->softc != softc) 168 printf("Caller of st_dmafree is not lock-owner!\n"); 169 170 /* 171 * Clear lock status, move request from active to free queue. 172 */ 173 *lock_stat = 0; 174 TAILQ_REMOVE(&dma_active, req, entries); 175 TAILQ_INSERT_HEAD(&dma_free, req, entries); 176 177 if((req = dma_active.tqh_first) != NULL) { 178 /* 179 * Call next request through softint handler. This avoids 180 * spl-conflicts. 181 */ 182 *req->lock_stat = DMA_LOCK_GRANT; 183 add_sicallback(req->call_func, req->softc, 0); 184 } 185 splx(sps); 186 return; 187 } 188 189 int 190 st_dmawanted() 191 { 192 return(dma_active.tqh_first->entries.tqe_next != NULL); 193 } 194 195 cdmaint(sr) 196 long sr; /* sr at time of interrupt */ 197 { 198 if(dma_active.tqh_first != NULL) { 199 if(!BASEPRI(sr)) { 200 if(!sched_soft++) 201 add_sicallback(cdmasoft, 0, 0); 202 } 203 else { 204 spl1(); 205 cdmasoft(); 206 } 207 } 208 else printf("DMA interrupt discarded\n"); 209 } 210 211 static void cdmasoft() 212 { 213 sched_soft = 0; 214 (*dma_active.tqh_first->int_func)(dma_active.tqh_first->softc); 215 } 216 217 /* 218 * Setup address for DMA-transfer. 219 * Note: The order _is_ important! 220 */ 221 void 222 st_dmaaddr(address) 223 caddr_t address; 224 { 225 register u_long ad = (u_long)address; 226 227 DMA->dma_addr[AD_LOW ] = (ad ) & 0xff; 228 DMA->dma_addr[AD_MID ] = (ad >> 8) & 0xff; 229 DMA->dma_addr[AD_HIGH] = (ad >>16) & 0xff; 230 } 231 232 /* 233 * Program the DMA-controller to transfer 'nblk' blocks of 512 bytes. 234 * The DMA_WRBIT trick flushes the FIFO before doing DMA. 235 */ 236 void 237 st_dmacomm(mode, data) 238 int mode, data; 239 { 240 DMA->dma_mode = mode; 241 DMA->dma_mode = mode ^ DMA_WRBIT; 242 DMA->dma_mode = mode; 243 DMA->dma_data = data; 244 } 245
Indexes created Tue Sep 30 20:09:53 GMT 2025