dma.c revision 1.20
1 /* $NetBSD: dma.c,v 1.20 2009/03/14 15:36:03 dsl 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/cdefs.h> 55 __KERNEL_RCSID(0, "$NetBSD: dma.c,v 1.20 2009/03/14 15:36:03 dsl Exp $"); 56 57 #include <sys/param.h> 58 #include <sys/systm.h> 59 #include <sys/kernel.h> 60 #include <sys/proc.h> 61 #include <sys/queue.h> 62 63 #include <machine/cpu.h> 64 #include <machine/iomap.h> 65 #include <machine/dma.h> 66 67 #include <atari/atari/intr.h> 68 69 #define NDMA_DEV 10 /* Max 2 floppy's, 8 hard-disks */ 70 typedef struct dma_entry { 71 TAILQ_ENTRY(dma_entry) entries; /* List pointers */ 72 void (*call_func)(void *); /* Call when lock granted */ 73 void (*int_func)(void *); /* Call on DMA interrupt */ 74 void *softc; /* Arg. to int_func */ 75 int *lock_stat; /* status of DMA lock */ 76 } DMA_ENTRY; 77 78 /* 79 * Preallocated entries. An allocator seem an overkill here. 80 */ 81 static DMA_ENTRY dmatable[NDMA_DEV]; /* preallocated entries */ 82 83 /* 84 * Heads of free and active lists: 85 */ 86 static TAILQ_HEAD(freehead, dma_entry) dma_free; 87 static TAILQ_HEAD(acthead, dma_entry) dma_active; 88 89 static int must_init = 1; /* Must initialize */ 90 91 int cdmaint(void *, int); 92 93 static void st_dma_init(void); 94 95 static void 96 st_dma_init() 97 { 98 int i; 99 100 TAILQ_INIT(&dma_free); 101 TAILQ_INIT(&dma_active); 102 103 for(i = 0; i < NDMA_DEV; i++) 104 TAILQ_INSERT_HEAD(&dma_free, &dmatable[i], entries); 105 106 if (intr_establish(7, USER_VEC, 0, cdmaint, NULL) == NULL) 107 panic("st_dma_init: Can't establish interrupt"); 108 } 109 110 int 111 st_dmagrab(dma_farg int_func, dma_farg call_func, void *softc, int *lock_stat, int rcaller) 112 { 113 int sps; 114 DMA_ENTRY *req; 115 116 if(must_init) { 117 st_dma_init(); 118 must_init = 0; 119 } 120 *lock_stat = DMA_LOCK_REQ; 121 122 sps = splhigh(); 123 124 /* 125 * Create a request... 126 */ 127 if(dma_free.tqh_first == NULL) 128 panic("st_dmagrab: Too many outstanding requests"); 129 req = dma_free.tqh_first; 130 TAILQ_REMOVE(&dma_free, dma_free.tqh_first, entries); 131 req->call_func = call_func; 132 req->int_func = int_func; 133 req->softc = softc; 134 req->lock_stat = lock_stat; 135 TAILQ_INSERT_TAIL(&dma_active, req, entries); 136 137 if(dma_active.tqh_first != req) { 138 if (call_func == NULL) { 139 do { 140 tsleep(&dma_active, PRIBIO, "dmalck", 0); 141 } while (*req->lock_stat != DMA_LOCK_GRANT); 142 splx(sps); 143 return(1); 144 } 145 splx(sps); 146 return(0); 147 } 148 splx(sps); 149 150 /* 151 * We're at the head of the queue, ergo: we got the lock. 152 */ 153 *lock_stat = DMA_LOCK_GRANT; 154 155 if(rcaller || (call_func == NULL)) { 156 /* 157 * Just return to caller immediately without going 158 * through 'call_func' first. 159 */ 160 return(1); 161 } 162 163 (*call_func)(softc); /* Call followup function */ 164 return(0); 165 } 166 167 void 168 st_dmafree(void *softc, int *lock_stat) 169 { 170 int sps; 171 DMA_ENTRY *req; 172 173 sps = splhigh(); 174 175 /* 176 * Some validity checks first. 177 */ 178 if((req = dma_active.tqh_first) == NULL) 179 panic("st_dmafree: empty active queue"); 180 if(req->softc != softc) 181 printf("Caller of st_dmafree is not lock-owner!\n"); 182 183 /* 184 * Clear lock status, move request from active to free queue. 185 */ 186 *lock_stat = 0; 187 TAILQ_REMOVE(&dma_active, req, entries); 188 TAILQ_INSERT_HEAD(&dma_free, req, entries); 189 190 if((req = dma_active.tqh_first) != NULL) { 191 *req->lock_stat = DMA_LOCK_GRANT; 192 193 if (req->call_func == NULL) 194 wakeup((void *)&dma_active); 195 else { 196 /* 197 * Call next request through softint handler. This avoids 198 * spl-conflicts. 199 */ 200 add_sicallback((si_farg)req->call_func, req->softc, 0); 201 } 202 } 203 splx(sps); 204 return; 205 } 206 207 int 208 st_dmawanted() 209 { 210 return(dma_active.tqh_first->entries.tqe_next != NULL); 211 } 212 213 int 214 cdmaint(unused, sr) 215 void *unused; 216 int sr; /* sr at time of interrupt */ 217 { 218 dma_farg int_func; 219 void *softc; 220 221 if(dma_active.tqh_first != NULL) { 222 /* 223 * Due to the logic of the ST-DMA chip, it is not possible to 224 * check for stray interrupts here... 225 */ 226 int_func = dma_active.tqh_first->int_func; 227 softc = dma_active.tqh_first->softc; 228 229 if(!BASEPRI(sr)) 230 add_sicallback((si_farg)int_func, softc, 0); 231 else { 232 spl1(); 233 (*int_func)(softc); 234 spl0(); 235 } 236 return 1; 237 } 238 return 0; 239 } 240 241 /* 242 * Setup address for DMA-transfer. 243 * Note: The order _is_ important! 244 */ 245 void 246 st_dmaaddr_set(void * address) 247 { 248 register u_long ad = (u_long)address; 249 250 DMA->dma_addr[AD_LOW ] = (ad ) & 0xff; 251 DMA->dma_addr[AD_MID ] = (ad >> 8) & 0xff; 252 DMA->dma_addr[AD_HIGH] = (ad >>16) & 0xff; 253 } 254 255 /* 256 * Get address from DMA unit. 257 */ 258 u_long 259 st_dmaaddr_get() 260 { 261 register u_long ad = 0; 262 263 ad = (DMA->dma_addr[AD_LOW ] & 0xff); 264 ad |= (DMA->dma_addr[AD_MID ] & 0xff) << 8; 265 ad |= (DMA->dma_addr[AD_HIGH] & 0xff) <<16; 266 return(ad); 267 } 268 269 /* 270 * Program the DMA-controller to transfer 'nblk' blocks of 512 bytes. 271 * The DMA_WRBIT trick flushes the FIFO before doing DMA. 272 */ 273 void 274 st_dmacomm(mode, nblk) 275 int mode, nblk; 276 { 277 DMA->dma_mode = mode; 278 DMA->dma_mode = mode ^ DMA_WRBIT; 279 DMA->dma_mode = mode; 280 DMA->dma_data = nblk; 281 delay(2); /* Needed for Falcon */ 282 DMA->dma_mode = DMA_SCREG | (mode & DMA_WRBIT); 283 } 284
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