1 /* $NetBSD: dma.c,v 1.29 2023/01/06 10:28:28 tsutsui 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 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 /* 29 * This file contains special code dealing with the DMA interface 30 * on the Atari ST. 31 * 32 * The DMA circuitry requires some special treatment for the peripheral 33 * devices which make use of the ST's DMA feature (the hard disk and the 34 * floppy drive). 35 * All devices using DMA need mutually exclusive access and can follow some 36 * standard pattern which will be provided in this file. 37 * 38 * The file contains the following entry points: 39 * 40 * st_dmagrab: ensure exclusive access to the DMA circuitry 41 * st_dmafree: free exclusive access to the DMA circuitry 42 * st_dmawanted: somebody is queued waiting for DMA-access 43 * dmaint: DMA interrupt routine, switches to the current driver 44 * st_dmaaddr_set: specify 24 bit RAM address 45 * st_dmaaddr_get: get address of last DMA-op 46 * st_dmacomm: program DMA, flush FIFO first 47 */ 48 49 #include <sys/cdefs.h> 50 __KERNEL_RCSID(0, "$NetBSD: dma.c,v 1.29 2023/01/06 10:28:28 tsutsui Exp $"); 51 52 #include <sys/param.h> 53 #include <sys/systm.h> 54 #include <sys/kernel.h> 55 #include <sys/proc.h> 56 #include <sys/queue.h> 57 58 #include <machine/cpu.h> 59 #include <machine/iomap.h> 60 #include <machine/dma.h> 61 #include <machine/intr.h> 62 63 #define NDMA_DEV 10 /* Max 2 floppy's, 8 hard-disks */ 64 typedef struct dma_entry { 65 TAILQ_ENTRY(dma_entry) entries; /* List pointers */ 66 void (*call_func)(void *); /* Call when lock granted */ 67 void (*int_func)(void *); /* Call on DMA interrupt */ 68 void *softc; /* Arg. to int_func */ 69 int *lock_stat; /* status of DMA lock */ 70 } DMA_ENTRY; 71 72 /* 73 * Preallocated entries. An allocator seem an overkill here. 74 */ 75 static DMA_ENTRY dmatable[NDMA_DEV]; /* preallocated entries */ 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 int cdmaint(void *, int); 86 87 static void st_dma_init(void); 88 89 static void 90 st_dma_init(void) 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 if (intr_establish(7, USER_VEC, 0, cdmaint, NULL) == NULL) 101 panic("st_dma_init: Can't establish interrupt"); 102 } 103 104 int 105 st_dmagrab(dma_farg int_func, dma_farg call_func, void *softc, int *lock_stat, 106 int rcaller, kmutex_t *interlock) 107 { 108 int s; 109 DMA_ENTRY *req; 110 111 if (must_init) { 112 st_dma_init(); 113 must_init = 0; 114 } 115 *lock_stat = DMA_LOCK_REQ; 116 117 s = splhigh(); 118 119 /* 120 * Create a request... 121 */ 122 if ((req = TAILQ_FIRST(&dma_free)) == NULL) 123 panic("st_dmagrab: Too many outstanding requests"); 124 TAILQ_REMOVE(&dma_free, req, entries); 125 req->call_func = call_func; 126 req->int_func = int_func; 127 req->softc = softc; 128 req->lock_stat = lock_stat; 129 TAILQ_INSERT_TAIL(&dma_active, req, entries); 130 131 if (TAILQ_FIRST(&dma_active) != req) { 132 if (call_func == NULL) { 133 do { 134 mtsleep(&dma_active, PRIBIO, "dmalck", 0, 135 interlock); 136 } while (*req->lock_stat != DMA_LOCK_GRANT); 137 splx(s); 138 return 1; 139 } 140 splx(s); 141 return 0; 142 } 143 splx(s); 144 145 /* 146 * We're at the head of the queue, ergo: we got the lock. 147 */ 148 *lock_stat = DMA_LOCK_GRANT; 149 150 if (rcaller || (call_func == NULL)) { 151 /* 152 * Just return to caller immediately without going 153 * through 'call_func' first. 154 */ 155 return 1; 156 } 157 158 (*call_func)(softc); /* Call followup function */ 159 return 0; 160 } 161 162 void 163 st_dmafree(void *softc, int *lock_stat) 164 { 165 int s; 166 DMA_ENTRY *req; 167 168 s = splhigh(); 169 170 /* 171 * Some validity checks first. 172 */ 173 if ((req = TAILQ_FIRST(&dma_active)) == NULL) 174 panic("st_dmafree: empty active queue"); 175 if (req->softc != softc) 176 printf("Caller of st_dmafree is not lock-owner!\n"); 177 178 /* 179 * Clear lock status, move request from active to free queue. 180 */ 181 *lock_stat = 0; 182 TAILQ_REMOVE(&dma_active, req, entries); 183 TAILQ_INSERT_HEAD(&dma_free, req, entries); 184 185 if ((req = TAILQ_FIRST(&dma_active)) != NULL) { 186 *req->lock_stat = DMA_LOCK_GRANT; 187 188 if (req->call_func == NULL) 189 wakeup((void *)&dma_active); 190 else { 191 /* 192 * Call next request through softint handler. 193 * This avoids spl-conflicts. 194 */ 195 add_sicallback((si_farg)req->call_func, req->softc, 0); 196 } 197 } 198 splx(s); 199 } 200 201 int 202 st_dmawanted(void) 203 { 204 205 return TAILQ_NEXT(TAILQ_FIRST(&dma_active), entries) != NULL; 206 } 207 208 int 209 cdmaint(void *unused, int sr) 210 /* sr: sr at time of interrupt */ 211 { 212 dma_farg int_func; 213 void *softc; 214 215 if (TAILQ_FIRST(&dma_active) != NULL) { 216 /* 217 * Due to the logic of the ST-DMA chip, it is not possible to 218 * check for stray interrupts here... 219 */ 220 int_func = TAILQ_FIRST(&dma_active)->int_func; 221 softc = TAILQ_FIRST(&dma_active)->softc; 222 add_sicallback((si_farg)int_func, softc, 0); 223 return 1; 224 } 225 return 0; 226 } 227 228 /* 229 * Setup address for DMA-transfer. 230 * Note: The order _is_ important! 231 */ 232 void 233 st_dmaaddr_set(void *address) 234 { 235 u_long ad = (u_long)address; 236 237 DMA->dma_addr[AD_LOW ] = (ad ) & 0xff; 238 DMA->dma_addr[AD_MID ] = (ad >> 8) & 0xff; 239 DMA->dma_addr[AD_HIGH] = (ad >>16) & 0xff; 240 } 241 242 /* 243 * Get address from DMA unit. 244 */ 245 u_long 246 st_dmaaddr_get(void) 247 { 248 u_long ad = 0; 249 250 ad = (DMA->dma_addr[AD_LOW ] & 0xff); 251 ad |= (DMA->dma_addr[AD_MID ] & 0xff) << 8; 252 ad |= (DMA->dma_addr[AD_HIGH] & 0xff) <<16; 253 return ad; 254 } 255 256 /* 257 * Program the DMA-controller to transfer 'nblk' blocks of 512 bytes. 258 * The DMA_WRBIT trick flushes the FIFO before doing DMA. 259 */ 260 void 261 st_dmacomm(int mode, int nblk) 262 { 263 264 DMA->dma_mode = mode; 265 DMA->dma_mode = mode ^ DMA_WRBIT; 266 DMA->dma_mode = mode; 267 DMA->dma_data = nblk; 268 delay(2); /* Needed for Falcon */ 269 DMA->dma_mode = DMA_SCREG | (mode & DMA_WRBIT); 270 } 271
Indexes created Sat Sep 20 22:09:52 GMT 2025