1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * linux/arch/arm/mach-rpc/dma.c 4 * 5 * Copyright (C) 1998 Russell King 6 * 7 * DMA functions specific to RiscPC architecture 8 */ 9 #include <linux/mman.h> 10 #include <linux/init.h> 11 #include <linux/interrupt.h> 12 #include <linux/dma-mapping.h> 13 #include <linux/io.h> 14 15 #include <asm/page.h> 16 #include <asm/dma.h> 17 #include <asm/fiq.h> 18 #include <asm/irq.h> 19 #include <mach/hardware.h> 20 #include <linux/uaccess.h> 21 22 #include <asm/mach/dma.h> 23 #include <asm/hardware/iomd.h> 24 25 struct iomd_dma { 26 struct dma_struct dma; 27 unsigned int state; 28 unsigned long base; /* Controller base address */ 29 int irq; /* Controller IRQ */ 30 struct scatterlist cur_sg; /* Current controller buffer */ 31 dma_addr_t dma_addr; 32 unsigned int dma_len; 33 }; 34 35 #if 0 36 typedef enum { 37 dma_size_8 = 1, 38 dma_size_16 = 2, 39 dma_size_32 = 4, 40 dma_size_128 = 16 41 } dma_size_t; 42 #endif 43 44 #define TRANSFER_SIZE 2 45 46 #define CURA (0) 47 #define ENDA (IOMD_IO0ENDA - IOMD_IO0CURA) 48 #define CURB (IOMD_IO0CURB - IOMD_IO0CURA) 49 #define ENDB (IOMD_IO0ENDB - IOMD_IO0CURA) 50 #define CR (IOMD_IO0CR - IOMD_IO0CURA) 51 #define ST (IOMD_IO0ST - IOMD_IO0CURA) 52 53 static void iomd_get_next_sg(struct scatterlist *sg, struct iomd_dma *idma) 54 { 55 unsigned long end, offset, flags = 0; 56 57 if (idma->dma.sg) { 58 sg->dma_address = idma->dma_addr; 59 offset = sg->dma_address & ~PAGE_MASK; 60 61 end = offset + idma->dma_len; 62 63 if (end > PAGE_SIZE) 64 end = PAGE_SIZE; 65 66 if (offset + TRANSFER_SIZE >= end) 67 flags |= DMA_END_L; 68 69 sg->length = end - TRANSFER_SIZE; 70 71 idma->dma_len -= end - offset; 72 idma->dma_addr += end - offset; 73 74 if (idma->dma_len == 0) { 75 if (idma->dma.sgcount > 1) { 76 idma->dma.sg = sg_next(idma->dma.sg); 77 idma->dma_addr = idma->dma.sg->dma_address; 78 idma->dma_len = idma->dma.sg->length; 79 idma->dma.sgcount--; 80 } else { 81 idma->dma.sg = NULL; 82 flags |= DMA_END_S; 83 } 84 } 85 } else { 86 flags = DMA_END_S | DMA_END_L; 87 sg->dma_address = 0; 88 sg->length = 0; 89 } 90 91 sg->length |= flags; 92 } 93 94 static irqreturn_t iomd_dma_handle(int irq, void *dev_id) 95 { 96 struct iomd_dma *idma = dev_id; 97 unsigned long base = idma->base; 98 99 do { 100 unsigned int status; 101 102 status = iomd_readb(base + ST); 103 if (!(status & DMA_ST_INT)) 104 return IRQ_HANDLED; 105 106 if ((idma->state ^ status) & DMA_ST_AB) 107 iomd_get_next_sg(&idma->cur_sg, idma); 108 109 switch (status & (DMA_ST_OFL | DMA_ST_AB)) { 110 case DMA_ST_OFL: /* OIA */ 111 case DMA_ST_AB: /* .IB */ 112 iomd_writel(idma->cur_sg.dma_address, base + CURA); 113 iomd_writel(idma->cur_sg.length, base + ENDA); 114 idma->state = DMA_ST_AB; 115 break; 116 117 case DMA_ST_OFL | DMA_ST_AB: /* OIB */ 118 case 0: /* .IA */ 119 iomd_writel(idma->cur_sg.dma_address, base + CURB); 120 iomd_writel(idma->cur_sg.length, base + ENDB); 121 idma->state = 0; 122 break; 123 } 124 125 if (status & DMA_ST_OFL && 126 idma->cur_sg.length == (DMA_END_S|DMA_END_L)) 127 break; 128 } while (1); 129 130 idma->state = ~DMA_ST_AB; 131 disable_irq(irq); 132 133 return IRQ_HANDLED; 134 } 135 136 static int iomd_request_dma(unsigned int chan, dma_t *dma) 137 { 138 struct iomd_dma *idma = container_of(dma, struct iomd_dma, dma); 139 140 return request_irq(idma->irq, iomd_dma_handle, 141 0, idma->dma.device_id, idma); 142 } 143 144 static void iomd_free_dma(unsigned int chan, dma_t *dma) 145 { 146 struct iomd_dma *idma = container_of(dma, struct iomd_dma, dma); 147 148 free_irq(idma->irq, idma); 149 } 150 151 static struct device isa_dma_dev = { 152 .init_name = "fallback device", 153 .coherent_dma_mask = ~(dma_addr_t)0, 154 .dma_mask = &isa_dma_dev.coherent_dma_mask, 155 }; 156 157 static void iomd_enable_dma(unsigned int chan, dma_t *dma) 158 { 159 struct iomd_dma *idma = container_of(dma, struct iomd_dma, dma); 160 unsigned long dma_base = idma->base; 161 unsigned int ctrl = TRANSFER_SIZE | DMA_CR_E; 162 163 if (idma->dma.invalid) { 164 idma->dma.invalid = 0; 165 166 /* 167 * Cope with ISA-style drivers which expect cache 168 * coherence. 169 */ 170 if (!idma->dma.sg) { 171 idma->dma.sg = &idma->dma.buf; 172 idma->dma.sgcount = 1; 173 idma->dma.buf.length = idma->dma.count; 174 idma->dma.buf.dma_address = dma_map_single(&isa_dma_dev, 175 idma->dma.addr, idma->dma.count, 176 idma->dma.dma_mode == DMA_MODE_READ ? 177 DMA_FROM_DEVICE : DMA_TO_DEVICE); 178 } 179 180 iomd_writeb(DMA_CR_C, dma_base + CR); 181 idma->state = DMA_ST_AB; 182 } 183 184 if (idma->dma.dma_mode == DMA_MODE_READ) 185 ctrl |= DMA_CR_D; 186 187 iomd_writeb(ctrl, dma_base + CR); 188 enable_irq(idma->irq); 189 } 190 191 static void iomd_disable_dma(unsigned int chan, dma_t *dma) 192 { 193 struct iomd_dma *idma = container_of(dma, struct iomd_dma, dma); 194 unsigned long dma_base = idma->base; 195 unsigned long flags; 196 197 local_irq_save(flags); 198 if (idma->state != ~DMA_ST_AB) 199 disable_irq(idma->irq); 200 iomd_writeb(0, dma_base + CR); 201 local_irq_restore(flags); 202 } 203 204 static int iomd_set_dma_speed(unsigned int chan, dma_t *dma, int cycle) 205 { 206 int tcr, speed; 207 208 if (cycle < 188) 209 speed = 3; 210 else if (cycle <= 250) 211 speed = 2; 212 else if (cycle < 438) 213 speed = 1; 214 else 215 speed = 0; 216 217 tcr = iomd_readb(IOMD_DMATCR); 218 speed &= 3; 219 220 switch (chan) { 221 case DMA_0: 222 tcr = (tcr & ~0x03) | speed; 223 break; 224 225 case DMA_1: 226 tcr = (tcr & ~0x0c) | (speed << 2); 227 break; 228 229 case DMA_2: 230 tcr = (tcr & ~0x30) | (speed << 4); 231 break; 232 233 case DMA_3: 234 tcr = (tcr & ~0xc0) | (speed << 6); 235 break; 236 237 default: 238 break; 239 } 240 241 iomd_writeb(tcr, IOMD_DMATCR); 242 243 return speed; 244 } 245 246 static struct dma_ops iomd_dma_ops = { 247 .type = "IOMD", 248 .request = iomd_request_dma, 249 .free = iomd_free_dma, 250 .enable = iomd_enable_dma, 251 .disable = iomd_disable_dma, 252 .setspeed = iomd_set_dma_speed, 253 }; 254 255 static struct fiq_handler fh = { 256 .name = "floppydma" 257 }; 258 259 struct floppy_dma { 260 struct dma_struct dma; 261 unsigned int fiq; 262 }; 263 264 static void floppy_enable_dma(unsigned int chan, dma_t *dma) 265 { 266 struct floppy_dma *fdma = container_of(dma, struct floppy_dma, dma); 267 void *fiqhandler_start; 268 unsigned int fiqhandler_length; 269 struct pt_regs regs; 270 271 if (fdma->dma.sg) 272 BUG(); 273 274 if (fdma->dma.dma_mode == DMA_MODE_READ) { 275 extern unsigned char floppy_fiqin_start, floppy_fiqin_end; 276 fiqhandler_start = &floppy_fiqin_start; 277 fiqhandler_length = &floppy_fiqin_end - &floppy_fiqin_start; 278 } else { 279 extern unsigned char floppy_fiqout_start, floppy_fiqout_end; 280 fiqhandler_start = &floppy_fiqout_start; 281 fiqhandler_length = &floppy_fiqout_end - &floppy_fiqout_start; 282 } 283 284 regs.ARM_r9 = fdma->dma.count; 285 regs.ARM_r10 = (unsigned long)fdma->dma.addr; 286 regs.ARM_fp = (unsigned long)FLOPPYDMA_BASE; 287 288 if (claim_fiq(&fh)) { 289 printk("floppydma: couldn't claim FIQ.\n"); 290 return; 291 } 292 293 set_fiq_handler(fiqhandler_start, fiqhandler_length); 294 set_fiq_regs(®s); 295 enable_fiq(fdma->fiq); 296 } 297 298 static void floppy_disable_dma(unsigned int chan, dma_t *dma) 299 { 300 struct floppy_dma *fdma = container_of(dma, struct floppy_dma, dma); 301 disable_fiq(fdma->fiq); 302 release_fiq(&fh); 303 } 304 305 static int floppy_get_residue(unsigned int chan, dma_t *dma) 306 { 307 struct pt_regs regs; 308 get_fiq_regs(®s); 309 return regs.ARM_r9; 310 } 311 312 static struct dma_ops floppy_dma_ops = { 313 .type = "FIQDMA", 314 .enable = floppy_enable_dma, 315 .disable = floppy_disable_dma, 316 .residue = floppy_get_residue, 317 }; 318 319 /* 320 * This is virtual DMA - we don't need anything here. 321 */ 322 static void sound_enable_disable_dma(unsigned int chan, dma_t *dma) 323 { 324 } 325 326 static struct dma_ops sound_dma_ops = { 327 .type = "VIRTUAL", 328 .enable = sound_enable_disable_dma, 329 .disable = sound_enable_disable_dma, 330 }; 331 332 static struct iomd_dma iomd_dma[6]; 333 334 static struct floppy_dma floppy_dma = { 335 .dma = { 336 .d_ops = &floppy_dma_ops, 337 }, 338 .fiq = FIQ_FLOPPYDATA, 339 }; 340 341 static dma_t sound_dma = { 342 .d_ops = &sound_dma_ops, 343 }; 344 345 static int __init rpc_dma_init(void) 346 { 347 unsigned int i; 348 int ret; 349 350 iomd_writeb(0, IOMD_IO0CR); 351 iomd_writeb(0, IOMD_IO1CR); 352 iomd_writeb(0, IOMD_IO2CR); 353 iomd_writeb(0, IOMD_IO3CR); 354 355 iomd_writeb(0xa0, IOMD_DMATCR); 356 357 /* 358 * Setup DMA channels 2,3 to be for podules 359 * and channels 0,1 for internal devices 360 */ 361 iomd_writeb(DMA_EXT_IO3|DMA_EXT_IO2, IOMD_DMAEXT); 362 363 iomd_dma[DMA_0].base = IOMD_IO0CURA; 364 iomd_dma[DMA_0].irq = IRQ_DMA0; 365 iomd_dma[DMA_1].base = IOMD_IO1CURA; 366 iomd_dma[DMA_1].irq = IRQ_DMA1; 367 iomd_dma[DMA_2].base = IOMD_IO2CURA; 368 iomd_dma[DMA_2].irq = IRQ_DMA2; 369 iomd_dma[DMA_3].base = IOMD_IO3CURA; 370 iomd_dma[DMA_3].irq = IRQ_DMA3; 371 iomd_dma[DMA_S0].base = IOMD_SD0CURA; 372 iomd_dma[DMA_S0].irq = IRQ_DMAS0; 373 iomd_dma[DMA_S1].base = IOMD_SD1CURA; 374 iomd_dma[DMA_S1].irq = IRQ_DMAS1; 375 376 for (i = DMA_0; i <= DMA_S1; i++) { 377 iomd_dma[i].dma.d_ops = &iomd_dma_ops; 378 379 ret = isa_dma_add(i, &iomd_dma[i].dma); 380 if (ret) 381 printk("IOMDDMA%u: unable to register: %d\n", i, ret); 382 } 383 384 ret = isa_dma_add(DMA_VIRTUAL_FLOPPY, &floppy_dma.dma); 385 if (ret) 386 printk("IOMDFLOPPY: unable to register: %d\n", ret); 387 ret = isa_dma_add(DMA_VIRTUAL_SOUND, &sound_dma); 388 if (ret) 389 printk("IOMDSOUND: unable to register: %d\n", ret); 390 return 0; 391 } 392 core_initcall(rpc_dma_init); 393