arch/arm/mach-rpc/dma.c

   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(&regs);
 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(&regs);
 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);