arch/arm/mach-rpc/dma.c

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