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