include/asm-mips/dma.h

   1 /* $Id: dma.h,v 1.6 1999/12/30 14:22:47 raiko Exp $
   2  * linux/include/asm/dma.h: Defines for using and allocating dma channels.
   3  * Written by Hennus Bergman, 1992.
   4  * High DMA channel support & info by Hannu Savolainen
   5  * and John Boyd, Nov. 1992.
   6  *
   7  * NOTE: all this is true *only* for ISA/EISA expansions on Mips boards
   8  * and can only be used for expansion cards. Onboard DMA controllers, such
   9  * as the R4030 on Jazz boards behave totally different!
  10  */
  11
  12 #ifndef __ASM_MIPS_DMA_H
  13 #define __ASM_MIPS_DMA_H
  14
  15 #include <linux/config.h>
  16 #include <asm/io.h>                     /* need byte IO */
  17 #include <linux/spinlock.h>             /* And spinlocks */
  18 #include <linux/delay.h>
  19 #include <asm/system.h>
  20
  21
  22 #ifdef HAVE_REALLY_SLOW_DMA_CONTROLLER
  23 #define dma_outb        outb_p
  24 #else
  25 #define dma_outb        outb
  26 #endif
  27
  28 #define dma_inb         inb
  29
  30 /*
  31  * NOTES about DMA transfers:
  32  *
  33  *  controller 1: channels 0-3, byte operations, ports 00-1F
  34  *  controller 2: channels 4-7, word operations, ports C0-DF
  35  *
  36  *  - ALL registers are 8 bits only, regardless of transfer size
  37  *  - channel 4 is not used - cascades 1 into 2.
  38  *  - channels 0-3 are byte - addresses/counts are for physical bytes
  39  *  - channels 5-7 are word - addresses/counts are for physical words
  40  *  - transfers must not cross physical 64K (0-3) or 128K (5-7) boundaries
  41  *  - transfer count loaded to registers is 1 less than actual count
  42  *  - controller 2 offsets are all even (2x offsets for controller 1)
  43  *  - page registers for 5-7 don't use data bit 0, represent 128K pages
  44  *  - page registers for 0-3 use bit 0, represent 64K pages
  45  *
  46  * DMA transfers are limited to the lower 16MB of _physical_ memory.
  47  * Note that addresses loaded into registers must be _physical_ addresses,
  48  * not logical addresses (which may differ if paging is active).
  49  *
  50  *  Address mapping for channels 0-3:
  51  *
  52  *   A23 ... A16 A15 ... A8  A7 ... A0    (Physical addresses)
  53  *    |  ...  |   |  ... |   |  ... |
  54  *    |  ...  |   |  ... |   |  ... |
  55  *    |  ...  |   |  ... |   |  ... |
  56  *   P7  ...  P0  A7 ... A0  A7 ... A0
  57  * |    Page    | Addr MSB | Addr LSB |   (DMA registers)
  58  *
  59  *  Address mapping for channels 5-7:
  60  *
  61  *   A23 ... A17 A16 A15 ... A9 A8 A7 ... A1 A0    (Physical addresses)
  62  *    |  ...  |   \   \   ... \  \  \  ... \  \
  63  *    |  ...  |    \   \   ... \  \  \  ... \  (not used)
  64  *    |  ...  |     \   \   ... \  \  \  ... \
  65  *   P7  ...  P1 (0) A7 A6  ... A0 A7 A6 ... A0
  66  * |      Page      |  Addr MSB   |  Addr LSB  |   (DMA registers)
  67  *
  68  * Again, channels 5-7 transfer _physical_ words (16 bits), so addresses
  69  * and counts _must_ be word-aligned (the lowest address bit is _ignored_ at
  70  * the hardware level, so odd-byte transfers aren't possible).
  71  *
  72  * Transfer count (_not # bytes_) is limited to 64K, represented as actual
  73  * count - 1 : 64K => 0xFFFF, 1 => 0x0000.  Thus, count is always 1 or more,
  74  * and up to 128K bytes may be transferred on channels 5-7 in one operation.
  75  *
  76  */
  77
  78 #define MAX_DMA_CHANNELS        8
  79
  80 /*
  81  * The maximum address in KSEG0 that we can perform a DMA transfer to on this
  82  * platform.  This describes only the PC style part of the DMA logic like on
  83  * Deskstations or Acer PICA but not the much more versatile DMA logic used
  84  * for the local devices on Acer PICA or Magnums.
  85  */
  86 #define MAX_DMA_ADDRESS         (PAGE_OFFSET + 0x01000000)
  87
  88 /* 8237 DMA controllers */
  89 #define IO_DMA1_BASE    0x00    /* 8 bit slave DMA, channels 0..3 */
  90 #define IO_DMA2_BASE    0xC0    /* 16 bit master DMA, ch 4(=slave input)..7 */
  91
  92 /* DMA controller registers */
  93 #define DMA1_CMD_REG            0x08    /* command register (w) */
  94 #define DMA1_STAT_REG           0x08    /* status register (r) */
  95 #define DMA1_REQ_REG            0x09    /* request register (w) */
  96 #define DMA1_MASK_REG           0x0A    /* single-channel mask (w) */
  97 #define DMA1_MODE_REG           0x0B    /* mode register (w) */
  98 #define DMA1_CLEAR_FF_REG       0x0C    /* clear pointer flip-flop (w) */
  99 #define DMA1_TEMP_REG           0x0D    /* Temporary Register (r) */
 100 #define DMA1_RESET_REG          0x0D    /* Master Clear (w) */
 101 #define DMA1_CLR_MASK_REG       0x0E    /* Clear Mask */
 102 #define DMA1_MASK_ALL_REG       0x0F    /* all-channels mask (w) */
 103
 104 #define DMA2_CMD_REG            0xD0    /* command register (w) */
 105 #define DMA2_STAT_REG           0xD0    /* status register (r) */
 106 #define DMA2_REQ_REG            0xD2    /* request register (w) */
 107 #define DMA2_MASK_REG           0xD4    /* single-channel mask (w) */
 108 #define DMA2_MODE_REG           0xD6    /* mode register (w) */
 109 #define DMA2_CLEAR_FF_REG       0xD8    /* clear pointer flip-flop (w) */
 110 #define DMA2_TEMP_REG           0xDA    /* Temporary Register (r) */
 111 #define DMA2_RESET_REG          0xDA    /* Master Clear (w) */
 112 #define DMA2_CLR_MASK_REG       0xDC    /* Clear Mask */
 113 #define DMA2_MASK_ALL_REG       0xDE    /* all-channels mask (w) */
 114
 115 #define DMA_ADDR_0              0x00    /* DMA address registers */
 116 #define DMA_ADDR_1              0x02
 117 #define DMA_ADDR_2              0x04
 118 #define DMA_ADDR_3              0x06
 119 #define DMA_ADDR_4              0xC0
 120 #define DMA_ADDR_5              0xC4
 121 #define DMA_ADDR_6              0xC8
 122 #define DMA_ADDR_7              0xCC
 123
 124 #define DMA_CNT_0               0x01    /* DMA count registers */
 125 #define DMA_CNT_1               0x03
 126 #define DMA_CNT_2               0x05
 127 #define DMA_CNT_3               0x07
 128 #define DMA_CNT_4               0xC2
 129 #define DMA_CNT_5               0xC6
 130 #define DMA_CNT_6               0xCA
 131 #define DMA_CNT_7               0xCE
 132
 133 #define DMA_PAGE_0              0x87    /* DMA page registers */
 134 #define DMA_PAGE_1              0x83
 135 #define DMA_PAGE_2              0x81
 136 #define DMA_PAGE_3              0x82
 137 #define DMA_PAGE_5              0x8B
 138 #define DMA_PAGE_6              0x89
 139 #define DMA_PAGE_7              0x8A
 140
 141 #define DMA_MODE_READ   0x44    /* I/O to memory, no autoinit, increment, single mode */
 142 #define DMA_MODE_WRITE  0x48    /* memory to I/O, no autoinit, increment, single mode */
 143 #define DMA_MODE_CASCADE 0xC0   /* pass thru DREQ->HRQ, DACK<-HLDA only */
 144
 145
 146 extern spinlock_t  dma_spin_lock;
 147
 148 static __inline__ unsigned long claim_dma_lock(void)
 149 {
 150         unsigned long flags;
 151         spin_lock_irqsave(&dma_spin_lock, flags);
 152         return flags;
 153 }
 154
 155 static __inline__ void release_dma_lock(unsigned long flags)
 156 {
 157         spin_unlock_irqrestore(&dma_spin_lock, flags);
 158 }
 159
 160 /* enable/disable a specific DMA channel */
 161 static __inline__ void enable_dma(unsigned int dmanr)
 162 {
 163         if (dmanr<=3)
 164                 dma_outb(dmanr,  DMA1_MASK_REG);
 165         else
 166                 dma_outb(dmanr & 3,  DMA2_MASK_REG);
 167 }
 168
 169 static __inline__ void disable_dma(unsigned int dmanr)
 170 {
 171         if (dmanr<=3)
 172                 dma_outb(dmanr | 4,  DMA1_MASK_REG);
 173         else
 174                 dma_outb((dmanr & 3) | 4,  DMA2_MASK_REG);
 175 }
 176
 177 /* Clear the 'DMA Pointer Flip Flop'.
 178  * Write 0 for LSB/MSB, 1 for MSB/LSB access.
 179  * Use this once to initialize the FF to a known state.
 180  * After that, keep track of it. :-)
 181  * --- In order to do that, the DMA routines below should ---
 182  * --- only be used while holding the DMA lock ! ---
 183  */
 184 static __inline__ void clear_dma_ff(unsigned int dmanr)
 185 {
 186         if (dmanr<=3)
 187                 dma_outb(0,  DMA1_CLEAR_FF_REG);
 188         else
 189                 dma_outb(0,  DMA2_CLEAR_FF_REG);
 190 }
 191
 192 /* set mode (above) for a specific DMA channel */
 193 static __inline__ void set_dma_mode(unsigned int dmanr, char mode)
 194 {
 195         if (dmanr<=3)
 196                 dma_outb(mode | dmanr,  DMA1_MODE_REG);
 197         else
 198                 dma_outb(mode | (dmanr&3),  DMA2_MODE_REG);
 199 }
 200
 201 /* Set only the page register bits of the transfer address.
 202  * This is used for successive transfers when we know the contents of
 203  * the lower 16 bits of the DMA current address register, but a 64k boundary
 204  * may have been crossed.
 205  */
 206 static __inline__ void set_dma_page(unsigned int dmanr, char pagenr)
 207 {
 208         switch(dmanr) {
 209                 case 0:
 210                         dma_outb(pagenr, DMA_PAGE_0);
 211                         break;
 212                 case 1:
 213                         dma_outb(pagenr, DMA_PAGE_1);
 214                         break;
 215                 case 2:
 216                         dma_outb(pagenr, DMA_PAGE_2);
 217                         break;
 218                 case 3:
 219                         dma_outb(pagenr, DMA_PAGE_3);
 220                         break;
 221                 case 5:
 222                         dma_outb(pagenr & 0xfe, DMA_PAGE_5);
 223                         break;
 224                 case 6:
 225                         dma_outb(pagenr & 0xfe, DMA_PAGE_6);
 226                         break;
 227                 case 7:
 228                         dma_outb(pagenr & 0xfe, DMA_PAGE_7);
 229                         break;
 230         }
 231 }
 232
 233
 234 /* Set transfer address & page bits for specific DMA channel.
 235  * Assumes dma flipflop is clear.
 236  */
 237 static __inline__ void set_dma_addr(unsigned int dmanr, unsigned int a)
 238 {
 239         set_dma_page(dmanr, a>>16);
 240         if (dmanr <= 3)  {
 241             dma_outb( a & 0xff, ((dmanr&3)<<1) + IO_DMA1_BASE );
 242             dma_outb( (a>>8) & 0xff, ((dmanr&3)<<1) + IO_DMA1_BASE );
 243         }  else  {
 244             dma_outb( (a>>1) & 0xff, ((dmanr&3)<<2) + IO_DMA2_BASE );
 245             dma_outb( (a>>9) & 0xff, ((dmanr&3)<<2) + IO_DMA2_BASE );
 246         }
 247 }
 248
 249
 250 /* Set transfer size (max 64k for DMA1..3, 128k for DMA5..7) for
 251  * a specific DMA channel.
 252  * You must ensure the parameters are valid.
 253  * NOTE: from a manual: "the number of transfers is one more
 254  * than the initial word count"! This is taken into account.
 255  * Assumes dma flip-flop is clear.
 256  * NOTE 2: "count" represents _bytes_ and must be even for channels 5-7.
 257  */
 258 static __inline__ void set_dma_count(unsigned int dmanr, unsigned int count)
 259 {
 260         count--;
 261         if (dmanr <= 3)  {
 262             dma_outb( count & 0xff, ((dmanr&3)<<1) + 1 + IO_DMA1_BASE );
 263             dma_outb( (count>>8) & 0xff, ((dmanr&3)<<1) + 1 + IO_DMA1_BASE );
 264         } else {
 265             dma_outb( (count>>1) & 0xff, ((dmanr&3)<<2) + 2 + IO_DMA2_BASE );
 266             dma_outb( (count>>9) & 0xff, ((dmanr&3)<<2) + 2 + IO_DMA2_BASE );
 267         }
 268 }
 269
 270
 271 /* Get DMA residue count. After a DMA transfer, this
 272  * should return zero. Reading this while a DMA transfer is
 273  * still in progress will return unpredictable results.
 274  * If called before the channel has been used, it may return 1.
 275  * Otherwise, it returns the number of _bytes_ left to transfer.
 276  *
 277  * Assumes DMA flip-flop is clear.
 278  */
 279 static __inline__ int get_dma_residue(unsigned int dmanr)
 280 {
 281         unsigned int io_port = (dmanr<=3)? ((dmanr&3)<<1) + 1 + IO_DMA1_BASE
 282                                          : ((dmanr&3)<<2) + 2 + IO_DMA2_BASE;
 283
 284         /* using short to get 16-bit wrap around */
 285         unsigned short count;
 286
 287         count = 1 + dma_inb(io_port);
 288         count += dma_inb(io_port) << 8;
 289
 290         return (dmanr<=3)? count : (count<<1);
 291 }
 292
 293
 294 /* These are in kernel/dma.c: */
 295 extern int request_dma(unsigned int dmanr, const char * device_id);     /* reserve a DMA channel */
 296 extern void free_dma(unsigned int dmanr);       /* release it again */
 297
 298 #ifdef CONFIG_PCI
 299 extern int isa_dma_bridge_buggy;
 300 #else
 301 #define isa_dma_bridge_buggy    (0)
 302 #endif
 303
 304 #endif /* __ASM_MIPS_DMA_H */