include/asm-x86/dma.h

   1 /*
   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
   8 #ifndef _ASM_X86_DMA_H
   9 #define _ASM_X86_DMA_H
  10
  11 #include <linux/spinlock.h>     /* And spinlocks */
  12 #include <asm/io.h>             /* need byte IO */
  13 #include <linux/delay.h>
  14
  15
  16 #ifdef HAVE_REALLY_SLOW_DMA_CONTROLLER
  17 #define dma_outb        outb_p
  18 #else
  19 #define dma_outb        outb
  20 #endif
  21
  22 #define dma_inb         inb
  23
  24 /*
  25  * NOTES about DMA transfers:
  26  *
  27  *  controller 1: channels 0-3, byte operations, ports 00-1F
  28  *  controller 2: channels 4-7, word operations, ports C0-DF
  29  *
  30  *  - ALL registers are 8 bits only, regardless of transfer size
  31  *  - channel 4 is not used - cascades 1 into 2.
  32  *  - channels 0-3 are byte - addresses/counts are for physical bytes
  33  *  - channels 5-7 are word - addresses/counts are for physical words
  34  *  - transfers must not cross physical 64K (0-3) or 128K (5-7) boundaries
  35  *  - transfer count loaded to registers is 1 less than actual count
  36  *  - controller 2 offsets are all even (2x offsets for controller 1)
  37  *  - page registers for 5-7 don't use data bit 0, represent 128K pages
  38  *  - page registers for 0-3 use bit 0, represent 64K pages
  39  *
  40  * DMA transfers are limited to the lower 16MB of _physical_ memory.
  41  * Note that addresses loaded into registers must be _physical_ addresses,
  42  * not logical addresses (which may differ if paging is active).
  43  *
  44  *  Address mapping for channels 0-3:
  45  *
  46  *   A23 ... A16 A15 ... A8  A7 ... A0    (Physical addresses)
  47  *    |  ...  |   |  ... |   |  ... |
  48  *    |  ...  |   |  ... |   |  ... |
  49  *    |  ...  |   |  ... |   |  ... |
  50  *   P7  ...  P0  A7 ... A0  A7 ... A0
  51  * |    Page    | Addr MSB | Addr LSB |   (DMA registers)
  52  *
  53  *  Address mapping for channels 5-7:
  54  *
  55  *   A23 ... A17 A16 A15 ... A9 A8 A7 ... A1 A0    (Physical addresses)
  56  *    |  ...  |   \   \   ... \  \  \  ... \  \
  57  *    |  ...  |    \   \   ... \  \  \  ... \  (not used)
  58  *    |  ...  |     \   \   ... \  \  \  ... \
  59  *   P7  ...  P1 (0) A7 A6  ... A0 A7 A6 ... A0
  60  * |      Page      |  Addr MSB   |  Addr LSB  |   (DMA registers)
  61  *
  62  * Again, channels 5-7 transfer _physical_ words (16 bits), so addresses
  63  * and counts _must_ be word-aligned (the lowest address bit is _ignored_ at
  64  * the hardware level, so odd-byte transfers aren't possible).
  65  *
  66  * Transfer count (_not # bytes_) is limited to 64K, represented as actual
  67  * count - 1 : 64K => 0xFFFF, 1 => 0x0000.  Thus, count is always 1 or more,
  68  * and up to 128K bytes may be transferred on channels 5-7 in one operation.
  69  *
  70  */
  71
  72 #define MAX_DMA_CHANNELS        8
  73
  74 #ifdef CONFIG_X86_32
  75
  76 /* The maximum address that we can perform a DMA transfer to on this platform */
  77 #define MAX_DMA_ADDRESS      (PAGE_OFFSET+0x1000000)
  78
  79 #else
  80
  81 /* 16MB ISA DMA zone */
  82 #define MAX_DMA_PFN   ((16*1024*1024) >> PAGE_SHIFT)
  83
  84 /* 4GB broken PCI/AGP hardware bus master zone */
  85 #define MAX_DMA32_PFN ((4UL*1024*1024*1024) >> PAGE_SHIFT)
  86
  87 /* Compat define for old dma zone */
  88 #define MAX_DMA_ADDRESS ((unsigned long)__va(MAX_DMA_PFN << PAGE_SHIFT))
  89
  90 #endif
  91
  92 /* 8237 DMA controllers */
  93 #define IO_DMA1_BASE    0x00    /* 8 bit slave DMA, channels 0..3 */
  94 #define IO_DMA2_BASE    0xC0    /* 16 bit master DMA, ch 4(=slave input)..7 */
  95
  96 /* DMA controller registers */
  97 #define DMA1_CMD_REG            0x08    /* command register (w) */
  98 #define DMA1_STAT_REG           0x08    /* status register (r) */
  99 #define DMA1_REQ_REG            0x09    /* request register (w) */
 100 #define DMA1_MASK_REG           0x0A    /* single-channel mask (w) */
 101 #define DMA1_MODE_REG           0x0B    /* mode register (w) */
 102 #define DMA1_CLEAR_FF_REG       0x0C    /* clear pointer flip-flop (w) */
 103 #define DMA1_TEMP_REG           0x0D    /* Temporary Register (r) */
 104 #define DMA1_RESET_REG          0x0D    /* Master Clear (w) */
 105 #define DMA1_CLR_MASK_REG       0x0E    /* Clear Mask */
 106 #define DMA1_MASK_ALL_REG       0x0F    /* all-channels mask (w) */
 107
 108 #define DMA2_CMD_REG            0xD0    /* command register (w) */
 109 #define DMA2_STAT_REG           0xD0    /* status register (r) */
 110 #define DMA2_REQ_REG            0xD2    /* request register (w) */
 111 #define DMA2_MASK_REG           0xD4    /* single-channel mask (w) */
 112 #define DMA2_MODE_REG           0xD6    /* mode register (w) */
 113 #define DMA2_CLEAR_FF_REG       0xD8    /* clear pointer flip-flop (w) */
 114 #define DMA2_TEMP_REG           0xDA    /* Temporary Register (r) */
 115 #define DMA2_RESET_REG          0xDA    /* Master Clear (w) */
 116 #define DMA2_CLR_MASK_REG       0xDC    /* Clear Mask */
 117 #define DMA2_MASK_ALL_REG       0xDE    /* all-channels mask (w) */
 118
 119 #define DMA_ADDR_0              0x00    /* DMA address registers */
 120 #define DMA_ADDR_1              0x02
 121 #define DMA_ADDR_2              0x04
 122 #define DMA_ADDR_3              0x06
 123 #define DMA_ADDR_4              0xC0
 124 #define DMA_ADDR_5              0xC4
 125 #define DMA_ADDR_6              0xC8
 126 #define DMA_ADDR_7              0xCC
 127
 128 #define DMA_CNT_0               0x01    /* DMA count registers */
 129 #define DMA_CNT_1               0x03
 130 #define DMA_CNT_2               0x05
 131 #define DMA_CNT_3               0x07
 132 #define DMA_CNT_4               0xC2
 133 #define DMA_CNT_5               0xC6
 134 #define DMA_CNT_6               0xCA
 135 #define DMA_CNT_7               0xCE
 136
 137 #define DMA_PAGE_0              0x87    /* DMA page registers */
 138 #define DMA_PAGE_1              0x83
 139 #define DMA_PAGE_2              0x81
 140 #define DMA_PAGE_3              0x82
 141 #define DMA_PAGE_5              0x8B
 142 #define DMA_PAGE_6              0x89
 143 #define DMA_PAGE_7              0x8A
 144
 145 /* I/O to memory, no autoinit, increment, single mode */
 146 #define DMA_MODE_READ           0x44
 147 /* memory to I/O, no autoinit, increment, single mode */
 148 #define DMA_MODE_WRITE          0x48
 149 /* pass thru DREQ->HRQ, DACK<-HLDA only */
 150 #define DMA_MODE_CASCADE        0xC0
 151
 152 #define DMA_AUTOINIT            0x10
 153
 154
 155 extern spinlock_t  dma_spin_lock;
 156
 157 static __inline__ unsigned long claim_dma_lock(void)
 158 {
 159         unsigned long flags;
 160         spin_lock_irqsave(&dma_spin_lock, flags);
 161         return flags;
 162 }
 163
 164 static __inline__ void release_dma_lock(unsigned long flags)
 165 {
 166         spin_unlock_irqrestore(&dma_spin_lock, flags);
 167 }
 168
 169 /* enable/disable a specific DMA channel */
 170 static __inline__ void enable_dma(unsigned int dmanr)
 171 {
 172         if (dmanr <= 3)
 173                 dma_outb(dmanr, DMA1_MASK_REG);
 174         else
 175                 dma_outb(dmanr & 3, DMA2_MASK_REG);
 176 }
 177
 178 static __inline__ void disable_dma(unsigned int dmanr)
 179 {
 180         if (dmanr <= 3)
 181                 dma_outb(dmanr | 4, DMA1_MASK_REG);
 182         else
 183                 dma_outb((dmanr & 3) | 4, DMA2_MASK_REG);
 184 }
 185
 186 /* Clear the 'DMA Pointer Flip Flop'.
 187  * Write 0 for LSB/MSB, 1 for MSB/LSB access.
 188  * Use this once to initialize the FF to a known state.
 189  * After that, keep track of it. :-)
 190  * --- In order to do that, the DMA routines below should ---
 191  * --- only be used while holding the DMA lock ! ---
 192  */
 193 static __inline__ void clear_dma_ff(unsigned int dmanr)
 194 {
 195         if (dmanr <= 3)
 196                 dma_outb(0, DMA1_CLEAR_FF_REG);
 197         else
 198                 dma_outb(0, DMA2_CLEAR_FF_REG);
 199 }
 200
 201 /* set mode (above) for a specific DMA channel */
 202 static __inline__ void set_dma_mode(unsigned int dmanr, char mode)
 203 {
 204         if (dmanr <= 3)
 205                 dma_outb(mode | dmanr, DMA1_MODE_REG);
 206         else
 207                 dma_outb(mode | (dmanr & 3), DMA2_MODE_REG);
 208 }
 209
 210 /* Set only the page register bits of the transfer address.
 211  * This is used for successive transfers when we know the contents of
 212  * the lower 16 bits of the DMA current address register, but a 64k boundary
 213  * may have been crossed.
 214  */
 215 static __inline__ void set_dma_page(unsigned int dmanr, char pagenr)
 216 {
 217         switch (dmanr) {
 218         case 0:
 219                 dma_outb(pagenr, DMA_PAGE_0);
 220                 break;
 221         case 1:
 222                 dma_outb(pagenr, DMA_PAGE_1);
 223                 break;
 224         case 2:
 225                 dma_outb(pagenr, DMA_PAGE_2);
 226                 break;
 227         case 3:
 228                 dma_outb(pagenr, DMA_PAGE_3);
 229                 break;
 230         case 5:
 231                 dma_outb(pagenr & 0xfe, DMA_PAGE_5);
 232                 break;
 233         case 6:
 234                 dma_outb(pagenr & 0xfe, DMA_PAGE_6);
 235                 break;
 236         case 7:
 237                 dma_outb(pagenr & 0xfe, DMA_PAGE_7);
 238                 break;
 239         }
 240 }
 241
 242
 243 /* Set transfer address & page bits for specific DMA channel.
 244  * Assumes dma flipflop is clear.
 245  */
 246 static __inline__ void set_dma_addr(unsigned int dmanr, unsigned int a)
 247 {
 248         set_dma_page(dmanr, a>>16);
 249         if (dmanr <= 3)  {
 250                 dma_outb(a & 0xff, ((dmanr & 3) << 1) + IO_DMA1_BASE);
 251                 dma_outb((a >> 8) & 0xff, ((dmanr & 3) << 1) + IO_DMA1_BASE);
 252         }  else  {
 253             dma_outb((a >> 1) & 0xff, ((dmanr & 3) << 2) + IO_DMA2_BASE);
 254             dma_outb((a >> 9) & 0xff, ((dmanr & 3) << 2) + IO_DMA2_BASE);
 255         }
 256 }
 257
 258
 259 /* Set transfer size (max 64k for DMA0..3, 128k for DMA5..7) for
 260  * a specific DMA channel.
 261  * You must ensure the parameters are valid.
 262  * NOTE: from a manual: "the number of transfers is one more
 263  * than the initial word count"! This is taken into account.
 264  * Assumes dma flip-flop is clear.
 265  * NOTE 2: "count" represents _bytes_ and must be even for channels 5-7.
 266  */
 267 static __inline__ void set_dma_count(unsigned int dmanr, unsigned int count)
 268 {
 269         count--;
 270         if (dmanr <= 3)  {
 271             dma_outb(count & 0xff, ((dmanr & 3) << 1) + 1 + IO_DMA1_BASE);
 272             dma_outb((count >> 8) & 0xff,
 273                      ((dmanr & 3) << 1) + 1 + IO_DMA1_BASE);
 274         } else {
 275             dma_outb((count >> 1) & 0xff,
 276                      ((dmanr & 3) << 2) + 2 + IO_DMA2_BASE);
 277             dma_outb((count >> 9) & 0xff,
 278                      ((dmanr & 3) << 2) + 2 + IO_DMA2_BASE);
 279         }
 280 }
 281
 282
 283 /* Get DMA residue count. After a DMA transfer, this
 284  * should return zero. Reading this while a DMA transfer is
 285  * still in progress will return unpredictable results.
 286  * If called before the channel has been used, it may return 1.
 287  * Otherwise, it returns the number of _bytes_ left to transfer.
 288  *
 289  * Assumes DMA flip-flop is clear.
 290  */
 291 static __inline__ int get_dma_residue(unsigned int dmanr)
 292 {
 293         unsigned int io_port;
 294         /* using short to get 16-bit wrap around */
 295         unsigned short count;
 296
 297         io_port = (dmanr <= 3) ? ((dmanr & 3) << 1) + 1 + IO_DMA1_BASE
 298                 : ((dmanr & 3) << 2) + 2 + IO_DMA2_BASE;
 299
 300         count = 1 + dma_inb(io_port);
 301         count += dma_inb(io_port) << 8;
 302
 303         return (dmanr <= 3) ? count : (count << 1);
 304 }
 305
 306
 307 /* These are in kernel/dma.c: */
 308 extern int request_dma(unsigned int dmanr, const char *device_id);
 309 extern void free_dma(unsigned int dmanr);
 310
 311 /* From PCI */
 312
 313 #ifdef CONFIG_PCI
 314 extern int isa_dma_bridge_buggy;
 315 #else
 316 #define isa_dma_bridge_buggy    (0)
 317 #endif
 318
 319 #endif /* _ASM_X86_DMA_H */