include/asm-parisc/dma.h

   1 /* $Id: dma.h,v 1.2 1999/04/27 00:46:18 deller 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  * (c) Copyright 2000, Grant Grundler
   7  */
   8
   9 #ifndef _ASM_DMA_H
  10 #define _ASM_DMA_H
  11
  12 #include <asm/io.h>             /* need byte IO */
  13 #include <asm/system.h>
  14
  15 #define dma_outb        outb
  16 #define dma_inb         inb
  17
  18 /*
  19 ** DMA_CHUNK_SIZE is used by the SCSI mid-layer to break up
  20 ** (or rather not merge) DMAs into manageable chunks.
  21 ** On parisc, this is more of the software/tuning constraint
  22 ** rather than the HW. I/O MMU allocation algorithms can be
  23 ** faster with smaller sizes (to some degree).
  24 */
  25 #define DMA_CHUNK_SIZE  (BITS_PER_LONG*PAGE_SIZE)
  26
  27 /* The maximum address that we can perform a DMA transfer to on this platform
  28 ** New dynamic DMA interfaces should obsolete this....
  29 */
  30 #define MAX_DMA_ADDRESS (~0UL)
  31
  32 /*
  33 ** We don't have DMA channels... well V-class does but the
  34 ** Dynamic DMA Mapping interface will support them... right? :^)
  35 ** Note: this is not relevant right now for PA-RISC, but we cannot
  36 ** leave this as undefined because some things (e.g. sound)
  37 ** won't compile :-(
  38 */
  39 #define MAX_DMA_CHANNELS 8
  40 #define DMA_MODE_READ   0x44    /* I/O to memory, no autoinit, increment, single mode */
  41 #define DMA_MODE_WRITE  0x48    /* memory to I/O, no autoinit, increment, single mode */
  42 #define DMA_MODE_CASCADE 0xC0   /* pass thru DREQ->HRQ, DACK<-HLDA only */
  43
  44 #define DMA_AUTOINIT    0x10
  45
  46 /* 8237 DMA controllers */
  47 #define IO_DMA1_BASE    0x00    /* 8 bit slave DMA, channels 0..3 */
  48 #define IO_DMA2_BASE    0xC0    /* 16 bit master DMA, ch 4(=slave input)..7 */
  49
  50 /* DMA controller registers */
  51 #define DMA1_CMD_REG            0x08    /* command register (w) */
  52 #define DMA1_STAT_REG           0x08    /* status register (r) */
  53 #define DMA1_REQ_REG            0x09    /* request register (w) */
  54 #define DMA1_MASK_REG           0x0A    /* single-channel mask (w) */
  55 #define DMA1_MODE_REG           0x0B    /* mode register (w) */
  56 #define DMA1_CLEAR_FF_REG       0x0C    /* clear pointer flip-flop (w) */
  57 #define DMA1_TEMP_REG           0x0D    /* Temporary Register (r) */
  58 #define DMA1_RESET_REG          0x0D    /* Master Clear (w) */
  59 #define DMA1_CLR_MASK_REG       0x0E    /* Clear Mask */
  60 #define DMA1_MASK_ALL_REG       0x0F    /* all-channels mask (w) */
  61 #define DMA1_EXT_MODE_REG       (0x400 | DMA1_MODE_REG)
  62
  63 #define DMA2_CMD_REG            0xD0    /* command register (w) */
  64 #define DMA2_STAT_REG           0xD0    /* status register (r) */
  65 #define DMA2_REQ_REG            0xD2    /* request register (w) */
  66 #define DMA2_MASK_REG           0xD4    /* single-channel mask (w) */
  67 #define DMA2_MODE_REG           0xD6    /* mode register (w) */
  68 #define DMA2_CLEAR_FF_REG       0xD8    /* clear pointer flip-flop (w) */
  69 #define DMA2_TEMP_REG           0xDA    /* Temporary Register (r) */
  70 #define DMA2_RESET_REG          0xDA    /* Master Clear (w) */
  71 #define DMA2_CLR_MASK_REG       0xDC    /* Clear Mask */
  72 #define DMA2_MASK_ALL_REG       0xDE    /* all-channels mask (w) */
  73 #define DMA2_EXT_MODE_REG       (0x400 | DMA2_MODE_REG)
  74
  75 static __inline__ unsigned long claim_dma_lock(void)
  76 {
  77         return 0;
  78 }
  79
  80 static __inline__ void release_dma_lock(unsigned long flags)
  81 {
  82 }
  83
  84
  85 /* Get DMA residue count. After a DMA transfer, this
  86  * should return zero. Reading this while a DMA transfer is
  87  * still in progress will return unpredictable results.
  88  * If called before the channel has been used, it may return 1.
  89  * Otherwise, it returns the number of _bytes_ left to transfer.
  90  *
  91  * Assumes DMA flip-flop is clear.
  92  */
  93 static __inline__ int get_dma_residue(unsigned int dmanr)
  94 {
  95         unsigned int io_port = (dmanr<=3)? ((dmanr&3)<<1) + 1 + IO_DMA1_BASE
  96                                          : ((dmanr&3)<<2) + 2 + IO_DMA2_BASE;
  97
  98         /* using short to get 16-bit wrap around */
  99         unsigned short count;
 100
 101         count = 1 + dma_inb(io_port);
 102         count += dma_inb(io_port) << 8;
 103
 104         return (dmanr<=3)? count : (count<<1);
 105 }
 106
 107 /* enable/disable a specific DMA channel */
 108 static __inline__ void enable_dma(unsigned int dmanr)
 109 {
 110 #ifdef CONFIG_SUPERIO
 111         if (dmanr<=3)
 112                 dma_outb(dmanr,  DMA1_MASK_REG);
 113         else
 114                 dma_outb(dmanr & 3,  DMA2_MASK_REG);
 115 #endif
 116 }
 117
 118 static __inline__ void disable_dma(unsigned int dmanr)
 119 {
 120 #ifdef CONFIG_SUPERIO
 121         if (dmanr<=3)
 122                 dma_outb(dmanr | 4,  DMA1_MASK_REG);
 123         else
 124                 dma_outb((dmanr & 3) | 4,  DMA2_MASK_REG);
 125 #endif
 126 }
 127
 128 /* reserve a DMA channel */
 129 #define request_dma(dmanr, device_id)   (0)
 130
 131 /* Clear the 'DMA Pointer Flip Flop'.
 132  * Write 0 for LSB/MSB, 1 for MSB/LSB access.
 133  * Use this once to initialize the FF to a known state.
 134  * After that, keep track of it. :-)
 135  * --- In order to do that, the DMA routines below should ---
 136  * --- only be used while holding the DMA lock ! ---
 137  */
 138 static __inline__ void clear_dma_ff(unsigned int dmanr)
 139 {
 140 }
 141
 142 /* set mode (above) for a specific DMA channel */
 143 static __inline__ void set_dma_mode(unsigned int dmanr, char mode)
 144 {
 145 }
 146
 147 /* Set only the page register bits of the transfer address.
 148  * This is used for successive transfers when we know the contents of
 149  * the lower 16 bits of the DMA current address register, but a 64k boundary
 150  * may have been crossed.
 151  */
 152 static __inline__ void set_dma_page(unsigned int dmanr, char pagenr)
 153 {
 154 }
 155
 156
 157 /* Set transfer address & page bits for specific DMA channel.
 158  * Assumes dma flipflop is clear.
 159  */
 160 static __inline__ void set_dma_addr(unsigned int dmanr, unsigned int a)
 161 {
 162 }
 163
 164
 165 /* Set transfer size (max 64k for DMA1..3, 128k for DMA5..7) for
 166  * a specific DMA channel.
 167  * You must ensure the parameters are valid.
 168  * NOTE: from a manual: "the number of transfers is one more
 169  * than the initial word count"! This is taken into account.
 170  * Assumes dma flip-flop is clear.
 171  * NOTE 2: "count" represents _bytes_ and must be even for channels 5-7.
 172  */
 173 static __inline__ void set_dma_count(unsigned int dmanr, unsigned int count)
 174 {
 175 }
 176
 177
 178 #define free_dma(dmanr)
 179
 180 #ifdef CONFIG_PCI
 181 extern int isa_dma_bridge_buggy;
 182 #else
 183 #define isa_dma_bridge_buggy    (0)
 184 #endif
 185
 186 #endif /* _ASM_DMA_H */