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 <linux/config.h>
  13 #include <asm/io.h>             /* need byte IO */
  14 #include <asm/system.h>
  15
  16 #define dma_outb        outb
  17 #define dma_inb         inb
  18
  19 /*
  20 ** DMA_CHUNK_SIZE is used by the SCSI mid-layer to break up
  21 ** (or rather not merge) DMA's into managable chunks.
  22 ** On parisc, this is more of the software/tuning constraint
  23 ** rather than the HW. I/O MMU allocation alogorithms can be
  24 ** faster with smaller size is (to some degree).
  25 */
  26 #define DMA_CHUNK_SIZE  (BITS_PER_LONG*PAGE_SIZE)
  27
  28 /* The maximum address that we can perform a DMA transfer to on this platform
  29 ** New dynamic DMA interfaces should obsolete this....
  30 */
  31 #define MAX_DMA_ADDRESS (~0UL)
  32
  33 /*
  34 ** We don't have DMA channels... well V-class does but the
  35 ** Dynamic DMA Mapping interface will support them... right? :^)
  36 ** Note: this is not relevant right now for PA-RISC, but we cannot
  37 ** leave this as undefined because some things (e.g. sound)
  38 ** won't compile :-(
  39 */
  40 #define MAX_DMA_CHANNELS 8
  41 #define DMA_MODE_READ    1
  42 #define DMA_MODE_WRITE   2
  43 #define DMA_AUTOINIT     0x10
  44
  45 /* 8237 DMA controllers */
  46 #define IO_DMA1_BASE    0x00    /* 8 bit slave DMA, channels 0..3 */
  47 #define IO_DMA2_BASE    0xC0    /* 16 bit master DMA, ch 4(=slave input)..7 */
  48
  49 /* DMA controller registers */
  50 #define DMA1_CMD_REG            0x08    /* command register (w) */
  51 #define DMA1_STAT_REG           0x08    /* status register (r) */
  52 #define DMA1_REQ_REG            0x09    /* request register (w) */
  53 #define DMA1_MASK_REG           0x0A    /* single-channel mask (w) */
  54 #define DMA1_MODE_REG           0x0B    /* mode register (w) */
  55 #define DMA1_CLEAR_FF_REG       0x0C    /* clear pointer flip-flop (w) */
  56 #define DMA1_TEMP_REG           0x0D    /* Temporary Register (r) */
  57 #define DMA1_RESET_REG          0x0D    /* Master Clear (w) */
  58 #define DMA1_CLR_MASK_REG       0x0E    /* Clear Mask */
  59 #define DMA1_MASK_ALL_REG       0x0F    /* all-channels mask (w) */
  60 #define DMA1_EXT_MODE_REG       (0x400 | DMA1_MODE_REG)
  61
  62 #define DMA2_CMD_REG            0xD0    /* command register (w) */
  63 #define DMA2_STAT_REG           0xD0    /* status register (r) */
  64 #define DMA2_REQ_REG            0xD2    /* request register (w) */
  65 #define DMA2_MASK_REG           0xD4    /* single-channel mask (w) */
  66 #define DMA2_MODE_REG           0xD6    /* mode register (w) */
  67 #define DMA2_CLEAR_FF_REG       0xD8    /* clear pointer flip-flop (w) */
  68 #define DMA2_TEMP_REG           0xDA    /* Temporary Register (r) */
  69 #define DMA2_RESET_REG          0xDA    /* Master Clear (w) */
  70 #define DMA2_CLR_MASK_REG       0xDC    /* Clear Mask */
  71 #define DMA2_MASK_ALL_REG       0xDE    /* all-channels mask (w) */
  72 #define DMA2_EXT_MODE_REG       (0x400 | DMA2_MODE_REG)
  73
  74 extern spinlock_t dma_spin_lock;
  75
  76 static __inline__ unsigned long claim_dma_lock(void)
  77 {
  78         unsigned long flags;
  79         spin_lock_irqsave(&dma_spin_lock, flags);
  80         return flags;
  81 }
  82
  83 static __inline__ void release_dma_lock(unsigned long flags)
  84 {
  85         spin_unlock_irqrestore(&dma_spin_lock, flags);
  86 }
  87
  88
  89 /* Get DMA residue count. After a DMA transfer, this
  90  * should return zero. Reading this while a DMA transfer is
  91  * still in progress will return unpredictable results.
  92  * If called before the channel has been used, it may return 1.
  93  * Otherwise, it returns the number of _bytes_ left to transfer.
  94  *
  95  * Assumes DMA flip-flop is clear.
  96  */
  97 static __inline__ int get_dma_residue(unsigned int dmanr)
  98 {
  99         unsigned int io_port = (dmanr<=3)? ((dmanr&3)<<1) + 1 + IO_DMA1_BASE
 100                                          : ((dmanr&3)<<2) + 2 + IO_DMA2_BASE;
 101
 102         /* using short to get 16-bit wrap around */
 103         unsigned short count;
 104
 105         count = 1 + dma_inb(io_port);
 106         count += dma_inb(io_port) << 8;
 107
 108         return (dmanr<=3)? count : (count<<1);
 109 }
 110
 111 /* enable/disable a specific DMA channel */
 112 static __inline__ void enable_dma(unsigned int dmanr)
 113 {
 114 #ifdef CONFIG_SUPERIO
 115         if (dmanr<=3)
 116                 dma_outb(dmanr,  DMA1_MASK_REG);
 117         else
 118                 dma_outb(dmanr & 3,  DMA2_MASK_REG);
 119 #endif
 120 }
 121
 122 static __inline__ void disable_dma(unsigned int dmanr)
 123 {
 124 #ifdef CONFIG_SUPERIO
 125         if (dmanr<=3)
 126                 dma_outb(dmanr | 4,  DMA1_MASK_REG);
 127         else
 128                 dma_outb((dmanr & 3) | 4,  DMA2_MASK_REG);
 129 #endif
 130 }
 131
 132 /* reserve a DMA channel */
 133 #define request_dma(dmanr, device_id)   (0)
 134
 135 /* Clear the 'DMA Pointer Flip Flop'.
 136  * Write 0 for LSB/MSB, 1 for MSB/LSB access.
 137  * Use this once to initialize the FF to a known state.
 138  * After that, keep track of it. :-)
 139  * --- In order to do that, the DMA routines below should ---
 140  * --- only be used while holding the DMA lock ! ---
 141  */
 142 static __inline__ void clear_dma_ff(unsigned int dmanr)
 143 {
 144 }
 145
 146 /* set mode (above) for a specific DMA channel */
 147 static __inline__ void set_dma_mode(unsigned int dmanr, char mode)
 148 {
 149 }
 150
 151 /* Set only the page register bits of the transfer address.
 152  * This is used for successive transfers when we know the contents of
 153  * the lower 16 bits of the DMA current address register, but a 64k boundary
 154  * may have been crossed.
 155  */
 156 static __inline__ void set_dma_page(unsigned int dmanr, char pagenr)
 157 {
 158 }
 159
 160
 161 /* Set transfer address & page bits for specific DMA channel.
 162  * Assumes dma flipflop is clear.
 163  */
 164 static __inline__ void set_dma_addr(unsigned int dmanr, unsigned int a)
 165 {
 166 }
 167
 168
 169 /* Set transfer size (max 64k for DMA1..3, 128k for DMA5..7) for
 170  * a specific DMA channel.
 171  * You must ensure the parameters are valid.
 172  * NOTE: from a manual: "the number of transfers is one more
 173  * than the initial word count"! This is taken into account.
 174  * Assumes dma flip-flop is clear.
 175  * NOTE 2: "count" represents _bytes_ and must be even for channels 5-7.
 176  */
 177 static __inline__ void set_dma_count(unsigned int dmanr, unsigned int count)
 178 {
 179 }
 180
 181
 182 #define free_dma(dmanr)
 183
 184 #ifdef CONFIG_PCI
 185 extern int isa_dma_bridge_buggy;
 186 #else
 187 #define isa_dma_bridge_buggy    (0)
 188 #endif
 189
 190 #endif /* _ASM_DMA_H */