arch/parisc/include/asm/dma.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /* 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
  14 #define dma_outb        outb
  15 #define dma_inb         inb
  16
  17 /*
  18 ** DMA_CHUNK_SIZE is used by the SCSI mid-layer to break up
  19 ** (or rather not merge) DMAs into manageable chunks.
  20 ** On parisc, this is more of the software/tuning constraint
  21 ** rather than the HW. I/O MMU allocation algorithms can be
  22 ** faster with smaller sizes (to some degree).
  23 */
  24 #define DMA_CHUNK_SIZE  (BITS_PER_LONG*PAGE_SIZE)
  25
  26 /* The maximum address that we can perform a DMA transfer to on this platform
  27 ** New dynamic DMA interfaces should obsolete this....
  28 */
  29 #define MAX_DMA_ADDRESS (~0UL)
  30
  31 /*
  32 ** We don't have DMA channels... well V-class does but the
  33 ** Dynamic DMA Mapping interface will support them... right? :^)
  34 ** Note: this is not relevant right now for PA-RISC, but we cannot
  35 ** leave this as undefined because some things (e.g. sound)
  36 ** won't compile :-(
  37 */
  38 #define MAX_DMA_CHANNELS 8
  39 #define DMA_MODE_READ   0x44    /* I/O to memory, no autoinit, increment, single mode */
  40 #define DMA_MODE_WRITE  0x48    /* memory to I/O, no autoinit, increment, single mode */
  41 #define DMA_MODE_CASCADE 0xC0   /* pass thru DREQ->HRQ, DACK<-HLDA only */
  42
  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 static __inline__ unsigned long claim_dma_lock(void)
  75 {
  76         return 0;
  77 }
  78
  79 static __inline__ void release_dma_lock(unsigned long flags)
  80 {
  81 }
  82
  83
  84 /* Get DMA residue count. After a DMA transfer, this
  85  * should return zero. Reading this while a DMA transfer is
  86  * still in progress will return unpredictable results.
  87  * If called before the channel has been used, it may return 1.
  88  * Otherwise, it returns the number of _bytes_ left to transfer.
  89  *
  90  * Assumes DMA flip-flop is clear.
  91  */
  92 static __inline__ int get_dma_residue(unsigned int dmanr)
  93 {
  94         unsigned int io_port = (dmanr<=3)? ((dmanr&3)<<1) + 1 + IO_DMA1_BASE
  95                                          : ((dmanr&3)<<2) + 2 + IO_DMA2_BASE;
  96
  97         /* using short to get 16-bit wrap around */
  98         unsigned short count;
  99
 100         count = 1 + dma_inb(io_port);
 101         count += dma_inb(io_port) << 8;
 102
 103         return (dmanr<=3)? count : (count<<1);
 104 }
 105
 106 /* enable/disable a specific DMA channel */
 107 static __inline__ void enable_dma(unsigned int dmanr)
 108 {
 109 #ifdef CONFIG_SUPERIO
 110         if (dmanr<=3)
 111                 dma_outb(dmanr,  DMA1_MASK_REG);
 112         else
 113                 dma_outb(dmanr & 3,  DMA2_MASK_REG);
 114 #endif
 115 }
 116
 117 static __inline__ void disable_dma(unsigned int dmanr)
 118 {
 119 #ifdef CONFIG_SUPERIO
 120         if (dmanr<=3)
 121                 dma_outb(dmanr | 4,  DMA1_MASK_REG);
 122         else
 123                 dma_outb((dmanr & 3) | 4,  DMA2_MASK_REG);
 124 #endif
 125 }
 126
 127 /* reserve a DMA channel */
 128 #define request_dma(dmanr, device_id)   (0)
 129
 130 /* Clear the 'DMA Pointer Flip Flop'.
 131  * Write 0 for LSB/MSB, 1 for MSB/LSB access.
 132  * Use this once to initialize the FF to a known state.
 133  * After that, keep track of it. :-)
 134  * --- In order to do that, the DMA routines below should ---
 135  * --- only be used while holding the DMA lock ! ---
 136  */
 137 static __inline__ void clear_dma_ff(unsigned int dmanr)
 138 {
 139 }
 140
 141 /* set mode (above) for a specific DMA channel */
 142 static __inline__ void set_dma_mode(unsigned int dmanr, char mode)
 143 {
 144 }
 145
 146 /* Set only the page register bits of the transfer address.
 147  * This is used for successive transfers when we know the contents of
 148  * the lower 16 bits of the DMA current address register, but a 64k boundary
 149  * may have been crossed.
 150  */
 151 static __inline__ void set_dma_page(unsigned int dmanr, char pagenr)
 152 {
 153 }
 154
 155
 156 /* Set transfer address & page bits for specific DMA channel.
 157  * Assumes dma flipflop is clear.
 158  */
 159 static __inline__ void set_dma_addr(unsigned int dmanr, unsigned int a)
 160 {
 161 }
 162
 163
 164 /* Set transfer size (max 64k for DMA1..3, 128k for DMA5..7) for
 165  * a specific DMA channel.
 166  * You must ensure the parameters are valid.
 167  * NOTE: from a manual: "the number of transfers is one more
 168  * than the initial word count"! This is taken into account.
 169  * Assumes dma flip-flop is clear.
 170  * NOTE 2: "count" represents _bytes_ and must be even for channels 5-7.
 171  */
 172 static __inline__ void set_dma_count(unsigned int dmanr, unsigned int count)
 173 {
 174 }
 175
 176
 177 #define free_dma(dmanr)
 178
 179 #ifdef CONFIG_PCI
 180 extern int isa_dma_bridge_buggy;
 181 #else
 182 #define isa_dma_bridge_buggy    (0)
 183 #endif
 184
 185 #endif /* _ASM_DMA_H */