include/asm-i386/mca_dma.h

   1 #ifndef MCA_DMA_H
   2 #define MCA_DMA_H
   3
   4 #include <asm/io.h>
   5 #include <linux/ioport.h>
   6
   7 /*
   8  * Microchannel specific DMA stuff.  DMA on an MCA machine is fairly similar to
   9  *   standard PC dma, but it certainly has its quirks.  DMA register addresses
  10  *   are in a different place and there are some added functions.  Most of this
  11  *   should be pretty obvious on inspection.  Note that the user must divide
  12  *   count by 2 when using 16-bit dma; that is not handled by these functions.
  13  *
  14  * Ramen Noodles are yummy.
  15  *
  16  *  1998 Tymm Twillman <tymm@computer.org>
  17  */
  18
  19 /*
  20  * Registers that are used by the DMA controller; FN is the function register
  21  *   (tell the controller what to do) and EXE is the execution register (how
  22  *   to do it)
  23  */
  24
  25 #define MCA_DMA_REG_FN  0x18
  26 #define MCA_DMA_REG_EXE 0x1A
  27
  28 /*
  29  * Functions that the DMA controller can do
  30  */
  31
  32 #define MCA_DMA_FN_SET_IO       0x00
  33 #define MCA_DMA_FN_SET_ADDR     0x20
  34 #define MCA_DMA_FN_GET_ADDR     0x30
  35 #define MCA_DMA_FN_SET_COUNT    0x40
  36 #define MCA_DMA_FN_GET_COUNT    0x50
  37 #define MCA_DMA_FN_GET_STATUS   0x60
  38 #define MCA_DMA_FN_SET_MODE     0x70
  39 #define MCA_DMA_FN_SET_ARBUS    0x80
  40 #define MCA_DMA_FN_MASK         0x90
  41 #define MCA_DMA_FN_RESET_MASK   0xA0
  42 #define MCA_DMA_FN_MASTER_CLEAR 0xD0
  43
  44 /*
  45  * Modes (used by setting MCA_DMA_FN_MODE in the function register)
  46  *
  47  * Note that the MODE_READ is read from memory (write to device), and
  48  *   MODE_WRITE is vice-versa.
  49  */
  50
  51 #define MCA_DMA_MODE_XFER  0x04  /* read by default */
  52 #define MCA_DMA_MODE_READ  0x04  /* same as XFER */
  53 #define MCA_DMA_MODE_WRITE 0x08  /* OR with MODE_XFER to use */
  54 #define MCA_DMA_MODE_IO    0x01  /* DMA from IO register */
  55 #define MCA_DMA_MODE_16    0x40  /* 16 bit xfers */
  56
  57
  58
  59 static __inline__ void mca_enable_dma(unsigned int dmanr)
  60 {
  61         outb(MCA_DMA_FN_RESET_MASK | dmanr, MCA_DMA_REG_FN);
  62 }
  63
  64 static __inline__ void mca_disable_dma(unsigned int dmanr)
  65 {
  66         outb(MCA_DMA_FN_MASK | dmanr, MCA_DMA_REG_FN);
  67 }
  68
  69 static __inline__ void mca_set_dma_addr(unsigned int dmanr, unsigned int a)
  70 {
  71         outb(MCA_DMA_FN_SET_ADDR | dmanr, MCA_DMA_REG_FN);
  72         outb(a & 0xff, MCA_DMA_REG_EXE);
  73         outb((a >> 8) & 0xff, MCA_DMA_REG_EXE);
  74         outb((a >> 16) & 0xff, MCA_DMA_REG_EXE);
  75 }
  76
  77 static __inline__ unsigned int mca_get_dma_addr(unsigned int dmanr)
  78 {
  79         unsigned int addr;
  80
  81         outb(MCA_DMA_FN_GET_ADDR | dmanr, MCA_DMA_REG_FN);
  82         addr = inb(MCA_DMA_REG_EXE);
  83         addr |= inb(MCA_DMA_REG_EXE) << 8;
  84         addr |= inb(MCA_DMA_REG_EXE) << 16;
  85
  86         return addr;
  87 }
  88
  89 static __inline__ void mca_set_dma_count(unsigned int dmanr, unsigned int count)
  90 {
  91         count--;  /* transfers one more than count -- correct for this */
  92
  93         outb(MCA_DMA_FN_SET_COUNT | dmanr, MCA_DMA_REG_FN);
  94         outb(count & 0xff, MCA_DMA_REG_EXE);
  95         outb((count >> 8) & 0xff, MCA_DMA_REG_EXE);
  96 }
  97
  98 static __inline__ unsigned int mca_get_dma_residue(unsigned int dmanr)
  99 {
 100         unsigned short count;
 101
 102         outb(MCA_DMA_FN_GET_COUNT | dmanr, MCA_DMA_REG_FN);
 103         count = 1 + inb(MCA_DMA_REG_EXE);
 104         count += inb(MCA_DMA_REG_EXE) << 8;
 105
 106         return count;
 107 }
 108
 109 static __inline__ void mca_set_dma_io(unsigned int dmanr, unsigned int io_addr)
 110 {
 111         /*
 112          * DMA from a port address -- set the io address
 113          */
 114
 115         outb(MCA_DMA_FN_SET_IO | dmanr, MCA_DMA_REG_FN);
 116         outb(io_addr & 0xff, MCA_DMA_REG_EXE);
 117         outb((io_addr >>  8) & 0xff, MCA_DMA_REG_EXE);
 118 }
 119
 120 static __inline__ void mca_set_dma_mode(unsigned int dmanr, unsigned int mode)
 121 {
 122         outb(MCA_DMA_FN_SET_MODE | dmanr, MCA_DMA_REG_FN);
 123         outb(mode, MCA_DMA_REG_EXE);
 124 }
 125
 126 #endif MCA_DMA_H