#ifndef MCA_DMA_H
#define MCA_DMA_H
#include <asm/io.h>
#include <linux/ioport.h>
/*
* Microchannel specific DMA stuff. DMA on an MCA machine is fairly similar to
* standard PC dma, but it certainly has its quirks. DMA register addresses
* are in a different place and there are some added functions. Most of this
* should be pretty obvious on inspection. Note that the user must divide
* count by 2 when using 16-bit dma; that is not handled by these functions.
*
* Ramen Noodles are yummy.
*
* 1998 Tymm Twillman <tymm@computer.org>
*/
/*
* Registers that are used by the DMA controller; FN is the function register
* (tell the controller what to do) and EXE is the execution register (how
* to do it)
*/
#define MCA_DMA_REG_FN 0x18
#define MCA_DMA_REG_EXE 0x1A
/*
* Functions that the DMA controller can do
*/
#define MCA_DMA_FN_SET_IO 0x00
#define MCA_DMA_FN_SET_ADDR 0x20
#define MCA_DMA_FN_GET_ADDR 0x30
#define MCA_DMA_FN_SET_COUNT 0x40
#define MCA_DMA_FN_GET_COUNT 0x50
#define MCA_DMA_FN_GET_STATUS 0x60
#define MCA_DMA_FN_SET_MODE 0x70
#define MCA_DMA_FN_SET_ARBUS 0x80
#define MCA_DMA_FN_MASK 0x90
#define MCA_DMA_FN_RESET_MASK 0xA0
#define MCA_DMA_FN_MASTER_CLEAR 0xD0
/*
* Modes (used by setting MCA_DMA_FN_MODE in the function register)
*
* Note that the MODE_READ is read from memory (write to device), and
* MODE_WRITE is vice-versa.
*/
#define MCA_DMA_MODE_XFER 0x04 /* read by default */
#define MCA_DMA_MODE_READ 0x04 /* same as XFER */
#define MCA_DMA_MODE_WRITE 0x08 /* OR with MODE_XFER to use */
#define MCA_DMA_MODE_IO 0x01 /* DMA from IO register */
#define MCA_DMA_MODE_16 0x40 /* 16 bit xfers */
/**
* mca_enable_dma - channel to enable DMA on
* @dmanr: DMA channel
*
* Enable the MCA bus DMA on a channel. This can be called from
* IRQ context.
*/
static __inline__ void mca_enable_dma(unsigned int dmanr)
{
outb(MCA_DMA_FN_RESET_MASK | dmanr, MCA_DMA_REG_FN);
}
/**
* mca_disble_dma - channel to disable DMA on
* @dmanr: DMA channel
*
* Enable the MCA bus DMA on a channel. This can be called from
* IRQ context.
*/
static __inline__ void mca_disable_dma(unsigned int dmanr)
{
outb(MCA_DMA_FN_MASK | dmanr, MCA_DMA_REG_FN);
}
/**
* mca_set_dma_addr - load a 24bit DMA address
* @dmanr: DMA channel
* @a: 24bit bus address
*
* Load the address register in the DMA controller. This has a 24bit
* limitation (16Mb).
*/
static __inline__ void mca_set_dma_addr(unsigned int dmanr, unsigned int a)
{
outb(MCA_DMA_FN_SET_ADDR | dmanr, MCA_DMA_REG_FN);
outb(a & 0xff, MCA_DMA_REG_EXE);
outb((a >> 8) & 0xff, MCA_DMA_REG_EXE);
outb((a >> 16) & 0xff, MCA_DMA_REG_EXE);
}
/**
* mca_get_dma_addr - load a 24bit DMA address
* @dmanr: DMA channel
*
* Read the address register in the DMA controller. This has a 24bit
* limitation (16Mb). The return is a bus address.
*/
static __inline__ unsigned int mca_get_dma_addr(unsigned int dmanr)
{
unsigned int addr;
outb(MCA_DMA_FN_GET_ADDR | dmanr, MCA_DMA_REG_FN);
addr = inb(MCA_DMA_REG_EXE);
addr |= inb(MCA_DMA_REG_EXE) << 8;
addr |= inb(MCA_DMA_REG_EXE) << 16;
return addr;
}
/**
* mca_set_dma_count - load a 16bit transfer count
* @dmanr: DMA channel
* @count: count
*
* Set the DMA count for this channel. This can be up to 64Kbytes.
* Setting a count of zero will not do what you expect.
*/
static __inline__ void mca_set_dma_count(unsigned int dmanr, unsigned int count)
{
count--; /* transfers one more than count -- correct for this */
outb(MCA_DMA_FN_SET_COUNT | dmanr, MCA_DMA_REG_FN);
outb(count & 0xff, MCA_DMA_REG_EXE);
outb((count >> 8) & 0xff, MCA_DMA_REG_EXE);
}
/**
* mca_get_dma_residue - get the remaining bytes to transfer
* @dmanr: DMA channel
*
* This function returns the number of bytes left to transfer
* on this DMA channel.
*/
static __inline__ unsigned int mca_get_dma_residue(unsigned int dmanr)
{
unsigned short count;
outb(MCA_DMA_FN_GET_COUNT | dmanr, MCA_DMA_REG_FN);
count = 1 + inb(MCA_DMA_REG_EXE);
count += inb(MCA_DMA_REG_EXE) << 8;
return count;
}
/**
* mca_set_dma_io - set the port for an I/O transfer
* @dmanr: DMA channel
* @io_addr: an I/O port number
*
* Unlike the ISA bus DMA controllers the DMA on MCA bus can transfer
* with an I/O port target.
*/
static __inline__ void mca_set_dma_io(unsigned int dmanr, unsigned int io_addr)
{
/*
* DMA from a port address -- set the io address
*/
outb(MCA_DMA_FN_SET_IO | dmanr, MCA_DMA_REG_FN);
outb(io_addr & 0xff, MCA_DMA_REG_EXE);
outb((io_addr >> 8) & 0xff, MCA_DMA_REG_EXE);
}
/**
* mca_set_dma_mode - set the DMA mode
* @dmanr: DMA channel
* @mode: mode to set
*
* The DMA controller supports several modes. The mode values you can
* set are-
*
* %MCA_DMA_MODE_READ when reading from the DMA device.
*
* %MCA_DMA_MODE_WRITE to writing to the DMA device.
*
* %MCA_DMA_MODE_IO to do DMA to or from an I/O port.
*
* %MCA_DMA_MODE_16 to do 16bit transfers.
*/
static __inline__ void mca_set_dma_mode(unsigned int dmanr, unsigned int mode)
{
outb(MCA_DMA_FN_SET_MODE | dmanr, MCA_DMA_REG_FN);
outb(mode, MCA_DMA_REG_EXE);
}
#endif /* MCA_DMA_H */
