diff options
Diffstat (limited to 'arch/x86/include/asm/mca_dma.h')
| -rw-r--r-- | arch/x86/include/asm/mca_dma.h | 201 |
1 files changed, 201 insertions, 0 deletions
diff --git a/arch/x86/include/asm/mca_dma.h b/arch/x86/include/asm/mca_dma.h new file mode 100644 index 0000000..49f22be --- /dev/null +++ b/arch/x86/include/asm/mca_dma.h @@ -0,0 +1,201 @@ +#ifndef ASM_X86__MCA_DMA_H +#define ASM_X86__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 /* ASM_X86__MCA_DMA_H */ |
