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 extern unsigned long pcxl_dma_start; 18 19 /* 20 ** DMA_CHUNK_SIZE is used by the SCSI mid-layer to break up 21 ** (or rather not merge) DMAs into manageable chunks. 22 ** On parisc, this is more of the software/tuning constraint 23 ** rather than the HW. I/O MMU allocation algorithms can be 24 ** faster with smaller sizes (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 0x44 /* I/O to memory, no autoinit, increment, single mode */ 42 #define DMA_MODE_WRITE 0x48 /* memory to I/O, no autoinit, increment, single mode */ 43 #define DMA_MODE_CASCADE 0xC0 /* pass thru DREQ->HRQ, DACK<-HLDA only */ 44 45 #define DMA_AUTOINIT 0x10 46 47 /* 8237 DMA controllers */ 48 #define IO_DMA1_BASE 0x00 /* 8 bit slave DMA, channels 0..3 */ 49 #define IO_DMA2_BASE 0xC0 /* 16 bit master DMA, ch 4(=slave input)..7 */ 50 51 /* DMA controller registers */ 52 #define DMA1_CMD_REG 0x08 /* command register (w) */ 53 #define DMA1_STAT_REG 0x08 /* status register (r) */ 54 #define DMA1_REQ_REG 0x09 /* request register (w) */ 55 #define DMA1_MASK_REG 0x0A /* single-channel mask (w) */ 56 #define DMA1_MODE_REG 0x0B /* mode register (w) */ 57 #define DMA1_CLEAR_FF_REG 0x0C /* clear pointer flip-flop (w) */ 58 #define DMA1_TEMP_REG 0x0D /* Temporary Register (r) */ 59 #define DMA1_RESET_REG 0x0D /* Master Clear (w) */ 60 #define DMA1_CLR_MASK_REG 0x0E /* Clear Mask */ 61 #define DMA1_MASK_ALL_REG 0x0F /* all-channels mask (w) */ 62 #define DMA1_EXT_MODE_REG (0x400 | DMA1_MODE_REG) 63 64 #define DMA2_CMD_REG 0xD0 /* command register (w) */ 65 #define DMA2_STAT_REG 0xD0 /* status register (r) */ 66 #define DMA2_REQ_REG 0xD2 /* request register (w) */ 67 #define DMA2_MASK_REG 0xD4 /* single-channel mask (w) */ 68 #define DMA2_MODE_REG 0xD6 /* mode register (w) */ 69 #define DMA2_CLEAR_FF_REG 0xD8 /* clear pointer flip-flop (w) */ 70 #define DMA2_TEMP_REG 0xDA /* Temporary Register (r) */ 71 #define DMA2_RESET_REG 0xDA /* Master Clear (w) */ 72 #define DMA2_CLR_MASK_REG 0xDC /* Clear Mask */ 73 #define DMA2_MASK_ALL_REG 0xDE /* all-channels mask (w) */ 74 #define DMA2_EXT_MODE_REG (0x400 | DMA2_MODE_REG) 75 76 static __inline__ unsigned long claim_dma_lock(void) 77 { 78 return 0; 79 } 80 81 static __inline__ void release_dma_lock(unsigned long flags) 82 { 83 } 84 85 86 /* Get DMA residue count. After a DMA transfer, this 87 * should return zero. Reading this while a DMA transfer is 88 * still in progress will return unpredictable results. 89 * If called before the channel has been used, it may return 1. 90 * Otherwise, it returns the number of _bytes_ left to transfer. 91 * 92 * Assumes DMA flip-flop is clear. 93 */ 94 static __inline__ int get_dma_residue(unsigned int dmanr) 95 { 96 unsigned int io_port = (dmanr<=3)? ((dmanr&3)<<1) + 1 + IO_DMA1_BASE 97 : ((dmanr&3)<<2) + 2 + IO_DMA2_BASE; 98 99 /* using short to get 16-bit wrap around */ 100 unsigned short count; 101 102 count = 1 + dma_inb(io_port); 103 count += dma_inb(io_port) << 8; 104 105 return (dmanr<=3)? count : (count<<1); 106 } 107 108 /* enable/disable a specific DMA channel */ 109 static __inline__ void enable_dma(unsigned int dmanr) 110 { 111 #ifdef CONFIG_SUPERIO 112 if (dmanr<=3) 113 dma_outb(dmanr, DMA1_MASK_REG); 114 else 115 dma_outb(dmanr & 3, DMA2_MASK_REG); 116 #endif 117 } 118 119 static __inline__ void disable_dma(unsigned int dmanr) 120 { 121 #ifdef CONFIG_SUPERIO 122 if (dmanr<=3) 123 dma_outb(dmanr | 4, DMA1_MASK_REG); 124 else 125 dma_outb((dmanr & 3) | 4, DMA2_MASK_REG); 126 #endif 127 } 128 129 /* reserve a DMA channel */ 130 #define request_dma(dmanr, device_id) (0) 131 132 /* Clear the 'DMA Pointer Flip Flop'. 133 * Write 0 for LSB/MSB, 1 for MSB/LSB access. 134 * Use this once to initialize the FF to a known state. 135 * After that, keep track of it. :-) 136 * --- In order to do that, the DMA routines below should --- 137 * --- only be used while holding the DMA lock ! --- 138 */ 139 static __inline__ void clear_dma_ff(unsigned int dmanr) 140 { 141 } 142 143 /* set mode (above) for a specific DMA channel */ 144 static __inline__ void set_dma_mode(unsigned int dmanr, char mode) 145 { 146 } 147 148 /* Set only the page register bits of the transfer address. 149 * This is used for successive transfers when we know the contents of 150 * the lower 16 bits of the DMA current address register, but a 64k boundary 151 * may have been crossed. 152 */ 153 static __inline__ void set_dma_page(unsigned int dmanr, char pagenr) 154 { 155 } 156 157 158 /* Set transfer address & page bits for specific DMA channel. 159 * Assumes dma flipflop is clear. 160 */ 161 static __inline__ void set_dma_addr(unsigned int dmanr, unsigned int a) 162 { 163 } 164 165 166 /* Set transfer size (max 64k for DMA1..3, 128k for DMA5..7) for 167 * a specific DMA channel. 168 * You must ensure the parameters are valid. 169 * NOTE: from a manual: "the number of transfers is one more 170 * than the initial word count"! This is taken into account. 171 * Assumes dma flip-flop is clear. 172 * NOTE 2: "count" represents _bytes_ and must be even for channels 5-7. 173 */ 174 static __inline__ void set_dma_count(unsigned int dmanr, unsigned int count) 175 { 176 } 177 178 179 #define free_dma(dmanr) 180 181 #endif /* _ASM_DMA_H */ 182