1 /* 2 * linux/include/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 */ 7 8 #ifndef _ASM_X86_DMA_H 9 #define _ASM_X86_DMA_H 10 11 #include <linux/spinlock.h> /* And spinlocks */ 12 #include <asm/io.h> /* need byte IO */ 13 14 #ifdef HAVE_REALLY_SLOW_DMA_CONTROLLER 15 #define dma_outb outb_p 16 #else 17 #define dma_outb outb 18 #endif 19 20 #define dma_inb inb 21 22 /* 23 * NOTES about DMA transfers: 24 * 25 * controller 1: channels 0-3, byte operations, ports 00-1F 26 * controller 2: channels 4-7, word operations, ports C0-DF 27 * 28 * - ALL registers are 8 bits only, regardless of transfer size 29 * - channel 4 is not used - cascades 1 into 2. 30 * - channels 0-3 are byte - addresses/counts are for physical bytes 31 * - channels 5-7 are word - addresses/counts are for physical words 32 * - transfers must not cross physical 64K (0-3) or 128K (5-7) boundaries 33 * - transfer count loaded to registers is 1 less than actual count 34 * - controller 2 offsets are all even (2x offsets for controller 1) 35 * - page registers for 5-7 don't use data bit 0, represent 128K pages 36 * - page registers for 0-3 use bit 0, represent 64K pages 37 * 38 * DMA transfers are limited to the lower 16MB of _physical_ memory. 39 * Note that addresses loaded into registers must be _physical_ addresses, 40 * not logical addresses (which may differ if paging is active). 41 * 42 * Address mapping for channels 0-3: 43 * 44 * A23 ... A16 A15 ... A8 A7 ... A0 (Physical addresses) 45 * | ... | | ... | | ... | 46 * | ... | | ... | | ... | 47 * | ... | | ... | | ... | 48 * P7 ... P0 A7 ... A0 A7 ... A0 49 * | Page | Addr MSB | Addr LSB | (DMA registers) 50 * 51 * Address mapping for channels 5-7: 52 * 53 * A23 ... A17 A16 A15 ... A9 A8 A7 ... A1 A0 (Physical addresses) 54 * | ... | \ \ ... \ \ \ ... \ \ 55 * | ... | \ \ ... \ \ \ ... \ (not used) 56 * | ... | \ \ ... \ \ \ ... \ 57 * P7 ... P1 (0) A7 A6 ... A0 A7 A6 ... A0 58 * | Page | Addr MSB | Addr LSB | (DMA registers) 59 * 60 * Again, channels 5-7 transfer _physical_ words (16 bits), so addresses 61 * and counts _must_ be word-aligned (the lowest address bit is _ignored_ at 62 * the hardware level, so odd-byte transfers aren't possible). 63 * 64 * Transfer count (_not # bytes_) is limited to 64K, represented as actual 65 * count - 1 : 64K => 0xFFFF, 1 => 0x0000. Thus, count is always 1 or more, 66 * and up to 128K bytes may be transferred on channels 5-7 in one operation. 67 * 68 */ 69 70 #define MAX_DMA_CHANNELS 8 71 72 /* 16MB ISA DMA zone */ 73 #define MAX_DMA_PFN ((16 * 1024 * 1024) >> PAGE_SHIFT) 74 75 /* 4GB broken PCI/AGP hardware bus master zone */ 76 #define MAX_DMA32_PFN ((4UL * 1024 * 1024 * 1024) >> PAGE_SHIFT) 77 78 #ifdef CONFIG_X86_32 79 /* The maximum address that we can perform a DMA transfer to on this platform */ 80 #define MAX_DMA_ADDRESS (PAGE_OFFSET + 0x1000000) 81 #else 82 /* Compat define for old dma zone */ 83 #define MAX_DMA_ADDRESS ((unsigned long)__va(MAX_DMA_PFN << PAGE_SHIFT)) 84 #endif 85 86 /* 8237 DMA controllers */ 87 #define IO_DMA1_BASE 0x00 /* 8 bit slave DMA, channels 0..3 */ 88 #define IO_DMA2_BASE 0xC0 /* 16 bit master DMA, ch 4(=slave input)..7 */ 89 90 /* DMA controller registers */ 91 #define DMA1_CMD_REG 0x08 /* command register (w) */ 92 #define DMA1_STAT_REG 0x08 /* status register (r) */ 93 #define DMA1_REQ_REG 0x09 /* request register (w) */ 94 #define DMA1_MASK_REG 0x0A /* single-channel mask (w) */ 95 #define DMA1_MODE_REG 0x0B /* mode register (w) */ 96 #define DMA1_CLEAR_FF_REG 0x0C /* clear pointer flip-flop (w) */ 97 #define DMA1_TEMP_REG 0x0D /* Temporary Register (r) */ 98 #define DMA1_RESET_REG 0x0D /* Master Clear (w) */ 99 #define DMA1_CLR_MASK_REG 0x0E /* Clear Mask */ 100 #define DMA1_MASK_ALL_REG 0x0F /* all-channels mask (w) */ 101 102 #define DMA2_CMD_REG 0xD0 /* command register (w) */ 103 #define DMA2_STAT_REG 0xD0 /* status register (r) */ 104 #define DMA2_REQ_REG 0xD2 /* request register (w) */ 105 #define DMA2_MASK_REG 0xD4 /* single-channel mask (w) */ 106 #define DMA2_MODE_REG 0xD6 /* mode register (w) */ 107 #define DMA2_CLEAR_FF_REG 0xD8 /* clear pointer flip-flop (w) */ 108 #define DMA2_TEMP_REG 0xDA /* Temporary Register (r) */ 109 #define DMA2_RESET_REG 0xDA /* Master Clear (w) */ 110 #define DMA2_CLR_MASK_REG 0xDC /* Clear Mask */ 111 #define DMA2_MASK_ALL_REG 0xDE /* all-channels mask (w) */ 112 113 #define DMA_ADDR_0 0x00 /* DMA address registers */ 114 #define DMA_ADDR_1 0x02 115 #define DMA_ADDR_2 0x04 116 #define DMA_ADDR_3 0x06 117 #define DMA_ADDR_4 0xC0 118 #define DMA_ADDR_5 0xC4 119 #define DMA_ADDR_6 0xC8 120 #define DMA_ADDR_7 0xCC 121 122 #define DMA_CNT_0 0x01 /* DMA count registers */ 123 #define DMA_CNT_1 0x03 124 #define DMA_CNT_2 0x05 125 #define DMA_CNT_3 0x07 126 #define DMA_CNT_4 0xC2 127 #define DMA_CNT_5 0xC6 128 #define DMA_CNT_6 0xCA 129 #define DMA_CNT_7 0xCE 130 131 #define DMA_PAGE_0 0x87 /* DMA page registers */ 132 #define DMA_PAGE_1 0x83 133 #define DMA_PAGE_2 0x81 134 #define DMA_PAGE_3 0x82 135 #define DMA_PAGE_5 0x8B 136 #define DMA_PAGE_6 0x89 137 #define DMA_PAGE_7 0x8A 138 139 /* I/O to memory, no autoinit, increment, single mode */ 140 #define DMA_MODE_READ 0x44 141 /* memory to I/O, no autoinit, increment, single mode */ 142 #define DMA_MODE_WRITE 0x48 143 /* pass thru DREQ->HRQ, DACK<-HLDA only */ 144 #define DMA_MODE_CASCADE 0xC0 145 146 #define DMA_AUTOINIT 0x10 147 148 149 #ifdef CONFIG_ISA_DMA_API 150 extern spinlock_t dma_spin_lock; 151 152 static inline unsigned long claim_dma_lock(void) 153 { 154 unsigned long flags; 155 spin_lock_irqsave(&dma_spin_lock, flags); 156 return flags; 157 } 158 159 static inline void release_dma_lock(unsigned long flags) 160 { 161 spin_unlock_irqrestore(&dma_spin_lock, flags); 162 } 163 #endif /* CONFIG_ISA_DMA_API */ 164 165 /* enable/disable a specific DMA channel */ 166 static inline void enable_dma(unsigned int dmanr) 167 { 168 if (dmanr <= 3) 169 dma_outb(dmanr, DMA1_MASK_REG); 170 else 171 dma_outb(dmanr & 3, DMA2_MASK_REG); 172 } 173 174 static inline void disable_dma(unsigned int dmanr) 175 { 176 if (dmanr <= 3) 177 dma_outb(dmanr | 4, DMA1_MASK_REG); 178 else 179 dma_outb((dmanr & 3) | 4, DMA2_MASK_REG); 180 } 181 182 /* Clear the 'DMA Pointer Flip Flop'. 183 * Write 0 for LSB/MSB, 1 for MSB/LSB access. 184 * Use this once to initialize the FF to a known state. 185 * After that, keep track of it. :-) 186 * --- In order to do that, the DMA routines below should --- 187 * --- only be used while holding the DMA lock ! --- 188 */ 189 static inline void clear_dma_ff(unsigned int dmanr) 190 { 191 if (dmanr <= 3) 192 dma_outb(0, DMA1_CLEAR_FF_REG); 193 else 194 dma_outb(0, DMA2_CLEAR_FF_REG); 195 } 196 197 /* set mode (above) for a specific DMA channel */ 198 static inline void set_dma_mode(unsigned int dmanr, char mode) 199 { 200 if (dmanr <= 3) 201 dma_outb(mode | dmanr, DMA1_MODE_REG); 202 else 203 dma_outb(mode | (dmanr & 3), DMA2_MODE_REG); 204 } 205 206 /* Set only the page register bits of the transfer address. 207 * This is used for successive transfers when we know the contents of 208 * the lower 16 bits of the DMA current address register, but a 64k boundary 209 * may have been crossed. 210 */ 211 static inline void set_dma_page(unsigned int dmanr, char pagenr) 212 { 213 switch (dmanr) { 214 case 0: 215 dma_outb(pagenr, DMA_PAGE_0); 216 break; 217 case 1: 218 dma_outb(pagenr, DMA_PAGE_1); 219 break; 220 case 2: 221 dma_outb(pagenr, DMA_PAGE_2); 222 break; 223 case 3: 224 dma_outb(pagenr, DMA_PAGE_3); 225 break; 226 case 5: 227 dma_outb(pagenr & 0xfe, DMA_PAGE_5); 228 break; 229 case 6: 230 dma_outb(pagenr & 0xfe, DMA_PAGE_6); 231 break; 232 case 7: 233 dma_outb(pagenr & 0xfe, DMA_PAGE_7); 234 break; 235 } 236 } 237 238 239 /* Set transfer address & page bits for specific DMA channel. 240 * Assumes dma flipflop is clear. 241 */ 242 static inline void set_dma_addr(unsigned int dmanr, unsigned int a) 243 { 244 set_dma_page(dmanr, a>>16); 245 if (dmanr <= 3) { 246 dma_outb(a & 0xff, ((dmanr & 3) << 1) + IO_DMA1_BASE); 247 dma_outb((a >> 8) & 0xff, ((dmanr & 3) << 1) + IO_DMA1_BASE); 248 } else { 249 dma_outb((a >> 1) & 0xff, ((dmanr & 3) << 2) + IO_DMA2_BASE); 250 dma_outb((a >> 9) & 0xff, ((dmanr & 3) << 2) + IO_DMA2_BASE); 251 } 252 } 253 254 255 /* Set transfer size (max 64k for DMA0..3, 128k for DMA5..7) for 256 * a specific DMA channel. 257 * You must ensure the parameters are valid. 258 * NOTE: from a manual: "the number of transfers is one more 259 * than the initial word count"! This is taken into account. 260 * Assumes dma flip-flop is clear. 261 * NOTE 2: "count" represents _bytes_ and must be even for channels 5-7. 262 */ 263 static inline void set_dma_count(unsigned int dmanr, unsigned int count) 264 { 265 count--; 266 if (dmanr <= 3) { 267 dma_outb(count & 0xff, ((dmanr & 3) << 1) + 1 + IO_DMA1_BASE); 268 dma_outb((count >> 8) & 0xff, 269 ((dmanr & 3) << 1) + 1 + IO_DMA1_BASE); 270 } else { 271 dma_outb((count >> 1) & 0xff, 272 ((dmanr & 3) << 2) + 2 + IO_DMA2_BASE); 273 dma_outb((count >> 9) & 0xff, 274 ((dmanr & 3) << 2) + 2 + IO_DMA2_BASE); 275 } 276 } 277 278 279 /* Get DMA residue count. After a DMA transfer, this 280 * should return zero. Reading this while a DMA transfer is 281 * still in progress will return unpredictable results. 282 * If called before the channel has been used, it may return 1. 283 * Otherwise, it returns the number of _bytes_ left to transfer. 284 * 285 * Assumes DMA flip-flop is clear. 286 */ 287 static inline int get_dma_residue(unsigned int dmanr) 288 { 289 unsigned int io_port; 290 /* using short to get 16-bit wrap around */ 291 unsigned short count; 292 293 io_port = (dmanr <= 3) ? ((dmanr & 3) << 1) + 1 + IO_DMA1_BASE 294 : ((dmanr & 3) << 2) + 2 + IO_DMA2_BASE; 295 296 count = 1 + dma_inb(io_port); 297 count += dma_inb(io_port) << 8; 298 299 return (dmanr <= 3) ? count : (count << 1); 300 } 301 302 303 /* These are in kernel/dma.c because x86 uses CONFIG_GENERIC_ISA_DMA */ 304 #ifdef CONFIG_ISA_DMA_API 305 extern int request_dma(unsigned int dmanr, const char *device_id); 306 extern void free_dma(unsigned int dmanr); 307 #endif 308 309 /* From PCI */ 310 311 #ifdef CONFIG_PCI 312 extern int isa_dma_bridge_buggy; 313 #else 314 #define isa_dma_bridge_buggy (0) 315 #endif 316 317 #endif /* _ASM_X86_DMA_H */ 318