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 * NOTE: all this is true *only* for ISA/EISA expansions on Mips boards 8 * and can only be used for expansion cards. Onboard DMA controllers, such 9 * as the R4030 on Jazz boards behave totally different! 10 */ 11 12 #ifndef _ASM_DMA_H 13 #define _ASM_DMA_H 14 15 #include <asm/io.h> /* need byte IO */ 16 #include <linux/spinlock.h> /* And spinlocks */ 17 #include <linux/delay.h> 18 #include <asm/system.h> 19 20 21 #ifdef HAVE_REALLY_SLOW_DMA_CONTROLLER 22 #define dma_outb outb_p 23 #else 24 #define dma_outb outb 25 #endif 26 27 #define dma_inb inb 28 29 /* 30 * NOTES about DMA transfers: 31 * 32 * controller 1: channels 0-3, byte operations, ports 00-1F 33 * controller 2: channels 4-7, word operations, ports C0-DF 34 * 35 * - ALL registers are 8 bits only, regardless of transfer size 36 * - channel 4 is not used - cascades 1 into 2. 37 * - channels 0-3 are byte - addresses/counts are for physical bytes 38 * - channels 5-7 are word - addresses/counts are for physical words 39 * - transfers must not cross physical 64K (0-3) or 128K (5-7) boundaries 40 * - transfer count loaded to registers is 1 less than actual count 41 * - controller 2 offsets are all even (2x offsets for controller 1) 42 * - page registers for 5-7 don't use data bit 0, represent 128K pages 43 * - page registers for 0-3 use bit 0, represent 64K pages 44 * 45 * DMA transfers are limited to the lower 16MB of _physical_ memory. 46 * Note that addresses loaded into registers must be _physical_ addresses, 47 * not logical addresses (which may differ if paging is active). 48 * 49 * Address mapping for channels 0-3: 50 * 51 * A23 ... A16 A15 ... A8 A7 ... A0 (Physical addresses) 52 * | ... | | ... | | ... | 53 * | ... | | ... | | ... | 54 * | ... | | ... | | ... | 55 * P7 ... P0 A7 ... A0 A7 ... A0 56 * | Page | Addr MSB | Addr LSB | (DMA registers) 57 * 58 * Address mapping for channels 5-7: 59 * 60 * A23 ... A17 A16 A15 ... A9 A8 A7 ... A1 A0 (Physical addresses) 61 * | ... | \ \ ... \ \ \ ... \ \ 62 * | ... | \ \ ... \ \ \ ... \ (not used) 63 * | ... | \ \ ... \ \ \ ... \ 64 * P7 ... P1 (0) A7 A6 ... A0 A7 A6 ... A0 65 * | Page | Addr MSB | Addr LSB | (DMA registers) 66 * 67 * Again, channels 5-7 transfer _physical_ words (16 bits), so addresses 68 * and counts _must_ be word-aligned (the lowest address bit is _ignored_ at 69 * the hardware level, so odd-byte transfers aren't possible). 70 * 71 * Transfer count (_not # bytes_) is limited to 64K, represented as actual 72 * count - 1 : 64K => 0xFFFF, 1 => 0x0000. Thus, count is always 1 or more, 73 * and up to 128K bytes may be transferred on channels 5-7 in one operation. 74 * 75 */ 76 77 #ifndef CONFIG_GENERIC_ISA_DMA_SUPPORT_BROKEN 78 #define MAX_DMA_CHANNELS 8 79 #endif 80 81 /* 82 * The maximum address in KSEG0 that we can perform a DMA transfer to on this 83 * platform. This describes only the PC style part of the DMA logic like on 84 * Deskstations or Acer PICA but not the much more versatile DMA logic used 85 * for the local devices on Acer PICA or Magnums. 86 */ 87 #if defined(CONFIG_SGI_IP22) || defined(CONFIG_SGI_IP28) 88 /* don't care; ISA bus master won't work, ISA slave DMA supports 32bit addr */ 89 #define MAX_DMA_ADDRESS PAGE_OFFSET 90 #else 91 #define MAX_DMA_ADDRESS (PAGE_OFFSET + 0x01000000) 92 #endif 93 #define MAX_DMA_PFN PFN_DOWN(virt_to_phys((void *)MAX_DMA_ADDRESS)) 94 #define MAX_DMA32_PFN (1UL << (32 - PAGE_SHIFT)) 95 96 /* 8237 DMA controllers */ 97 #define IO_DMA1_BASE 0x00 /* 8 bit slave DMA, channels 0..3 */ 98 #define IO_DMA2_BASE 0xC0 /* 16 bit master DMA, ch 4(=slave input)..7 */ 99 100 /* DMA controller registers */ 101 #define DMA1_CMD_REG 0x08 /* command register (w) */ 102 #define DMA1_STAT_REG 0x08 /* status register (r) */ 103 #define DMA1_REQ_REG 0x09 /* request register (w) */ 104 #define DMA1_MASK_REG 0x0A /* single-channel mask (w) */ 105 #define DMA1_MODE_REG 0x0B /* mode register (w) */ 106 #define DMA1_CLEAR_FF_REG 0x0C /* clear pointer flip-flop (w) */ 107 #define DMA1_TEMP_REG 0x0D /* Temporary Register (r) */ 108 #define DMA1_RESET_REG 0x0D /* Master Clear (w) */ 109 #define DMA1_CLR_MASK_REG 0x0E /* Clear Mask */ 110 #define DMA1_MASK_ALL_REG 0x0F /* all-channels mask (w) */ 111 112 #define DMA2_CMD_REG 0xD0 /* command register (w) */ 113 #define DMA2_STAT_REG 0xD0 /* status register (r) */ 114 #define DMA2_REQ_REG 0xD2 /* request register (w) */ 115 #define DMA2_MASK_REG 0xD4 /* single-channel mask (w) */ 116 #define DMA2_MODE_REG 0xD6 /* mode register (w) */ 117 #define DMA2_CLEAR_FF_REG 0xD8 /* clear pointer flip-flop (w) */ 118 #define DMA2_TEMP_REG 0xDA /* Temporary Register (r) */ 119 #define DMA2_RESET_REG 0xDA /* Master Clear (w) */ 120 #define DMA2_CLR_MASK_REG 0xDC /* Clear Mask */ 121 #define DMA2_MASK_ALL_REG 0xDE /* all-channels mask (w) */ 122 123 #define DMA_ADDR_0 0x00 /* DMA address registers */ 124 #define DMA_ADDR_1 0x02 125 #define DMA_ADDR_2 0x04 126 #define DMA_ADDR_3 0x06 127 #define DMA_ADDR_4 0xC0 128 #define DMA_ADDR_5 0xC4 129 #define DMA_ADDR_6 0xC8 130 #define DMA_ADDR_7 0xCC 131 132 #define DMA_CNT_0 0x01 /* DMA count registers */ 133 #define DMA_CNT_1 0x03 134 #define DMA_CNT_2 0x05 135 #define DMA_CNT_3 0x07 136 #define DMA_CNT_4 0xC2 137 #define DMA_CNT_5 0xC6 138 #define DMA_CNT_6 0xCA 139 #define DMA_CNT_7 0xCE 140 141 #define DMA_PAGE_0 0x87 /* DMA page registers */ 142 #define DMA_PAGE_1 0x83 143 #define DMA_PAGE_2 0x81 144 #define DMA_PAGE_3 0x82 145 #define DMA_PAGE_5 0x8B 146 #define DMA_PAGE_6 0x89 147 #define DMA_PAGE_7 0x8A 148 149 #define DMA_MODE_READ 0x44 /* I/O to memory, no autoinit, increment, single mode */ 150 #define DMA_MODE_WRITE 0x48 /* memory to I/O, no autoinit, increment, single mode */ 151 #define DMA_MODE_CASCADE 0xC0 /* pass thru DREQ->HRQ, DACK<-HLDA only */ 152 153 #define DMA_AUTOINIT 0x10 154 155 extern spinlock_t dma_spin_lock; 156 157 static __inline__ unsigned long claim_dma_lock(void) 158 { 159 unsigned long flags; 160 spin_lock_irqsave(&dma_spin_lock, flags); 161 return flags; 162 } 163 164 static __inline__ void release_dma_lock(unsigned long flags) 165 { 166 spin_unlock_irqrestore(&dma_spin_lock, flags); 167 } 168 169 /* enable/disable a specific DMA channel */ 170 static __inline__ void enable_dma(unsigned int dmanr) 171 { 172 if (dmanr<=3) 173 dma_outb(dmanr, DMA1_MASK_REG); 174 else 175 dma_outb(dmanr & 3, DMA2_MASK_REG); 176 } 177 178 static __inline__ void disable_dma(unsigned int dmanr) 179 { 180 if (dmanr<=3) 181 dma_outb(dmanr | 4, DMA1_MASK_REG); 182 else 183 dma_outb((dmanr & 3) | 4, DMA2_MASK_REG); 184 } 185 186 /* Clear the 'DMA Pointer Flip Flop'. 187 * Write 0 for LSB/MSB, 1 for MSB/LSB access. 188 * Use this once to initialize the FF to a known state. 189 * After that, keep track of it. :-) 190 * --- In order to do that, the DMA routines below should --- 191 * --- only be used while holding the DMA lock ! --- 192 */ 193 static __inline__ void clear_dma_ff(unsigned int dmanr) 194 { 195 if (dmanr<=3) 196 dma_outb(0, DMA1_CLEAR_FF_REG); 197 else 198 dma_outb(0, DMA2_CLEAR_FF_REG); 199 } 200 201 /* set mode (above) for a specific DMA channel */ 202 static __inline__ void set_dma_mode(unsigned int dmanr, char mode) 203 { 204 if (dmanr<=3) 205 dma_outb(mode | dmanr, DMA1_MODE_REG); 206 else 207 dma_outb(mode | (dmanr&3), DMA2_MODE_REG); 208 } 209 210 /* Set only the page register bits of the transfer address. 211 * This is used for successive transfers when we know the contents of 212 * the lower 16 bits of the DMA current address register, but a 64k boundary 213 * may have been crossed. 214 */ 215 static __inline__ void set_dma_page(unsigned int dmanr, char pagenr) 216 { 217 switch(dmanr) { 218 case 0: 219 dma_outb(pagenr, DMA_PAGE_0); 220 break; 221 case 1: 222 dma_outb(pagenr, DMA_PAGE_1); 223 break; 224 case 2: 225 dma_outb(pagenr, DMA_PAGE_2); 226 break; 227 case 3: 228 dma_outb(pagenr, DMA_PAGE_3); 229 break; 230 case 5: 231 dma_outb(pagenr & 0xfe, DMA_PAGE_5); 232 break; 233 case 6: 234 dma_outb(pagenr & 0xfe, DMA_PAGE_6); 235 break; 236 case 7: 237 dma_outb(pagenr & 0xfe, DMA_PAGE_7); 238 break; 239 } 240 } 241 242 243 /* Set transfer address & page bits for specific DMA channel. 244 * Assumes dma flipflop is clear. 245 */ 246 static __inline__ void set_dma_addr(unsigned int dmanr, unsigned int a) 247 { 248 set_dma_page(dmanr, a>>16); 249 if (dmanr <= 3) { 250 dma_outb( a & 0xff, ((dmanr&3)<<1) + IO_DMA1_BASE ); 251 dma_outb( (a>>8) & 0xff, ((dmanr&3)<<1) + IO_DMA1_BASE ); 252 } else { 253 dma_outb( (a>>1) & 0xff, ((dmanr&3)<<2) + IO_DMA2_BASE ); 254 dma_outb( (a>>9) & 0xff, ((dmanr&3)<<2) + IO_DMA2_BASE ); 255 } 256 } 257 258 259 /* Set transfer size (max 64k for DMA0..3, 128k for DMA5..7) for 260 * a specific DMA channel. 261 * You must ensure the parameters are valid. 262 * NOTE: from a manual: "the number of transfers is one more 263 * than the initial word count"! This is taken into account. 264 * Assumes dma flip-flop is clear. 265 * NOTE 2: "count" represents _bytes_ and must be even for channels 5-7. 266 */ 267 static __inline__ void set_dma_count(unsigned int dmanr, unsigned int count) 268 { 269 count--; 270 if (dmanr <= 3) { 271 dma_outb( count & 0xff, ((dmanr&3)<<1) + 1 + IO_DMA1_BASE ); 272 dma_outb( (count>>8) & 0xff, ((dmanr&3)<<1) + 1 + IO_DMA1_BASE ); 273 } else { 274 dma_outb( (count>>1) & 0xff, ((dmanr&3)<<2) + 2 + IO_DMA2_BASE ); 275 dma_outb( (count>>9) & 0xff, ((dmanr&3)<<2) + 2 + IO_DMA2_BASE ); 276 } 277 } 278 279 280 /* Get DMA residue count. After a DMA transfer, this 281 * should return zero. Reading this while a DMA transfer is 282 * still in progress will return unpredictable results. 283 * If called before the channel has been used, it may return 1. 284 * Otherwise, it returns the number of _bytes_ left to transfer. 285 * 286 * Assumes DMA flip-flop is clear. 287 */ 288 static __inline__ int get_dma_residue(unsigned int dmanr) 289 { 290 unsigned int io_port = (dmanr<=3)? ((dmanr&3)<<1) + 1 + IO_DMA1_BASE 291 : ((dmanr&3)<<2) + 2 + IO_DMA2_BASE; 292 293 /* using short to get 16-bit wrap around */ 294 unsigned short count; 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: */ 304 extern int request_dma(unsigned int dmanr, const char * device_id); /* reserve a DMA channel */ 305 extern void free_dma(unsigned int dmanr); /* release it again */ 306 307 /* From PCI */ 308 309 #ifdef CONFIG_PCI 310 extern int isa_dma_bridge_buggy; 311 #else 312 #define isa_dma_bridge_buggy (0) 313 #endif 314 315 #endif /* _ASM_DMA_H */ 316
