1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * linux/include/asm/dma.h: Defines for using and allocating dma channels. 4 * Written by Hennus Bergman, 1992. 5 * High DMA channel support & info by Hannu Savolainen 6 * and John Boyd, Nov. 1992. 7 * 8 * NOTE: all this is true *only* for ISA/EISA expansions on Mips boards 9 * and can only be used for expansion cards. Onboard DMA controllers, such 10 * as the R4030 on Jazz boards behave totally different! 11 */ 12 13 #ifndef _ASM_DMA_H 14 #define _ASM_DMA_H 15 16 #include <asm/io.h> /* need byte IO */ 17 #include <linux/spinlock.h> /* And spinlocks */ 18 #include <linux/delay.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 95 #ifndef MAX_DMA32_PFN 96 #define MAX_DMA32_PFN (1UL << (32 - PAGE_SHIFT)) 97 #endif 98 99 /* 8237 DMA controllers */ 100 #define IO_DMA1_BASE 0x00 /* 8 bit slave DMA, channels 0..3 */ 101 #define IO_DMA2_BASE 0xC0 /* 16 bit master DMA, ch 4(=slave input)..7 */ 102 103 /* DMA controller registers */ 104 #define DMA1_CMD_REG 0x08 /* command register (w) */ 105 #define DMA1_STAT_REG 0x08 /* status register (r) */ 106 #define DMA1_REQ_REG 0x09 /* request register (w) */ 107 #define DMA1_MASK_REG 0x0A /* single-channel mask (w) */ 108 #define DMA1_MODE_REG 0x0B /* mode register (w) */ 109 #define DMA1_CLEAR_FF_REG 0x0C /* clear pointer flip-flop (w) */ 110 #define DMA1_TEMP_REG 0x0D /* Temporary Register (r) */ 111 #define DMA1_RESET_REG 0x0D /* Master Clear (w) */ 112 #define DMA1_CLR_MASK_REG 0x0E /* Clear Mask */ 113 #define DMA1_MASK_ALL_REG 0x0F /* all-channels mask (w) */ 114 115 #define DMA2_CMD_REG 0xD0 /* command register (w) */ 116 #define DMA2_STAT_REG 0xD0 /* status register (r) */ 117 #define DMA2_REQ_REG 0xD2 /* request register (w) */ 118 #define DMA2_MASK_REG 0xD4 /* single-channel mask (w) */ 119 #define DMA2_MODE_REG 0xD6 /* mode register (w) */ 120 #define DMA2_CLEAR_FF_REG 0xD8 /* clear pointer flip-flop (w) */ 121 #define DMA2_TEMP_REG 0xDA /* Temporary Register (r) */ 122 #define DMA2_RESET_REG 0xDA /* Master Clear (w) */ 123 #define DMA2_CLR_MASK_REG 0xDC /* Clear Mask */ 124 #define DMA2_MASK_ALL_REG 0xDE /* all-channels mask (w) */ 125 126 #define DMA_ADDR_0 0x00 /* DMA address registers */ 127 #define DMA_ADDR_1 0x02 128 #define DMA_ADDR_2 0x04 129 #define DMA_ADDR_3 0x06 130 #define DMA_ADDR_4 0xC0 131 #define DMA_ADDR_5 0xC4 132 #define DMA_ADDR_6 0xC8 133 #define DMA_ADDR_7 0xCC 134 135 #define DMA_CNT_0 0x01 /* DMA count registers */ 136 #define DMA_CNT_1 0x03 137 #define DMA_CNT_2 0x05 138 #define DMA_CNT_3 0x07 139 #define DMA_CNT_4 0xC2 140 #define DMA_CNT_5 0xC6 141 #define DMA_CNT_6 0xCA 142 #define DMA_CNT_7 0xCE 143 144 #define DMA_PAGE_0 0x87 /* DMA page registers */ 145 #define DMA_PAGE_1 0x83 146 #define DMA_PAGE_2 0x81 147 #define DMA_PAGE_3 0x82 148 #define DMA_PAGE_5 0x8B 149 #define DMA_PAGE_6 0x89 150 #define DMA_PAGE_7 0x8A 151 152 #define DMA_MODE_READ 0x44 /* I/O to memory, no autoinit, increment, single mode */ 153 #define DMA_MODE_WRITE 0x48 /* memory to I/O, no autoinit, increment, single mode */ 154 #define DMA_MODE_CASCADE 0xC0 /* pass thru DREQ->HRQ, DACK<-HLDA only */ 155 156 #define DMA_AUTOINIT 0x10 157 158 extern spinlock_t dma_spin_lock; 159 160 static __inline__ unsigned long claim_dma_lock(void) 161 { 162 unsigned long flags; 163 spin_lock_irqsave(&dma_spin_lock, flags); 164 return flags; 165 } 166 167 static __inline__ void release_dma_lock(unsigned long flags) 168 { 169 spin_unlock_irqrestore(&dma_spin_lock, flags); 170 } 171 172 /* enable/disable a specific DMA channel */ 173 static __inline__ void enable_dma(unsigned int dmanr) 174 { 175 if (dmanr<=3) 176 dma_outb(dmanr, DMA1_MASK_REG); 177 else 178 dma_outb(dmanr & 3, DMA2_MASK_REG); 179 } 180 181 static __inline__ void disable_dma(unsigned int dmanr) 182 { 183 if (dmanr<=3) 184 dma_outb(dmanr | 4, DMA1_MASK_REG); 185 else 186 dma_outb((dmanr & 3) | 4, DMA2_MASK_REG); 187 } 188 189 /* Clear the 'DMA Pointer Flip Flop'. 190 * Write 0 for LSB/MSB, 1 for MSB/LSB access. 191 * Use this once to initialize the FF to a known state. 192 * After that, keep track of it. :-) 193 * --- In order to do that, the DMA routines below should --- 194 * --- only be used while holding the DMA lock ! --- 195 */ 196 static __inline__ void clear_dma_ff(unsigned int dmanr) 197 { 198 if (dmanr<=3) 199 dma_outb(0, DMA1_CLEAR_FF_REG); 200 else 201 dma_outb(0, DMA2_CLEAR_FF_REG); 202 } 203 204 /* set mode (above) for a specific DMA channel */ 205 static __inline__ void set_dma_mode(unsigned int dmanr, char mode) 206 { 207 if (dmanr<=3) 208 dma_outb(mode | dmanr, DMA1_MODE_REG); 209 else 210 dma_outb(mode | (dmanr&3), DMA2_MODE_REG); 211 } 212 213 /* Set only the page register bits of the transfer address. 214 * This is used for successive transfers when we know the contents of 215 * the lower 16 bits of the DMA current address register, but a 64k boundary 216 * may have been crossed. 217 */ 218 static __inline__ void set_dma_page(unsigned int dmanr, char pagenr) 219 { 220 switch(dmanr) { 221 case 0: 222 dma_outb(pagenr, DMA_PAGE_0); 223 break; 224 case 1: 225 dma_outb(pagenr, DMA_PAGE_1); 226 break; 227 case 2: 228 dma_outb(pagenr, DMA_PAGE_2); 229 break; 230 case 3: 231 dma_outb(pagenr, DMA_PAGE_3); 232 break; 233 case 5: 234 dma_outb(pagenr & 0xfe, DMA_PAGE_5); 235 break; 236 case 6: 237 dma_outb(pagenr & 0xfe, DMA_PAGE_6); 238 break; 239 case 7: 240 dma_outb(pagenr & 0xfe, DMA_PAGE_7); 241 break; 242 } 243 } 244 245 246 /* Set transfer address & page bits for specific DMA channel. 247 * Assumes dma flipflop is clear. 248 */ 249 static __inline__ void set_dma_addr(unsigned int dmanr, unsigned int a) 250 { 251 set_dma_page(dmanr, a>>16); 252 if (dmanr <= 3) { 253 dma_outb( a & 0xff, ((dmanr&3)<<1) + IO_DMA1_BASE ); 254 dma_outb( (a>>8) & 0xff, ((dmanr&3)<<1) + IO_DMA1_BASE ); 255 } else { 256 dma_outb( (a>>1) & 0xff, ((dmanr&3)<<2) + IO_DMA2_BASE ); 257 dma_outb( (a>>9) & 0xff, ((dmanr&3)<<2) + IO_DMA2_BASE ); 258 } 259 } 260 261 262 /* Set transfer size (max 64k for DMA0..3, 128k for DMA5..7) for 263 * a specific DMA channel. 264 * You must ensure the parameters are valid. 265 * NOTE: from a manual: "the number of transfers is one more 266 * than the initial word count"! This is taken into account. 267 * Assumes dma flip-flop is clear. 268 * NOTE 2: "count" represents _bytes_ and must be even for channels 5-7. 269 */ 270 static __inline__ void set_dma_count(unsigned int dmanr, unsigned int count) 271 { 272 count--; 273 if (dmanr <= 3) { 274 dma_outb( count & 0xff, ((dmanr&3)<<1) + 1 + IO_DMA1_BASE ); 275 dma_outb( (count>>8) & 0xff, ((dmanr&3)<<1) + 1 + IO_DMA1_BASE ); 276 } else { 277 dma_outb( (count>>1) & 0xff, ((dmanr&3)<<2) + 2 + IO_DMA2_BASE ); 278 dma_outb( (count>>9) & 0xff, ((dmanr&3)<<2) + 2 + IO_DMA2_BASE ); 279 } 280 } 281 282 283 /* Get DMA residue count. After a DMA transfer, this 284 * should return zero. Reading this while a DMA transfer is 285 * still in progress will return unpredictable results. 286 * If called before the channel has been used, it may return 1. 287 * Otherwise, it returns the number of _bytes_ left to transfer. 288 * 289 * Assumes DMA flip-flop is clear. 290 */ 291 static __inline__ int get_dma_residue(unsigned int dmanr) 292 { 293 unsigned int io_port = (dmanr<=3)? ((dmanr&3)<<1) + 1 + IO_DMA1_BASE 294 : ((dmanr&3)<<2) + 2 + IO_DMA2_BASE; 295 296 /* using short to get 16-bit wrap around */ 297 unsigned short count; 298 299 count = 1 + dma_inb(io_port); 300 count += dma_inb(io_port) << 8; 301 302 return (dmanr<=3)? count : (count<<1); 303 } 304 305 306 /* These are in kernel/dma.c: */ 307 extern int request_dma(unsigned int dmanr, const char * device_id); /* reserve a DMA channel */ 308 extern void free_dma(unsigned int dmanr); /* release it again */ 309 310 #endif /* _ASM_DMA_H */ 311