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 19 20#ifdef HAVE_REALLY_SLOW_DMA_CONTROLLER 21#define dma_outb outb_p 22#else 23#define dma_outb outb 24#endif 25 26#define dma_inb inb 27 28/* 29 * NOTES about DMA transfers: 30 * 31 * controller 1: channels 0-3, byte operations, ports 00-1F 32 * controller 2: channels 4-7, word operations, ports C0-DF 33 * 34 * - ALL registers are 8 bits only, regardless of transfer size 35 * - channel 4 is not used - cascades 1 into 2. 36 * - channels 0-3 are byte - addresses/counts are for physical bytes 37 * - channels 5-7 are word - addresses/counts are for physical words 38 * - transfers must not cross physical 64K (0-3) or 128K (5-7) boundaries 39 * - transfer count loaded to registers is 1 less than actual count 40 * - controller 2 offsets are all even (2x offsets for controller 1) 41 * - page registers for 5-7 don't use data bit 0, represent 128K pages 42 * - page registers for 0-3 use bit 0, represent 64K pages 43 * 44 * DMA transfers are limited to the lower 16MB of _physical_ memory. 45 * Note that addresses loaded into registers must be _physical_ addresses, 46 * not logical addresses (which may differ if paging is active). 47 * 48 * Address mapping for channels 0-3: 49 * 50 * A23 ... A16 A15 ... A8 A7 ... A0 (Physical addresses) 51 * | ... | | ... | | ... | 52 * | ... | | ... | | ... | 53 * | ... | | ... | | ... | 54 * P7 ... P0 A7 ... A0 A7 ... A0 55 * | Page | Addr MSB | Addr LSB | (DMA registers) 56 * 57 * Address mapping for channels 5-7: 58 * 59 * A23 ... A17 A16 A15 ... A9 A8 A7 ... A1 A0 (Physical addresses) 60 * | ... | \ \ ... \ \ \ ... \ \ 61 * | ... | \ \ ... \ \ \ ... \ (not used) 62 * | ... | \ \ ... \ \ \ ... \ 63 * P7 ... P1 (0) A7 A6 ... A0 A7 A6 ... A0 64 * | Page | Addr MSB | Addr LSB | (DMA registers) 65 * 66 * Again, channels 5-7 transfer _physical_ words (16 bits), so addresses 67 * and counts _must_ be word-aligned (the lowest address bit is _ignored_ at 68 * the hardware level, so odd-byte transfers aren't possible). 69 * 70 * Transfer count (_not # bytes_) is limited to 64K, represented as actual 71 * count - 1 : 64K => 0xFFFF, 1 => 0x0000. Thus, count is always 1 or more, 72 * and up to 128K bytes may be transferred on channels 5-7 in one operation. 73 * 74 */ 75 76#ifndef CONFIG_GENERIC_ISA_DMA_SUPPORT_BROKEN 77#define MAX_DMA_CHANNELS 8 78#endif 79 80/* 81 * The maximum address in KSEG0 that we can perform a DMA transfer to on this 82 * platform. This describes only the PC style part of the DMA logic like on 83 * Deskstations or Acer PICA but not the much more versatile DMA logic used 84 * for the local devices on Acer PICA or Magnums. 85 */ 86#if defined(CONFIG_SGI_IP22) || defined(CONFIG_SGI_IP28) 87/* don't care; ISA bus master won't work, ISA slave DMA supports 32bit addr */ 88#define MAX_DMA_ADDRESS PAGE_OFFSET 89#else 90#define MAX_DMA_ADDRESS (PAGE_OFFSET + 0x01000000) 91#endif 92#define MAX_DMA_PFN PFN_DOWN(virt_to_phys((void *)MAX_DMA_ADDRESS)) 93 94#ifndef MAX_DMA32_PFN 95#define MAX_DMA32_PFN (1UL << (32 - PAGE_SHIFT)) 96#endif 97 98/* 8237 DMA controllers */ 99#define IO_DMA1_BASE 0x00 /* 8 bit slave DMA, channels 0..3 */ 100#define IO_DMA2_BASE 0xC0 /* 16 bit master DMA, ch 4(=slave input)..7 */ 101 102/* DMA controller registers */ 103#define DMA1_CMD_REG 0x08 /* command register (w) */ 104#define DMA1_STAT_REG 0x08 /* status register (r) */ 105#define DMA1_REQ_REG 0x09 /* request register (w) */ 106#define DMA1_MASK_REG 0x0A /* single-channel mask (w) */ 107#define DMA1_MODE_REG 0x0B /* mode register (w) */ 108#define DMA1_CLEAR_FF_REG 0x0C /* clear pointer flip-flop (w) */ 109#define DMA1_TEMP_REG 0x0D /* Temporary Register (r) */ 110#define DMA1_RESET_REG 0x0D /* Master Clear (w) */ 111#define DMA1_CLR_MASK_REG 0x0E /* Clear Mask */ 112#define DMA1_MASK_ALL_REG 0x0F /* all-channels mask (w) */ 113 114#define DMA2_CMD_REG 0xD0 /* command register (w) */ 115#define DMA2_STAT_REG 0xD0 /* status register (r) */ 116#define DMA2_REQ_REG 0xD2 /* request register (w) */ 117#define DMA2_MASK_REG 0xD4 /* single-channel mask (w) */ 118#define DMA2_MODE_REG 0xD6 /* mode register (w) */ 119#define DMA2_CLEAR_FF_REG 0xD8 /* clear pointer flip-flop (w) */ 120#define DMA2_TEMP_REG 0xDA /* Temporary Register (r) */ 121#define DMA2_RESET_REG 0xDA /* Master Clear (w) */ 122#define DMA2_CLR_MASK_REG 0xDC /* Clear Mask */ 123#define DMA2_MASK_ALL_REG 0xDE /* all-channels mask (w) */ 124 125#define DMA_ADDR_0 0x00 /* DMA address registers */ 126#define DMA_ADDR_1 0x02 127#define DMA_ADDR_2 0x04 128#define DMA_ADDR_3 0x06 129#define DMA_ADDR_4 0xC0 130#define DMA_ADDR_5 0xC4 131#define DMA_ADDR_6 0xC8 132#define DMA_ADDR_7 0xCC 133 134#define DMA_CNT_0 0x01 /* DMA count registers */ 135#define DMA_CNT_1 0x03 136#define DMA_CNT_2 0x05 137#define DMA_CNT_3 0x07 138#define DMA_CNT_4 0xC2 139#define DMA_CNT_5 0xC6 140#define DMA_CNT_6 0xCA 141#define DMA_CNT_7 0xCE 142 143#define DMA_PAGE_0 0x87 /* DMA page registers */ 144#define DMA_PAGE_1 0x83 145#define DMA_PAGE_2 0x81 146#define DMA_PAGE_3 0x82 147#define DMA_PAGE_5 0x8B 148#define DMA_PAGE_6 0x89 149#define DMA_PAGE_7 0x8A 150 151#define DMA_MODE_READ 0x44 /* I/O to memory, no autoinit, increment, single mode */ 152#define DMA_MODE_WRITE 0x48 /* memory to I/O, no autoinit, increment, single mode */ 153#define DMA_MODE_CASCADE 0xC0 /* pass thru DREQ->HRQ, DACK<-HLDA only */ 154 155#define DMA_AUTOINIT 0x10 156 157extern spinlock_t dma_spin_lock; 158 159static __inline__ unsigned long claim_dma_lock(void) 160{ 161 unsigned long flags; 162 spin_lock_irqsave(&dma_spin_lock, flags); 163 return flags; 164} 165 166static __inline__ void release_dma_lock(unsigned long flags) 167{ 168 spin_unlock_irqrestore(&dma_spin_lock, flags); 169} 170 171/* enable/disable a specific DMA channel */ 172static __inline__ void enable_dma(unsigned int dmanr) 173{ 174 if (dmanr<=3) 175 dma_outb(dmanr, DMA1_MASK_REG); 176 else 177 dma_outb(dmanr & 3, DMA2_MASK_REG); 178} 179 180static __inline__ void disable_dma(unsigned int dmanr) 181{ 182 if (dmanr<=3) 183 dma_outb(dmanr | 4, DMA1_MASK_REG); 184 else 185 dma_outb((dmanr & 3) | 4, DMA2_MASK_REG); 186} 187 188/* Clear the 'DMA Pointer Flip Flop'. 189 * Write 0 for LSB/MSB, 1 for MSB/LSB access. 190 * Use this once to initialize the FF to a known state. 191 * After that, keep track of it. :-) 192 * --- In order to do that, the DMA routines below should --- 193 * --- only be used while holding the DMA lock ! --- 194 */ 195static __inline__ void clear_dma_ff(unsigned int dmanr) 196{ 197 if (dmanr<=3) 198 dma_outb(0, DMA1_CLEAR_FF_REG); 199 else 200 dma_outb(0, DMA2_CLEAR_FF_REG); 201} 202 203/* set mode (above) for a specific DMA channel */ 204static __inline__ void set_dma_mode(unsigned int dmanr, char mode) 205{ 206 if (dmanr<=3) 207 dma_outb(mode | dmanr, DMA1_MODE_REG); 208 else 209 dma_outb(mode | (dmanr&3), DMA2_MODE_REG); 210} 211 212/* Set only the page register bits of the transfer address. 213 * This is used for successive transfers when we know the contents of 214 * the lower 16 bits of the DMA current address register, but a 64k boundary 215 * may have been crossed. 216 */ 217static __inline__ void set_dma_page(unsigned int dmanr, char pagenr) 218{ 219 switch(dmanr) { 220 case 0: 221 dma_outb(pagenr, DMA_PAGE_0); 222 break; 223 case 1: 224 dma_outb(pagenr, DMA_PAGE_1); 225 break; 226 case 2: 227 dma_outb(pagenr, DMA_PAGE_2); 228 break; 229 case 3: 230 dma_outb(pagenr, DMA_PAGE_3); 231 break; 232 case 5: 233 dma_outb(pagenr & 0xfe, DMA_PAGE_5); 234 break; 235 case 6: 236 dma_outb(pagenr & 0xfe, DMA_PAGE_6); 237 break; 238 case 7: 239 dma_outb(pagenr & 0xfe, DMA_PAGE_7); 240 break; 241 } 242} 243 244 245/* Set transfer address & page bits for specific DMA channel. 246 * Assumes dma flipflop is clear. 247 */ 248static __inline__ void set_dma_addr(unsigned int dmanr, unsigned int a) 249{ 250 set_dma_page(dmanr, a>>16); 251 if (dmanr <= 3) { 252 dma_outb( a & 0xff, ((dmanr&3)<<1) + IO_DMA1_BASE ); 253 dma_outb( (a>>8) & 0xff, ((dmanr&3)<<1) + IO_DMA1_BASE ); 254 } else { 255 dma_outb( (a>>1) & 0xff, ((dmanr&3)<<2) + IO_DMA2_BASE ); 256 dma_outb( (a>>9) & 0xff, ((dmanr&3)<<2) + IO_DMA2_BASE ); 257 } 258} 259 260 261/* Set transfer size (max 64k for DMA0..3, 128k for DMA5..7) for 262 * a specific DMA channel. 263 * You must ensure the parameters are valid. 264 * NOTE: from a manual: "the number of transfers is one more 265 * than the initial word count"! This is taken into account. 266 * Assumes dma flip-flop is clear. 267 * NOTE 2: "count" represents _bytes_ and must be even for channels 5-7. 268 */ 269static __inline__ void set_dma_count(unsigned int dmanr, unsigned int count) 270{ 271 count--; 272 if (dmanr <= 3) { 273 dma_outb( count & 0xff, ((dmanr&3)<<1) + 1 + IO_DMA1_BASE ); 274 dma_outb( (count>>8) & 0xff, ((dmanr&3)<<1) + 1 + IO_DMA1_BASE ); 275 } else { 276 dma_outb( (count>>1) & 0xff, ((dmanr&3)<<2) + 2 + IO_DMA2_BASE ); 277 dma_outb( (count>>9) & 0xff, ((dmanr&3)<<2) + 2 + IO_DMA2_BASE ); 278 } 279} 280 281 282/* Get DMA residue count. After a DMA transfer, this 283 * should return zero. Reading this while a DMA transfer is 284 * still in progress will return unpredictable results. 285 * If called before the channel has been used, it may return 1. 286 * Otherwise, it returns the number of _bytes_ left to transfer. 287 * 288 * Assumes DMA flip-flop is clear. 289 */ 290static __inline__ int get_dma_residue(unsigned int dmanr) 291{ 292 unsigned int io_port = (dmanr<=3)? ((dmanr&3)<<1) + 1 + IO_DMA1_BASE 293 : ((dmanr&3)<<2) + 2 + IO_DMA2_BASE; 294 295 /* using short to get 16-bit wrap around */ 296 unsigned short count; 297 298 count = 1 + dma_inb(io_port); 299 count += dma_inb(io_port) << 8; 300 301 return (dmanr<=3)? count : (count<<1); 302} 303 304 305/* These are in kernel/dma.c: */ 306extern int request_dma(unsigned int dmanr, const char * device_id); /* reserve a DMA channel */ 307extern void free_dma(unsigned int dmanr); /* release it again */ 308 309/* From PCI */ 310 311#ifdef CONFIG_PCI 312extern int isa_dma_bridge_buggy; 313#else 314#define isa_dma_bridge_buggy (0) 315#endif 316 317#endif /* _ASM_DMA_H */ 318