1 /* $Id: dma.h,v 1.7 1992/12/14 00:29:34 root Exp root $
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_APOLLO_DMA_H
9 #define _ASM_APOLLO_DMA_H
10
11 #include <asm/apollohw.h> /* need byte IO */
12 #include <asm/spinlock.h> /* And spinlocks */
13 #include <linux/delay.h>
14
15
16 #define dma_outb(val,addr) (*((volatile unsigned char *)(addr+IO_BASE)) = (val))
17 #define dma_inb(addr) (*((volatile unsigned char *)(addr+IO_BASE)))
18
19 /*
20 * NOTES about DMA transfers:
21 *
22 * controller 1: channels 0-3, byte operations, ports 00-1F
23 * controller 2: channels 4-7, word operations, ports C0-DF
24 *
25 * - ALL registers are 8 bits only, regardless of transfer size
26 * - channel 4 is not used - cascades 1 into 2.
27 * - channels 0-3 are byte - addresses/counts are for physical bytes
28 * - channels 5-7 are word - addresses/counts are for physical words
29 * - transfers must not cross physical 64K (0-3) or 128K (5-7) boundaries
30 * - transfer count loaded to registers is 1 less than actual count
31 * - controller 2 offsets are all even (2x offsets for controller 1)
32 * - page registers for 5-7 don't use data bit 0, represent 128K pages
33 * - page registers for 0-3 use bit 0, represent 64K pages
34 *
35 * DMA transfers are limited to the lower 16MB of _physical_ memory.
36 * Note that addresses loaded into registers must be _physical_ addresses,
37 * not logical addresses (which may differ if paging is active).
38 *
39 * Address mapping for channels 0-3:
40 *
41 * A23 ... A16 A15 ... A8 A7 ... A0 (Physical addresses)
42 * | ... | | ... | | ... |
43 * | ... | | ... | | ... |
44 * | ... | | ... | | ... |
45 * P7 ... P0 A7 ... A0 A7 ... A0
46 * | Page | Addr MSB | Addr LSB | (DMA registers)
47 *
48 * Address mapping for channels 5-7:
49 *
50 * A23 ... A17 A16 A15 ... A9 A8 A7 ... A1 A0 (Physical addresses)
51 * | ... | \ \ ... \ \ \ ... \ \
52 * | ... | \ \ ... \ \ \ ... \ (not used)
53 * | ... | \ \ ... \ \ \ ... \
54 * P7 ... P1 (0) A7 A6 ... A0 A7 A6 ... A0
55 * | Page | Addr MSB | Addr LSB | (DMA registers)
56 *
57 * Again, channels 5-7 transfer _physical_ words (16 bits), so addresses
58 * and counts _must_ be word-aligned (the lowest address bit is _ignored_ at
59 * the hardware level, so odd-byte transfers aren't possible).
60 *
61 * Transfer count (_not # bytes_) is limited to 64K, represented as actual
62 * count - 1 : 64K => 0xFFFF, 1 => 0x0000. Thus, count is always 1 or more,
63 * and up to 128K bytes may be transferred on channels 5-7 in one operation.
64 *
65 */
66
67 #define MAX_DMA_CHANNELS 8
68
69 /* The maximum address that we can perform a DMA transfer to on this platform */#define MAX_DMA_ADDRESS (PAGE_OFFSET+0x1000000)
70
71 /* 8237 DMA controllers */
72 #define IO_DMA1_BASE 0x10C00 /* 8 bit slave DMA, channels 0..3 */
73 #define IO_DMA2_BASE 0x10D00 /* 16 bit master DMA, ch 4(=slave input)..7 */
74
75 /* DMA controller registers */
76 #define DMA1_CMD_REG (IO_DMA1_BASE+0x08) /* command register (w) */
77 #define DMA1_STAT_REG (IO_DMA1_BASE+0x08) /* status register (r) */
78 #define DMA1_REQ_REG (IO_DMA1_BASE+0x09) /* request register (w) */
79 #define DMA1_MASK_REG (IO_DMA1_BASE+0x0A) /* single-channel mask (w) */
80 #define DMA1_MODE_REG (IO_DMA1_BASE+0x0B) /* mode register (w) */
81 #define DMA1_CLEAR_FF_REG (IO_DMA1_BASE+0x0C) /* clear pointer flip-flop (w) */
82 #define DMA1_TEMP_REG (IO_DMA1_BASE+0x0D) /* Temporary Register (r) */
83 #define DMA1_RESET_REG (IO_DMA1_BASE+0x0D) /* Master Clear (w) */
84 #define DMA1_CLR_MASK_REG (IO_DMA1_BASE+0x0E) /* Clear Mask */
85 #define DMA1_MASK_ALL_REG (IO_DMA1_BASE+0x0F) /* all-channels mask (w) */
86
87 #define DMA2_CMD_REG (IO_DMA2_BASE+0x10) /* command register (w) */
88 #define DMA2_STAT_REG (IO_DMA2_BASE+0x10) /* status register (r) */
89 #define DMA2_REQ_REG (IO_DMA2_BASE+0x12) /* request register (w) */
90 #define DMA2_MASK_REG (IO_DMA2_BASE+0x14) /* single-channel mask (w) */
91 #define DMA2_MODE_REG (IO_DMA2_BASE+0x16) /* mode register (w) */
92 #define DMA2_CLEAR_FF_REG (IO_DMA2_BASE+0x18) /* clear pointer flip-flop (w) */
93 #define DMA2_TEMP_REG (IO_DMA2_BASE+0x1A) /* Temporary Register (r) */
94 #define DMA2_RESET_REG (IO_DMA2_BASE+0x1A) /* Master Clear (w) */
95 #define DMA2_CLR_MASK_REG (IO_DMA2_BASE+0x1C) /* Clear Mask */
96 #define DMA2_MASK_ALL_REG (IO_DMA2_BASE+0x1E) /* all-channels mask (w) */
97
98 #define DMA_ADDR_0 (IO_DMA1_BASE+0x00) /* DMA address registers */
99 #define DMA_ADDR_1 (IO_DMA1_BASE+0x02)
100 #define DMA_ADDR_2 (IO_DMA1_BASE+0x04)
101 #define DMA_ADDR_3 (IO_DMA1_BASE+0x06)
102 #define DMA_ADDR_4 (IO_DMA2_BASE+0x00)
103 #define DMA_ADDR_5 (IO_DMA2_BASE+0x04)
104 #define DMA_ADDR_6 (IO_DMA2_BASE+0x08)
105 #define DMA_ADDR_7 (IO_DMA2_BASE+0x0C)
106
107 #define DMA_CNT_0 (IO_DMA1_BASE+0x01) /* DMA count registers */
108 #define DMA_CNT_1 (IO_DMA1_BASE+0x03)
109 #define DMA_CNT_2 (IO_DMA1_BASE+0x05)
110 #define DMA_CNT_3 (IO_DMA1_BASE+0x07)
111 #define DMA_CNT_4 (IO_DMA2_BASE+0x02)
112 #define DMA_CNT_5 (IO_DMA2_BASE+0x06)
113 #define DMA_CNT_6 (IO_DMA2_BASE+0x0A)
114 #define DMA_CNT_7 (IO_DMA2_BASE+0x0E)
115
116 #define DMA_MODE_READ 0x44 /* I/O to memory, no autoinit, increment, single mode */
117 #define DMA_MODE_WRITE 0x48 /* memory to I/O, no autoinit, increment, single mode */
118 #define DMA_MODE_CASCADE 0xC0 /* pass thru DREQ->HRQ, DACK<-HLDA only */
119
120 #define DMA_AUTOINIT 0x10
121
122 #define DMA_8BIT 0
123 #define DMA_16BIT 1
124 #define DMA_BUSMASTER 2
125
126 extern spinlock_t dma_spin_lock;
127
128 static __inline__ unsigned long claim_dma_lock(void)
129 {
130 unsigned long flags;
131 spin_lock_irqsave(&dma_spin_lock, flags);
132 return flags;
133 }
134
135 static __inline__ void release_dma_lock(unsigned long flags)
136 {
137 spin_unlock_irqrestore(&dma_spin_lock, flags);
138 }
139
140 /* enable/disable a specific DMA channel */
141 static __inline__ void enable_dma(unsigned int dmanr)
142 {
143 if (dmanr<=3)
144 dma_outb(dmanr, DMA1_MASK_REG);
145 else
146 dma_outb(dmanr & 3, DMA2_MASK_REG);
147 }
148
149 static __inline__ void disable_dma(unsigned int dmanr)
150 {
151 if (dmanr<=3)
152 dma_outb(dmanr | 4, DMA1_MASK_REG);
153 else
154 dma_outb((dmanr & 3) | 4, DMA2_MASK_REG);
155 }
156
157 /* Clear the 'DMA Pointer Flip Flop'.
158 * Write 0 for LSB/MSB, 1 for MSB/LSB access.
159 * Use this once to initialize the FF to a known state.
160 * After that, keep track of it. :-)
161 * --- In order to do that, the DMA routines below should ---
162 * --- only be used while holding the DMA lock ! ---
163 */
164 static __inline__ void clear_dma_ff(unsigned int dmanr)
165 {
166 if (dmanr<=3)
167 dma_outb(0, DMA1_CLEAR_FF_REG);
168 else
169 dma_outb(0, DMA2_CLEAR_FF_REG);
170 }
171
172 /* set mode (above) for a specific DMA channel */
173 static __inline__ void set_dma_mode(unsigned int dmanr, char mode)
174 {
175 if (dmanr<=3)
176 dma_outb(mode | dmanr, DMA1_MODE_REG);
177 else
178 dma_outb(mode | (dmanr&3), DMA2_MODE_REG);
179 }
180
181 /* Set transfer address & page bits for specific DMA channel.
182 * Assumes dma flipflop is clear.
183 */
184 static __inline__ void set_dma_addr(unsigned int dmanr, unsigned int a)
185 {
186 if (dmanr <= 3) {
187 dma_outb( a & 0xff, ((dmanr&3)<<1) + IO_DMA1_BASE );
188 dma_outb( (a>>8) & 0xff, ((dmanr&3)<<1) + IO_DMA1_BASE );
189 } else {
190 dma_outb( (a>>1) & 0xff, ((dmanr&3)<<2) + IO_DMA2_BASE );
191 dma_outb( (a>>9) & 0xff, ((dmanr&3)<<2) + IO_DMA2_BASE );
192 }
193 }
194
195
196 /* Set transfer size (max 64k for DMA1..3, 128k for DMA5..7) for
197 * a specific DMA channel.
198 * You must ensure the parameters are valid.
199 * NOTE: from a manual: "the number of transfers is one more
200 * than the initial word count"! This is taken into account.
201 * Assumes dma flip-flop is clear.
202 * NOTE 2: "count" represents _bytes_ and must be even for channels 5-7.
203 */
204 static __inline__ void set_dma_count(unsigned int dmanr, unsigned int count)
205 {
206 count--;
207 if (dmanr <= 3) {
208 dma_outb( count & 0xff, ((dmanr&3)<<1) + 1 + IO_DMA1_BASE );
209 dma_outb( (count>>8) & 0xff, ((dmanr&3)<<1) + 1 + IO_DMA1_BASE );
210 } else {
211 dma_outb( (count>>1) & 0xff, ((dmanr&3)<<2) + 2 + IO_DMA2_BASE );
212 dma_outb( (count>>9) & 0xff, ((dmanr&3)<<2) + 2 + IO_DMA2_BASE );
213 }
214 }
215
216
217 /* Get DMA residue count. After a DMA transfer, this
218 * should return zero. Reading this while a DMA transfer is
219 * still in progress will return unpredictable results.
220 * If called before the channel has been used, it may return 1.
221 * Otherwise, it returns the number of _bytes_ left to transfer.
222 *
223 * Assumes DMA flip-flop is clear.
224 */
225 static __inline__ int get_dma_residue(unsigned int dmanr)
226 {
227 unsigned int io_port = (dmanr<=3)? ((dmanr&3)<<1) + 1 + IO_DMA1_BASE
228 : ((dmanr&3)<<2) + 2 + IO_DMA2_BASE;
229
230 /* using short to get 16-bit wrap around */
231 unsigned short count;
232
233 count = 1 + dma_inb(io_port);
234 count += dma_inb(io_port) << 8;
235
236 return (dmanr<=3)? count : (count<<1);
237 }
238
239
240 /* These are in kernel/dma.c: */
241 extern int request_dma(unsigned int dmanr, const char * device_id); /* reserve a DMA channel */
242 extern void free_dma(unsigned int dmanr); /* release it again */
243
244 /* These are in arch/m68k/apollo/dma.c: */
245 extern unsigned short dma_map_page(unsigned long phys_addr,int count,int type);
246 extern void dma_unmap_page(unsigned short dma_addr);
247
248 #endif /* _ASM_APOLLO_DMA_H */
249
This page was automatically generated by the
LXR engine.
Visit the LXR main site for more
information.