1 /*
2 * linux/arch/arm/mach-rpc/dma.c
3 *
4 * Copyright (C) 1998 Russell King
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * DMA functions specific to RiscPC architecture
11 */
12 #include <linux/slab.h>
13 #include <linux/mman.h>
14 #include <linux/init.h>
15 #include <linux/interrupt.h>
16 #include <linux/dma-mapping.h>
17
18 #include <asm/page.h>
19 #include <asm/dma.h>
20 #include <asm/fiq.h>
21 #include <asm/io.h>
22 #include <asm/irq.h>
23 #include <asm/hardware.h>
24 #include <asm/uaccess.h>
25
26 #include <asm/mach/dma.h>
27 #include <asm/hardware/iomd.h>
28
29 #if 0
30 typedef enum {
31 dma_size_8 = 1,
32 dma_size_16 = 2,
33 dma_size_32 = 4,
34 dma_size_128 = 16
35 } dma_size_t;
36 #endif
37
38 #define TRANSFER_SIZE 2
39
40 #define CURA (0)
41 #define ENDA (IOMD_IO0ENDA - IOMD_IO0CURA)
42 #define CURB (IOMD_IO0CURB - IOMD_IO0CURA)
43 #define ENDB (IOMD_IO0ENDB - IOMD_IO0CURA)
44 #define CR (IOMD_IO0CR - IOMD_IO0CURA)
45 #define ST (IOMD_IO0ST - IOMD_IO0CURA)
46
47 static void iomd_get_next_sg(struct scatterlist *sg, dma_t *dma)
48 {
49 unsigned long end, offset, flags = 0;
50
51 if (dma->sg) {
52 sg->dma_address = dma->sg->dma_address;
53 offset = sg->dma_address & ~PAGE_MASK;
54
55 end = offset + dma->sg->length;
56
57 if (end > PAGE_SIZE)
58 end = PAGE_SIZE;
59
60 if (offset + TRANSFER_SIZE >= end)
61 flags |= DMA_END_L;
62
63 sg->length = end - TRANSFER_SIZE;
64
65 dma->sg->length -= end - offset;
66 dma->sg->dma_address += end - offset;
67
68 if (dma->sg->length == 0) {
69 if (dma->sgcount > 1) {
70 dma->sg++;
71 dma->sgcount--;
72 } else {
73 dma->sg = NULL;
74 flags |= DMA_END_S;
75 }
76 }
77 } else {
78 flags = DMA_END_S | DMA_END_L;
79 sg->dma_address = 0;
80 sg->length = 0;
81 }
82
83 sg->length |= flags;
84 }
85
86 static irqreturn_t iomd_dma_handle(int irq, void *dev_id)
87 {
88 dma_t *dma = (dma_t *)dev_id;
89 unsigned long base = dma->dma_base;
90
91 do {
92 unsigned int status;
93
94 status = iomd_readb(base + ST);
95 if (!(status & DMA_ST_INT))
96 return IRQ_HANDLED;
97
98 if ((dma->state ^ status) & DMA_ST_AB)
99 iomd_get_next_sg(&dma->cur_sg, dma);
100
101 switch (status & (DMA_ST_OFL | DMA_ST_AB)) {
102 case DMA_ST_OFL: /* OIA */
103 case DMA_ST_AB: /* .IB */
104 iomd_writel(dma->cur_sg.dma_address, base + CURA);
105 iomd_writel(dma->cur_sg.length, base + ENDA);
106 dma->state = DMA_ST_AB;
107 break;
108
109 case DMA_ST_OFL | DMA_ST_AB: /* OIB */
110 case 0: /* .IA */
111 iomd_writel(dma->cur_sg.dma_address, base + CURB);
112 iomd_writel(dma->cur_sg.length, base + ENDB);
113 dma->state = 0;
114 break;
115 }
116
117 if (status & DMA_ST_OFL &&
118 dma->cur_sg.length == (DMA_END_S|DMA_END_L))
119 break;
120 } while (1);
121
122 dma->state = ~DMA_ST_AB;
123 disable_irq(irq);
124
125 return IRQ_HANDLED;
126 }
127
128 static int iomd_request_dma(dmach_t channel, dma_t *dma)
129 {
130 return request_irq(dma->dma_irq, iomd_dma_handle,
131 IRQF_DISABLED, dma->device_id, dma);
132 }
133
134 static void iomd_free_dma(dmach_t channel, dma_t *dma)
135 {
136 free_irq(dma->dma_irq, dma);
137 }
138
139 static void iomd_enable_dma(dmach_t channel, dma_t *dma)
140 {
141 unsigned long dma_base = dma->dma_base;
142 unsigned int ctrl = TRANSFER_SIZE | DMA_CR_E;
143
144 if (dma->invalid) {
145 dma->invalid = 0;
146
147 /*
148 * Cope with ISA-style drivers which expect cache
149 * coherence.
150 */
151 if (!dma->sg) {
152 dma->sg = &dma->buf;
153 dma->sgcount = 1;
154 dma->buf.length = dma->count;
155 dma->buf.dma_address = dma_map_single(NULL,
156 dma->addr, dma->count,
157 dma->dma_mode == DMA_MODE_READ ?
158 DMA_FROM_DEVICE : DMA_TO_DEVICE);
159 }
160
161 iomd_writeb(DMA_CR_C, dma_base + CR);
162 dma->state = DMA_ST_AB;
163 }
164
165 if (dma->dma_mode == DMA_MODE_READ)
166 ctrl |= DMA_CR_D;
167
168 iomd_writeb(ctrl, dma_base + CR);
169 enable_irq(dma->dma_irq);
170 }
171
172 static void iomd_disable_dma(dmach_t channel, dma_t *dma)
173 {
174 unsigned long dma_base = dma->dma_base;
175 unsigned long flags;
176
177 local_irq_save(flags);
178 if (dma->state != ~DMA_ST_AB)
179 disable_irq(dma->dma_irq);
180 iomd_writeb(0, dma_base + CR);
181 local_irq_restore(flags);
182 }
183
184 static int iomd_set_dma_speed(dmach_t channel, dma_t *dma, int cycle)
185 {
186 int tcr, speed;
187
188 if (cycle < 188)
189 speed = 3;
190 else if (cycle <= 250)
191 speed = 2;
192 else if (cycle < 438)
193 speed = 1;
194 else
195 speed = 0;
196
197 tcr = iomd_readb(IOMD_DMATCR);
198 speed &= 3;
199
200 switch (channel) {
201 case DMA_0:
202 tcr = (tcr & ~0x03) | speed;
203 break;
204
205 case DMA_1:
206 tcr = (tcr & ~0x0c) | (speed << 2);
207 break;
208
209 case DMA_2:
210 tcr = (tcr & ~0x30) | (speed << 4);
211 break;
212
213 case DMA_3:
214 tcr = (tcr & ~0xc0) | (speed << 6);
215 break;
216
217 default:
218 break;
219 }
220
221 iomd_writeb(tcr, IOMD_DMATCR);
222
223 return speed;
224 }
225
226 static struct dma_ops iomd_dma_ops = {
227 .type = "IOMD",
228 .request = iomd_request_dma,
229 .free = iomd_free_dma,
230 .enable = iomd_enable_dma,
231 .disable = iomd_disable_dma,
232 .setspeed = iomd_set_dma_speed,
233 };
234
235 static struct fiq_handler fh = {
236 .name = "floppydma"
237 };
238
239 static void floppy_enable_dma(dmach_t channel, dma_t *dma)
240 {
241 void *fiqhandler_start;
242 unsigned int fiqhandler_length;
243 struct pt_regs regs;
244
245 if (dma->sg)
246 BUG();
247
248 if (dma->dma_mode == DMA_MODE_READ) {
249 extern unsigned char floppy_fiqin_start, floppy_fiqin_end;
250 fiqhandler_start = &floppy_fiqin_start;
251 fiqhandler_length = &floppy_fiqin_end - &floppy_fiqin_start;
252 } else {
253 extern unsigned char floppy_fiqout_start, floppy_fiqout_end;
254 fiqhandler_start = &floppy_fiqout_start;
255 fiqhandler_length = &floppy_fiqout_end - &floppy_fiqout_start;
256 }
257
258 regs.ARM_r9 = dma->count;
259 regs.ARM_r10 = (unsigned long)dma->addr;
260 regs.ARM_fp = (unsigned long)FLOPPYDMA_BASE;
261
262 if (claim_fiq(&fh)) {
263 printk("floppydma: couldn't claim FIQ.\n");
264 return;
265 }
266
267 set_fiq_handler(fiqhandler_start, fiqhandler_length);
268 set_fiq_regs(®s);
269 enable_fiq(dma->dma_irq);
270 }
271
272 static void floppy_disable_dma(dmach_t channel, dma_t *dma)
273 {
274 disable_fiq(dma->dma_irq);
275 release_fiq(&fh);
276 }
277
278 static int floppy_get_residue(dmach_t channel, dma_t *dma)
279 {
280 struct pt_regs regs;
281 get_fiq_regs(®s);
282 return regs.ARM_r9;
283 }
284
285 static struct dma_ops floppy_dma_ops = {
286 .type = "FIQDMA",
287 .enable = floppy_enable_dma,
288 .disable = floppy_disable_dma,
289 .residue = floppy_get_residue,
290 };
291
292 /*
293 * This is virtual DMA - we don't need anything here.
294 */
295 static void sound_enable_disable_dma(dmach_t channel, dma_t *dma)
296 {
297 }
298
299 static struct dma_ops sound_dma_ops = {
300 .type = "VIRTUAL",
301 .enable = sound_enable_disable_dma,
302 .disable = sound_enable_disable_dma,
303 };
304
305 void __init arch_dma_init(dma_t *dma)
306 {
307 iomd_writeb(0, IOMD_IO0CR);
308 iomd_writeb(0, IOMD_IO1CR);
309 iomd_writeb(0, IOMD_IO2CR);
310 iomd_writeb(0, IOMD_IO3CR);
311
312 iomd_writeb(0xa0, IOMD_DMATCR);
313
314 dma[DMA_0].dma_base = IOMD_IO0CURA;
315 dma[DMA_0].dma_irq = IRQ_DMA0;
316 dma[DMA_0].d_ops = &iomd_dma_ops;
317 dma[DMA_1].dma_base = IOMD_IO1CURA;
318 dma[DMA_1].dma_irq = IRQ_DMA1;
319 dma[DMA_1].d_ops = &iomd_dma_ops;
320 dma[DMA_2].dma_base = IOMD_IO2CURA;
321 dma[DMA_2].dma_irq = IRQ_DMA2;
322 dma[DMA_2].d_ops = &iomd_dma_ops;
323 dma[DMA_3].dma_base = IOMD_IO3CURA;
324 dma[DMA_3].dma_irq = IRQ_DMA3;
325 dma[DMA_3].d_ops = &iomd_dma_ops;
326 dma[DMA_S0].dma_base = IOMD_SD0CURA;
327 dma[DMA_S0].dma_irq = IRQ_DMAS0;
328 dma[DMA_S0].d_ops = &iomd_dma_ops;
329 dma[DMA_S1].dma_base = IOMD_SD1CURA;
330 dma[DMA_S1].dma_irq = IRQ_DMAS1;
331 dma[DMA_S1].d_ops = &iomd_dma_ops;
332 dma[DMA_VIRTUAL_FLOPPY].dma_irq = FIQ_FLOPPYDATA;
333 dma[DMA_VIRTUAL_FLOPPY].d_ops = &floppy_dma_ops;
334 dma[DMA_VIRTUAL_SOUND].d_ops = &sound_dma_ops;
335
336 /*
337 * Setup DMA channels 2,3 to be for podules
338 * and channels 0,1 for internal devices
339 */
340 iomd_writeb(DMA_EXT_IO3|DMA_EXT_IO2, IOMD_DMAEXT);
341 }
342
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