nilfs2: fix oopses with doubly mounted snapshots
[linux-2.6/mini2440.git] / arch / arm / mach-rpc / dma.c
blobc47d974d52bdacbe5fddcc40b9a630c2f5a914f0
1 /*
2 * linux/arch/arm/mach-rpc/dma.c
4 * Copyright (C) 1998 Russell King
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.
10 * DMA functions specific to RiscPC architecture
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 #include <linux/io.h>
19 #include <asm/page.h>
20 #include <asm/dma.h>
21 #include <asm/fiq.h>
22 #include <asm/irq.h>
23 #include <mach/hardware.h>
24 #include <asm/uaccess.h>
26 #include <asm/mach/dma.h>
27 #include <asm/hardware/iomd.h>
29 struct iomd_dma {
30 struct dma_struct dma;
31 unsigned int state;
32 unsigned long base; /* Controller base address */
33 int irq; /* Controller IRQ */
34 struct scatterlist cur_sg; /* Current controller buffer */
35 dma_addr_t dma_addr;
36 unsigned int dma_len;
39 #if 0
40 typedef enum {
41 dma_size_8 = 1,
42 dma_size_16 = 2,
43 dma_size_32 = 4,
44 dma_size_128 = 16
45 } dma_size_t;
46 #endif
48 #define TRANSFER_SIZE 2
50 #define CURA (0)
51 #define ENDA (IOMD_IO0ENDA - IOMD_IO0CURA)
52 #define CURB (IOMD_IO0CURB - IOMD_IO0CURA)
53 #define ENDB (IOMD_IO0ENDB - IOMD_IO0CURA)
54 #define CR (IOMD_IO0CR - IOMD_IO0CURA)
55 #define ST (IOMD_IO0ST - IOMD_IO0CURA)
57 static void iomd_get_next_sg(struct scatterlist *sg, struct iomd_dma *idma)
59 unsigned long end, offset, flags = 0;
61 if (idma->dma.sg) {
62 sg->dma_address = idma->dma_addr;
63 offset = sg->dma_address & ~PAGE_MASK;
65 end = offset + idma->dma_len;
67 if (end > PAGE_SIZE)
68 end = PAGE_SIZE;
70 if (offset + TRANSFER_SIZE >= end)
71 flags |= DMA_END_L;
73 sg->length = end - TRANSFER_SIZE;
75 idma->dma_len -= end - offset;
76 idma->dma_addr += end - offset;
78 if (idma->dma_len == 0) {
79 if (idma->dma.sgcount > 1) {
80 idma->dma.sg = sg_next(idma->dma.sg);
81 idma->dma_addr = idma->dma.sg->dma_address;
82 idma->dma_len = idma->dma.sg->length;
83 idma->dma.sgcount--;
84 } else {
85 idma->dma.sg = NULL;
86 flags |= DMA_END_S;
89 } else {
90 flags = DMA_END_S | DMA_END_L;
91 sg->dma_address = 0;
92 sg->length = 0;
95 sg->length |= flags;
98 static irqreturn_t iomd_dma_handle(int irq, void *dev_id)
100 struct iomd_dma *idma = dev_id;
101 unsigned long base = idma->base;
103 do {
104 unsigned int status;
106 status = iomd_readb(base + ST);
107 if (!(status & DMA_ST_INT))
108 return IRQ_HANDLED;
110 if ((idma->state ^ status) & DMA_ST_AB)
111 iomd_get_next_sg(&idma->cur_sg, idma);
113 switch (status & (DMA_ST_OFL | DMA_ST_AB)) {
114 case DMA_ST_OFL: /* OIA */
115 case DMA_ST_AB: /* .IB */
116 iomd_writel(idma->cur_sg.dma_address, base + CURA);
117 iomd_writel(idma->cur_sg.length, base + ENDA);
118 idma->state = DMA_ST_AB;
119 break;
121 case DMA_ST_OFL | DMA_ST_AB: /* OIB */
122 case 0: /* .IA */
123 iomd_writel(idma->cur_sg.dma_address, base + CURB);
124 iomd_writel(idma->cur_sg.length, base + ENDB);
125 idma->state = 0;
126 break;
129 if (status & DMA_ST_OFL &&
130 idma->cur_sg.length == (DMA_END_S|DMA_END_L))
131 break;
132 } while (1);
134 idma->state = ~DMA_ST_AB;
135 disable_irq(irq);
137 return IRQ_HANDLED;
140 static int iomd_request_dma(unsigned int chan, dma_t *dma)
142 struct iomd_dma *idma = container_of(dma, struct iomd_dma, dma);
144 return request_irq(idma->irq, iomd_dma_handle,
145 IRQF_DISABLED, idma->dma.device_id, idma);
148 static void iomd_free_dma(unsigned int chan, dma_t *dma)
150 struct iomd_dma *idma = container_of(dma, struct iomd_dma, dma);
152 free_irq(idma->irq, idma);
155 static void iomd_enable_dma(unsigned int chan, dma_t *dma)
157 struct iomd_dma *idma = container_of(dma, struct iomd_dma, dma);
158 unsigned long dma_base = idma->base;
159 unsigned int ctrl = TRANSFER_SIZE | DMA_CR_E;
161 if (idma->dma.invalid) {
162 idma->dma.invalid = 0;
165 * Cope with ISA-style drivers which expect cache
166 * coherence.
168 if (!idma->dma.sg) {
169 idma->dma.sg = &idma->dma.buf;
170 idma->dma.sgcount = 1;
171 idma->dma.buf.length = idma->dma.count;
172 idma->dma.buf.dma_address = dma_map_single(NULL,
173 idma->dma.addr, idma->dma.count,
174 idma->dma.dma_mode == DMA_MODE_READ ?
175 DMA_FROM_DEVICE : DMA_TO_DEVICE);
178 iomd_writeb(DMA_CR_C, dma_base + CR);
179 idma->state = DMA_ST_AB;
182 if (idma->dma.dma_mode == DMA_MODE_READ)
183 ctrl |= DMA_CR_D;
185 iomd_writeb(ctrl, dma_base + CR);
186 enable_irq(idma->irq);
189 static void iomd_disable_dma(unsigned int chan, dma_t *dma)
191 struct iomd_dma *idma = container_of(dma, struct iomd_dma, dma);
192 unsigned long dma_base = idma->base;
193 unsigned long flags;
195 local_irq_save(flags);
196 if (idma->state != ~DMA_ST_AB)
197 disable_irq(idma->irq);
198 iomd_writeb(0, dma_base + CR);
199 local_irq_restore(flags);
202 static int iomd_set_dma_speed(unsigned int chan, dma_t *dma, int cycle)
204 int tcr, speed;
206 if (cycle < 188)
207 speed = 3;
208 else if (cycle <= 250)
209 speed = 2;
210 else if (cycle < 438)
211 speed = 1;
212 else
213 speed = 0;
215 tcr = iomd_readb(IOMD_DMATCR);
216 speed &= 3;
218 switch (chan) {
219 case DMA_0:
220 tcr = (tcr & ~0x03) | speed;
221 break;
223 case DMA_1:
224 tcr = (tcr & ~0x0c) | (speed << 2);
225 break;
227 case DMA_2:
228 tcr = (tcr & ~0x30) | (speed << 4);
229 break;
231 case DMA_3:
232 tcr = (tcr & ~0xc0) | (speed << 6);
233 break;
235 default:
236 break;
239 iomd_writeb(tcr, IOMD_DMATCR);
241 return speed;
244 static struct dma_ops iomd_dma_ops = {
245 .type = "IOMD",
246 .request = iomd_request_dma,
247 .free = iomd_free_dma,
248 .enable = iomd_enable_dma,
249 .disable = iomd_disable_dma,
250 .setspeed = iomd_set_dma_speed,
253 static struct fiq_handler fh = {
254 .name = "floppydma"
257 struct floppy_dma {
258 struct dma_struct dma;
259 unsigned int fiq;
262 static void floppy_enable_dma(unsigned int chan, dma_t *dma)
264 struct floppy_dma *fdma = container_of(dma, struct floppy_dma, dma);
265 void *fiqhandler_start;
266 unsigned int fiqhandler_length;
267 struct pt_regs regs;
269 if (fdma->dma.sg)
270 BUG();
272 if (fdma->dma.dma_mode == DMA_MODE_READ) {
273 extern unsigned char floppy_fiqin_start, floppy_fiqin_end;
274 fiqhandler_start = &floppy_fiqin_start;
275 fiqhandler_length = &floppy_fiqin_end - &floppy_fiqin_start;
276 } else {
277 extern unsigned char floppy_fiqout_start, floppy_fiqout_end;
278 fiqhandler_start = &floppy_fiqout_start;
279 fiqhandler_length = &floppy_fiqout_end - &floppy_fiqout_start;
282 regs.ARM_r9 = fdma->dma.count;
283 regs.ARM_r10 = (unsigned long)fdma->dma.addr;
284 regs.ARM_fp = (unsigned long)FLOPPYDMA_BASE;
286 if (claim_fiq(&fh)) {
287 printk("floppydma: couldn't claim FIQ.\n");
288 return;
291 set_fiq_handler(fiqhandler_start, fiqhandler_length);
292 set_fiq_regs(&regs);
293 enable_fiq(fdma->fiq);
296 static void floppy_disable_dma(unsigned int chan, dma_t *dma)
298 struct floppy_dma *fdma = container_of(dma, struct floppy_dma, dma);
299 disable_fiq(fdma->fiq);
300 release_fiq(&fh);
303 static int floppy_get_residue(unsigned int chan, dma_t *dma)
305 struct pt_regs regs;
306 get_fiq_regs(&regs);
307 return regs.ARM_r9;
310 static struct dma_ops floppy_dma_ops = {
311 .type = "FIQDMA",
312 .enable = floppy_enable_dma,
313 .disable = floppy_disable_dma,
314 .residue = floppy_get_residue,
318 * This is virtual DMA - we don't need anything here.
320 static void sound_enable_disable_dma(unsigned int chan, dma_t *dma)
324 static struct dma_ops sound_dma_ops = {
325 .type = "VIRTUAL",
326 .enable = sound_enable_disable_dma,
327 .disable = sound_enable_disable_dma,
330 static struct iomd_dma iomd_dma[6];
332 static struct floppy_dma floppy_dma = {
333 .dma = {
334 .d_ops = &floppy_dma_ops,
336 .fiq = FIQ_FLOPPYDATA,
339 static dma_t sound_dma = {
340 .d_ops = &sound_dma_ops,
343 static int __init rpc_dma_init(void)
345 unsigned int i;
346 int ret;
348 iomd_writeb(0, IOMD_IO0CR);
349 iomd_writeb(0, IOMD_IO1CR);
350 iomd_writeb(0, IOMD_IO2CR);
351 iomd_writeb(0, IOMD_IO3CR);
353 iomd_writeb(0xa0, IOMD_DMATCR);
356 * Setup DMA channels 2,3 to be for podules
357 * and channels 0,1 for internal devices
359 iomd_writeb(DMA_EXT_IO3|DMA_EXT_IO2, IOMD_DMAEXT);
361 iomd_dma[DMA_0].base = IOMD_IO0CURA;
362 iomd_dma[DMA_0].irq = IRQ_DMA0;
363 iomd_dma[DMA_1].base = IOMD_IO1CURA;
364 iomd_dma[DMA_1].irq = IRQ_DMA1;
365 iomd_dma[DMA_2].base = IOMD_IO2CURA;
366 iomd_dma[DMA_2].irq = IRQ_DMA2;
367 iomd_dma[DMA_3].base = IOMD_IO3CURA;
368 iomd_dma[DMA_3].irq = IRQ_DMA3;
369 iomd_dma[DMA_S0].base = IOMD_SD0CURA;
370 iomd_dma[DMA_S0].irq = IRQ_DMAS0;
371 iomd_dma[DMA_S1].base = IOMD_SD1CURA;
372 iomd_dma[DMA_S1].irq = IRQ_DMAS1;
374 for (i = DMA_0; i <= DMA_S1; i++) {
375 iomd_dma[i].dma.d_ops = &iomd_dma_ops;
377 ret = isa_dma_add(i, &iomd_dma[i].dma);
378 if (ret)
379 printk("IOMDDMA%u: unable to register: %d\n", i, ret);
382 ret = isa_dma_add(DMA_VIRTUAL_FLOPPY, &floppy_dma.dma);
383 if (ret)
384 printk("IOMDFLOPPY: unable to register: %d\n", ret);
385 ret = isa_dma_add(DMA_VIRTUAL_SOUND, &sound_dma);
386 if (ret)
387 printk("IOMDSOUND: unable to register: %d\n", ret);
388 return 0;
390 core_initcall(rpc_dma_init);