diff options
Diffstat (limited to 'arch/arm/mach-sa1100/dma.c')
-rw-r--r-- | arch/arm/mach-sa1100/dma.c | 348 |
1 files changed, 0 insertions, 348 deletions
diff --git a/arch/arm/mach-sa1100/dma.c b/arch/arm/mach-sa1100/dma.c deleted file mode 100644 index ad660350c296..000000000000 --- a/arch/arm/mach-sa1100/dma.c +++ /dev/null | |||
@@ -1,348 +0,0 @@ | |||
1 | /* | ||
2 | * arch/arm/mach-sa1100/dma.c | ||
3 | * | ||
4 | * Support functions for the SA11x0 internal DMA channels. | ||
5 | * | ||
6 | * Copyright (C) 2000, 2001 by Nicolas Pitre | ||
7 | * | ||
8 | * This program is free software; you can redistribute it and/or modify | ||
9 | * it under the terms of the GNU General Public License version 2 as | ||
10 | * published by the Free Software Foundation. | ||
11 | */ | ||
12 | |||
13 | #include <linux/module.h> | ||
14 | #include <linux/interrupt.h> | ||
15 | #include <linux/init.h> | ||
16 | #include <linux/spinlock.h> | ||
17 | #include <linux/errno.h> | ||
18 | |||
19 | #include <asm/system.h> | ||
20 | #include <asm/irq.h> | ||
21 | #include <mach/hardware.h> | ||
22 | #include <mach/dma.h> | ||
23 | |||
24 | |||
25 | #undef DEBUG | ||
26 | #ifdef DEBUG | ||
27 | #define DPRINTK( s, arg... ) printk( "dma<%p>: " s, regs , ##arg ) | ||
28 | #else | ||
29 | #define DPRINTK( x... ) | ||
30 | #endif | ||
31 | |||
32 | |||
33 | typedef struct { | ||
34 | const char *device_id; /* device name */ | ||
35 | u_long device; /* this channel device, 0 if unused*/ | ||
36 | dma_callback_t callback; /* to call when DMA completes */ | ||
37 | void *data; /* ... with private data ptr */ | ||
38 | } sa1100_dma_t; | ||
39 | |||
40 | static sa1100_dma_t dma_chan[SA1100_DMA_CHANNELS]; | ||
41 | |||
42 | static DEFINE_SPINLOCK(dma_list_lock); | ||
43 | |||
44 | |||
45 | static irqreturn_t dma_irq_handler(int irq, void *dev_id) | ||
46 | { | ||
47 | dma_regs_t *dma_regs = dev_id; | ||
48 | sa1100_dma_t *dma = dma_chan + (((u_int)dma_regs >> 5) & 7); | ||
49 | int status = dma_regs->RdDCSR; | ||
50 | |||
51 | if (status & (DCSR_ERROR)) { | ||
52 | printk(KERN_CRIT "DMA on \"%s\" caused an error\n", dma->device_id); | ||
53 | dma_regs->ClrDCSR = DCSR_ERROR; | ||
54 | } | ||
55 | |||
56 | dma_regs->ClrDCSR = status & (DCSR_DONEA | DCSR_DONEB); | ||
57 | if (dma->callback) { | ||
58 | if (status & DCSR_DONEA) | ||
59 | dma->callback(dma->data); | ||
60 | if (status & DCSR_DONEB) | ||
61 | dma->callback(dma->data); | ||
62 | } | ||
63 | return IRQ_HANDLED; | ||
64 | } | ||
65 | |||
66 | |||
67 | /** | ||
68 | * sa1100_request_dma - allocate one of the SA11x0's DMA channels | ||
69 | * @device: The SA11x0 peripheral targeted by this request | ||
70 | * @device_id: An ascii name for the claiming device | ||
71 | * @callback: Function to be called when the DMA completes | ||
72 | * @data: A cookie passed back to the callback function | ||
73 | * @dma_regs: Pointer to the location of the allocated channel's identifier | ||
74 | * | ||
75 | * This function will search for a free DMA channel and returns the | ||
76 | * address of the hardware registers for that channel as the channel | ||
77 | * identifier. This identifier is written to the location pointed by | ||
78 | * @dma_regs. The list of possible values for @device are listed into | ||
79 | * arch/arm/mach-sa1100/include/mach/dma.h as a dma_device_t enum. | ||
80 | * | ||
81 | * Note that reading from a port and writing to the same port are | ||
82 | * actually considered as two different streams requiring separate | ||
83 | * DMA registrations. | ||
84 | * | ||
85 | * The @callback function is called from interrupt context when one | ||
86 | * of the two possible DMA buffers in flight has terminated. That | ||
87 | * function has to be small and efficient while posponing more complex | ||
88 | * processing to a lower priority execution context. | ||
89 | * | ||
90 | * If no channels are available, or if the desired @device is already in | ||
91 | * use by another DMA channel, then an error code is returned. This | ||
92 | * function must be called before any other DMA calls. | ||
93 | **/ | ||
94 | |||
95 | int sa1100_request_dma (dma_device_t device, const char *device_id, | ||
96 | dma_callback_t callback, void *data, | ||
97 | dma_regs_t **dma_regs) | ||
98 | { | ||
99 | sa1100_dma_t *dma = NULL; | ||
100 | dma_regs_t *regs; | ||
101 | int i, err; | ||
102 | |||
103 | *dma_regs = NULL; | ||
104 | |||
105 | err = 0; | ||
106 | spin_lock(&dma_list_lock); | ||
107 | for (i = 0; i < SA1100_DMA_CHANNELS; i++) { | ||
108 | if (dma_chan[i].device == device) { | ||
109 | err = -EBUSY; | ||
110 | break; | ||
111 | } else if (!dma_chan[i].device && !dma) { | ||
112 | dma = &dma_chan[i]; | ||
113 | } | ||
114 | } | ||
115 | if (!err) { | ||
116 | if (dma) | ||
117 | dma->device = device; | ||
118 | else | ||
119 | err = -ENOSR; | ||
120 | } | ||
121 | spin_unlock(&dma_list_lock); | ||
122 | if (err) | ||
123 | return err; | ||
124 | |||
125 | i = dma - dma_chan; | ||
126 | regs = (dma_regs_t *)&DDAR(i); | ||
127 | err = request_irq(IRQ_DMA0 + i, dma_irq_handler, IRQF_DISABLED, | ||
128 | device_id, regs); | ||
129 | if (err) { | ||
130 | printk(KERN_ERR | ||
131 | "%s: unable to request IRQ %d for %s\n", | ||
132 | __func__, IRQ_DMA0 + i, device_id); | ||
133 | dma->device = 0; | ||
134 | return err; | ||
135 | } | ||
136 | |||
137 | *dma_regs = regs; | ||
138 | dma->device_id = device_id; | ||
139 | dma->callback = callback; | ||
140 | dma->data = data; | ||
141 | |||
142 | regs->ClrDCSR = | ||
143 | (DCSR_DONEA | DCSR_DONEB | DCSR_STRTA | DCSR_STRTB | | ||
144 | DCSR_IE | DCSR_ERROR | DCSR_RUN); | ||
145 | regs->DDAR = device; | ||
146 | |||
147 | return 0; | ||
148 | } | ||
149 | |||
150 | |||
151 | /** | ||
152 | * sa1100_free_dma - free a SA11x0 DMA channel | ||
153 | * @regs: identifier for the channel to free | ||
154 | * | ||
155 | * This clears all activities on a given DMA channel and releases it | ||
156 | * for future requests. The @regs identifier is provided by a | ||
157 | * successful call to sa1100_request_dma(). | ||
158 | **/ | ||
159 | |||
160 | void sa1100_free_dma(dma_regs_t *regs) | ||
161 | { | ||
162 | int i; | ||
163 | |||
164 | for (i = 0; i < SA1100_DMA_CHANNELS; i++) | ||
165 | if (regs == (dma_regs_t *)&DDAR(i)) | ||
166 | break; | ||
167 | if (i >= SA1100_DMA_CHANNELS) { | ||
168 | printk(KERN_ERR "%s: bad DMA identifier\n", __func__); | ||
169 | return; | ||
170 | } | ||
171 | |||
172 | if (!dma_chan[i].device) { | ||
173 | printk(KERN_ERR "%s: Trying to free free DMA\n", __func__); | ||
174 | return; | ||
175 | } | ||
176 | |||
177 | regs->ClrDCSR = | ||
178 | (DCSR_DONEA | DCSR_DONEB | DCSR_STRTA | DCSR_STRTB | | ||
179 | DCSR_IE | DCSR_ERROR | DCSR_RUN); | ||
180 | free_irq(IRQ_DMA0 + i, regs); | ||
181 | dma_chan[i].device = 0; | ||
182 | } | ||
183 | |||
184 | |||
185 | /** | ||
186 | * sa1100_start_dma - submit a data buffer for DMA | ||
187 | * @regs: identifier for the channel to use | ||
188 | * @dma_ptr: buffer physical (or bus) start address | ||
189 | * @size: buffer size | ||
190 | * | ||
191 | * This function hands the given data buffer to the hardware for DMA | ||
192 | * access. If another buffer is already in flight then this buffer | ||
193 | * will be queued so the DMA engine will switch to it automatically | ||
194 | * when the previous one is done. The DMA engine is actually toggling | ||
195 | * between two buffers so at most 2 successful calls can be made before | ||
196 | * one of them terminates and the callback function is called. | ||
197 | * | ||
198 | * The @regs identifier is provided by a successful call to | ||
199 | * sa1100_request_dma(). | ||
200 | * | ||
201 | * The @size must not be larger than %MAX_DMA_SIZE. If a given buffer | ||
202 | * is larger than that then it's the caller's responsibility to split | ||
203 | * it into smaller chunks and submit them separately. If this is the | ||
204 | * case then a @size of %CUT_DMA_SIZE is recommended to avoid ending | ||
205 | * up with too small chunks. The callback function can be used to chain | ||
206 | * submissions of buffer chunks. | ||
207 | * | ||
208 | * Error return values: | ||
209 | * %-EOVERFLOW: Given buffer size is too big. | ||
210 | * %-EBUSY: Both DMA buffers are already in use. | ||
211 | * %-EAGAIN: Both buffers were busy but one of them just completed | ||
212 | * but the interrupt handler has to execute first. | ||
213 | * | ||
214 | * This function returs 0 on success. | ||
215 | **/ | ||
216 | |||
217 | int sa1100_start_dma(dma_regs_t *regs, dma_addr_t dma_ptr, u_int size) | ||
218 | { | ||
219 | unsigned long flags; | ||
220 | u_long status; | ||
221 | int ret; | ||
222 | |||
223 | if (dma_ptr & 3) | ||
224 | printk(KERN_WARNING "DMA: unaligned start address (0x%08lx)\n", | ||
225 | (unsigned long)dma_ptr); | ||
226 | |||
227 | if (size > MAX_DMA_SIZE) | ||
228 | return -EOVERFLOW; | ||
229 | |||
230 | local_irq_save(flags); | ||
231 | status = regs->RdDCSR; | ||
232 | |||
233 | /* If both DMA buffers are started, there's nothing else we can do. */ | ||
234 | if ((status & (DCSR_STRTA | DCSR_STRTB)) == (DCSR_STRTA | DCSR_STRTB)) { | ||
235 | DPRINTK("start: st %#x busy\n", status); | ||
236 | ret = -EBUSY; | ||
237 | goto out; | ||
238 | } | ||
239 | |||
240 | if (((status & DCSR_BIU) && (status & DCSR_STRTB)) || | ||
241 | (!(status & DCSR_BIU) && !(status & DCSR_STRTA))) { | ||
242 | if (status & DCSR_DONEA) { | ||
243 | /* give a chance for the interrupt to be processed */ | ||
244 | ret = -EAGAIN; | ||
245 | goto out; | ||
246 | } | ||
247 | regs->DBSA = dma_ptr; | ||
248 | regs->DBTA = size; | ||
249 | regs->SetDCSR = DCSR_STRTA | DCSR_IE | DCSR_RUN; | ||
250 | DPRINTK("start a=%#x s=%d on A\n", dma_ptr, size); | ||
251 | } else { | ||
252 | if (status & DCSR_DONEB) { | ||
253 | /* give a chance for the interrupt to be processed */ | ||
254 | ret = -EAGAIN; | ||
255 | goto out; | ||
256 | } | ||
257 | regs->DBSB = dma_ptr; | ||
258 | regs->DBTB = size; | ||
259 | regs->SetDCSR = DCSR_STRTB | DCSR_IE | DCSR_RUN; | ||
260 | DPRINTK("start a=%#x s=%d on B\n", dma_ptr, size); | ||
261 | } | ||
262 | ret = 0; | ||
263 | |||
264 | out: | ||
265 | local_irq_restore(flags); | ||
266 | return ret; | ||
267 | } | ||
268 | |||
269 | |||
270 | /** | ||
271 | * sa1100_get_dma_pos - return current DMA position | ||
272 | * @regs: identifier for the channel to use | ||
273 | * | ||
274 | * This function returns the current physical (or bus) address for the | ||
275 | * given DMA channel. If the channel is running i.e. not in a stopped | ||
276 | * state then the caller must disable interrupts prior calling this | ||
277 | * function and process the returned value before re-enabling them to | ||
278 | * prevent races with the completion interrupt handler and the callback | ||
279 | * function. The validation of the returned value is the caller's | ||
280 | * responsibility as well -- the hardware seems to return out of range | ||
281 | * values when the DMA engine completes a buffer. | ||
282 | * | ||
283 | * The @regs identifier is provided by a successful call to | ||
284 | * sa1100_request_dma(). | ||
285 | **/ | ||
286 | |||
287 | dma_addr_t sa1100_get_dma_pos(dma_regs_t *regs) | ||
288 | { | ||
289 | int status; | ||
290 | |||
291 | /* | ||
292 | * We must determine whether buffer A or B is active. | ||
293 | * Two possibilities: either we are in the middle of | ||
294 | * a buffer, or the DMA controller just switched to the | ||
295 | * next toggle but the interrupt hasn't been serviced yet. | ||
296 | * The former case is straight forward. In the later case, | ||
297 | * we'll do like if DMA is just at the end of the previous | ||
298 | * toggle since all registers haven't been reset yet. | ||
299 | * This goes around the edge case and since we're always | ||
300 | * a little behind anyways it shouldn't make a big difference. | ||
301 | * If DMA has been stopped prior calling this then the | ||
302 | * position is exact. | ||
303 | */ | ||
304 | status = regs->RdDCSR; | ||
305 | if ((!(status & DCSR_BIU) && (status & DCSR_STRTA)) || | ||
306 | ( (status & DCSR_BIU) && !(status & DCSR_STRTB))) | ||
307 | return regs->DBSA; | ||
308 | else | ||
309 | return regs->DBSB; | ||
310 | } | ||
311 | |||
312 | |||
313 | /** | ||
314 | * sa1100_reset_dma - reset a DMA channel | ||
315 | * @regs: identifier for the channel to use | ||
316 | * | ||
317 | * This function resets and reconfigure the given DMA channel. This is | ||
318 | * particularly useful after a sleep/wakeup event. | ||
319 | * | ||
320 | * The @regs identifier is provided by a successful call to | ||
321 | * sa1100_request_dma(). | ||
322 | **/ | ||
323 | |||
324 | void sa1100_reset_dma(dma_regs_t *regs) | ||
325 | { | ||
326 | int i; | ||
327 | |||
328 | for (i = 0; i < SA1100_DMA_CHANNELS; i++) | ||
329 | if (regs == (dma_regs_t *)&DDAR(i)) | ||
330 | break; | ||
331 | if (i >= SA1100_DMA_CHANNELS) { | ||
332 | printk(KERN_ERR "%s: bad DMA identifier\n", __func__); | ||
333 | return; | ||
334 | } | ||
335 | |||
336 | regs->ClrDCSR = | ||
337 | (DCSR_DONEA | DCSR_DONEB | DCSR_STRTA | DCSR_STRTB | | ||
338 | DCSR_IE | DCSR_ERROR | DCSR_RUN); | ||
339 | regs->DDAR = dma_chan[i].device; | ||
340 | } | ||
341 | |||
342 | |||
343 | EXPORT_SYMBOL(sa1100_request_dma); | ||
344 | EXPORT_SYMBOL(sa1100_free_dma); | ||
345 | EXPORT_SYMBOL(sa1100_start_dma); | ||
346 | EXPORT_SYMBOL(sa1100_get_dma_pos); | ||
347 | EXPORT_SYMBOL(sa1100_reset_dma); | ||
348 | |||