1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Isochronous I/O functionality:
4 * - Isochronous DMA context management
5 * - Isochronous bus resource management (channels, bandwidth), client side
6 *
7 * Copyright (C) 2006 Kristian Hoegsberg <krh@bitplanet.net>
8 */
9
10#include <linux/dma-mapping.h>
11#include <linux/errno.h>
12#include <linux/firewire.h>
13#include <linux/firewire-constants.h>
14#include <linux/kernel.h>
15#include <linux/mm.h>
16#include <linux/slab.h>
17#include <linux/spinlock.h>
18#include <linux/vmalloc.h>
19#include <linux/export.h>
20
21#include <asm/byteorder.h>
22
23#include "core.h"
24
25#include <trace/events/firewire.h>
26
27/*
28 * Isochronous DMA context management
29 */
30
31int fw_iso_buffer_alloc(struct fw_iso_buffer *buffer, int page_count)
32{
33 int i;
34
35 buffer->page_count = 0;
36 buffer->page_count_mapped = 0;
37 buffer->pages = kmalloc_array(page_count, sizeof(buffer->pages[0]),
38 GFP_KERNEL);
39 if (buffer->pages == NULL)
40 return -ENOMEM;
41
42 for (i = 0; i < page_count; i++) {
43 buffer->pages[i] = alloc_page(GFP_KERNEL | GFP_DMA32 | __GFP_ZERO);
44 if (buffer->pages[i] == NULL)
45 break;
46 }
47 buffer->page_count = i;
48 if (i < page_count) {
49 fw_iso_buffer_destroy(buffer, NULL);
50 return -ENOMEM;
51 }
52
53 return 0;
54}
55
56int fw_iso_buffer_map_dma(struct fw_iso_buffer *buffer, struct fw_card *card,
57 enum dma_data_direction direction)
58{
59 dma_addr_t address;
60 int i;
61
62 buffer->direction = direction;
63
64 for (i = 0; i < buffer->page_count; i++) {
65 address = dma_map_page(card->device, buffer->pages[i],
66 0, PAGE_SIZE, direction);
67 if (dma_mapping_error(dev: card->device, dma_addr: address))
68 break;
69
70 set_page_private(page: buffer->pages[i], private: address);
71 }
72 buffer->page_count_mapped = i;
73 if (i < buffer->page_count)
74 return -ENOMEM;
75
76 return 0;
77}
78
79int fw_iso_buffer_init(struct fw_iso_buffer *buffer, struct fw_card *card,
80 int page_count, enum dma_data_direction direction)
81{
82 int ret;
83
84 ret = fw_iso_buffer_alloc(buffer, page_count);
85 if (ret < 0)
86 return ret;
87
88 ret = fw_iso_buffer_map_dma(buffer, card, direction);
89 if (ret < 0)
90 fw_iso_buffer_destroy(buffer, card);
91
92 return ret;
93}
94EXPORT_SYMBOL(fw_iso_buffer_init);
95
96void fw_iso_buffer_destroy(struct fw_iso_buffer *buffer,
97 struct fw_card *card)
98{
99 int i;
100 dma_addr_t address;
101
102 for (i = 0; i < buffer->page_count_mapped; i++) {
103 address = page_private(buffer->pages[i]);
104 dma_unmap_page(card->device, address,
105 PAGE_SIZE, buffer->direction);
106 }
107 for (i = 0; i < buffer->page_count; i++)
108 __free_page(buffer->pages[i]);
109
110 kfree(objp: buffer->pages);
111 buffer->pages = NULL;
112 buffer->page_count = 0;
113 buffer->page_count_mapped = 0;
114}
115EXPORT_SYMBOL(fw_iso_buffer_destroy);
116
117/* Convert DMA address to offset into virtually contiguous buffer. */
118size_t fw_iso_buffer_lookup(struct fw_iso_buffer *buffer, dma_addr_t completed)
119{
120 size_t i;
121 dma_addr_t address;
122 ssize_t offset;
123
124 for (i = 0; i < buffer->page_count; i++) {
125 address = page_private(buffer->pages[i]);
126 offset = (ssize_t)completed - (ssize_t)address;
127 if (offset > 0 && offset <= PAGE_SIZE)
128 return (i << PAGE_SHIFT) + offset;
129 }
130
131 return 0;
132}
133
134struct fw_iso_context *fw_iso_context_create(struct fw_card *card,
135 int type, int channel, int speed, size_t header_size,
136 fw_iso_callback_t callback, void *callback_data)
137{
138 struct fw_iso_context *ctx;
139
140 ctx = card->driver->allocate_iso_context(card,
141 type, channel, header_size);
142 if (IS_ERR(ptr: ctx))
143 return ctx;
144
145 ctx->card = card;
146 ctx->type = type;
147 ctx->channel = channel;
148 ctx->speed = speed;
149 ctx->header_size = header_size;
150 ctx->callback.sc = callback;
151 ctx->callback_data = callback_data;
152
153 trace_isoc_outbound_allocate(ctx, channel, scode: speed);
154 trace_isoc_inbound_single_allocate(ctx, channel, header_size);
155 trace_isoc_inbound_multiple_allocate(ctx);
156
157 return ctx;
158}
159EXPORT_SYMBOL(fw_iso_context_create);
160
161void fw_iso_context_destroy(struct fw_iso_context *ctx)
162{
163 trace_isoc_outbound_destroy(ctx);
164 trace_isoc_inbound_single_destroy(ctx);
165 trace_isoc_inbound_multiple_destroy(ctx);
166
167 ctx->card->driver->free_iso_context(ctx);
168}
169EXPORT_SYMBOL(fw_iso_context_destroy);
170
171int fw_iso_context_start(struct fw_iso_context *ctx,
172 int cycle, int sync, int tags)
173{
174 trace_isoc_outbound_start(ctx, cycle_match: cycle);
175 trace_isoc_inbound_single_start(ctx, cycle_match: cycle, sync, tags);
176 trace_isoc_inbound_multiple_start(ctx, cycle_match: cycle, sync, tags);
177
178 return ctx->card->driver->start_iso(ctx, cycle, sync, tags);
179}
180EXPORT_SYMBOL(fw_iso_context_start);
181
182int fw_iso_context_set_channels(struct fw_iso_context *ctx, u64 *channels)
183{
184 trace_isoc_inbound_multiple_channels(ctx, channels: *channels);
185
186 return ctx->card->driver->set_iso_channels(ctx, channels);
187}
188
189int fw_iso_context_queue(struct fw_iso_context *ctx,
190 struct fw_iso_packet *packet,
191 struct fw_iso_buffer *buffer,
192 unsigned long payload)
193{
194 trace_isoc_outbound_queue(ctx, buffer_offset: payload, packet);
195 trace_isoc_inbound_single_queue(ctx, buffer_offset: payload, packet);
196 trace_isoc_inbound_multiple_queue(ctx, buffer_offset: payload, packet);
197
198 return ctx->card->driver->queue_iso(ctx, packet, buffer, payload);
199}
200EXPORT_SYMBOL(fw_iso_context_queue);
201
202void fw_iso_context_queue_flush(struct fw_iso_context *ctx)
203{
204 trace_isoc_outbound_flush(ctx);
205 trace_isoc_inbound_single_flush(ctx);
206 trace_isoc_inbound_multiple_flush(ctx);
207
208 ctx->card->driver->flush_queue_iso(ctx);
209}
210EXPORT_SYMBOL(fw_iso_context_queue_flush);
211
212/**
213 * fw_iso_context_flush_completions() - process isochronous context in current process context.
214 * @ctx: the isochronous context
215 *
216 * Process the isochronous context in the current process context. The registered callback function
217 * is called when a queued packet buffer with the interrupt flag is completed, either after
218 * transmission in the IT context or after being filled in the IR context. Additionally, the
219 * callback function is also called for the packet buffer completed at last. Furthermore, the
220 * callback function is called as well when the header buffer in the context becomes full. If it is
221 * required to process the context asynchronously, fw_iso_context_schedule_flush_completions() is
222 * available instead.
223 *
224 * Context: Process context. May sleep due to disable_work_sync().
225 */
226int fw_iso_context_flush_completions(struct fw_iso_context *ctx)
227{
228 int err;
229
230 trace_isoc_outbound_flush_completions(ctx);
231 trace_isoc_inbound_single_flush_completions(ctx);
232 trace_isoc_inbound_multiple_flush_completions(ctx);
233
234 might_sleep();
235
236 // Avoid dead lock due to programming mistake.
237 if (WARN_ON_ONCE(current_work() == &ctx->work))
238 return 0;
239
240 disable_work_sync(work: &ctx->work);
241
242 err = ctx->card->driver->flush_iso_completions(ctx);
243
244 enable_work(work: &ctx->work);
245
246 return err;
247}
248EXPORT_SYMBOL(fw_iso_context_flush_completions);
249
250int fw_iso_context_stop(struct fw_iso_context *ctx)
251{
252 int err;
253
254 trace_isoc_outbound_stop(ctx);
255 trace_isoc_inbound_single_stop(ctx);
256 trace_isoc_inbound_multiple_stop(ctx);
257
258 might_sleep();
259
260 // Avoid dead lock due to programming mistake.
261 if (WARN_ON_ONCE(current_work() == &ctx->work))
262 return 0;
263
264 err = ctx->card->driver->stop_iso(ctx);
265
266 cancel_work_sync(work: &ctx->work);
267
268 return err;
269}
270EXPORT_SYMBOL(fw_iso_context_stop);
271
272/*
273 * Isochronous bus resource management (channels, bandwidth), client side
274 */
275
276static int manage_bandwidth(struct fw_card *card, int irm_id, int generation,
277 int bandwidth, bool allocate)
278{
279 int try, new, old = allocate ? BANDWIDTH_AVAILABLE_INITIAL : 0;
280 __be32 data[2];
281
282 /*
283 * On a 1394a IRM with low contention, try < 1 is enough.
284 * On a 1394-1995 IRM, we need at least try < 2.
285 * Let's just do try < 5.
286 */
287 for (try = 0; try < 5; try++) {
288 new = allocate ? old - bandwidth : old + bandwidth;
289 if (new < 0 || new > BANDWIDTH_AVAILABLE_INITIAL)
290 return -EBUSY;
291
292 data[0] = cpu_to_be32(old);
293 data[1] = cpu_to_be32(new);
294 switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
295 destination_id: irm_id, generation, SCODE_100,
296 CSR_REGISTER_BASE + CSR_BANDWIDTH_AVAILABLE,
297 payload: data, length: 8)) {
298 case RCODE_GENERATION:
299 /* A generation change frees all bandwidth. */
300 return allocate ? -EAGAIN : bandwidth;
301
302 case RCODE_COMPLETE:
303 if (be32_to_cpup(p: data) == old)
304 return bandwidth;
305
306 old = be32_to_cpup(p: data);
307 /* Fall through. */
308 }
309 }
310
311 return -EIO;
312}
313
314static int manage_channel(struct fw_card *card, int irm_id, int generation,
315 u32 channels_mask, u64 offset, bool allocate)
316{
317 __be32 bit, all, old;
318 __be32 data[2];
319 int channel, ret = -EIO, retry = 5;
320
321 old = all = allocate ? cpu_to_be32(~0) : 0;
322
323 for (channel = 0; channel < 32; channel++) {
324 if (!(channels_mask & 1 << channel))
325 continue;
326
327 ret = -EBUSY;
328
329 bit = cpu_to_be32(1 << (31 - channel));
330 if ((old & bit) != (all & bit))
331 continue;
332
333 data[0] = old;
334 data[1] = old ^ bit;
335 switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
336 destination_id: irm_id, generation, SCODE_100,
337 offset, payload: data, length: 8)) {
338 case RCODE_GENERATION:
339 /* A generation change frees all channels. */
340 return allocate ? -EAGAIN : channel;
341
342 case RCODE_COMPLETE:
343 if (data[0] == old)
344 return channel;
345
346 old = data[0];
347
348 /* Is the IRM 1394a-2000 compliant? */
349 if ((data[0] & bit) == (data[1] & bit))
350 continue;
351
352 fallthrough; /* It's a 1394-1995 IRM, retry */
353 default:
354 if (retry) {
355 retry--;
356 channel--;
357 } else {
358 ret = -EIO;
359 }
360 }
361 }
362
363 return ret;
364}
365
366static void deallocate_channel(struct fw_card *card, int irm_id,
367 int generation, int channel)
368{
369 u32 mask;
370 u64 offset;
371
372 mask = channel < 32 ? 1 << channel : 1 << (channel - 32);
373 offset = channel < 32 ? CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI :
374 CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO;
375
376 manage_channel(card, irm_id, generation, channels_mask: mask, offset, allocate: false);
377}
378
379/**
380 * fw_iso_resource_manage() - Allocate or deallocate a channel and/or bandwidth
381 * @card: card interface for this action
382 * @generation: bus generation
383 * @channels_mask: bitmask for channel allocation
384 * @channel: pointer for returning channel allocation result
385 * @bandwidth: pointer for returning bandwidth allocation result
386 * @allocate: whether to allocate (true) or deallocate (false)
387 *
388 * In parameters: card, generation, channels_mask, bandwidth, allocate
389 * Out parameters: channel, bandwidth
390 *
391 * This function blocks (sleeps) during communication with the IRM.
392 *
393 * Allocates or deallocates at most one channel out of channels_mask.
394 * channels_mask is a bitfield with MSB for channel 63 and LSB for channel 0.
395 * (Note, the IRM's CHANNELS_AVAILABLE is a big-endian bitfield with MSB for
396 * channel 0 and LSB for channel 63.)
397 * Allocates or deallocates as many bandwidth allocation units as specified.
398 *
399 * Returns channel < 0 if no channel was allocated or deallocated.
400 * Returns bandwidth = 0 if no bandwidth was allocated or deallocated.
401 *
402 * If generation is stale, deallocations succeed but allocations fail with
403 * channel = -EAGAIN.
404 *
405 * If channel allocation fails, no bandwidth will be allocated either.
406 * If bandwidth allocation fails, no channel will be allocated either.
407 * But deallocations of channel and bandwidth are tried independently
408 * of each other's success.
409 */
410void fw_iso_resource_manage(struct fw_card *card, int generation,
411 u64 channels_mask, int *channel, int *bandwidth,
412 bool allocate)
413{
414 u32 channels_hi = channels_mask; /* channels 31...0 */
415 u32 channels_lo = channels_mask >> 32; /* channels 63...32 */
416 int irm_id, ret, c = -EINVAL;
417
418 scoped_guard(spinlock_irq, &card->lock)
419 irm_id = card->irm_node->node_id;
420
421 if (channels_hi)
422 c = manage_channel(card, irm_id, generation, channels_mask: channels_hi,
423 CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI,
424 allocate);
425 if (channels_lo && c < 0) {
426 c = manage_channel(card, irm_id, generation, channels_mask: channels_lo,
427 CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO,
428 allocate);
429 if (c >= 0)
430 c += 32;
431 }
432 *channel = c;
433
434 if (allocate && channels_mask != 0 && c < 0)
435 *bandwidth = 0;
436
437 if (*bandwidth == 0)
438 return;
439
440 ret = manage_bandwidth(card, irm_id, generation, bandwidth: *bandwidth, allocate);
441 if (ret < 0)
442 *bandwidth = 0;
443
444 if (allocate && ret < 0) {
445 if (c >= 0)
446 deallocate_channel(card, irm_id, generation, channel: c);
447 *channel = ret;
448 }
449}
450EXPORT_SYMBOL(fw_iso_resource_manage);
451

source code of linux/drivers/firewire/core-iso.c