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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 <[email protected]>
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 struct page **page_array __free(kfree) = kzalloc_objs(page_array[0],
34 page_count);
35
36 if (!page_array)
37 return -ENOMEM;
38
39 // Retrieve noncontiguous pages. The descriptors for 1394 OHCI isochronous DMA contexts
40 // have a set of address and length per each, while the reason to use pages is the
41 // convenience to map them into virtual address space of user process.
42 unsigned long nr_populated = alloc_pages_bulk(GFP_KERNEL | GFP_DMA32 | __GFP_ZERO,
43 page_count, page_array);
44 if (nr_populated != page_count) {
45 // Assuming the above call fills page_array sequentially from the beginning.
46 release_pages(page_array, nr_populated);
47 return -ENOMEM;
48 }
49
50 buffer->page_count = page_count;
51 buffer->pages = no_free_ptr(page_array);
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 *dma_addrs __free(kfree) = kzalloc_objs(dma_addrs[0],
60 buffer->page_count);
61 int i;
62
63 if (!dma_addrs)
64 return -ENOMEM;
65
66 // Retrieve DMA mapping addresses for the pages. They are not contiguous. Maintain the cache
67 // coherency for the pages by hand.
68 for (i = 0; i < buffer->page_count; i++) {
69 // The dma_map_phys() with a physical address per page is available here, instead.
70 dma_addr_t dma_addr = dma_map_page(card->device, buffer->pages[i], 0, PAGE_SIZE,
71 direction);
72 if (dma_mapping_error(card->device, dma_addr))
73 break;
74
75 dma_addrs[i] = dma_addr;
76 }
77 if (i < buffer->page_count) {
78 while (i-- > 0)
79 dma_unmap_page(card->device, dma_addrs[i], PAGE_SIZE, buffer->direction);
80 return -ENOMEM;
81 }
82
83 buffer->direction = direction;
84 buffer->dma_addrs = no_free_ptr(dma_addrs);
85
86 return 0;
87}
88
89int fw_iso_buffer_init(struct fw_iso_buffer *buffer, struct fw_card *card,
90 int page_count, enum dma_data_direction direction)
91{
92 int ret;
93
94 ret = fw_iso_buffer_alloc(buffer, page_count);
95 if (ret < 0)
96 return ret;
97
98 ret = fw_iso_buffer_map_dma(buffer, card, direction);
99 if (ret < 0)
100 fw_iso_buffer_destroy(buffer, card);
101
102 return ret;
103}
104EXPORT_SYMBOL(fw_iso_buffer_init);
105
106void fw_iso_buffer_destroy(struct fw_iso_buffer *buffer,
107 struct fw_card *card)
108{
109 if (buffer->dma_addrs) {
110 for (int i = 0; i < buffer->page_count; ++i) {
111 dma_addr_t dma_addr = buffer->dma_addrs[i];
112 dma_unmap_page(card->device, dma_addr, PAGE_SIZE, buffer->direction);
113 }
114 kfree(buffer->dma_addrs);
115 buffer->dma_addrs = NULL;
116 }
117
118 if (buffer->pages) {
119 release_pages(buffer->pages, buffer->page_count);
120 kfree(buffer->pages);
121 buffer->pages = NULL;
122 }
123
124 buffer->page_count = 0;
125}
126EXPORT_SYMBOL(fw_iso_buffer_destroy);
127
128/* Convert DMA address to offset into virtually contiguous buffer. */
129size_t fw_iso_buffer_lookup(struct fw_iso_buffer *buffer, dma_addr_t completed)
130{
131 for (int i = 0; i < buffer->page_count; i++) {
132 dma_addr_t dma_addr = buffer->dma_addrs[i];
133 ssize_t offset = (ssize_t)completed - (ssize_t)dma_addr;
134 if (offset > 0 && offset <= PAGE_SIZE)
135 return (i << PAGE_SHIFT) + offset;
136 }
137
138 return 0;
139}
140
141struct fw_iso_context *__fw_iso_context_create(struct fw_card *card, int type, int channel,
142 int speed, size_t header_size, size_t header_storage_size,
143 union fw_iso_callback callback, void *callback_data)
144{
145 struct fw_iso_context *ctx;
146
147 ctx = card->driver->allocate_iso_context(card, type, channel, header_size,
148 header_storage_size);
149 if (IS_ERR(ctx))
150 return ctx;
151
152 ctx->card = card;
153 ctx->type = type;
154 ctx->channel = channel;
155 ctx->speed = speed;
156 ctx->flags = 0;
157 ctx->header_size = header_size;
158 ctx->header_storage_size = header_storage_size;
159 ctx->callback = callback;
160 ctx->callback_data = callback_data;
161
162 trace_isoc_outbound_allocate(ctx, channel, speed);
163 trace_isoc_inbound_single_allocate(ctx, channel, header_size);
164 trace_isoc_inbound_multiple_allocate(ctx);
165
166 return ctx;
167}
168EXPORT_SYMBOL(__fw_iso_context_create);
169
170void fw_iso_context_destroy(struct fw_iso_context *ctx)
171{
172 trace_isoc_outbound_destroy(ctx);
173 trace_isoc_inbound_single_destroy(ctx);
174 trace_isoc_inbound_multiple_destroy(ctx);
175
176 ctx->card->driver->free_iso_context(ctx);
177}
178EXPORT_SYMBOL(fw_iso_context_destroy);
179
180int fw_iso_context_start(struct fw_iso_context *ctx,
181 int cycle, int sync, int tags)
182{
183 trace_isoc_outbound_start(ctx, cycle);
184 trace_isoc_inbound_single_start(ctx, cycle, sync, tags);
185 trace_isoc_inbound_multiple_start(ctx, cycle, sync, tags);
186
187 return ctx->card->driver->start_iso(ctx, cycle, sync, tags);
188}
189EXPORT_SYMBOL(fw_iso_context_start);
190
191int fw_iso_context_set_channels(struct fw_iso_context *ctx, u64 *channels)
192{
193 trace_isoc_inbound_multiple_channels(ctx, *channels);
194
195 return ctx->card->driver->set_iso_channels(ctx, channels);
196}
197
198int fw_iso_context_queue(struct fw_iso_context *ctx,
199 struct fw_iso_packet *packet,
200 struct fw_iso_buffer *buffer,
201 unsigned long payload)
202{
203 trace_isoc_outbound_queue(ctx, payload, packet);
204 trace_isoc_inbound_single_queue(ctx, payload, packet);
205 trace_isoc_inbound_multiple_queue(ctx, payload, packet);
206
207 return ctx->card->driver->queue_iso(ctx, packet, buffer, payload);
208}
209EXPORT_SYMBOL(fw_iso_context_queue);
210
211void fw_iso_context_queue_flush(struct fw_iso_context *ctx)
212{
213 trace_isoc_outbound_flush(ctx);
214 trace_isoc_inbound_single_flush(ctx);
215 trace_isoc_inbound_multiple_flush(ctx);
216
217 ctx->card->driver->flush_queue_iso(ctx);
218}
219EXPORT_SYMBOL(fw_iso_context_queue_flush);
220
221/**
222 * fw_iso_context_flush_completions() - process isochronous context in current process context.
223 * @ctx: the isochronous context
224 *
225 * Process the isochronous context in the current process context. The registered callback function
226 * is called when a queued packet buffer with the interrupt flag is completed, either after
227 * transmission in the IT context or after being filled in the IR context. Additionally, the
228 * callback function is also called for the packet buffer completed at last. Furthermore, the
229 * callback function is called as well when the header buffer in the context becomes full. If it is
230 * required to process the context asynchronously, fw_iso_context_schedule_flush_completions() is
231 * available instead.
232 *
233 * Context: Process context. May sleep due to disable_work_sync().
234 */
235int fw_iso_context_flush_completions(struct fw_iso_context *ctx)
236{
237 int err;
238
239 trace_isoc_outbound_flush_completions(ctx);
240 trace_isoc_inbound_single_flush_completions(ctx);
241 trace_isoc_inbound_multiple_flush_completions(ctx);
242
243 might_sleep();
244
245 // Avoid dead lock due to programming mistake.
246 if (WARN_ON_ONCE(current_work() == &ctx->work))
247 return 0;
248
249 disable_work_sync(&ctx->work);
250
251 err = ctx->card->driver->flush_iso_completions(ctx);
252
253 enable_work(&ctx->work);
254
255 return err;
256}
257EXPORT_SYMBOL(fw_iso_context_flush_completions);
258
259int fw_iso_context_stop(struct fw_iso_context *ctx)
260{
261 int err;
262
263 trace_isoc_outbound_stop(ctx);
264 trace_isoc_inbound_single_stop(ctx);
265 trace_isoc_inbound_multiple_stop(ctx);
266
267 might_sleep();
268
269 // Avoid dead lock due to programming mistake.
270 if (WARN_ON_ONCE(current_work() == &ctx->work))
271 return 0;
272
273 err = ctx->card->driver->stop_iso(ctx);
274
275 cancel_work_sync(&ctx->work);
276
277 return err;
278}
279EXPORT_SYMBOL(fw_iso_context_stop);
280
281/*
282 * Isochronous bus resource management (channels, bandwidth), client side
283 */
284
285static int manage_bandwidth(struct fw_card *card, int irm_id, int generation,
286 int bandwidth, bool allocate)
287{
288 int try, new, old = allocate ? BANDWIDTH_AVAILABLE_INITIAL : 0;
289 __be32 data[2];
290
291 /*
292 * On a 1394a IRM with low contention, try < 1 is enough.
293 * On a 1394-1995 IRM, we need at least try < 2.
294 * Let's just do try < 5.
295 */
296 for (try = 0; try < 5; try++) {
297 new = allocate ? old - bandwidth : old + bandwidth;
298 if (new < 0 || new > BANDWIDTH_AVAILABLE_INITIAL)
299 return -EBUSY;
300
301 data[0] = cpu_to_be32(old);
302 data[1] = cpu_to_be32(new);
303 switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
304 irm_id, generation, SCODE_100,
305 CSR_REGISTER_BASE + CSR_BANDWIDTH_AVAILABLE,
306 data, 8)) {
307 case RCODE_GENERATION:
308 /* A generation change frees all bandwidth. */
309 return allocate ? -EAGAIN : bandwidth;
310
311 case RCODE_COMPLETE:
312 if (be32_to_cpup(data) == old)
313 return bandwidth;
314
315 old = be32_to_cpup(data);
316 /* Fall through. */
317 }
318 }
319
320 return -EIO;
321}
322
323static int manage_channel(struct fw_card *card, int irm_id, int generation,
324 u32 channels_mask, u64 offset, bool allocate)
325{
326 __be32 bit, all, old;
327 __be32 data[2];
328 int channel, ret = -EIO, retry = 5;
329
330 old = all = allocate ? cpu_to_be32(~0) : 0;
331
332 for (channel = 0; channel < 32; channel++) {
333 if (!(channels_mask & 1 << channel))
334 continue;
335
336 ret = -EBUSY;
337
338 bit = cpu_to_be32(1 << (31 - channel));
339 if ((old & bit) != (all & bit))
340 continue;
341
342 data[0] = old;
343 data[1] = old ^ bit;
344 switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
345 irm_id, generation, SCODE_100,
346 offset, data, 8)) {
347 case RCODE_GENERATION:
348 /* A generation change frees all channels. */
349 return allocate ? -EAGAIN : channel;
350
351 case RCODE_COMPLETE:
352 if (data[0] == old)
353 return channel;
354
355 old = data[0];
356
357 /* Is the IRM 1394a-2000 compliant? */
358 if ((data[0] & bit) == (data[1] & bit))
359 continue;
360
361 fallthrough; /* It's a 1394-1995 IRM, retry */
362 default:
363 if (retry) {
364 retry--;
365 channel--;
366 } else {
367 ret = -EIO;
368 }
369 }
370 }
371
372 return ret;
373}
374
375static void deallocate_channel(struct fw_card *card, int irm_id,
376 int generation, int channel)
377{
378 u32 mask;
379 u64 offset;
380
381 mask = channel < 32 ? 1 << channel : 1 << (channel - 32);
382 offset = channel < 32 ? CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI :
383 CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO;
384
385 manage_channel(card, irm_id, generation, mask, offset, false);
386}
387
388/**
389 * fw_iso_resource_manage() - Allocate or deallocate a channel and/or bandwidth
390 * @card: card interface for this action
391 * @generation: bus generation
392 * @channels_mask: bitmask for channel allocation
393 * @channel: pointer for returning channel allocation result
394 * @bandwidth: pointer for returning bandwidth allocation result
395 * @allocate: whether to allocate (true) or deallocate (false)
396 *
397 * In parameters: card, generation, channels_mask, bandwidth, allocate
398 * Out parameters: channel, bandwidth
399 *
400 * This function blocks (sleeps) during communication with the IRM.
401 *
402 * Allocates or deallocates at most one channel out of channels_mask.
403 * channels_mask is a bitfield with MSB for channel 63 and LSB for channel 0.
404 * (Note, the IRM's CHANNELS_AVAILABLE is a big-endian bitfield with MSB for
405 * channel 0 and LSB for channel 63.)
406 * Allocates or deallocates as many bandwidth allocation units as specified.
407 *
408 * Returns channel < 0 if no channel was allocated or deallocated.
409 * Returns bandwidth = 0 if no bandwidth was allocated or deallocated.
410 *
411 * If generation is stale, deallocations succeed but allocations fail with
412 * channel = -EAGAIN.
413 *
414 * If channel allocation fails, no bandwidth will be allocated either.
415 * If bandwidth allocation fails, no channel will be allocated either.
416 * But deallocations of channel and bandwidth are tried independently
417 * of each other's success.
418 */
419void fw_iso_resource_manage(struct fw_card *card, int generation,
420 u64 channels_mask, int *channel, int *bandwidth,
421 bool allocate)
422{
423 u32 channels_hi = channels_mask; /* channels 31...0 */
424 u32 channels_lo = channels_mask >> 32; /* channels 63...32 */
425 int irm_id, ret, c = -EINVAL;
426
427 scoped_guard(spinlock_irq, &card->lock)
428 irm_id = card->irm_node->node_id;
429
430 if (channels_hi)
431 c = manage_channel(card, irm_id, generation, channels_hi,
432 CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI,
433 allocate);
434 if (channels_lo && c < 0) {
435 c = manage_channel(card, irm_id, generation, channels_lo,
436 CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO,
437 allocate);
438 if (c >= 0)
439 c += 32;
440 }
441 *channel = c;
442
443 if (allocate && channels_mask != 0 && c < 0)
444 *bandwidth = 0;
445
446 if (*bandwidth == 0)
447 return;
448
449 ret = manage_bandwidth(card, irm_id, generation, *bandwidth, allocate);
450 if (ret < 0)
451 *bandwidth = 0;
452
453 if (allocate && ret < 0) {
454 if (c >= 0)
455 deallocate_channel(card, irm_id, generation, c);
456 *channel = ret;
457 }
458}
459EXPORT_SYMBOL(fw_iso_resource_manage);