core-iso.c

  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(card->device, address))
 68			break;
 69
 70		set_page_private(buffer->pages[i], 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(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(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, 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);
175	trace_isoc_inbound_single_start(ctx, cycle, sync, tags);
176	trace_isoc_inbound_multiple_start(ctx, 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);
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, payload, packet);
195	trace_isoc_inbound_single_queue(ctx, payload, packet);
196	trace_isoc_inbound_multiple_queue(ctx, 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(&ctx->work);
241
242	err = ctx->card->driver->flush_iso_completions(ctx);
243
244	enable_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(&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				irm_id, generation, SCODE_100,
296				CSR_REGISTER_BASE + CSR_BANDWIDTH_AVAILABLE,
297				data, 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(data) == old)
304				return bandwidth;
305
306			old = be32_to_cpup(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					   irm_id, generation, SCODE_100,
337					   offset, data, 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, mask, offset, 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_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_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, 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, c);
447		*channel = ret;
448	}
449}
450EXPORT_SYMBOL(fw_iso_resource_manage);