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/*
26 * Isochronous DMA context management
27 */
28
29int fw_iso_buffer_alloc(struct fw_iso_buffer *buffer, int page_count)
30{
31	int i;
32
33	buffer->page_count = 0;
34	buffer->page_count_mapped = 0;
35	buffer->pages = kmalloc_array(page_count, sizeof(buffer->pages[0]),
36				      GFP_KERNEL);
37	if (buffer->pages == NULL)
38		return -ENOMEM;
39
40	for (i = 0; i < page_count; i++) {
41		buffer->pages[i] = alloc_page(GFP_KERNEL | GFP_DMA32 | __GFP_ZERO);
42		if (buffer->pages[i] == NULL)
43			break;
44	}
45	buffer->page_count = i;
46	if (i < page_count) {
47		fw_iso_buffer_destroy(buffer, NULL);
48		return -ENOMEM;
49	}
50
51	return 0;
52}
53
54int fw_iso_buffer_map_dma(struct fw_iso_buffer *buffer, struct fw_card *card,
55			  enum dma_data_direction direction)
56{
57	dma_addr_t address;
58	int i;
59
60	buffer->direction = direction;
61
62	for (i = 0; i < buffer->page_count; i++) {
63		address = dma_map_page(card->device, buffer->pages[i],
64				       0, PAGE_SIZE, direction);
65		if (dma_mapping_error(card->device, address))
66			break;
67
68		set_page_private(buffer->pages[i], address);
69	}
70	buffer->page_count_mapped = i;
71	if (i < buffer->page_count)
72		return -ENOMEM;
73
74	return 0;
75}
76
77int fw_iso_buffer_init(struct fw_iso_buffer *buffer, struct fw_card *card,
78		       int page_count, enum dma_data_direction direction)
79{
80	int ret;
81
82	ret = fw_iso_buffer_alloc(buffer, page_count);
83	if (ret < 0)
84		return ret;
85
86	ret = fw_iso_buffer_map_dma(buffer, card, direction);
87	if (ret < 0)
88		fw_iso_buffer_destroy(buffer, card);
89
90	return ret;
91}
92EXPORT_SYMBOL(fw_iso_buffer_init);
93
94void fw_iso_buffer_destroy(struct fw_iso_buffer *buffer,
95			   struct fw_card *card)
96{
97	int i;
98	dma_addr_t address;
99
100	for (i = 0; i < buffer->page_count_mapped; i++) {
101		address = page_private(buffer->pages[i]);
102		dma_unmap_page(card->device, address,
103			       PAGE_SIZE, buffer->direction);
104	}
105	for (i = 0; i < buffer->page_count; i++)
106		__free_page(buffer->pages[i]);
107
108	kfree(buffer->pages);
109	buffer->pages = NULL;
110	buffer->page_count = 0;
111	buffer->page_count_mapped = 0;
112}
113EXPORT_SYMBOL(fw_iso_buffer_destroy);
114
115/* Convert DMA address to offset into virtually contiguous buffer. */
116size_t fw_iso_buffer_lookup(struct fw_iso_buffer *buffer, dma_addr_t completed)
117{
118	size_t i;
119	dma_addr_t address;
120	ssize_t offset;
121
122	for (i = 0; i < buffer->page_count; i++) {
123		address = page_private(buffer->pages[i]);
124		offset = (ssize_t)completed - (ssize_t)address;
125		if (offset > 0 && offset <= PAGE_SIZE)
126			return (i << PAGE_SHIFT) + offset;
127	}
128
129	return 0;
130}
131
132struct fw_iso_context *fw_iso_context_create(struct fw_card *card,
133		int type, int channel, int speed, size_t header_size,
134		fw_iso_callback_t callback, void *callback_data)
135{
136	struct fw_iso_context *ctx;
137
138	ctx = card->driver->allocate_iso_context(card,
139						 type, channel, header_size);
140	if (IS_ERR(ctx))
141		return ctx;
142
143	ctx->card = card;
144	ctx->type = type;
145	ctx->channel = channel;
146	ctx->speed = speed;
147	ctx->header_size = header_size;
148	ctx->callback.sc = callback;
149	ctx->callback_data = callback_data;
150
151	return ctx;
152}
153EXPORT_SYMBOL(fw_iso_context_create);
154
155void fw_iso_context_destroy(struct fw_iso_context *ctx)
156{
157	ctx->card->driver->free_iso_context(ctx);
158}
159EXPORT_SYMBOL(fw_iso_context_destroy);
160
161int fw_iso_context_start(struct fw_iso_context *ctx,
162			 int cycle, int sync, int tags)
163{
164	return ctx->card->driver->start_iso(ctx, cycle, sync, tags);
165}
166EXPORT_SYMBOL(fw_iso_context_start);
167
168int fw_iso_context_set_channels(struct fw_iso_context *ctx, u64 *channels)
169{
170	return ctx->card->driver->set_iso_channels(ctx, channels);
171}
172
173int fw_iso_context_queue(struct fw_iso_context *ctx,
174			 struct fw_iso_packet *packet,
175			 struct fw_iso_buffer *buffer,
176			 unsigned long payload)
177{
178	return ctx->card->driver->queue_iso(ctx, packet, buffer, payload);
179}
180EXPORT_SYMBOL(fw_iso_context_queue);
181
182void fw_iso_context_queue_flush(struct fw_iso_context *ctx)
183{
184	ctx->card->driver->flush_queue_iso(ctx);
185}
186EXPORT_SYMBOL(fw_iso_context_queue_flush);
187
188int fw_iso_context_flush_completions(struct fw_iso_context *ctx)
189{
190	return ctx->card->driver->flush_iso_completions(ctx);
191}
192EXPORT_SYMBOL(fw_iso_context_flush_completions);
193
194int fw_iso_context_stop(struct fw_iso_context *ctx)
195{
196	return ctx->card->driver->stop_iso(ctx);
197}
198EXPORT_SYMBOL(fw_iso_context_stop);
199
200/*
201 * Isochronous bus resource management (channels, bandwidth), client side
202 */
203
204static int manage_bandwidth(struct fw_card *card, int irm_id, int generation,
205			    int bandwidth, bool allocate)
206{
207	int try, new, old = allocate ? BANDWIDTH_AVAILABLE_INITIAL : 0;
208	__be32 data[2];
209
210	/*
211	 * On a 1394a IRM with low contention, try < 1 is enough.
212	 * On a 1394-1995 IRM, we need at least try < 2.
213	 * Let's just do try < 5.
214	 */
215	for (try = 0; try < 5; try++) {
216		new = allocate ? old - bandwidth : old + bandwidth;
217		if (new < 0 || new > BANDWIDTH_AVAILABLE_INITIAL)
218			return -EBUSY;
219
220		data[0] = cpu_to_be32(old);
221		data[1] = cpu_to_be32(new);
222		switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
223				irm_id, generation, SCODE_100,
224				CSR_REGISTER_BASE + CSR_BANDWIDTH_AVAILABLE,
225				data, 8)) {
226		case RCODE_GENERATION:
227			/* A generation change frees all bandwidth. */
228			return allocate ? -EAGAIN : bandwidth;
229
230		case RCODE_COMPLETE:
231			if (be32_to_cpup(data) == old)
232				return bandwidth;
233
234			old = be32_to_cpup(data);
235			/* Fall through. */
236		}
237	}
238
239	return -EIO;
240}
241
242static int manage_channel(struct fw_card *card, int irm_id, int generation,
243		u32 channels_mask, u64 offset, bool allocate)
244{
245	__be32 bit, all, old;
246	__be32 data[2];
247	int channel, ret = -EIO, retry = 5;
248
249	old = all = allocate ? cpu_to_be32(~0) : 0;
250
251	for (channel = 0; channel < 32; channel++) {
252		if (!(channels_mask & 1 << channel))
253			continue;
254
255		ret = -EBUSY;
256
257		bit = cpu_to_be32(1 << (31 - channel));
258		if ((old & bit) != (all & bit))
259			continue;
260
261		data[0] = old;
262		data[1] = old ^ bit;
263		switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
264					   irm_id, generation, SCODE_100,
265					   offset, data, 8)) {
266		case RCODE_GENERATION:
267			/* A generation change frees all channels. */
268			return allocate ? -EAGAIN : channel;
269
270		case RCODE_COMPLETE:
271			if (data[0] == old)
272				return channel;
273
274			old = data[0];
275
276			/* Is the IRM 1394a-2000 compliant? */
277			if ((data[0] & bit) == (data[1] & bit))
278				continue;
279
280			fallthrough;	/* It's a 1394-1995 IRM, retry */
281		default:
282			if (retry) {
283				retry--;
284				channel--;
285			} else {
286				ret = -EIO;
287			}
288		}
289	}
290
291	return ret;
292}
293
294static void deallocate_channel(struct fw_card *card, int irm_id,
295			       int generation, int channel)
296{
297	u32 mask;
298	u64 offset;
299
300	mask = channel < 32 ? 1 << channel : 1 << (channel - 32);
301	offset = channel < 32 ? CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI :
302				CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO;
303
304	manage_channel(card, irm_id, generation, mask, offset, false);
305}
306
307/**
308 * fw_iso_resource_manage() - Allocate or deallocate a channel and/or bandwidth
309 * @card: card interface for this action
310 * @generation: bus generation
311 * @channels_mask: bitmask for channel allocation
312 * @channel: pointer for returning channel allocation result
313 * @bandwidth: pointer for returning bandwidth allocation result
314 * @allocate: whether to allocate (true) or deallocate (false)
315 *
316 * In parameters: card, generation, channels_mask, bandwidth, allocate
317 * Out parameters: channel, bandwidth
318 *
319 * This function blocks (sleeps) during communication with the IRM.
320 *
321 * Allocates or deallocates at most one channel out of channels_mask.
322 * channels_mask is a bitfield with MSB for channel 63 and LSB for channel 0.
323 * (Note, the IRM's CHANNELS_AVAILABLE is a big-endian bitfield with MSB for
324 * channel 0 and LSB for channel 63.)
325 * Allocates or deallocates as many bandwidth allocation units as specified.
326 *
327 * Returns channel < 0 if no channel was allocated or deallocated.
328 * Returns bandwidth = 0 if no bandwidth was allocated or deallocated.
329 *
330 * If generation is stale, deallocations succeed but allocations fail with
331 * channel = -EAGAIN.
332 *
333 * If channel allocation fails, no bandwidth will be allocated either.
334 * If bandwidth allocation fails, no channel will be allocated either.
335 * But deallocations of channel and bandwidth are tried independently
336 * of each other's success.
337 */
338void fw_iso_resource_manage(struct fw_card *card, int generation,
339			    u64 channels_mask, int *channel, int *bandwidth,
340			    bool allocate)
341{
342	u32 channels_hi = channels_mask;	/* channels 31...0 */
343	u32 channels_lo = channels_mask >> 32;	/* channels 63...32 */
344	int irm_id, ret, c = -EINVAL;
345
346	spin_lock_irq(&card->lock);
347	irm_id = card->irm_node->node_id;
348	spin_unlock_irq(&card->lock);
349
350	if (channels_hi)
351		c = manage_channel(card, irm_id, generation, channels_hi,
352				CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI,
353				allocate);
354	if (channels_lo && c < 0) {
355		c = manage_channel(card, irm_id, generation, channels_lo,
356				CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO,
357				allocate);
358		if (c >= 0)
359			c += 32;
360	}
361	*channel = c;
362
363	if (allocate && channels_mask != 0 && c < 0)
364		*bandwidth = 0;
365
366	if (*bandwidth == 0)
367		return;
368
369	ret = manage_bandwidth(card, irm_id, generation, *bandwidth, allocate);
370	if (ret < 0)
371		*bandwidth = 0;
372
373	if (allocate && ret < 0) {
374		if (c >= 0)
375			deallocate_channel(card, irm_id, generation, c);
376		*channel = ret;
377	}
378}
379EXPORT_SYMBOL(fw_iso_resource_manage);
380