xref: /openbmc/linux/drivers/firewire/core-iso.c (revision df561f66)
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 
fw_iso_buffer_alloc(struct fw_iso_buffer * buffer,int page_count)29 int 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 
fw_iso_buffer_map_dma(struct fw_iso_buffer * buffer,struct fw_card * card,enum dma_data_direction direction)54 int 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 
fw_iso_buffer_init(struct fw_iso_buffer * buffer,struct fw_card * card,int page_count,enum dma_data_direction direction)77 int 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 }
92 EXPORT_SYMBOL(fw_iso_buffer_init);
93 
fw_iso_buffer_destroy(struct fw_iso_buffer * buffer,struct fw_card * card)94 void 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 }
113 EXPORT_SYMBOL(fw_iso_buffer_destroy);
114 
115 /* Convert DMA address to offset into virtually contiguous buffer. */
fw_iso_buffer_lookup(struct fw_iso_buffer * buffer,dma_addr_t completed)116 size_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 
fw_iso_context_create(struct fw_card * card,int type,int channel,int speed,size_t header_size,fw_iso_callback_t callback,void * callback_data)132 struct 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 }
153 EXPORT_SYMBOL(fw_iso_context_create);
154 
fw_iso_context_destroy(struct fw_iso_context * ctx)155 void fw_iso_context_destroy(struct fw_iso_context *ctx)
156 {
157 	ctx->card->driver->free_iso_context(ctx);
158 }
159 EXPORT_SYMBOL(fw_iso_context_destroy);
160 
fw_iso_context_start(struct fw_iso_context * ctx,int cycle,int sync,int tags)161 int 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 }
166 EXPORT_SYMBOL(fw_iso_context_start);
167 
fw_iso_context_set_channels(struct fw_iso_context * ctx,u64 * channels)168 int 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 
fw_iso_context_queue(struct fw_iso_context * ctx,struct fw_iso_packet * packet,struct fw_iso_buffer * buffer,unsigned long payload)173 int 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 }
180 EXPORT_SYMBOL(fw_iso_context_queue);
181 
fw_iso_context_queue_flush(struct fw_iso_context * ctx)182 void fw_iso_context_queue_flush(struct fw_iso_context *ctx)
183 {
184 	ctx->card->driver->flush_queue_iso(ctx);
185 }
186 EXPORT_SYMBOL(fw_iso_context_queue_flush);
187 
fw_iso_context_flush_completions(struct fw_iso_context * ctx)188 int fw_iso_context_flush_completions(struct fw_iso_context *ctx)
189 {
190 	return ctx->card->driver->flush_iso_completions(ctx);
191 }
192 EXPORT_SYMBOL(fw_iso_context_flush_completions);
193 
fw_iso_context_stop(struct fw_iso_context * ctx)194 int fw_iso_context_stop(struct fw_iso_context *ctx)
195 {
196 	return ctx->card->driver->stop_iso(ctx);
197 }
198 EXPORT_SYMBOL(fw_iso_context_stop);
199 
200 /*
201  * Isochronous bus resource management (channels, bandwidth), client side
202  */
203 
manage_bandwidth(struct fw_card * card,int irm_id,int generation,int bandwidth,bool allocate)204 static 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 
manage_channel(struct fw_card * card,int irm_id,int generation,u32 channels_mask,u64 offset,bool allocate)242 static 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 
deallocate_channel(struct fw_card * card,int irm_id,int generation,int channel)294 static 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  */
fw_iso_resource_manage(struct fw_card * card,int generation,u64 channels_mask,int * channel,int * bandwidth,bool allocate)338 void 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 }
379 EXPORT_SYMBOL(fw_iso_resource_manage);
380