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 | |
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(n: page_count, size: 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 | |
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(dev: card->device, dma_addr: address)) |
66 | break; |
67 | |
68 | set_page_private(page: buffer->pages[i], private: address); |
69 | } |
70 | buffer->page_count_mapped = i; |
71 | if (i < buffer->page_count) |
72 | return -ENOMEM; |
73 | |
74 | return 0; |
75 | } |
76 | |
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 | |
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(objp: 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. */ |
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 | |
132 | struct fw_iso_context *fw_iso_context_create(struct fw_card *card, |
133 | int type, int channel, int speed, size_t , |
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(ptr: 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 | |
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 | |
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 | |
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 | |
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 | |
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 | |
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 | |
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 | |
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 | destination_id: irm_id, generation, SCODE_100, |
224 | CSR_REGISTER_BASE + CSR_BANDWIDTH_AVAILABLE, |
225 | payload: data, length: 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(p: data) == old) |
232 | return bandwidth; |
233 | |
234 | old = be32_to_cpup(p: data); |
235 | /* Fall through. */ |
236 | } |
237 | } |
238 | |
239 | return -EIO; |
240 | } |
241 | |
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 | destination_id: irm_id, generation, SCODE_100, |
265 | offset, payload: data, length: 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 | |
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, channels_mask: mask, offset, allocate: 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 | */ |
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(lock: &card->lock); |
347 | irm_id = card->irm_node->node_id; |
348 | spin_unlock_irq(lock: &card->lock); |
349 | |
350 | if (channels_hi) |
351 | c = manage_channel(card, irm_id, generation, channels_mask: 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_mask: 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: *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, channel: c); |
376 | *channel = ret; |
377 | } |
378 | } |
379 | EXPORT_SYMBOL(fw_iso_resource_manage); |
380 | |