Loading...
Note: File does not exist in v3.1.
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2010 - 2015 UNISYS CORPORATION
4 * All rights reserved.
5 */
6
7/*
8 * This provides s-Par channel communication primitives, which are
9 * independent of the mechanism used to access the channel data.
10 */
11
12#include <linux/uuid.h>
13#include <linux/io.h>
14#include <linux/slab.h>
15#include <linux/visorbus.h>
16
17#include "visorbus_private.h"
18#include "controlvmchannel.h"
19
20#define VISOR_DRV_NAME "visorchannel"
21
22#define VISOR_CONSOLEVIDEO_CHANNEL_GUID \
23 GUID_INIT(0x3cd6e705, 0xd6a2, 0x4aa5, \
24 0xad, 0x5c, 0x7b, 0x8, 0x88, 0x9d, 0xff, 0xe2)
25
26static const guid_t visor_video_guid = VISOR_CONSOLEVIDEO_CHANNEL_GUID;
27
28struct visorchannel {
29 u64 physaddr;
30 ulong nbytes;
31 void *mapped;
32 bool requested;
33 struct channel_header chan_hdr;
34 guid_t guid;
35 /*
36 * channel creator knows if more than one thread will be inserting or
37 * removing
38 */
39 bool needs_lock;
40 /* protect head writes in chan_hdr */
41 spinlock_t insert_lock;
42 /* protect tail writes in chan_hdr */
43 spinlock_t remove_lock;
44 guid_t type;
45 guid_t inst;
46};
47
48void visorchannel_destroy(struct visorchannel *channel)
49{
50 if (!channel)
51 return;
52
53 if (channel->mapped) {
54 memunmap(channel->mapped);
55 if (channel->requested)
56 release_mem_region(channel->physaddr, channel->nbytes);
57 }
58 kfree(channel);
59}
60
61u64 visorchannel_get_physaddr(struct visorchannel *channel)
62{
63 return channel->physaddr;
64}
65
66ulong visorchannel_get_nbytes(struct visorchannel *channel)
67{
68 return channel->nbytes;
69}
70
71char *visorchannel_guid_id(const guid_t *guid, char *s)
72{
73 sprintf(s, "%pUL", guid);
74 return s;
75}
76
77char *visorchannel_id(struct visorchannel *channel, char *s)
78{
79 return visorchannel_guid_id(&channel->guid, s);
80}
81
82char *visorchannel_zoneid(struct visorchannel *channel, char *s)
83{
84 return visorchannel_guid_id(&channel->chan_hdr.zone_guid, s);
85}
86
87u64 visorchannel_get_clientpartition(struct visorchannel *channel)
88{
89 return channel->chan_hdr.partition_handle;
90}
91
92int visorchannel_set_clientpartition(struct visorchannel *channel,
93 u64 partition_handle)
94{
95 channel->chan_hdr.partition_handle = partition_handle;
96 return 0;
97}
98
99/**
100 * visorchannel_get_guid() - queries the GUID of the designated channel
101 * @channel: the channel to query
102 *
103 * Return: the GUID of the provided channel
104 */
105const guid_t *visorchannel_get_guid(struct visorchannel *channel)
106{
107 return &channel->guid;
108}
109EXPORT_SYMBOL_GPL(visorchannel_get_guid);
110
111int visorchannel_read(struct visorchannel *channel, ulong offset, void *dest,
112 ulong nbytes)
113{
114 if (offset + nbytes > channel->nbytes)
115 return -EIO;
116
117 memcpy(dest, channel->mapped + offset, nbytes);
118 return 0;
119}
120
121int visorchannel_write(struct visorchannel *channel, ulong offset, void *dest,
122 ulong nbytes)
123{
124 size_t chdr_size = sizeof(struct channel_header);
125 size_t copy_size;
126
127 if (offset + nbytes > channel->nbytes)
128 return -EIO;
129
130 if (offset < chdr_size) {
131 copy_size = min(chdr_size - offset, nbytes);
132 memcpy(((char *)(&channel->chan_hdr)) + offset,
133 dest, copy_size);
134 }
135 memcpy(channel->mapped + offset, dest, nbytes);
136 return 0;
137}
138
139void *visorchannel_get_header(struct visorchannel *channel)
140{
141 return &channel->chan_hdr;
142}
143
144/*
145 * Return offset of a specific SIGNAL_QUEUE_HEADER from the beginning of a
146 * channel header
147 */
148static int sig_queue_offset(struct channel_header *chan_hdr, int q)
149{
150 return ((chan_hdr)->ch_space_offset +
151 ((q) * sizeof(struct signal_queue_header)));
152}
153
154/*
155 * Return offset of a specific queue entry (data) from the beginning of a
156 * channel header
157 */
158static int sig_data_offset(struct channel_header *chan_hdr, int q,
159 struct signal_queue_header *sig_hdr, int slot)
160{
161 return (sig_queue_offset(chan_hdr, q) + sig_hdr->sig_base_offset +
162 (slot * sig_hdr->signal_size));
163}
164
165/*
166 * Write the contents of a specific field within a SIGNAL_QUEUE_HEADER back into
167 * host memory
168 */
169#define SIG_WRITE_FIELD(channel, queue, sig_hdr, FIELD) \
170 visorchannel_write(channel, \
171 sig_queue_offset(&channel->chan_hdr, queue) + \
172 offsetof(struct signal_queue_header, FIELD), \
173 &((sig_hdr)->FIELD), \
174 sizeof((sig_hdr)->FIELD))
175
176static int sig_read_header(struct visorchannel *channel, u32 queue,
177 struct signal_queue_header *sig_hdr)
178{
179 if (channel->chan_hdr.ch_space_offset < sizeof(struct channel_header))
180 return -EINVAL;
181
182 /* Read the appropriate SIGNAL_QUEUE_HEADER into local memory. */
183 return visorchannel_read(channel,
184 sig_queue_offset(&channel->chan_hdr, queue),
185 sig_hdr, sizeof(struct signal_queue_header));
186}
187
188static int sig_read_data(struct visorchannel *channel, u32 queue,
189 struct signal_queue_header *sig_hdr, u32 slot,
190 void *data)
191{
192 int signal_data_offset = sig_data_offset(&channel->chan_hdr, queue,
193 sig_hdr, slot);
194
195 return visorchannel_read(channel, signal_data_offset,
196 data, sig_hdr->signal_size);
197}
198
199static int sig_write_data(struct visorchannel *channel, u32 queue,
200 struct signal_queue_header *sig_hdr, u32 slot,
201 void *data)
202{
203 int signal_data_offset = sig_data_offset(&channel->chan_hdr, queue,
204 sig_hdr, slot);
205
206 return visorchannel_write(channel, signal_data_offset,
207 data, sig_hdr->signal_size);
208}
209
210static int signalremove_inner(struct visorchannel *channel, u32 queue,
211 void *msg)
212{
213 struct signal_queue_header sig_hdr;
214 int error;
215
216 error = sig_read_header(channel, queue, &sig_hdr);
217 if (error)
218 return error;
219 /* No signals to remove; have caller try again. */
220 if (sig_hdr.head == sig_hdr.tail)
221 return -EAGAIN;
222 sig_hdr.tail = (sig_hdr.tail + 1) % sig_hdr.max_slots;
223 error = sig_read_data(channel, queue, &sig_hdr, sig_hdr.tail, msg);
224 if (error)
225 return error;
226 sig_hdr.num_received++;
227 /*
228 * For each data field in SIGNAL_QUEUE_HEADER that was modified, update
229 * host memory. Required for channel sync.
230 */
231 mb();
232 error = SIG_WRITE_FIELD(channel, queue, &sig_hdr, tail);
233 if (error)
234 return error;
235 error = SIG_WRITE_FIELD(channel, queue, &sig_hdr, num_received);
236 if (error)
237 return error;
238 return 0;
239}
240
241/**
242 * visorchannel_signalremove() - removes a message from the designated
243 * channel/queue
244 * @channel: the channel the message will be removed from
245 * @queue: the queue the message will be removed from
246 * @msg: the message to remove
247 *
248 * Return: integer error code indicating the status of the removal
249 */
250int visorchannel_signalremove(struct visorchannel *channel, u32 queue,
251 void *msg)
252{
253 int rc;
254 unsigned long flags;
255
256 if (channel->needs_lock) {
257 spin_lock_irqsave(&channel->remove_lock, flags);
258 rc = signalremove_inner(channel, queue, msg);
259 spin_unlock_irqrestore(&channel->remove_lock, flags);
260 } else {
261 rc = signalremove_inner(channel, queue, msg);
262 }
263
264 return rc;
265}
266EXPORT_SYMBOL_GPL(visorchannel_signalremove);
267
268static bool queue_empty(struct visorchannel *channel, u32 queue)
269{
270 struct signal_queue_header sig_hdr;
271
272 if (sig_read_header(channel, queue, &sig_hdr))
273 return true;
274 return (sig_hdr.head == sig_hdr.tail);
275}
276
277/**
278 * visorchannel_signalempty() - checks if the designated channel/queue contains
279 * any messages
280 * @channel: the channel to query
281 * @queue: the queue in the channel to query
282 *
283 * Return: boolean indicating whether any messages in the designated
284 * channel/queue are present
285 */
286bool visorchannel_signalempty(struct visorchannel *channel, u32 queue)
287{
288 bool rc;
289 unsigned long flags;
290
291 if (!channel->needs_lock)
292 return queue_empty(channel, queue);
293 spin_lock_irqsave(&channel->remove_lock, flags);
294 rc = queue_empty(channel, queue);
295 spin_unlock_irqrestore(&channel->remove_lock, flags);
296 return rc;
297}
298EXPORT_SYMBOL_GPL(visorchannel_signalempty);
299
300static int signalinsert_inner(struct visorchannel *channel, u32 queue,
301 void *msg)
302{
303 struct signal_queue_header sig_hdr;
304 int err;
305
306 err = sig_read_header(channel, queue, &sig_hdr);
307 if (err)
308 return err;
309 sig_hdr.head = (sig_hdr.head + 1) % sig_hdr.max_slots;
310 if (sig_hdr.head == sig_hdr.tail) {
311 sig_hdr.num_overflows++;
312 err = SIG_WRITE_FIELD(channel, queue, &sig_hdr, num_overflows);
313 if (err)
314 return err;
315 return -EIO;
316 }
317 err = sig_write_data(channel, queue, &sig_hdr, sig_hdr.head, msg);
318 if (err)
319 return err;
320 sig_hdr.num_sent++;
321 /*
322 * For each data field in SIGNAL_QUEUE_HEADER that was modified, update
323 * host memory. Required for channel sync.
324 */
325 mb();
326 err = SIG_WRITE_FIELD(channel, queue, &sig_hdr, head);
327 if (err)
328 return err;
329 err = SIG_WRITE_FIELD(channel, queue, &sig_hdr, num_sent);
330 if (err)
331 return err;
332 return 0;
333}
334
335/*
336 * visorchannel_create() - creates the struct visorchannel abstraction for a
337 * data area in memory, but does NOT modify this data
338 * area
339 * @physaddr: physical address of start of channel
340 * @gfp: gfp_t to use when allocating memory for the data struct
341 * @guid: GUID that identifies channel type;
342 * @needs_lock: must specify true if you have multiple threads of execution
343 * that will be calling visorchannel methods of this
344 * visorchannel at the same time
345 *
346 * Return: pointer to visorchannel that was created if successful,
347 * otherwise NULL
348 */
349struct visorchannel *visorchannel_create(u64 physaddr, gfp_t gfp,
350 const guid_t *guid, bool needs_lock)
351{
352 struct visorchannel *channel;
353 int err;
354 size_t size = sizeof(struct channel_header);
355
356 if (physaddr == 0)
357 return NULL;
358
359 channel = kzalloc(sizeof(*channel), gfp);
360 if (!channel)
361 return NULL;
362 channel->needs_lock = needs_lock;
363 spin_lock_init(&channel->insert_lock);
364 spin_lock_init(&channel->remove_lock);
365 /*
366 * Video driver constains the efi framebuffer so it will get a conflict
367 * resource when requesting its full mem region. Since we are only
368 * using the efi framebuffer for video we can ignore this. Remember that
369 * we haven't requested it so we don't try to release later on.
370 */
371 channel->requested = request_mem_region(physaddr, size, VISOR_DRV_NAME);
372 if (!channel->requested && !guid_equal(guid, &visor_video_guid))
373 /* we only care about errors if this is not the video channel */
374 goto err_destroy_channel;
375 channel->mapped = memremap(physaddr, size, MEMREMAP_WB);
376 if (!channel->mapped) {
377 release_mem_region(physaddr, size);
378 goto err_destroy_channel;
379 }
380 channel->physaddr = physaddr;
381 channel->nbytes = size;
382 err = visorchannel_read(channel, 0, &channel->chan_hdr, size);
383 if (err)
384 goto err_destroy_channel;
385 size = (ulong)channel->chan_hdr.size;
386 memunmap(channel->mapped);
387 if (channel->requested)
388 release_mem_region(channel->physaddr, channel->nbytes);
389 channel->mapped = NULL;
390 channel->requested = request_mem_region(channel->physaddr, size,
391 VISOR_DRV_NAME);
392 if (!channel->requested && !guid_equal(guid, &visor_video_guid))
393 /* we only care about errors if this is not the video channel */
394 goto err_destroy_channel;
395 channel->mapped = memremap(channel->physaddr, size, MEMREMAP_WB);
396 if (!channel->mapped) {
397 release_mem_region(channel->physaddr, size);
398 goto err_destroy_channel;
399 }
400 channel->nbytes = size;
401 guid_copy(&channel->guid, guid);
402 return channel;
403
404err_destroy_channel:
405 visorchannel_destroy(channel);
406 return NULL;
407}
408
409/**
410 * visorchannel_signalinsert() - inserts a message into the designated
411 * channel/queue
412 * @channel: the channel the message will be added to
413 * @queue: the queue the message will be added to
414 * @msg: the message to insert
415 *
416 * Return: integer error code indicating the status of the insertion
417 */
418int visorchannel_signalinsert(struct visorchannel *channel, u32 queue,
419 void *msg)
420{
421 int rc;
422 unsigned long flags;
423
424 if (channel->needs_lock) {
425 spin_lock_irqsave(&channel->insert_lock, flags);
426 rc = signalinsert_inner(channel, queue, msg);
427 spin_unlock_irqrestore(&channel->insert_lock, flags);
428 } else {
429 rc = signalinsert_inner(channel, queue, msg);
430 }
431
432 return rc;
433}
434EXPORT_SYMBOL_GPL(visorchannel_signalinsert);