1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
|
/*
* SPI bridge driver for the Greybus "generic" SPI module.
*
* Copyright 2014-2015 Google Inc.
* Copyright 2014-2015 Linaro Ltd.
*
* Released under the GPLv2 only.
*/
#include <linux/bitops.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/spi/spi.h>
#include "greybus.h"
struct gb_spi {
struct gb_connection *connection;
u16 mode;
u16 flags;
u32 bits_per_word_mask;
u8 num_chipselect;
u32 min_speed_hz;
u32 max_speed_hz;
};
static struct spi_master *get_master_from_spi(struct gb_spi *spi)
{
return spi->connection->private;
}
static int tx_header_fit_operation(u32 tx_size, u32 count, size_t data_max)
{
size_t headers_size;
data_max -= sizeof(struct gb_spi_transfer_request);
headers_size = (count + 1) * sizeof(struct gb_spi_transfer);
return tx_size + headers_size > data_max ? 0 : 1;
}
static size_t calc_rx_xfer_size(u32 rx_size, u32 *tx_xfer_size, u32 len,
size_t data_max)
{
size_t rx_xfer_size;
data_max -= sizeof(struct gb_spi_transfer_response);
if (rx_size + len > data_max)
rx_xfer_size = data_max - rx_size;
else
rx_xfer_size = len;
/* if this is a write_read, for symmetry read the same as write */
if (*tx_xfer_size && rx_xfer_size > *tx_xfer_size)
rx_xfer_size = *tx_xfer_size;
if (*tx_xfer_size && rx_xfer_size < *tx_xfer_size)
*tx_xfer_size = rx_xfer_size;
return rx_xfer_size;
}
static size_t calc_tx_xfer_size(u32 tx_size, u32 count, size_t len,
size_t data_max)
{
size_t headers_size;
data_max -= sizeof(struct gb_spi_transfer_request);
headers_size = (count + 1) * sizeof(struct gb_spi_transfer);
if (tx_size + headers_size + len > data_max)
return data_max - (tx_size + sizeof(struct gb_spi_transfer));
return len;
}
/* Routines to transfer data */
static struct gb_operation *
gb_spi_operation_create(struct gb_connection *connection,
struct spi_message *msg, u32 *total_len)
{
struct gb_spi_transfer_request *request;
struct spi_device *dev = msg->spi;
struct spi_transfer *xfer;
struct gb_spi_transfer *gb_xfer;
struct gb_operation *operation;
struct spi_transfer *last_xfer = NULL;
u32 tx_size = 0, rx_size = 0, count = 0, xfer_len = 0, request_size;
u32 tx_xfer_size = 0, rx_xfer_size = 0, last_xfer_size = 0;
size_t data_max;
void *tx_data;
data_max = gb_operation_get_payload_size_max(connection);
/* Find number of transfers queued and tx/rx length in the message */
list_for_each_entry(xfer, &msg->transfers, transfer_list) {
if (!xfer->tx_buf && !xfer->rx_buf) {
dev_err(&connection->bundle->dev,
"bufferless transfer, length %u\n", xfer->len);
return NULL;
}
last_xfer = xfer;
tx_xfer_size = 0;
rx_xfer_size = 0;
if (xfer->tx_buf) {
if (!tx_header_fit_operation(tx_size, count, data_max))
break;
tx_xfer_size = calc_tx_xfer_size(tx_size, count,
xfer->len, data_max);
last_xfer_size = tx_xfer_size;
}
if (xfer->rx_buf) {
rx_xfer_size = calc_rx_xfer_size(rx_size, &tx_xfer_size,
xfer->len, data_max);
last_xfer_size = rx_xfer_size;
}
tx_size += tx_xfer_size;
rx_size += rx_xfer_size;
*total_len += last_xfer_size;
count++;
if (xfer->len != last_xfer_size)
break;
}
/*
* In addition to space for all message descriptors we need
* to have enough to hold all tx data.
*/
request_size = sizeof(*request);
request_size += count * sizeof(*gb_xfer);
request_size += tx_size;
/* Response consists only of incoming data */
operation = gb_operation_create(connection, GB_SPI_TYPE_TRANSFER,
request_size, rx_size, GFP_KERNEL);
if (!operation)
return NULL;
request = operation->request->payload;
request->count = cpu_to_le16(count);
request->mode = dev->mode;
request->chip_select = dev->chip_select;
gb_xfer = &request->transfers[0];
tx_data = gb_xfer + count; /* place tx data after last gb_xfer */
/* Fill in the transfers array */
list_for_each_entry(xfer, &msg->transfers, transfer_list) {
if (last_xfer && xfer == last_xfer)
xfer_len = last_xfer_size;
else
xfer_len = xfer->len;
gb_xfer->speed_hz = cpu_to_le32(xfer->speed_hz);
gb_xfer->len = cpu_to_le32(xfer_len);
gb_xfer->delay_usecs = cpu_to_le16(xfer->delay_usecs);
gb_xfer->cs_change = xfer->cs_change;
gb_xfer->bits_per_word = xfer->bits_per_word;
/* Copy tx data */
if (xfer->tx_buf) {
gb_xfer->rdwr |= GB_SPI_XFER_WRITE;
memcpy(tx_data, xfer->tx_buf, xfer_len);
tx_data += xfer_len;
}
if (xfer->rx_buf)
gb_xfer->rdwr |= GB_SPI_XFER_READ;
if (last_xfer && xfer == last_xfer)
break;
gb_xfer++;
}
return operation;
}
static void gb_spi_decode_response(struct spi_message *msg,
struct gb_spi_transfer_response *response)
{
struct spi_transfer *xfer;
void *rx_data = response->data;
list_for_each_entry(xfer, &msg->transfers, transfer_list) {
/* Copy rx data */
if (xfer->rx_buf) {
memcpy(xfer->rx_buf, rx_data, xfer->len);
rx_data += xfer->len;
}
}
}
static int gb_spi_transfer_one_message(struct spi_master *master,
struct spi_message *msg)
{
struct gb_spi *spi = spi_master_get_devdata(master);
struct gb_connection *connection = spi->connection;
struct gb_spi_transfer_response *response;
struct gb_operation *operation;
u32 len = 0;
int ret;
operation = gb_spi_operation_create(connection, msg, &len);
if (!operation)
return -ENOMEM;
ret = gb_operation_request_send_sync(operation);
if (!ret) {
response = operation->response->payload;
if (response)
gb_spi_decode_response(msg, response);
} else {
pr_err("transfer operation failed (%d)\n", ret);
}
gb_operation_put(operation);
msg->actual_length = len;
msg->status = 0;
spi_finalize_current_message(master);
return ret;
}
static int gb_spi_setup(struct spi_device *spi)
{
/* Nothing to do for now */
return 0;
}
static void gb_spi_cleanup(struct spi_device *spi)
{
/* Nothing to do for now */
}
/* Routines to get controller information */
/*
* Map Greybus spi mode bits/flags/bpw into Linux ones.
* All bits are same for now and so these macro's return same values.
*/
#define gb_spi_mode_map(mode) mode
#define gb_spi_flags_map(flags) flags
static int gb_spi_get_master_config(struct gb_spi *spi)
{
struct gb_spi_master_config_response response;
u16 mode, flags;
int ret;
ret = gb_operation_sync(spi->connection, GB_SPI_TYPE_MASTER_CONFIG,
NULL, 0, &response, sizeof(response));
if (ret < 0)
return ret;
mode = le16_to_cpu(response.mode);
spi->mode = gb_spi_mode_map(mode);
flags = le16_to_cpu(response.flags
|