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7ed98ddd EJ |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | ||
3 | #include <linux/device.h> | |
4 | #include <linux/err.h> | |
5 | #include <linux/errno.h> | |
6 | #include <linux/fs.h> | |
7 | #include <linux/fsi-sbefifo.h> | |
8 | #include <linux/gfp.h> | |
9 | #include <linux/idr.h> | |
10 | #include <linux/kernel.h> | |
11 | #include <linux/list.h> | |
12 | #include <linux/miscdevice.h> | |
13 | #include <linux/module.h> | |
14 | #include <linux/mutex.h> | |
15 | #include <linux/fsi-occ.h> | |
16 | #include <linux/of.h> | |
17 | #include <linux/platform_device.h> | |
18 | #include <linux/sched.h> | |
19 | #include <linux/slab.h> | |
20 | #include <linux/uaccess.h> | |
21 | #include <asm/unaligned.h> | |
22 | ||
23 | #define OCC_SRAM_BYTES 4096 | |
24 | #define OCC_CMD_DATA_BYTES 4090 | |
25 | #define OCC_RESP_DATA_BYTES 4089 | |
26 | ||
27 | #define OCC_SRAM_CMD_ADDR 0xFFFBE000 | |
28 | #define OCC_SRAM_RSP_ADDR 0xFFFBF000 | |
29 | ||
30 | /* | |
31 | * Assume we don't have much FFDC, if we do we'll overflow and | |
32 | * fail the command. This needs to be big enough for simple | |
33 | * commands as well. | |
34 | */ | |
35 | #define OCC_SBE_STATUS_WORDS 32 | |
36 | ||
37 | #define OCC_TIMEOUT_MS 1000 | |
38 | #define OCC_CMD_IN_PRG_WAIT_MS 50 | |
39 | ||
40 | struct occ { | |
41 | struct device *dev; | |
42 | struct device *sbefifo; | |
43 | char name[32]; | |
44 | int idx; | |
45 | struct miscdevice mdev; | |
46 | struct mutex occ_lock; | |
47 | }; | |
48 | ||
49 | #define to_occ(x) container_of((x), struct occ, mdev) | |
50 | ||
51 | struct occ_response { | |
52 | u8 seq_no; | |
53 | u8 cmd_type; | |
54 | u8 return_status; | |
55 | __be16 data_length; | |
56 | u8 data[OCC_RESP_DATA_BYTES + 2]; /* two bytes checksum */ | |
57 | } __packed; | |
58 | ||
59 | struct occ_client { | |
60 | struct occ *occ; | |
61 | struct mutex lock; | |
62 | size_t data_size; | |
63 | size_t read_offset; | |
64 | u8 *buffer; | |
65 | }; | |
66 | ||
67 | #define to_client(x) container_of((x), struct occ_client, xfr) | |
68 | ||
69 | static DEFINE_IDA(occ_ida); | |
70 | ||
71 | static int occ_open(struct inode *inode, struct file *file) | |
72 | { | |
73 | struct occ_client *client = kzalloc(sizeof(*client), GFP_KERNEL); | |
74 | struct miscdevice *mdev = file->private_data; | |
75 | struct occ *occ = to_occ(mdev); | |
76 | ||
77 | if (!client) | |
78 | return -ENOMEM; | |
79 | ||
80 | client->buffer = (u8 *)__get_free_page(GFP_KERNEL); | |
81 | if (!client->buffer) { | |
82 | kfree(client); | |
83 | return -ENOMEM; | |
84 | } | |
85 | ||
86 | client->occ = occ; | |
87 | mutex_init(&client->lock); | |
88 | file->private_data = client; | |
89 | ||
90 | /* We allocate a 1-page buffer, make sure it all fits */ | |
91 | BUILD_BUG_ON((OCC_CMD_DATA_BYTES + 3) > PAGE_SIZE); | |
92 | BUILD_BUG_ON((OCC_RESP_DATA_BYTES + 7) > PAGE_SIZE); | |
93 | ||
94 | return 0; | |
95 | } | |
96 | ||
97 | static ssize_t occ_read(struct file *file, char __user *buf, size_t len, | |
98 | loff_t *offset) | |
99 | { | |
100 | struct occ_client *client = file->private_data; | |
101 | ssize_t rc = 0; | |
102 | ||
103 | if (!client) | |
104 | return -ENODEV; | |
105 | ||
106 | if (len > OCC_SRAM_BYTES) | |
107 | return -EINVAL; | |
108 | ||
109 | mutex_lock(&client->lock); | |
110 | ||
111 | /* This should not be possible ... */ | |
112 | if (WARN_ON_ONCE(client->read_offset > client->data_size)) { | |
113 | rc = -EIO; | |
114 | goto done; | |
115 | } | |
116 | ||
117 | /* Grab how much data we have to read */ | |
118 | rc = min(len, client->data_size - client->read_offset); | |
119 | if (copy_to_user(buf, client->buffer + client->read_offset, rc)) | |
120 | rc = -EFAULT; | |
121 | else | |
122 | client->read_offset += rc; | |
123 | ||
124 | done: | |
125 | mutex_unlock(&client->lock); | |
126 | ||
127 | return rc; | |
128 | } | |
129 | ||
130 | static ssize_t occ_write(struct file *file, const char __user *buf, | |
131 | size_t len, loff_t *offset) | |
132 | { | |
133 | struct occ_client *client = file->private_data; | |
134 | size_t rlen, data_length; | |
135 | u16 checksum = 0; | |
136 | ssize_t rc, i; | |
137 | u8 *cmd; | |
138 | ||
139 | if (!client) | |
140 | return -ENODEV; | |
141 | ||
142 | if (len > (OCC_CMD_DATA_BYTES + 3) || len < 3) | |
143 | return -EINVAL; | |
144 | ||
145 | mutex_lock(&client->lock); | |
146 | ||
147 | /* Construct the command */ | |
148 | cmd = client->buffer; | |
149 | ||
150 | /* Sequence number (we could increment and compare with response) */ | |
151 | cmd[0] = 1; | |
152 | ||
153 | /* | |
154 | * Copy the user command (assume user data follows the occ command | |
155 | * format) | |
156 | * byte 0: command type | |
157 | * bytes 1-2: data length (msb first) | |
158 | * bytes 3-n: data | |
159 | */ | |
160 | if (copy_from_user(&cmd[1], buf, len)) { | |
161 | rc = -EFAULT; | |
162 | goto done; | |
163 | } | |
164 | ||
165 | /* Extract data length */ | |
166 | data_length = (cmd[2] << 8) + cmd[3]; | |
167 | if (data_length > OCC_CMD_DATA_BYTES) { | |
168 | rc = -EINVAL; | |
169 | goto done; | |
170 | } | |
171 | ||
172 | /* Calculate checksum */ | |
173 | for (i = 0; i < data_length + 4; ++i) | |
174 | checksum += cmd[i]; | |
175 | ||
176 | cmd[data_length + 4] = checksum >> 8; | |
177 | cmd[data_length + 5] = checksum & 0xFF; | |
178 | ||
179 | /* Submit command */ | |
180 | rlen = PAGE_SIZE; | |
181 | rc = fsi_occ_submit(client->occ->dev, cmd, data_length + 6, cmd, | |
182 | &rlen); | |
183 | if (rc) | |
184 | goto done; | |
185 | ||
186 | /* Set read tracking data */ | |
187 | client->data_size = rlen; | |
188 | client->read_offset = 0; | |
189 | ||
190 | /* Done */ | |
191 | rc = len; | |
192 | ||
193 | done: | |
194 | mutex_unlock(&client->lock); | |
195 | ||
196 | return rc; | |
197 | } | |
198 | ||
199 | static int occ_release(struct inode *inode, struct file *file) | |
200 | { | |
201 | struct occ_client *client = file->private_data; | |
202 | ||
203 | free_page((unsigned long)client->buffer); | |
204 | kfree(client); | |
205 | ||
206 | return 0; | |
207 | } | |
208 | ||
209 | static const struct file_operations occ_fops = { | |
210 | .owner = THIS_MODULE, | |
211 | .open = occ_open, | |
212 | .read = occ_read, | |
213 | .write = occ_write, | |
214 | .release = occ_release, | |
215 | }; | |
216 | ||
217 | static int occ_verify_checksum(struct occ_response *resp, u16 data_length) | |
218 | { | |
219 | /* Fetch the two bytes after the data for the checksum. */ | |
220 | u16 checksum_resp = get_unaligned_be16(&resp->data[data_length]); | |
221 | u16 checksum; | |
222 | u16 i; | |
223 | ||
224 | checksum = resp->seq_no; | |
225 | checksum += resp->cmd_type; | |
226 | checksum += resp->return_status; | |
227 | checksum += (data_length >> 8) + (data_length & 0xFF); | |
228 | ||
229 | for (i = 0; i < data_length; ++i) | |
230 | checksum += resp->data[i]; | |
231 | ||
232 | if (checksum != checksum_resp) | |
233 | return -EBADMSG; | |
234 | ||
235 | return 0; | |
236 | } | |
237 | ||
238 | static int occ_getsram(struct occ *occ, u32 address, void *data, ssize_t len) | |
239 | { | |
240 | u32 data_len = ((len + 7) / 8) * 8; /* must be multiples of 8 B */ | |
241 | size_t resp_len, resp_data_len; | |
242 | __be32 *resp, cmd[5]; | |
243 | int rc; | |
244 | ||
245 | /* | |
246 | * Magic sequence to do SBE getsram command. SBE will fetch data from | |
247 | * specified SRAM address. | |
248 | */ | |
249 | cmd[0] = cpu_to_be32(0x5); | |
250 | cmd[1] = cpu_to_be32(SBEFIFO_CMD_GET_OCC_SRAM); | |
251 | cmd[2] = cpu_to_be32(1); | |
252 | cmd[3] = cpu_to_be32(address); | |
253 | cmd[4] = cpu_to_be32(data_len); | |
254 | ||
255 | resp_len = (data_len >> 2) + OCC_SBE_STATUS_WORDS; | |
256 | resp = kzalloc(resp_len << 2, GFP_KERNEL); | |
257 | if (!resp) | |
258 | return -ENOMEM; | |
259 | ||
260 | rc = sbefifo_submit(occ->sbefifo, cmd, 5, resp, &resp_len); | |
261 | if (rc) | |
262 | goto free; | |
263 | ||
264 | rc = sbefifo_parse_status(occ->sbefifo, SBEFIFO_CMD_GET_OCC_SRAM, | |
265 | resp, resp_len, &resp_len); | |
266 | if (rc) | |
267 | goto free; | |
268 | ||
269 | resp_data_len = be32_to_cpu(resp[resp_len - 1]); | |
270 | if (resp_data_len != data_len) { | |
271 | dev_err(occ->dev, "SRAM read expected %d bytes got %zd\n", | |
272 | data_len, resp_data_len); | |
273 | rc = -EBADMSG; | |
274 | } else { | |
275 | memcpy(data, resp, len); | |
276 | } | |
277 | ||
278 | free: | |
279 | /* Convert positive SBEI status */ | |
280 | if (rc > 0) { | |
281 | dev_err(occ->dev, "SRAM read returned failure status: %08x\n", | |
282 | rc); | |
283 | rc = -EBADMSG; | |
284 | } | |
285 | ||
286 | kfree(resp); | |
287 | return rc; | |
288 | } | |
289 | ||
290 | static int occ_putsram(struct occ *occ, u32 address, const void *data, | |
291 | ssize_t len) | |
292 | { | |
293 | size_t cmd_len, buf_len, resp_len, resp_data_len; | |
294 | u32 data_len = ((len + 7) / 8) * 8; /* must be multiples of 8 B */ | |
295 | __be32 *buf; | |
296 | int rc; | |
297 | ||
298 | /* | |
299 | * We use the same buffer for command and response, make | |
300 | * sure it's big enough | |
301 | */ | |
302 | resp_len = OCC_SBE_STATUS_WORDS; | |
303 | cmd_len = (data_len >> 2) + 5; | |
304 | buf_len = max(cmd_len, resp_len); | |
305 | buf = kzalloc(buf_len << 2, GFP_KERNEL); | |
306 | if (!buf) | |
307 | return -ENOMEM; | |
308 | ||
309 | /* | |
310 | * Magic sequence to do SBE putsram command. SBE will transfer | |
311 | * data to specified SRAM address. | |
312 | */ | |
313 | buf[0] = cpu_to_be32(cmd_len); | |
314 | buf[1] = cpu_to_be32(SBEFIFO_CMD_PUT_OCC_SRAM); | |
315 | buf[2] = cpu_to_be32(1); | |
316 | buf[3] = cpu_to_be32(address); | |
317 | buf[4] = cpu_to_be32(data_len); | |
318 | ||
319 | memcpy(&buf[5], data, len); | |
320 | ||
321 | rc = sbefifo_submit(occ->sbefifo, buf, cmd_len, buf, &resp_len); | |
322 | if (rc) | |
323 | goto free; | |
324 | ||
325 | rc = sbefifo_parse_status(occ->sbefifo, SBEFIFO_CMD_PUT_OCC_SRAM, | |
326 | buf, resp_len, &resp_len); | |
327 | if (rc) | |
328 | goto free; | |
329 | ||
330 | if (resp_len != 1) { | |
331 | dev_err(occ->dev, "SRAM write response length invalid: %zd\n", | |
332 | resp_len); | |
333 | rc = -EBADMSG; | |
334 | } else { | |
335 | resp_data_len = be32_to_cpu(buf[0]); | |
336 | if (resp_data_len != data_len) { | |
337 | dev_err(occ->dev, | |
338 | "SRAM write expected %d bytes got %zd\n", | |
339 | data_len, resp_data_len); | |
340 | rc = -EBADMSG; | |
341 | } | |
342 | } | |
343 | ||
344 | free: | |
345 | /* Convert positive SBEI status */ | |
346 | if (rc > 0) { | |
347 | dev_err(occ->dev, "SRAM write returned failure status: %08x\n", | |
348 | rc); | |
349 | rc = -EBADMSG; | |
350 | } | |
351 | ||
352 | kfree(buf); | |
353 | return rc; | |
354 | } | |
355 | ||
356 | static int occ_trigger_attn(struct occ *occ) | |
357 | { | |
358 | __be32 buf[OCC_SBE_STATUS_WORDS]; | |
359 | size_t resp_len, resp_data_len; | |
360 | int rc; | |
361 | ||
362 | BUILD_BUG_ON(OCC_SBE_STATUS_WORDS < 7); | |
363 | resp_len = OCC_SBE_STATUS_WORDS; | |
364 | ||
365 | buf[0] = cpu_to_be32(0x5 + 0x2); /* Chip-op length in words */ | |
366 | buf[1] = cpu_to_be32(SBEFIFO_CMD_PUT_OCC_SRAM); | |
367 | buf[2] = cpu_to_be32(0x3); /* Mode: Circular */ | |
368 | buf[3] = cpu_to_be32(0x0); /* Address: ignore in mode 3 */ | |
369 | buf[4] = cpu_to_be32(0x8); /* Data length in bytes */ | |
370 | buf[5] = cpu_to_be32(0x20010000); /* Trigger OCC attention */ | |
371 | buf[6] = 0; | |
372 | ||
373 | rc = sbefifo_submit(occ->sbefifo, buf, 7, buf, &resp_len); | |
374 | if (rc) | |
375 | goto error; | |
376 | ||
377 | rc = sbefifo_parse_status(occ->sbefifo, SBEFIFO_CMD_PUT_OCC_SRAM, | |
378 | buf, resp_len, &resp_len); | |
379 | if (rc) | |
380 | goto error; | |
381 | ||
382 | if (resp_len != 1) { | |
383 | dev_err(occ->dev, "SRAM attn response length invalid: %zd\n", | |
384 | resp_len); | |
385 | rc = -EBADMSG; | |
386 | } else { | |
387 | resp_data_len = be32_to_cpu(buf[0]); | |
388 | if (resp_data_len != 8) { | |
389 | dev_err(occ->dev, | |
390 | "SRAM attn expected 8 bytes got %zd\n", | |
391 | resp_data_len); | |
392 | rc = -EBADMSG; | |
393 | } | |
394 | } | |
395 | ||
396 | error: | |
397 | /* Convert positive SBEI status */ | |
398 | if (rc > 0) { | |
399 | dev_err(occ->dev, "SRAM attn returned failure status: %08x\n", | |
400 | rc); | |
401 | rc = -EBADMSG; | |
402 | } | |
403 | ||
404 | return rc; | |
405 | } | |
406 | ||
407 | int fsi_occ_submit(struct device *dev, const void *request, size_t req_len, | |
408 | void *response, size_t *resp_len) | |
409 | { | |
410 | const unsigned long timeout = msecs_to_jiffies(OCC_TIMEOUT_MS); | |
411 | const unsigned long wait_time = | |
412 | msecs_to_jiffies(OCC_CMD_IN_PRG_WAIT_MS); | |
413 | struct occ *occ = dev_get_drvdata(dev); | |
414 | struct occ_response *resp = response; | |
afd26118 | 415 | u8 seq_no; |
7ed98ddd EJ |
416 | u16 resp_data_length; |
417 | unsigned long start; | |
418 | int rc; | |
419 | ||
420 | if (!occ) | |
421 | return -ENODEV; | |
422 | ||
423 | if (*resp_len < 7) { | |
424 | dev_dbg(dev, "Bad resplen %zd\n", *resp_len); | |
425 | return -EINVAL; | |
426 | } | |
427 | ||
428 | mutex_lock(&occ->occ_lock); | |
429 | ||
afd26118 EJ |
430 | /* Extract the seq_no from the command (first byte) */ |
431 | seq_no = *(const u8 *)request; | |
7ed98ddd EJ |
432 | rc = occ_putsram(occ, OCC_SRAM_CMD_ADDR, request, req_len); |
433 | if (rc) | |
434 | goto done; | |
435 | ||
436 | rc = occ_trigger_attn(occ); | |
437 | if (rc) | |
438 | goto done; | |
439 | ||
440 | /* Read occ response header */ | |
441 | start = jiffies; | |
442 | do { | |
443 | rc = occ_getsram(occ, OCC_SRAM_RSP_ADDR, resp, 8); | |
444 | if (rc) | |
445 | goto done; | |
446 | ||
afd26118 EJ |
447 | if (resp->return_status == OCC_RESP_CMD_IN_PRG || |
448 | resp->seq_no != seq_no) { | |
7ed98ddd EJ |
449 | rc = -ETIMEDOUT; |
450 | ||
afd26118 EJ |
451 | if (time_after(jiffies, start + timeout)) { |
452 | dev_err(occ->dev, "resp timeout status=%02x " | |
453 | "resp seq_no=%d our seq_no=%d\n", | |
454 | resp->return_status, resp->seq_no, | |
455 | seq_no); | |
456 | goto done; | |
457 | } | |
7ed98ddd EJ |
458 | |
459 | set_current_state(TASK_UNINTERRUPTIBLE); | |
460 | schedule_timeout(wait_time); | |
461 | } | |
462 | } while (rc); | |
463 | ||
464 | /* Extract size of response data */ | |
465 | resp_data_length = get_unaligned_be16(&resp->data_length); | |
466 | ||
467 | /* Message size is data length + 5 bytes header + 2 bytes checksum */ | |
468 | if ((resp_data_length + 7) > *resp_len) { | |
469 | rc = -EMSGSIZE; | |
470 | goto done; | |
471 | } | |
472 | ||
473 | dev_dbg(dev, "resp_status=%02x resp_data_len=%d\n", | |
474 | resp->return_status, resp_data_length); | |
475 | ||
476 | /* Grab the rest */ | |
477 | if (resp_data_length > 1) { | |
478 | /* already got 3 bytes resp, also need 2 bytes checksum */ | |
479 | rc = occ_getsram(occ, OCC_SRAM_RSP_ADDR + 8, | |
480 | &resp->data[3], resp_data_length - 1); | |
481 | if (rc) | |
482 | goto done; | |
483 | } | |
484 | ||
485 | *resp_len = resp_data_length + 7; | |
486 | rc = occ_verify_checksum(resp, resp_data_length); | |
487 | ||
488 | done: | |
489 | mutex_unlock(&occ->occ_lock); | |
490 | ||
491 | return rc; | |
492 | } | |
493 | EXPORT_SYMBOL_GPL(fsi_occ_submit); | |
494 | ||
495 | static int occ_unregister_child(struct device *dev, void *data) | |
496 | { | |
497 | struct platform_device *hwmon_dev = to_platform_device(dev); | |
498 | ||
499 | platform_device_unregister(hwmon_dev); | |
500 | ||
501 | return 0; | |
502 | } | |
503 | ||
504 | static int occ_probe(struct platform_device *pdev) | |
505 | { | |
506 | int rc; | |
507 | u32 reg; | |
508 | struct occ *occ; | |
509 | struct platform_device *hwmon_dev; | |
510 | struct device *dev = &pdev->dev; | |
511 | struct platform_device_info hwmon_dev_info = { | |
512 | .parent = dev, | |
513 | .name = "occ-hwmon", | |
514 | }; | |
515 | ||
516 | occ = devm_kzalloc(dev, sizeof(*occ), GFP_KERNEL); | |
517 | if (!occ) | |
518 | return -ENOMEM; | |
519 | ||
520 | occ->dev = dev; | |
521 | occ->sbefifo = dev->parent; | |
522 | mutex_init(&occ->occ_lock); | |
523 | ||
524 | if (dev->of_node) { | |
525 | rc = of_property_read_u32(dev->of_node, "reg", ®); | |
526 | if (!rc) { | |
527 | /* make sure we don't have a duplicate from dts */ | |
528 | occ->idx = ida_simple_get(&occ_ida, reg, reg + 1, | |
529 | GFP_KERNEL); | |
530 | if (occ->idx < 0) | |
531 | occ->idx = ida_simple_get(&occ_ida, 1, INT_MAX, | |
532 | GFP_KERNEL); | |
533 | } else { | |
534 | occ->idx = ida_simple_get(&occ_ida, 1, INT_MAX, | |
535 | GFP_KERNEL); | |
536 | } | |
537 | } else { | |
538 | occ->idx = ida_simple_get(&occ_ida, 1, INT_MAX, GFP_KERNEL); | |
539 | } | |
540 | ||
541 | platform_set_drvdata(pdev, occ); | |
542 | ||
543 | snprintf(occ->name, sizeof(occ->name), "occ%d", occ->idx); | |
544 | occ->mdev.fops = &occ_fops; | |
545 | occ->mdev.minor = MISC_DYNAMIC_MINOR; | |
546 | occ->mdev.name = occ->name; | |
547 | occ->mdev.parent = dev; | |
548 | ||
549 | rc = misc_register(&occ->mdev); | |
550 | if (rc) { | |
551 | dev_err(dev, "failed to register miscdevice: %d\n", rc); | |
552 | ida_simple_remove(&occ_ida, occ->idx); | |
553 | return rc; | |
554 | } | |
555 | ||
556 | hwmon_dev_info.id = occ->idx; | |
557 | hwmon_dev = platform_device_register_full(&hwmon_dev_info); | |
558 | if (!hwmon_dev) | |
559 | dev_warn(dev, "failed to create hwmon device\n"); | |
560 | ||
561 | return 0; | |
562 | } | |
563 | ||
564 | static int occ_remove(struct platform_device *pdev) | |
565 | { | |
566 | struct occ *occ = platform_get_drvdata(pdev); | |
567 | ||
568 | misc_deregister(&occ->mdev); | |
569 | ||
570 | device_for_each_child(&pdev->dev, NULL, occ_unregister_child); | |
571 | ||
572 | ida_simple_remove(&occ_ida, occ->idx); | |
573 | ||
574 | return 0; | |
575 | } | |
576 | ||
577 | static const struct of_device_id occ_match[] = { | |
578 | { .compatible = "ibm,p9-occ" }, | |
579 | { }, | |
580 | }; | |
581 | ||
582 | static struct platform_driver occ_driver = { | |
583 | .driver = { | |
584 | .name = "occ", | |
585 | .of_match_table = occ_match, | |
586 | }, | |
587 | .probe = occ_probe, | |
588 | .remove = occ_remove, | |
589 | }; | |
590 | ||
591 | static int occ_init(void) | |
592 | { | |
593 | return platform_driver_register(&occ_driver); | |
594 | } | |
595 | ||
596 | static void occ_exit(void) | |
597 | { | |
598 | platform_driver_unregister(&occ_driver); | |
599 | ||
600 | ida_destroy(&occ_ida); | |
601 | } | |
602 | ||
603 | module_init(occ_init); | |
604 | module_exit(occ_exit); | |
605 | ||
606 | MODULE_AUTHOR("Eddie James <eajames@linux.ibm.com>"); | |
607 | MODULE_DESCRIPTION("BMC P9 OCC driver"); | |
608 | MODULE_LICENSE("GPL"); |