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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * dell_rbu.c
4 * Bios Update driver for Dell systems
5 * Author: Dell Inc
6 * Abhay Salunke <abhay_salunke@dell.com>
7 *
8 * Copyright (C) 2005 Dell Inc.
9 *
10 * Remote BIOS Update (rbu) driver is used for updating DELL BIOS by
11 * creating entries in the /sys file systems on Linux 2.6 and higher
12 * kernels. The driver supports two mechanism to update the BIOS namely
13 * contiguous and packetized. Both these methods still require having some
14 * application to set the CMOS bit indicating the BIOS to update itself
15 * after a reboot.
16 *
17 * Contiguous method:
18 * This driver writes the incoming data in a monolithic image by allocating
19 * contiguous physical pages large enough to accommodate the incoming BIOS
20 * image size.
21 *
22 * Packetized method:
23 * The driver writes the incoming packet image by allocating a new packet
24 * on every time the packet data is written. This driver requires an
25 * application to break the BIOS image in to fixed sized packet chunks.
26 *
27 * See Documentation/driver-api/dell_rbu.rst for more info.
28 */
29#include <linux/init.h>
30#include <linux/module.h>
31#include <linux/slab.h>
32#include <linux/string.h>
33#include <linux/errno.h>
34#include <linux/blkdev.h>
35#include <linux/platform_device.h>
36#include <linux/spinlock.h>
37#include <linux/moduleparam.h>
38#include <linux/firmware.h>
39#include <linux/dma-mapping.h>
40#include <asm/set_memory.h>
41
42MODULE_AUTHOR("Abhay Salunke <abhay_salunke@dell.com>");
43MODULE_DESCRIPTION("Driver for updating BIOS image on DELL systems");
44MODULE_LICENSE("GPL");
45MODULE_VERSION("3.2");
46
47#define BIOS_SCAN_LIMIT 0xffffffff
48#define MAX_IMAGE_LENGTH 16
49static struct _rbu_data {
50 void *image_update_buffer;
51 unsigned long image_update_buffer_size;
52 unsigned long bios_image_size;
53 int image_update_ordernum;
54 spinlock_t lock;
55 unsigned long packet_read_count;
56 unsigned long num_packets;
57 unsigned long packetsize;
58 unsigned long imagesize;
59 int entry_created;
60} rbu_data;
61
62static char image_type[MAX_IMAGE_LENGTH + 1] = "mono";
63module_param_string(image_type, image_type, sizeof (image_type), 0);
64MODULE_PARM_DESC(image_type,
65 "BIOS image type. choose- mono or packet or init");
66
67static unsigned long allocation_floor = 0x100000;
68module_param(allocation_floor, ulong, 0644);
69MODULE_PARM_DESC(allocation_floor,
70 "Minimum address for allocations when using Packet mode");
71
72struct packet_data {
73 struct list_head list;
74 size_t length;
75 void *data;
76 int ordernum;
77};
78
79static struct packet_data packet_data_head;
80
81static struct platform_device *rbu_device;
82static int context;
83
84static void init_packet_head(void)
85{
86 INIT_LIST_HEAD(&packet_data_head.list);
87 rbu_data.packet_read_count = 0;
88 rbu_data.num_packets = 0;
89 rbu_data.packetsize = 0;
90 rbu_data.imagesize = 0;
91}
92
93static int create_packet(void *data, size_t length)
94{
95 struct packet_data *newpacket;
96 int ordernum = 0;
97 int retval = 0;
98 unsigned int packet_array_size = 0;
99 void **invalid_addr_packet_array = NULL;
100 void *packet_data_temp_buf = NULL;
101 unsigned int idx = 0;
102
103 pr_debug("create_packet: entry \n");
104
105 if (!rbu_data.packetsize) {
106 pr_debug("create_packet: packetsize not specified\n");
107 retval = -EINVAL;
108 goto out_noalloc;
109 }
110
111 spin_unlock(&rbu_data.lock);
112
113 newpacket = kzalloc(sizeof (struct packet_data), GFP_KERNEL);
114
115 if (!newpacket) {
116 printk(KERN_WARNING
117 "dell_rbu:%s: failed to allocate new "
118 "packet\n", __func__);
119 retval = -ENOMEM;
120 spin_lock(&rbu_data.lock);
121 goto out_noalloc;
122 }
123
124 ordernum = get_order(length);
125
126 /*
127 * BIOS errata mean we cannot allocate packets below 1MB or they will
128 * be overwritten by BIOS.
129 *
130 * array to temporarily hold packets
131 * that are below the allocation floor
132 *
133 * NOTE: very simplistic because we only need the floor to be at 1MB
134 * due to BIOS errata. This shouldn't be used for higher floors
135 * or you will run out of mem trying to allocate the array.
136 */
137 packet_array_size = max(
138 (unsigned int)(allocation_floor / rbu_data.packetsize),
139 (unsigned int)1);
140 invalid_addr_packet_array = kcalloc(packet_array_size, sizeof(void *),
141 GFP_KERNEL);
142
143 if (!invalid_addr_packet_array) {
144 printk(KERN_WARNING
145 "dell_rbu:%s: failed to allocate "
146 "invalid_addr_packet_array \n",
147 __func__);
148 retval = -ENOMEM;
149 spin_lock(&rbu_data.lock);
150 goto out_alloc_packet;
151 }
152
153 while (!packet_data_temp_buf) {
154 packet_data_temp_buf = (unsigned char *)
155 __get_free_pages(GFP_KERNEL, ordernum);
156 if (!packet_data_temp_buf) {
157 printk(KERN_WARNING
158 "dell_rbu:%s: failed to allocate new "
159 "packet\n", __func__);
160 retval = -ENOMEM;
161 spin_lock(&rbu_data.lock);
162 goto out_alloc_packet_array;
163 }
164
165 if ((unsigned long)virt_to_phys(packet_data_temp_buf)
166 < allocation_floor) {
167 pr_debug("packet 0x%lx below floor at 0x%lx.\n",
168 (unsigned long)virt_to_phys(
169 packet_data_temp_buf),
170 allocation_floor);
171 invalid_addr_packet_array[idx++] = packet_data_temp_buf;
172 packet_data_temp_buf = NULL;
173 }
174 }
175 /*
176 * set to uncachable or it may never get written back before reboot
177 */
178 set_memory_uc((unsigned long)packet_data_temp_buf, 1 << ordernum);
179
180 spin_lock(&rbu_data.lock);
181
182 newpacket->data = packet_data_temp_buf;
183
184 pr_debug("create_packet: newpacket at physical addr %lx\n",
185 (unsigned long)virt_to_phys(newpacket->data));
186
187 /* packets may not have fixed size */
188 newpacket->length = length;
189 newpacket->ordernum = ordernum;
190 ++rbu_data.num_packets;
191
192 /* initialize the newly created packet headers */
193 INIT_LIST_HEAD(&newpacket->list);
194 list_add_tail(&newpacket->list, &packet_data_head.list);
195
196 memcpy(newpacket->data, data, length);
197
198 pr_debug("create_packet: exit \n");
199
200out_alloc_packet_array:
201 /* always free packet array */
202 for (;idx>0;idx--) {
203 pr_debug("freeing unused packet below floor 0x%lx.\n",
204 (unsigned long)virt_to_phys(
205 invalid_addr_packet_array[idx-1]));
206 free_pages((unsigned long)invalid_addr_packet_array[idx-1],
207 ordernum);
208 }
209 kfree(invalid_addr_packet_array);
210
211out_alloc_packet:
212 /* if error, free data */
213 if (retval)
214 kfree(newpacket);
215
216out_noalloc:
217 return retval;
218}
219
220static int packetize_data(const u8 *data, size_t length)
221{
222 int rc = 0;
223 int done = 0;
224 int packet_length;
225 u8 *temp;
226 u8 *end = (u8 *) data + length;
227 pr_debug("packetize_data: data length %zd\n", length);
228 if (!rbu_data.packetsize) {
229 printk(KERN_WARNING
230 "dell_rbu: packetsize not specified\n");
231 return -EIO;
232 }
233
234 temp = (u8 *) data;
235
236 /* packetize the hunk */
237 while (!done) {
238 if ((temp + rbu_data.packetsize) < end)
239 packet_length = rbu_data.packetsize;
240 else {
241 /* this is the last packet */
242 packet_length = end - temp;
243 done = 1;
244 }
245
246 if ((rc = create_packet(temp, packet_length)))
247 return rc;
248
249 pr_debug("%p:%td\n", temp, (end - temp));
250 temp += packet_length;
251 }
252
253 rbu_data.imagesize = length;
254
255 return rc;
256}
257
258static int do_packet_read(char *data, struct list_head *ptemp_list,
259 int length, int bytes_read, int *list_read_count)
260{
261 void *ptemp_buf;
262 struct packet_data *newpacket = NULL;
263 int bytes_copied = 0;
264 int j = 0;
265
266 newpacket = list_entry(ptemp_list, struct packet_data, list);
267 *list_read_count += newpacket->length;
268
269 if (*list_read_count > bytes_read) {
270 /* point to the start of unread data */
271 j = newpacket->length - (*list_read_count - bytes_read);
272 /* point to the offset in the packet buffer */
273 ptemp_buf = (u8 *) newpacket->data + j;
274 /*
275 * check if there is enough room in
276 * * the incoming buffer
277 */
278 if (length > (*list_read_count - bytes_read))
279 /*
280 * copy what ever is there in this
281 * packet and move on
282 */
283 bytes_copied = (*list_read_count - bytes_read);
284 else
285 /* copy the remaining */
286 bytes_copied = length;
287 memcpy(data, ptemp_buf, bytes_copied);
288 }
289 return bytes_copied;
290}
291
292static int packet_read_list(char *data, size_t * pread_length)
293{
294 struct list_head *ptemp_list;
295 int temp_count = 0;
296 int bytes_copied = 0;
297 int bytes_read = 0;
298 int remaining_bytes = 0;
299 char *pdest = data;
300
301 /* check if we have any packets */
302 if (0 == rbu_data.num_packets)
303 return -ENOMEM;
304
305 remaining_bytes = *pread_length;
306 bytes_read = rbu_data.packet_read_count;
307
308 ptemp_list = (&packet_data_head.list)->next;
309 while (!list_empty(ptemp_list)) {
310 bytes_copied = do_packet_read(pdest, ptemp_list,
311 remaining_bytes, bytes_read, &temp_count);
312 remaining_bytes -= bytes_copied;
313 bytes_read += bytes_copied;
314 pdest += bytes_copied;
315 /*
316 * check if we reached end of buffer before reaching the
317 * last packet
318 */
319 if (remaining_bytes == 0)
320 break;
321
322 ptemp_list = ptemp_list->next;
323 }
324 /*finally set the bytes read */
325 *pread_length = bytes_read - rbu_data.packet_read_count;
326 rbu_data.packet_read_count = bytes_read;
327 return 0;
328}
329
330static void packet_empty_list(void)
331{
332 struct list_head *ptemp_list;
333 struct list_head *pnext_list;
334 struct packet_data *newpacket;
335
336 ptemp_list = (&packet_data_head.list)->next;
337 while (!list_empty(ptemp_list)) {
338 newpacket =
339 list_entry(ptemp_list, struct packet_data, list);
340 pnext_list = ptemp_list->next;
341 list_del(ptemp_list);
342 ptemp_list = pnext_list;
343 /*
344 * zero out the RBU packet memory before freeing
345 * to make sure there are no stale RBU packets left in memory
346 */
347 memset(newpacket->data, 0, rbu_data.packetsize);
348 set_memory_wb((unsigned long)newpacket->data,
349 1 << newpacket->ordernum);
350 free_pages((unsigned long) newpacket->data,
351 newpacket->ordernum);
352 kfree(newpacket);
353 }
354 rbu_data.packet_read_count = 0;
355 rbu_data.num_packets = 0;
356 rbu_data.imagesize = 0;
357}
358
359/*
360 * img_update_free: Frees the buffer allocated for storing BIOS image
361 * Always called with lock held and returned with lock held
362 */
363static void img_update_free(void)
364{
365 if (!rbu_data.image_update_buffer)
366 return;
367 /*
368 * zero out this buffer before freeing it to get rid of any stale
369 * BIOS image copied in memory.
370 */
371 memset(rbu_data.image_update_buffer, 0,
372 rbu_data.image_update_buffer_size);
373 free_pages((unsigned long) rbu_data.image_update_buffer,
374 rbu_data.image_update_ordernum);
375
376 /*
377 * Re-initialize the rbu_data variables after a free
378 */
379 rbu_data.image_update_ordernum = -1;
380 rbu_data.image_update_buffer = NULL;
381 rbu_data.image_update_buffer_size = 0;
382 rbu_data.bios_image_size = 0;
383}
384
385/*
386 * img_update_realloc: This function allocates the contiguous pages to
387 * accommodate the requested size of data. The memory address and size
388 * values are stored globally and on every call to this function the new
389 * size is checked to see if more data is required than the existing size.
390 * If true the previous memory is freed and new allocation is done to
391 * accommodate the new size. If the incoming size is less then than the
392 * already allocated size, then that memory is reused. This function is
393 * called with lock held and returns with lock held.
394 */
395static int img_update_realloc(unsigned long size)
396{
397 unsigned char *image_update_buffer = NULL;
398 unsigned long img_buf_phys_addr;
399 int ordernum;
400
401 /*
402 * check if the buffer of sufficient size has been
403 * already allocated
404 */
405 if (rbu_data.image_update_buffer_size >= size) {
406 /*
407 * check for corruption
408 */
409 if ((size != 0) && (rbu_data.image_update_buffer == NULL)) {
410 printk(KERN_ERR "dell_rbu:%s: corruption "
411 "check failed\n", __func__);
412 return -EINVAL;
413 }
414 /*
415 * we have a valid pre-allocated buffer with
416 * sufficient size
417 */
418 return 0;
419 }
420
421 /*
422 * free any previously allocated buffer
423 */
424 img_update_free();
425
426 spin_unlock(&rbu_data.lock);
427
428 ordernum = get_order(size);
429 image_update_buffer =
430 (unsigned char *)__get_free_pages(GFP_DMA32, ordernum);
431 spin_lock(&rbu_data.lock);
432 if (!image_update_buffer) {
433 pr_debug("Not enough memory for image update:"
434 "size = %ld\n", size);
435 return -ENOMEM;
436 }
437
438 img_buf_phys_addr = (unsigned long)virt_to_phys(image_update_buffer);
439 if (WARN_ON_ONCE(img_buf_phys_addr > BIOS_SCAN_LIMIT))
440 return -EINVAL; /* can't happen per definition */
441
442 rbu_data.image_update_buffer = image_update_buffer;
443 rbu_data.image_update_buffer_size = size;
444 rbu_data.bios_image_size = rbu_data.image_update_buffer_size;
445 rbu_data.image_update_ordernum = ordernum;
446 return 0;
447}
448
449static ssize_t read_packet_data(char *buffer, loff_t pos, size_t count)
450{
451 int retval;
452 size_t bytes_left;
453 size_t data_length;
454 char *ptempBuf = buffer;
455
456 /* check to see if we have something to return */
457 if (rbu_data.num_packets == 0) {
458 pr_debug("read_packet_data: no packets written\n");
459 retval = -ENOMEM;
460 goto read_rbu_data_exit;
461 }
462
463 if (pos > rbu_data.imagesize) {
464 retval = 0;
465 printk(KERN_WARNING "dell_rbu:read_packet_data: "
466 "data underrun\n");
467 goto read_rbu_data_exit;
468 }
469
470 bytes_left = rbu_data.imagesize - pos;
471 data_length = min(bytes_left, count);
472
473 if ((retval = packet_read_list(ptempBuf, &data_length)) < 0)
474 goto read_rbu_data_exit;
475
476 if ((pos + count) > rbu_data.imagesize) {
477 rbu_data.packet_read_count = 0;
478 /* this was the last copy */
479 retval = bytes_left;
480 } else
481 retval = count;
482
483 read_rbu_data_exit:
484 return retval;
485}
486
487static ssize_t read_rbu_mono_data(char *buffer, loff_t pos, size_t count)
488{
489 /* check to see if we have something to return */
490 if ((rbu_data.image_update_buffer == NULL) ||
491 (rbu_data.bios_image_size == 0)) {
492 pr_debug("read_rbu_data_mono: image_update_buffer %p ,"
493 "bios_image_size %lu\n",
494 rbu_data.image_update_buffer,
495 rbu_data.bios_image_size);
496 return -ENOMEM;
497 }
498
499 return memory_read_from_buffer(buffer, count, &pos,
500 rbu_data.image_update_buffer, rbu_data.bios_image_size);
501}
502
503static ssize_t read_rbu_data(struct file *filp, struct kobject *kobj,
504 struct bin_attribute *bin_attr,
505 char *buffer, loff_t pos, size_t count)
506{
507 ssize_t ret_count = 0;
508
509 spin_lock(&rbu_data.lock);
510
511 if (!strcmp(image_type, "mono"))
512 ret_count = read_rbu_mono_data(buffer, pos, count);
513 else if (!strcmp(image_type, "packet"))
514 ret_count = read_packet_data(buffer, pos, count);
515 else
516 pr_debug("read_rbu_data: invalid image type specified\n");
517
518 spin_unlock(&rbu_data.lock);
519 return ret_count;
520}
521
522static void callbackfn_rbu(const struct firmware *fw, void *context)
523{
524 rbu_data.entry_created = 0;
525
526 if (!fw)
527 return;
528
529 if (!fw->size)
530 goto out;
531
532 spin_lock(&rbu_data.lock);
533 if (!strcmp(image_type, "mono")) {
534 if (!img_update_realloc(fw->size))
535 memcpy(rbu_data.image_update_buffer,
536 fw->data, fw->size);
537 } else if (!strcmp(image_type, "packet")) {
538 /*
539 * we need to free previous packets if a
540 * new hunk of packets needs to be downloaded
541 */
542 packet_empty_list();
543 if (packetize_data(fw->data, fw->size))
544 /* Incase something goes wrong when we are
545 * in middle of packetizing the data, we
546 * need to free up whatever packets might
547 * have been created before we quit.
548 */
549 packet_empty_list();
550 } else
551 pr_debug("invalid image type specified.\n");
552 spin_unlock(&rbu_data.lock);
553 out:
554 release_firmware(fw);
555}
556
557static ssize_t read_rbu_image_type(struct file *filp, struct kobject *kobj,
558 struct bin_attribute *bin_attr,
559 char *buffer, loff_t pos, size_t count)
560{
561 int size = 0;
562 if (!pos)
563 size = scnprintf(buffer, count, "%s\n", image_type);
564 return size;
565}
566
567static ssize_t write_rbu_image_type(struct file *filp, struct kobject *kobj,
568 struct bin_attribute *bin_attr,
569 char *buffer, loff_t pos, size_t count)
570{
571 int rc = count;
572 int req_firm_rc = 0;
573 int i;
574 spin_lock(&rbu_data.lock);
575 /*
576 * Find the first newline or space
577 */
578 for (i = 0; i < count; ++i)
579 if (buffer[i] == '\n' || buffer[i] == ' ') {
580 buffer[i] = '\0';
581 break;
582 }
583 if (i == count)
584 buffer[count] = '\0';
585
586 if (strstr(buffer, "mono"))
587 strcpy(image_type, "mono");
588 else if (strstr(buffer, "packet"))
589 strcpy(image_type, "packet");
590 else if (strstr(buffer, "init")) {
591 /*
592 * If due to the user error the driver gets in a bad
593 * state where even though it is loaded , the
594 * /sys/class/firmware/dell_rbu entries are missing.
595 * to cover this situation the user can recreate entries
596 * by writing init to image_type.
597 */
598 if (!rbu_data.entry_created) {
599 spin_unlock(&rbu_data.lock);
600 req_firm_rc = request_firmware_nowait(THIS_MODULE,
601 FW_ACTION_NOHOTPLUG, "dell_rbu",
602 &rbu_device->dev, GFP_KERNEL, &context,
603 callbackfn_rbu);
604 if (req_firm_rc) {
605 printk(KERN_ERR
606 "dell_rbu:%s request_firmware_nowait"
607 " failed %d\n", __func__, rc);
608 rc = -EIO;
609 } else
610 rbu_data.entry_created = 1;
611
612 spin_lock(&rbu_data.lock);
613 }
614 } else {
615 printk(KERN_WARNING "dell_rbu: image_type is invalid\n");
616 spin_unlock(&rbu_data.lock);
617 return -EINVAL;
618 }
619
620 /* we must free all previous allocations */
621 packet_empty_list();
622 img_update_free();
623 spin_unlock(&rbu_data.lock);
624
625 return rc;
626}
627
628static ssize_t read_rbu_packet_size(struct file *filp, struct kobject *kobj,
629 struct bin_attribute *bin_attr,
630 char *buffer, loff_t pos, size_t count)
631{
632 int size = 0;
633 if (!pos) {
634 spin_lock(&rbu_data.lock);
635 size = scnprintf(buffer, count, "%lu\n", rbu_data.packetsize);
636 spin_unlock(&rbu_data.lock);
637 }
638 return size;
639}
640
641static ssize_t write_rbu_packet_size(struct file *filp, struct kobject *kobj,
642 struct bin_attribute *bin_attr,
643 char *buffer, loff_t pos, size_t count)
644{
645 unsigned long temp;
646 spin_lock(&rbu_data.lock);
647 packet_empty_list();
648 sscanf(buffer, "%lu", &temp);
649 if (temp < 0xffffffff)
650 rbu_data.packetsize = temp;
651
652 spin_unlock(&rbu_data.lock);
653 return count;
654}
655
656static struct bin_attribute rbu_data_attr = {
657 .attr = {.name = "data", .mode = 0444},
658 .read = read_rbu_data,
659};
660
661static struct bin_attribute rbu_image_type_attr = {
662 .attr = {.name = "image_type", .mode = 0644},
663 .read = read_rbu_image_type,
664 .write = write_rbu_image_type,
665};
666
667static struct bin_attribute rbu_packet_size_attr = {
668 .attr = {.name = "packet_size", .mode = 0644},
669 .read = read_rbu_packet_size,
670 .write = write_rbu_packet_size,
671};
672
673static int __init dcdrbu_init(void)
674{
675 int rc;
676 spin_lock_init(&rbu_data.lock);
677
678 init_packet_head();
679 rbu_device = platform_device_register_simple("dell_rbu", -1, NULL, 0);
680 if (IS_ERR(rbu_device)) {
681 printk(KERN_ERR
682 "dell_rbu:%s:platform_device_register_simple "
683 "failed\n", __func__);
684 return PTR_ERR(rbu_device);
685 }
686
687 rc = sysfs_create_bin_file(&rbu_device->dev.kobj, &rbu_data_attr);
688 if (rc)
689 goto out_devreg;
690 rc = sysfs_create_bin_file(&rbu_device->dev.kobj, &rbu_image_type_attr);
691 if (rc)
692 goto out_data;
693 rc = sysfs_create_bin_file(&rbu_device->dev.kobj,
694 &rbu_packet_size_attr);
695 if (rc)
696 goto out_imtype;
697
698 rbu_data.entry_created = 0;
699 return 0;
700
701out_imtype:
702 sysfs_remove_bin_file(&rbu_device->dev.kobj, &rbu_image_type_attr);
703out_data:
704 sysfs_remove_bin_file(&rbu_device->dev.kobj, &rbu_data_attr);
705out_devreg:
706 platform_device_unregister(rbu_device);
707 return rc;
708}
709
710static __exit void dcdrbu_exit(void)
711{
712 spin_lock(&rbu_data.lock);
713 packet_empty_list();
714 img_update_free();
715 spin_unlock(&rbu_data.lock);
716 platform_device_unregister(rbu_device);
717}
718
719module_exit(dcdrbu_exit);
720module_init(dcdrbu_init);
721
722/* vim:noet:ts=8:sw=8
723*/