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[linux.git] / drivers / platform / x86 / dell_rbu.c
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/admin-guide/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
42 MODULE_AUTHOR("Abhay Salunke <abhay_salunke@dell.com>");
43 MODULE_DESCRIPTION("Driver for updating BIOS image on DELL systems");
44 MODULE_LICENSE("GPL");
45 MODULE_VERSION("3.2");
46
47 #define BIOS_SCAN_LIMIT 0xffffffff
48 #define MAX_IMAGE_LENGTH 16
49 static 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
62 static char image_type[MAX_IMAGE_LENGTH + 1] = "mono";
63 module_param_string(image_type, image_type, sizeof (image_type), 0);
64 MODULE_PARM_DESC(image_type,
65         "BIOS image type. choose- mono or packet or init");
66
67 static unsigned long allocation_floor = 0x100000;
68 module_param(allocation_floor, ulong, 0644);
69 MODULE_PARM_DESC(allocation_floor,
70     "Minimum address for allocations when using Packet mode");
71
72 struct packet_data {
73         struct list_head list;
74         size_t length;
75         void *data;
76         int ordernum;
77 };
78
79 static struct packet_data packet_data_head;
80
81 static struct platform_device *rbu_device;
82 static int context;
83
84 static 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
93 static 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
200 out_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
211 out_alloc_packet:
212         /* if error, free data */
213         if (retval)
214                 kfree(newpacket);
215
216 out_noalloc:
217         return retval;
218 }
219
220 static 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
258 static 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
292 static 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
330 static 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  */
363 static 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  */
395 static 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
449 static 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
487 static 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
503 static 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
522 static 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
557 static 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
567 static 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
628 static 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
641 static 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
656 static struct bin_attribute rbu_data_attr = {
657         .attr = {.name = "data", .mode = 0444},
658         .read = read_rbu_data,
659 };
660
661 static 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
667 static 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
673 static 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
701 out_imtype:
702         sysfs_remove_bin_file(&rbu_device->dev.kobj, &rbu_image_type_attr);
703 out_data:
704         sysfs_remove_bin_file(&rbu_device->dev.kobj, &rbu_data_attr);
705 out_devreg:
706         platform_device_unregister(rbu_device);
707         return rc;
708 }
709
710 static __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
719 module_exit(dcdrbu_exit);
720 module_init(dcdrbu_init);
721
722 /* vim:noet:ts=8:sw=8
723 */