2 * LPDDR flash memory device operations. This module provides read, write,
3 * erase, lock/unlock support for LPDDR flash memories
4 * (C) 2008 Korolev Alexey <akorolev@infradead.org>
5 * (C) 2008 Vasiliy Leonenko <vasiliy.leonenko@gmail.com>
6 * Many thanks to Roman Borisov for initial enabling
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version 2
11 * of the License, or (at your option) any later version.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
23 * Implement VPP management
24 * Implement XIP support
25 * Implement OTP support
27 #include <linux/mtd/pfow.h>
28 #include <linux/mtd/qinfo.h>
29 #include <linux/slab.h>
31 static int lpddr_read(struct mtd_info
*mtd
, loff_t adr
, size_t len
,
32 size_t *retlen
, u_char
*buf
);
33 static int lpddr_write_buffers(struct mtd_info
*mtd
, loff_t to
,
34 size_t len
, size_t *retlen
, const u_char
*buf
);
35 static int lpddr_writev(struct mtd_info
*mtd
, const struct kvec
*vecs
,
36 unsigned long count
, loff_t to
, size_t *retlen
);
37 static int lpddr_erase(struct mtd_info
*mtd
, struct erase_info
*instr
);
38 static int lpddr_lock(struct mtd_info
*mtd
, loff_t ofs
, uint64_t len
);
39 static int lpddr_unlock(struct mtd_info
*mtd
, loff_t ofs
, uint64_t len
);
40 static int lpddr_point(struct mtd_info
*mtd
, loff_t adr
, size_t len
,
41 size_t *retlen
, void **mtdbuf
, resource_size_t
*phys
);
42 static void lpddr_unpoint(struct mtd_info
*mtd
, loff_t adr
, size_t len
);
43 static int get_chip(struct map_info
*map
, struct flchip
*chip
, int mode
);
44 static int chip_ready(struct map_info
*map
, struct flchip
*chip
, int mode
);
45 static void put_chip(struct map_info
*map
, struct flchip
*chip
);
47 struct mtd_info
*lpddr_cmdset(struct map_info
*map
)
49 struct lpddr_private
*lpddr
= map
->fldrv_priv
;
50 struct flchip_shared
*shared
;
56 mtd
= kzalloc(sizeof(*mtd
), GFP_KERNEL
);
58 printk(KERN_ERR
"Failed to allocate memory for MTD device\n");
62 mtd
->type
= MTD_NORFLASH
;
64 /* Fill in the default mtd operations */
65 mtd
->read
= lpddr_read
;
66 mtd
->type
= MTD_NORFLASH
;
67 mtd
->flags
= MTD_CAP_NORFLASH
;
68 mtd
->flags
&= ~MTD_BIT_WRITEABLE
;
69 mtd
->erase
= lpddr_erase
;
70 mtd
->write
= lpddr_write_buffers
;
71 mtd
->writev
= lpddr_writev
;
73 mtd
->write_oob
= NULL
;
75 mtd
->lock
= lpddr_lock
;
76 mtd
->unlock
= lpddr_unlock
;
79 if (map_is_linear(map
)) {
80 mtd
->point
= lpddr_point
;
81 mtd
->unpoint
= lpddr_unpoint
;
83 mtd
->block_isbad
= NULL
;
84 mtd
->block_markbad
= NULL
;
85 mtd
->size
= 1 << lpddr
->qinfo
->DevSizeShift
;
86 mtd
->erasesize
= 1 << lpddr
->qinfo
->UniformBlockSizeShift
;
87 mtd
->writesize
= 1 << lpddr
->qinfo
->BufSizeShift
;
89 shared
= kmalloc(sizeof(struct flchip_shared
) * lpddr
->numchips
,
97 chip
= &lpddr
->chips
[0];
98 numchips
= lpddr
->numchips
/ lpddr
->qinfo
->HWPartsNum
;
99 for (i
= 0; i
< numchips
; i
++) {
100 shared
[i
].writing
= shared
[i
].erasing
= NULL
;
101 mutex_init(&shared
[i
].lock
);
102 for (j
= 0; j
< lpddr
->qinfo
->HWPartsNum
; j
++) {
103 *chip
= lpddr
->chips
[i
];
104 chip
->start
+= j
<< lpddr
->chipshift
;
105 chip
->oldstate
= chip
->state
= FL_READY
;
106 chip
->priv
= &shared
[i
];
107 /* those should be reset too since
108 they create memory references. */
109 init_waitqueue_head(&chip
->wq
);
110 mutex_init(&chip
->mutex
);
117 EXPORT_SYMBOL(lpddr_cmdset
);
119 static int wait_for_ready(struct map_info
*map
, struct flchip
*chip
,
120 unsigned int chip_op_time
)
122 unsigned int timeo
, reset_timeo
, sleep_time
;
124 flstate_t chip_state
= chip
->state
;
127 /* set our timeout to 8 times the expected delay */
128 timeo
= chip_op_time
* 8;
132 sleep_time
= chip_op_time
/ 2;
135 dsr
= CMDVAL(map_read(map
, map
->pfow_base
+ PFOW_DSR
));
136 if (dsr
& DSR_READY_STATUS
)
139 printk(KERN_ERR
"%s: Flash timeout error state %d \n",
140 map
->name
, chip_state
);
145 /* OK Still waiting. Drop the lock, wait a while and retry. */
146 mutex_unlock(&chip
->mutex
);
147 if (sleep_time
>= 1000000/HZ
) {
149 * Half of the normal delay still remaining
150 * can be performed with a sleeping delay instead
153 msleep(sleep_time
/1000);
155 sleep_time
= 1000000/HZ
;
161 mutex_lock(&chip
->mutex
);
163 while (chip
->state
!= chip_state
) {
164 /* Someone's suspended the operation: sleep */
165 DECLARE_WAITQUEUE(wait
, current
);
166 set_current_state(TASK_UNINTERRUPTIBLE
);
167 add_wait_queue(&chip
->wq
, &wait
);
168 mutex_unlock(&chip
->mutex
);
170 remove_wait_queue(&chip
->wq
, &wait
);
171 mutex_lock(&chip
->mutex
);
173 if (chip
->erase_suspended
|| chip
->write_suspended
) {
174 /* Suspend has occurred while sleep: reset timeout */
176 chip
->erase_suspended
= chip
->write_suspended
= 0;
179 /* check status for errors */
182 map_write(map
, CMD(~(DSR_ERR
)), map
->pfow_base
+ PFOW_DSR
);
183 printk(KERN_WARNING
"%s: Bad status on wait: 0x%x \n",
185 print_drs_error(dsr
);
188 chip
->state
= FL_READY
;
192 static int get_chip(struct map_info
*map
, struct flchip
*chip
, int mode
)
195 DECLARE_WAITQUEUE(wait
, current
);
198 if (chip
->priv
&& (mode
== FL_WRITING
|| mode
== FL_ERASING
)
199 && chip
->state
!= FL_SYNCING
) {
201 * OK. We have possibility for contension on the write/erase
202 * operations which are global to the real chip and not per
203 * partition. So let's fight it over in the partition which
204 * currently has authority on the operation.
206 * The rules are as follows:
208 * - any write operation must own shared->writing.
210 * - any erase operation must own _both_ shared->writing and
213 * - contension arbitration is handled in the owner's context.
215 * The 'shared' struct can be read and/or written only when
218 struct flchip_shared
*shared
= chip
->priv
;
219 struct flchip
*contender
;
220 mutex_lock(&shared
->lock
);
221 contender
= shared
->writing
;
222 if (contender
&& contender
!= chip
) {
224 * The engine to perform desired operation on this
225 * partition is already in use by someone else.
226 * Let's fight over it in the context of the chip
227 * currently using it. If it is possible to suspend,
228 * that other partition will do just that, otherwise
229 * it'll happily send us to sleep. In any case, when
230 * get_chip returns success we're clear to go ahead.
232 ret
= mutex_trylock(&contender
->mutex
);
233 mutex_unlock(&shared
->lock
);
236 mutex_unlock(&chip
->mutex
);
237 ret
= chip_ready(map
, contender
, mode
);
238 mutex_lock(&chip
->mutex
);
240 if (ret
== -EAGAIN
) {
241 mutex_unlock(&contender
->mutex
);
245 mutex_unlock(&contender
->mutex
);
248 mutex_lock(&shared
->lock
);
250 /* We should not own chip if it is already in FL_SYNCING
251 * state. Put contender and retry. */
252 if (chip
->state
== FL_SYNCING
) {
253 put_chip(map
, contender
);
254 mutex_unlock(&contender
->mutex
);
257 mutex_unlock(&contender
->mutex
);
260 /* Check if we have suspended erase on this chip.
261 Must sleep in such a case. */
262 if (mode
== FL_ERASING
&& shared
->erasing
263 && shared
->erasing
->oldstate
== FL_ERASING
) {
264 mutex_unlock(&shared
->lock
);
265 set_current_state(TASK_UNINTERRUPTIBLE
);
266 add_wait_queue(&chip
->wq
, &wait
);
267 mutex_unlock(&chip
->mutex
);
269 remove_wait_queue(&chip
->wq
, &wait
);
270 mutex_lock(&chip
->mutex
);
275 shared
->writing
= chip
;
276 if (mode
== FL_ERASING
)
277 shared
->erasing
= chip
;
278 mutex_unlock(&shared
->lock
);
281 ret
= chip_ready(map
, chip
, mode
);
288 static int chip_ready(struct map_info
*map
, struct flchip
*chip
, int mode
)
290 struct lpddr_private
*lpddr
= map
->fldrv_priv
;
292 DECLARE_WAITQUEUE(wait
, current
);
294 /* Prevent setting state FL_SYNCING for chip in suspended state. */
295 if (FL_SYNCING
== mode
&& FL_READY
!= chip
->oldstate
)
298 switch (chip
->state
) {
304 if (!lpddr
->qinfo
->SuspEraseSupp
||
305 !(mode
== FL_READY
|| mode
== FL_POINT
))
308 map_write(map
, CMD(LPDDR_SUSPEND
),
309 map
->pfow_base
+ PFOW_PROGRAM_ERASE_SUSPEND
);
310 chip
->oldstate
= FL_ERASING
;
311 chip
->state
= FL_ERASE_SUSPENDING
;
312 ret
= wait_for_ready(map
, chip
, 0);
314 /* Oops. something got wrong. */
315 /* Resume and pretend we weren't here. */
317 printk(KERN_ERR
"%s: suspend operation failed."
318 "State may be wrong \n", map
->name
);
321 chip
->erase_suspended
= 1;
322 chip
->state
= FL_READY
;
326 /* Only if there's no operation suspended... */
327 if (mode
== FL_READY
&& chip
->oldstate
== FL_READY
)
332 set_current_state(TASK_UNINTERRUPTIBLE
);
333 add_wait_queue(&chip
->wq
, &wait
);
334 mutex_unlock(&chip
->mutex
);
336 remove_wait_queue(&chip
->wq
, &wait
);
337 mutex_lock(&chip
->mutex
);
342 static void put_chip(struct map_info
*map
, struct flchip
*chip
)
345 struct flchip_shared
*shared
= chip
->priv
;
346 mutex_lock(&shared
->lock
);
347 if (shared
->writing
== chip
&& chip
->oldstate
== FL_READY
) {
348 /* We own the ability to write, but we're done */
349 shared
->writing
= shared
->erasing
;
350 if (shared
->writing
&& shared
->writing
!= chip
) {
351 /* give back the ownership */
352 struct flchip
*loaner
= shared
->writing
;
353 mutex_lock(&loaner
->mutex
);
354 mutex_unlock(&shared
->lock
);
355 mutex_unlock(&chip
->mutex
);
356 put_chip(map
, loaner
);
357 mutex_lock(&chip
->mutex
);
358 mutex_unlock(&loaner
->mutex
);
362 shared
->erasing
= NULL
;
363 shared
->writing
= NULL
;
364 } else if (shared
->erasing
== chip
&& shared
->writing
!= chip
) {
366 * We own the ability to erase without the ability
367 * to write, which means the erase was suspended
368 * and some other partition is currently writing.
369 * Don't let the switch below mess things up since
370 * we don't have ownership to resume anything.
372 mutex_unlock(&shared
->lock
);
376 mutex_unlock(&shared
->lock
);
379 switch (chip
->oldstate
) {
381 map_write(map
, CMD(LPDDR_RESUME
),
382 map
->pfow_base
+ PFOW_COMMAND_CODE
);
383 map_write(map
, CMD(LPDDR_START_EXECUTION
),
384 map
->pfow_base
+ PFOW_COMMAND_EXECUTE
);
385 chip
->oldstate
= FL_READY
;
386 chip
->state
= FL_ERASING
;
391 printk(KERN_ERR
"%s: put_chip() called with oldstate %d!\n",
392 map
->name
, chip
->oldstate
);
397 int do_write_buffer(struct map_info
*map
, struct flchip
*chip
,
398 unsigned long adr
, const struct kvec
**pvec
,
399 unsigned long *pvec_seek
, int len
)
401 struct lpddr_private
*lpddr
= map
->fldrv_priv
;
403 int ret
, wbufsize
, word_gap
, words
;
404 const struct kvec
*vec
;
405 unsigned long vec_seek
;
406 unsigned long prog_buf_ofs
;
408 wbufsize
= 1 << lpddr
->qinfo
->BufSizeShift
;
410 mutex_lock(&chip
->mutex
);
411 ret
= get_chip(map
, chip
, FL_WRITING
);
413 mutex_unlock(&chip
->mutex
);
416 /* Figure out the number of words to write */
417 word_gap
= (-adr
& (map_bankwidth(map
)-1));
418 words
= (len
- word_gap
+ map_bankwidth(map
) - 1) / map_bankwidth(map
);
422 word_gap
= map_bankwidth(map
) - word_gap
;
424 datum
= map_word_ff(map
);
427 /* Get the program buffer offset from PFOW register data first*/
428 prog_buf_ofs
= map
->pfow_base
+ CMDVAL(map_read(map
,
429 map
->pfow_base
+ PFOW_PROGRAM_BUFFER_OFFSET
));
431 vec_seek
= *pvec_seek
;
433 int n
= map_bankwidth(map
) - word_gap
;
435 if (n
> vec
->iov_len
- vec_seek
)
436 n
= vec
->iov_len
- vec_seek
;
440 if (!word_gap
&& (len
< map_bankwidth(map
)))
441 datum
= map_word_ff(map
);
443 datum
= map_word_load_partial(map
, datum
,
444 vec
->iov_base
+ vec_seek
, word_gap
, n
);
448 if (!len
|| word_gap
== map_bankwidth(map
)) {
449 map_write(map
, datum
, prog_buf_ofs
);
450 prog_buf_ofs
+= map_bankwidth(map
);
455 if (vec_seek
== vec
->iov_len
) {
461 *pvec_seek
= vec_seek
;
464 send_pfow_command(map
, LPDDR_BUFF_PROGRAM
, adr
, wbufsize
, NULL
);
465 chip
->state
= FL_WRITING
;
466 ret
= wait_for_ready(map
, chip
, (1<<lpddr
->qinfo
->ProgBufferTime
));
468 printk(KERN_WARNING
"%s Buffer program error: %d at %lx; \n",
469 map
->name
, ret
, adr
);
473 out
: put_chip(map
, chip
);
474 mutex_unlock(&chip
->mutex
);
478 int do_erase_oneblock(struct mtd_info
*mtd
, loff_t adr
)
480 struct map_info
*map
= mtd
->priv
;
481 struct lpddr_private
*lpddr
= map
->fldrv_priv
;
482 int chipnum
= adr
>> lpddr
->chipshift
;
483 struct flchip
*chip
= &lpddr
->chips
[chipnum
];
486 mutex_lock(&chip
->mutex
);
487 ret
= get_chip(map
, chip
, FL_ERASING
);
489 mutex_unlock(&chip
->mutex
);
492 send_pfow_command(map
, LPDDR_BLOCK_ERASE
, adr
, 0, NULL
);
493 chip
->state
= FL_ERASING
;
494 ret
= wait_for_ready(map
, chip
, (1<<lpddr
->qinfo
->BlockEraseTime
)*1000);
496 printk(KERN_WARNING
"%s Erase block error %d at : %llx\n",
497 map
->name
, ret
, adr
);
500 out
: put_chip(map
, chip
);
501 mutex_unlock(&chip
->mutex
);
505 static int lpddr_read(struct mtd_info
*mtd
, loff_t adr
, size_t len
,
506 size_t *retlen
, u_char
*buf
)
508 struct map_info
*map
= mtd
->priv
;
509 struct lpddr_private
*lpddr
= map
->fldrv_priv
;
510 int chipnum
= adr
>> lpddr
->chipshift
;
511 struct flchip
*chip
= &lpddr
->chips
[chipnum
];
514 mutex_lock(&chip
->mutex
);
515 ret
= get_chip(map
, chip
, FL_READY
);
517 mutex_unlock(&chip
->mutex
);
521 map_copy_from(map
, buf
, adr
, len
);
525 mutex_unlock(&chip
->mutex
);
529 static int lpddr_point(struct mtd_info
*mtd
, loff_t adr
, size_t len
,
530 size_t *retlen
, void **mtdbuf
, resource_size_t
*phys
)
532 struct map_info
*map
= mtd
->priv
;
533 struct lpddr_private
*lpddr
= map
->fldrv_priv
;
534 int chipnum
= adr
>> lpddr
->chipshift
;
535 unsigned long ofs
, last_end
= 0;
536 struct flchip
*chip
= &lpddr
->chips
[chipnum
];
539 if (!map
->virt
|| (adr
+ len
> mtd
->size
))
542 /* ofs: offset within the first chip that the first read should start */
543 ofs
= adr
- (chipnum
<< lpddr
->chipshift
);
545 *mtdbuf
= (void *)map
->virt
+ chip
->start
+ ofs
;
549 unsigned long thislen
;
551 if (chipnum
>= lpddr
->numchips
)
554 /* We cannot point across chips that are virtually disjoint */
556 last_end
= chip
->start
;
557 else if (chip
->start
!= last_end
)
560 if ((len
+ ofs
- 1) >> lpddr
->chipshift
)
561 thislen
= (1<<lpddr
->chipshift
) - ofs
;
565 mutex_lock(&chip
->mutex
);
566 ret
= get_chip(map
, chip
, FL_POINT
);
567 mutex_unlock(&chip
->mutex
);
571 chip
->state
= FL_POINT
;
572 chip
->ref_point_counter
++;
577 last_end
+= 1 << lpddr
->chipshift
;
579 chip
= &lpddr
->chips
[chipnum
];
584 static void lpddr_unpoint (struct mtd_info
*mtd
, loff_t adr
, size_t len
)
586 struct map_info
*map
= mtd
->priv
;
587 struct lpddr_private
*lpddr
= map
->fldrv_priv
;
588 int chipnum
= adr
>> lpddr
->chipshift
;
591 /* ofs: offset within the first chip that the first read should start */
592 ofs
= adr
- (chipnum
<< lpddr
->chipshift
);
595 unsigned long thislen
;
598 chip
= &lpddr
->chips
[chipnum
];
599 if (chipnum
>= lpddr
->numchips
)
602 if ((len
+ ofs
- 1) >> lpddr
->chipshift
)
603 thislen
= (1<<lpddr
->chipshift
) - ofs
;
607 mutex_lock(&chip
->mutex
);
608 if (chip
->state
== FL_POINT
) {
609 chip
->ref_point_counter
--;
610 if (chip
->ref_point_counter
== 0)
611 chip
->state
= FL_READY
;
613 printk(KERN_WARNING
"%s: Warning: unpoint called on non"
614 "pointed region\n", map
->name
);
617 mutex_unlock(&chip
->mutex
);
625 static int lpddr_write_buffers(struct mtd_info
*mtd
, loff_t to
, size_t len
,
626 size_t *retlen
, const u_char
*buf
)
630 vec
.iov_base
= (void *) buf
;
633 return lpddr_writev(mtd
, &vec
, 1, to
, retlen
);
637 static int lpddr_writev(struct mtd_info
*mtd
, const struct kvec
*vecs
,
638 unsigned long count
, loff_t to
, size_t *retlen
)
640 struct map_info
*map
= mtd
->priv
;
641 struct lpddr_private
*lpddr
= map
->fldrv_priv
;
644 unsigned long ofs
, vec_seek
, i
;
645 int wbufsize
= 1 << lpddr
->qinfo
->BufSizeShift
;
649 for (i
= 0; i
< count
; i
++)
650 len
+= vecs
[i
].iov_len
;
656 chipnum
= to
>> lpddr
->chipshift
;
662 /* We must not cross write block boundaries */
663 int size
= wbufsize
- (ofs
& (wbufsize
-1));
668 ret
= do_write_buffer(map
, &lpddr
->chips
[chipnum
],
669 ofs
, &vecs
, &vec_seek
, size
);
677 /* Be nice and reschedule with the chip in a usable
678 * state for other processes */
686 static int lpddr_erase(struct mtd_info
*mtd
, struct erase_info
*instr
)
688 unsigned long ofs
, len
;
690 struct map_info
*map
= mtd
->priv
;
691 struct lpddr_private
*lpddr
= map
->fldrv_priv
;
692 int size
= 1 << lpddr
->qinfo
->UniformBlockSizeShift
;
697 if (ofs
> mtd
->size
|| (len
+ ofs
) > mtd
->size
)
701 ret
= do_erase_oneblock(mtd
, ofs
);
707 instr
->state
= MTD_ERASE_DONE
;
708 mtd_erase_callback(instr
);
713 #define DO_XXLOCK_LOCK 1
714 #define DO_XXLOCK_UNLOCK 2
715 int do_xxlock(struct mtd_info
*mtd
, loff_t adr
, uint32_t len
, int thunk
)
718 struct map_info
*map
= mtd
->priv
;
719 struct lpddr_private
*lpddr
= map
->fldrv_priv
;
720 int chipnum
= adr
>> lpddr
->chipshift
;
721 struct flchip
*chip
= &lpddr
->chips
[chipnum
];
723 mutex_lock(&chip
->mutex
);
724 ret
= get_chip(map
, chip
, FL_LOCKING
);
726 mutex_unlock(&chip
->mutex
);
730 if (thunk
== DO_XXLOCK_LOCK
) {
731 send_pfow_command(map
, LPDDR_LOCK_BLOCK
, adr
, adr
+ len
, NULL
);
732 chip
->state
= FL_LOCKING
;
733 } else if (thunk
== DO_XXLOCK_UNLOCK
) {
734 send_pfow_command(map
, LPDDR_UNLOCK_BLOCK
, adr
, adr
+ len
, NULL
);
735 chip
->state
= FL_UNLOCKING
;
739 ret
= wait_for_ready(map
, chip
, 1);
741 printk(KERN_ERR
"%s: block unlock error status %d \n",
745 out
: put_chip(map
, chip
);
746 mutex_unlock(&chip
->mutex
);
750 static int lpddr_lock(struct mtd_info
*mtd
, loff_t ofs
, uint64_t len
)
752 return do_xxlock(mtd
, ofs
, len
, DO_XXLOCK_LOCK
);
755 static int lpddr_unlock(struct mtd_info
*mtd
, loff_t ofs
, uint64_t len
)
757 return do_xxlock(mtd
, ofs
, len
, DO_XXLOCK_UNLOCK
);
760 int word_program(struct map_info
*map
, loff_t adr
, uint32_t curval
)
763 struct lpddr_private
*lpddr
= map
->fldrv_priv
;
764 int chipnum
= adr
>> lpddr
->chipshift
;
765 struct flchip
*chip
= &lpddr
->chips
[chipnum
];
767 mutex_lock(&chip
->mutex
);
768 ret
= get_chip(map
, chip
, FL_WRITING
);
770 mutex_unlock(&chip
->mutex
);
774 send_pfow_command(map
, LPDDR_WORD_PROGRAM
, adr
, 0x00, (map_word
*)&curval
);
776 ret
= wait_for_ready(map
, chip
, (1<<lpddr
->qinfo
->SingleWordProgTime
));
778 printk(KERN_WARNING
"%s word_program error at: %llx; val: %x\n",
779 map
->name
, adr
, curval
);
783 out
: put_chip(map
, chip
);
784 mutex_unlock(&chip
->mutex
);
788 MODULE_LICENSE("GPL");
789 MODULE_AUTHOR("Alexey Korolev <akorolev@infradead.org>");
790 MODULE_DESCRIPTION("MTD driver for LPDDR flash chips");