xref: /openbmc/u-boot/drivers/mtd/ubi/fastmap-wl.c (revision 3eceff64)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (c) 2012 Linutronix GmbH
4  * Copyright (c) 2014 sigma star gmbh
5  * Author: Richard Weinberger <richard@nod.at>
6  *
7  */
8 
9 /**
10  * update_fastmap_work_fn - calls ubi_update_fastmap from a work queue
11  * @wrk: the work description object
12  */
13 #ifndef __UBOOT__
update_fastmap_work_fn(struct work_struct * wrk)14 static void update_fastmap_work_fn(struct work_struct *wrk)
15 #else
16 void update_fastmap_work_fn(struct ubi_device *ubi)
17 #endif
18 {
19 #ifndef __UBOOT__
20 	struct ubi_device *ubi = container_of(wrk, struct ubi_device, fm_work);
21 #endif
22 
23 	ubi_update_fastmap(ubi);
24 	spin_lock(&ubi->wl_lock);
25 	ubi->fm_work_scheduled = 0;
26 	spin_unlock(&ubi->wl_lock);
27 }
28 
29 /**
30  * find_anchor_wl_entry - find wear-leveling entry to used as anchor PEB.
31  * @root: the RB-tree where to look for
32  */
find_anchor_wl_entry(struct rb_root * root)33 static struct ubi_wl_entry *find_anchor_wl_entry(struct rb_root *root)
34 {
35 	struct rb_node *p;
36 	struct ubi_wl_entry *e, *victim = NULL;
37 	int max_ec = UBI_MAX_ERASECOUNTER;
38 
39 	ubi_rb_for_each_entry(p, e, root, u.rb) {
40 		if (e->pnum < UBI_FM_MAX_START && e->ec < max_ec) {
41 			victim = e;
42 			max_ec = e->ec;
43 		}
44 	}
45 
46 	return victim;
47 }
48 
49 /**
50  * return_unused_pool_pebs - returns unused PEB to the free tree.
51  * @ubi: UBI device description object
52  * @pool: fastmap pool description object
53  */
return_unused_pool_pebs(struct ubi_device * ubi,struct ubi_fm_pool * pool)54 static void return_unused_pool_pebs(struct ubi_device *ubi,
55 				    struct ubi_fm_pool *pool)
56 {
57 	int i;
58 	struct ubi_wl_entry *e;
59 
60 	for (i = pool->used; i < pool->size; i++) {
61 		e = ubi->lookuptbl[pool->pebs[i]];
62 		wl_tree_add(e, &ubi->free);
63 		ubi->free_count++;
64 	}
65 }
66 
anchor_pebs_avalible(struct rb_root * root)67 static int anchor_pebs_avalible(struct rb_root *root)
68 {
69 	struct rb_node *p;
70 	struct ubi_wl_entry *e;
71 
72 	ubi_rb_for_each_entry(p, e, root, u.rb)
73 		if (e->pnum < UBI_FM_MAX_START)
74 			return 1;
75 
76 	return 0;
77 }
78 
79 /**
80  * ubi_wl_get_fm_peb - find a physical erase block with a given maximal number.
81  * @ubi: UBI device description object
82  * @anchor: This PEB will be used as anchor PEB by fastmap
83  *
84  * The function returns a physical erase block with a given maximal number
85  * and removes it from the wl subsystem.
86  * Must be called with wl_lock held!
87  */
ubi_wl_get_fm_peb(struct ubi_device * ubi,int anchor)88 struct ubi_wl_entry *ubi_wl_get_fm_peb(struct ubi_device *ubi, int anchor)
89 {
90 	struct ubi_wl_entry *e = NULL;
91 
92 	if (!ubi->free.rb_node || (ubi->free_count - ubi->beb_rsvd_pebs < 1))
93 		goto out;
94 
95 	if (anchor)
96 		e = find_anchor_wl_entry(&ubi->free);
97 	else
98 		e = find_mean_wl_entry(ubi, &ubi->free);
99 
100 	if (!e)
101 		goto out;
102 
103 	self_check_in_wl_tree(ubi, e, &ubi->free);
104 
105 	/* remove it from the free list,
106 	 * the wl subsystem does no longer know this erase block */
107 	rb_erase(&e->u.rb, &ubi->free);
108 	ubi->free_count--;
109 out:
110 	return e;
111 }
112 
113 /**
114  * ubi_refill_pools - refills all fastmap PEB pools.
115  * @ubi: UBI device description object
116  */
ubi_refill_pools(struct ubi_device * ubi)117 void ubi_refill_pools(struct ubi_device *ubi)
118 {
119 	struct ubi_fm_pool *wl_pool = &ubi->fm_wl_pool;
120 	struct ubi_fm_pool *pool = &ubi->fm_pool;
121 	struct ubi_wl_entry *e;
122 	int enough;
123 
124 	spin_lock(&ubi->wl_lock);
125 
126 	return_unused_pool_pebs(ubi, wl_pool);
127 	return_unused_pool_pebs(ubi, pool);
128 
129 	wl_pool->size = 0;
130 	pool->size = 0;
131 
132 	for (;;) {
133 		enough = 0;
134 		if (pool->size < pool->max_size) {
135 			if (!ubi->free.rb_node)
136 				break;
137 
138 			e = wl_get_wle(ubi);
139 			if (!e)
140 				break;
141 
142 			pool->pebs[pool->size] = e->pnum;
143 			pool->size++;
144 		} else
145 			enough++;
146 
147 		if (wl_pool->size < wl_pool->max_size) {
148 			if (!ubi->free.rb_node ||
149 			   (ubi->free_count - ubi->beb_rsvd_pebs < 5))
150 				break;
151 
152 			e = find_wl_entry(ubi, &ubi->free, WL_FREE_MAX_DIFF);
153 			self_check_in_wl_tree(ubi, e, &ubi->free);
154 			rb_erase(&e->u.rb, &ubi->free);
155 			ubi->free_count--;
156 
157 			wl_pool->pebs[wl_pool->size] = e->pnum;
158 			wl_pool->size++;
159 		} else
160 			enough++;
161 
162 		if (enough == 2)
163 			break;
164 	}
165 
166 	wl_pool->used = 0;
167 	pool->used = 0;
168 
169 	spin_unlock(&ubi->wl_lock);
170 }
171 
172 /**
173  * produce_free_peb - produce a free physical eraseblock.
174  * @ubi: UBI device description object
175  *
176  * This function tries to make a free PEB by means of synchronous execution of
177  * pending works. This may be needed if, for example the background thread is
178  * disabled. Returns zero in case of success and a negative error code in case
179  * of failure.
180  */
produce_free_peb(struct ubi_device * ubi)181 static int produce_free_peb(struct ubi_device *ubi)
182 {
183 	int err;
184 
185 	while (!ubi->free.rb_node && ubi->works_count) {
186 		dbg_wl("do one work synchronously");
187 		err = do_work(ubi);
188 
189 		if (err)
190 			return err;
191 	}
192 
193 	return 0;
194 }
195 
196 /**
197  * ubi_wl_get_peb - get a physical eraseblock.
198  * @ubi: UBI device description object
199  *
200  * This function returns a physical eraseblock in case of success and a
201  * negative error code in case of failure.
202  * Returns with ubi->fm_eba_sem held in read mode!
203  */
ubi_wl_get_peb(struct ubi_device * ubi)204 int ubi_wl_get_peb(struct ubi_device *ubi)
205 {
206 	int ret, retried = 0;
207 	struct ubi_fm_pool *pool = &ubi->fm_pool;
208 	struct ubi_fm_pool *wl_pool = &ubi->fm_wl_pool;
209 
210 again:
211 	down_read(&ubi->fm_eba_sem);
212 	spin_lock(&ubi->wl_lock);
213 
214 	/* We check here also for the WL pool because at this point we can
215 	 * refill the WL pool synchronous. */
216 	if (pool->used == pool->size || wl_pool->used == wl_pool->size) {
217 		spin_unlock(&ubi->wl_lock);
218 		up_read(&ubi->fm_eba_sem);
219 		ret = ubi_update_fastmap(ubi);
220 		if (ret) {
221 			ubi_msg(ubi, "Unable to write a new fastmap: %i", ret);
222 			down_read(&ubi->fm_eba_sem);
223 			return -ENOSPC;
224 		}
225 		down_read(&ubi->fm_eba_sem);
226 		spin_lock(&ubi->wl_lock);
227 	}
228 
229 	if (pool->used == pool->size) {
230 		spin_unlock(&ubi->wl_lock);
231 		if (retried) {
232 			ubi_err(ubi, "Unable to get a free PEB from user WL pool");
233 			ret = -ENOSPC;
234 			goto out;
235 		}
236 		retried = 1;
237 		up_read(&ubi->fm_eba_sem);
238 		ret = produce_free_peb(ubi);
239 		if (ret < 0) {
240 			down_read(&ubi->fm_eba_sem);
241 			goto out;
242 		}
243 		goto again;
244 	}
245 
246 	ubi_assert(pool->used < pool->size);
247 	ret = pool->pebs[pool->used++];
248 	prot_queue_add(ubi, ubi->lookuptbl[ret]);
249 	spin_unlock(&ubi->wl_lock);
250 out:
251 	return ret;
252 }
253 
254 /* get_peb_for_wl - returns a PEB to be used internally by the WL sub-system.
255  *
256  * @ubi: UBI device description object
257  */
get_peb_for_wl(struct ubi_device * ubi)258 static struct ubi_wl_entry *get_peb_for_wl(struct ubi_device *ubi)
259 {
260 	struct ubi_fm_pool *pool = &ubi->fm_wl_pool;
261 	int pnum;
262 
263 	if (pool->used == pool->size) {
264 #ifndef __UBOOT__
265 		/* We cannot update the fastmap here because this
266 		 * function is called in atomic context.
267 		 * Let's fail here and refill/update it as soon as possible. */
268 		if (!ubi->fm_work_scheduled) {
269 			ubi->fm_work_scheduled = 1;
270 			schedule_work(&ubi->fm_work);
271 		}
272 		return NULL;
273 #else
274 		/*
275 		 * No work queues in U-Boot, we must do this immediately
276 		 */
277 		update_fastmap_work_fn(ubi);
278 #endif
279 	}
280 
281 	pnum = pool->pebs[pool->used++];
282 	return ubi->lookuptbl[pnum];
283 }
284 
285 /**
286  * ubi_ensure_anchor_pebs - schedule wear-leveling to produce an anchor PEB.
287  * @ubi: UBI device description object
288  */
ubi_ensure_anchor_pebs(struct ubi_device * ubi)289 int ubi_ensure_anchor_pebs(struct ubi_device *ubi)
290 {
291 	struct ubi_work *wrk;
292 
293 	spin_lock(&ubi->wl_lock);
294 	if (ubi->wl_scheduled) {
295 		spin_unlock(&ubi->wl_lock);
296 		return 0;
297 	}
298 	ubi->wl_scheduled = 1;
299 	spin_unlock(&ubi->wl_lock);
300 
301 	wrk = kmalloc(sizeof(struct ubi_work), GFP_NOFS);
302 	if (!wrk) {
303 		spin_lock(&ubi->wl_lock);
304 		ubi->wl_scheduled = 0;
305 		spin_unlock(&ubi->wl_lock);
306 		return -ENOMEM;
307 	}
308 
309 	wrk->anchor = 1;
310 	wrk->func = &wear_leveling_worker;
311 	schedule_ubi_work(ubi, wrk);
312 	return 0;
313 }
314 
315 /**
316  * ubi_wl_put_fm_peb - returns a PEB used in a fastmap to the wear-leveling
317  * sub-system.
318  * see: ubi_wl_put_peb()
319  *
320  * @ubi: UBI device description object
321  * @fm_e: physical eraseblock to return
322  * @lnum: the last used logical eraseblock number for the PEB
323  * @torture: if this physical eraseblock has to be tortured
324  */
ubi_wl_put_fm_peb(struct ubi_device * ubi,struct ubi_wl_entry * fm_e,int lnum,int torture)325 int ubi_wl_put_fm_peb(struct ubi_device *ubi, struct ubi_wl_entry *fm_e,
326 		      int lnum, int torture)
327 {
328 	struct ubi_wl_entry *e;
329 	int vol_id, pnum = fm_e->pnum;
330 
331 	dbg_wl("PEB %d", pnum);
332 
333 	ubi_assert(pnum >= 0);
334 	ubi_assert(pnum < ubi->peb_count);
335 
336 	spin_lock(&ubi->wl_lock);
337 	e = ubi->lookuptbl[pnum];
338 
339 	/* This can happen if we recovered from a fastmap the very
340 	 * first time and writing now a new one. In this case the wl system
341 	 * has never seen any PEB used by the original fastmap.
342 	 */
343 	if (!e) {
344 		e = fm_e;
345 		ubi_assert(e->ec >= 0);
346 		ubi->lookuptbl[pnum] = e;
347 	}
348 
349 	spin_unlock(&ubi->wl_lock);
350 
351 	vol_id = lnum ? UBI_FM_DATA_VOLUME_ID : UBI_FM_SB_VOLUME_ID;
352 	return schedule_erase(ubi, e, vol_id, lnum, torture);
353 }
354 
355 /**
356  * ubi_is_erase_work - checks whether a work is erase work.
357  * @wrk: The work object to be checked
358  */
ubi_is_erase_work(struct ubi_work * wrk)359 int ubi_is_erase_work(struct ubi_work *wrk)
360 {
361 	return wrk->func == erase_worker;
362 }
363 
ubi_fastmap_close(struct ubi_device * ubi)364 static void ubi_fastmap_close(struct ubi_device *ubi)
365 {
366 	int i;
367 
368 	return_unused_pool_pebs(ubi, &ubi->fm_pool);
369 	return_unused_pool_pebs(ubi, &ubi->fm_wl_pool);
370 
371 	if (ubi->fm) {
372 		for (i = 0; i < ubi->fm->used_blocks; i++)
373 			kfree(ubi->fm->e[i]);
374 	}
375 	kfree(ubi->fm);
376 }
377 
378 /**
379  * may_reserve_for_fm - tests whether a PEB shall be reserved for fastmap.
380  * See find_mean_wl_entry()
381  *
382  * @ubi: UBI device description object
383  * @e: physical eraseblock to return
384  * @root: RB tree to test against.
385  */
may_reserve_for_fm(struct ubi_device * ubi,struct ubi_wl_entry * e,struct rb_root * root)386 static struct ubi_wl_entry *may_reserve_for_fm(struct ubi_device *ubi,
387 					   struct ubi_wl_entry *e,
388 					   struct rb_root *root) {
389 	if (e && !ubi->fm_disabled && !ubi->fm &&
390 	    e->pnum < UBI_FM_MAX_START)
391 		e = rb_entry(rb_next(root->rb_node),
392 			     struct ubi_wl_entry, u.rb);
393 
394 	return e;
395 }
396