xref: /openbmc/u-boot/drivers/mtd/ubi/fastmap-wl.c (revision 63e22517) 
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__
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  */
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  */
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 
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  */
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  */
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  * ubi_wl_get_peb - get a physical eraseblock.
174  * @ubi: UBI device description object
175  *
176  * This function returns a physical eraseblock in case of success and a
177  * negative error code in case of failure.
178  * Returns with ubi->fm_eba_sem held in read mode!
179  */
180 int ubi_wl_get_peb(struct ubi_device *ubi)
181 {
182 	int ret, retried = 0;
183 	struct ubi_fm_pool *pool = &ubi->fm_pool;
184 	struct ubi_fm_pool *wl_pool = &ubi->fm_wl_pool;
185 
186 again:
187 	down_read(&ubi->fm_eba_sem);
188 	spin_lock(&ubi->wl_lock);
189 
190 	/* We check here also for the WL pool because at this point we can
191 	 * refill the WL pool synchronous. */
192 	if (pool->used == pool->size || wl_pool->used == wl_pool->size) {
193 		spin_unlock(&ubi->wl_lock);
194 		up_read(&ubi->fm_eba_sem);
195 		ret = ubi_update_fastmap(ubi);
196 		if (ret) {
197 			ubi_msg(ubi, "Unable to write a new fastmap: %i", ret);
198 			down_read(&ubi->fm_eba_sem);
199 			return -ENOSPC;
200 		}
201 		down_read(&ubi->fm_eba_sem);
202 		spin_lock(&ubi->wl_lock);
203 	}
204 
205 	if (pool->used == pool->size) {
206 		spin_unlock(&ubi->wl_lock);
207 		if (retried) {
208 			ubi_err(ubi, "Unable to get a free PEB from user WL pool");
209 			ret = -ENOSPC;
210 			goto out;
211 		}
212 		retried = 1;
213 		up_read(&ubi->fm_eba_sem);
214 		goto again;
215 	}
216 
217 	ubi_assert(pool->used < pool->size);
218 	ret = pool->pebs[pool->used++];
219 	prot_queue_add(ubi, ubi->lookuptbl[ret]);
220 	spin_unlock(&ubi->wl_lock);
221 out:
222 	return ret;
223 }
224 
225 /* get_peb_for_wl - returns a PEB to be used internally by the WL sub-system.
226  *
227  * @ubi: UBI device description object
228  */
229 static struct ubi_wl_entry *get_peb_for_wl(struct ubi_device *ubi)
230 {
231 	struct ubi_fm_pool *pool = &ubi->fm_wl_pool;
232 	int pnum;
233 
234 	if (pool->used == pool->size) {
235 #ifndef __UBOOT__
236 		/* We cannot update the fastmap here because this
237 		 * function is called in atomic context.
238 		 * Let's fail here and refill/update it as soon as possible. */
239 		if (!ubi->fm_work_scheduled) {
240 			ubi->fm_work_scheduled = 1;
241 			schedule_work(&ubi->fm_work);
242 		}
243 		return NULL;
244 #else
245 		/*
246 		 * No work queues in U-Boot, we must do this immediately
247 		 */
248 		update_fastmap_work_fn(ubi);
249 #endif
250 	}
251 
252 	pnum = pool->pebs[pool->used++];
253 	return ubi->lookuptbl[pnum];
254 }
255 
256 /**
257  * ubi_ensure_anchor_pebs - schedule wear-leveling to produce an anchor PEB.
258  * @ubi: UBI device description object
259  */
260 int ubi_ensure_anchor_pebs(struct ubi_device *ubi)
261 {
262 	struct ubi_work *wrk;
263 
264 	spin_lock(&ubi->wl_lock);
265 	if (ubi->wl_scheduled) {
266 		spin_unlock(&ubi->wl_lock);
267 		return 0;
268 	}
269 	ubi->wl_scheduled = 1;
270 	spin_unlock(&ubi->wl_lock);
271 
272 	wrk = kmalloc(sizeof(struct ubi_work), GFP_NOFS);
273 	if (!wrk) {
274 		spin_lock(&ubi->wl_lock);
275 		ubi->wl_scheduled = 0;
276 		spin_unlock(&ubi->wl_lock);
277 		return -ENOMEM;
278 	}
279 
280 	wrk->anchor = 1;
281 	wrk->func = &wear_leveling_worker;
282 	schedule_ubi_work(ubi, wrk);
283 	return 0;
284 }
285 
286 /**
287  * ubi_wl_put_fm_peb - returns a PEB used in a fastmap to the wear-leveling
288  * sub-system.
289  * see: ubi_wl_put_peb()
290  *
291  * @ubi: UBI device description object
292  * @fm_e: physical eraseblock to return
293  * @lnum: the last used logical eraseblock number for the PEB
294  * @torture: if this physical eraseblock has to be tortured
295  */
296 int ubi_wl_put_fm_peb(struct ubi_device *ubi, struct ubi_wl_entry *fm_e,
297 		      int lnum, int torture)
298 {
299 	struct ubi_wl_entry *e;
300 	int vol_id, pnum = fm_e->pnum;
301 
302 	dbg_wl("PEB %d", pnum);
303 
304 	ubi_assert(pnum >= 0);
305 	ubi_assert(pnum < ubi->peb_count);
306 
307 	spin_lock(&ubi->wl_lock);
308 	e = ubi->lookuptbl[pnum];
309 
310 	/* This can happen if we recovered from a fastmap the very
311 	 * first time and writing now a new one. In this case the wl system
312 	 * has never seen any PEB used by the original fastmap.
313 	 */
314 	if (!e) {
315 		e = fm_e;
316 		ubi_assert(e->ec >= 0);
317 		ubi->lookuptbl[pnum] = e;
318 	}
319 
320 	spin_unlock(&ubi->wl_lock);
321 
322 	vol_id = lnum ? UBI_FM_DATA_VOLUME_ID : UBI_FM_SB_VOLUME_ID;
323 	return schedule_erase(ubi, e, vol_id, lnum, torture);
324 }
325 
326 /**
327  * ubi_is_erase_work - checks whether a work is erase work.
328  * @wrk: The work object to be checked
329  */
330 int ubi_is_erase_work(struct ubi_work *wrk)
331 {
332 	return wrk->func == erase_worker;
333 }
334 
335 static void ubi_fastmap_close(struct ubi_device *ubi)
336 {
337 	int i;
338 
339 	return_unused_pool_pebs(ubi, &ubi->fm_pool);
340 	return_unused_pool_pebs(ubi, &ubi->fm_wl_pool);
341 
342 	if (ubi->fm) {
343 		for (i = 0; i < ubi->fm->used_blocks; i++)
344 			kfree(ubi->fm->e[i]);
345 	}
346 	kfree(ubi->fm);
347 }
348 
349 /**
350  * may_reserve_for_fm - tests whether a PEB shall be reserved for fastmap.
351  * See find_mean_wl_entry()
352  *
353  * @ubi: UBI device description object
354  * @e: physical eraseblock to return
355  * @root: RB tree to test against.
356  */
357 static struct ubi_wl_entry *may_reserve_for_fm(struct ubi_device *ubi,
358 					   struct ubi_wl_entry *e,
359 					   struct rb_root *root) {
360 	if (e && !ubi->fm_disabled && !ubi->fm &&
361 	    e->pnum < UBI_FM_MAX_START)
362 		e = rb_entry(rb_next(root->rb_node),
363 			     struct ubi_wl_entry, u.rb);
364 
365 	return e;
366 }
367