1 /**************************************************************************/
2 /* */
3 /* Copyright (c) Microsoft Corporation. All rights reserved. */
4 /* */
5 /* This software is licensed under the Microsoft Software License */
6 /* Terms for Microsoft Azure RTOS. Full text of the license can be */
7 /* found in the LICENSE file at https://aka.ms/AzureRTOS_EULA */
8 /* and in the root directory of this software. */
9 /* */
10 /**************************************************************************/
11
12
13 /**************************************************************************/
14 /**************************************************************************/
15 /** */
16 /** LevelX Component */
17 /** */
18 /** NOR Flash */
19 /** */
20 /**************************************************************************/
21 /**************************************************************************/
22
23 #define LX_SOURCE_CODE
24
25
26 /* Disable ThreadX error checking. */
27
28 #ifndef LX_DISABLE_ERROR_CHECKING
29 #define LX_DISABLE_ERROR_CHECKING
30 #endif
31
32
33 /* Include necessary system files. */
34
35 #include "lx_api.h"
36
37
38 /**************************************************************************/
39 /* */
40 /* FUNCTION RELEASE */
41 /* */
42 /* _lx_nor_flash_next_block_to_erase_find PORTABLE C */
43 /* 6.1.7 */
44 /* AUTHOR */
45 /* */
46 /* William E. Lamie, Microsoft Corporation */
47 /* */
48 /* DESCRIPTION */
49 /* */
50 /* This function finds the next block to erase in the NOR flash. */
51 /* */
52 /* INPUT */
53 /* */
54 /* nor_flash NOR flash instance */
55 /* return_erase_block Returned block to erase */
56 /* return_erase_count Returned erase count of block */
57 /* return_mapped_sectors Returned number of mapped */
58 /* sectors */
59 /* return_obsolete_sectors Returned number of obsolete */
60 /* sectors */
61 /* */
62 /* OUTPUT */
63 /* */
64 /* return status */
65 /* */
66 /* CALLS */
67 /* */
68 /* _lx_nor_flash_driver_read Driver flash sector read */
69 /* _lx_nor_flash_system_error Internal system error handler */
70 /* */
71 /* CALLED BY */
72 /* */
73 /* Internal LevelX */
74 /* */
75 /* RELEASE HISTORY */
76 /* */
77 /* DATE NAME DESCRIPTION */
78 /* */
79 /* 05-19-2020 William E. Lamie Initial Version 6.0 */
80 /* 09-30-2020 William E. Lamie Modified comment(s), */
81 /* resulting in version 6.1 */
82 /* 06-02-2021 Bhupendra Naphade Modified comment(s), */
83 /* resulting in version 6.1.7 */
84 /* */
85 /**************************************************************************/
_lx_nor_flash_next_block_to_erase_find(LX_NOR_FLASH * nor_flash,ULONG * return_erase_block,ULONG * return_erase_count,ULONG * return_mapped_sectors,ULONG * return_obsolete_sectors)86 UINT _lx_nor_flash_next_block_to_erase_find(LX_NOR_FLASH *nor_flash, ULONG *return_erase_block, ULONG *return_erase_count, ULONG *return_mapped_sectors, ULONG *return_obsolete_sectors)
87 {
88
89 ULONG *block_word_ptr;
90 ULONG *list_word_ptr;
91 ULONG list_word;
92 ULONG i, j;
93 ULONG mapped_sectors;
94 ULONG erase_count;
95 ULONG obsolete_sectors;
96 ULONG min_block_erase = 0;
97 ULONG min_block_erase_count;
98 ULONG min_block_obsolete_count = 0;
99 ULONG min_block_mapped_count = 0;
100 ULONG max_obsolete_sectors;
101 ULONG max_obsolete_block = 0;
102 ULONG max_obsolete_erase_count = 0;
103 ULONG max_obsolete_mapped_count = 0;
104 ULONG min_system_block_erase_count;
105 ULONG max_system_block_erase_count;
106 ULONG erase_count_threshold;
107 #ifndef LX_DIRECT_READ
108 UINT status;
109 #endif
110
111
112 /* Setup the block word pointer to the first word of the search block. */
113 block_word_ptr = nor_flash -> lx_nor_flash_base_address;
114
115 /* Initialize the minimum erase count. */
116 min_block_erase_count = LX_ALL_ONES;
117
118 /* Initialize the system minimum and maximum erase counts. */
119 min_system_block_erase_count = LX_ALL_ONES;
120 max_system_block_erase_count = 0;
121
122 /* Initialize the maximum obsolete sector count. */
123 max_obsolete_sectors = 0;
124
125 /* Calculate the erase count threshold. */
126 if (nor_flash -> lx_nor_flash_free_physical_sectors >= nor_flash -> lx_nor_flash_physical_sectors_per_block)
127 {
128
129 /* Calculate erase count threshold by adding constant to the current minimum. */
130 erase_count_threshold = nor_flash -> lx_nor_flash_minimum_erase_count + LX_NOR_FLASH_MAX_ERASE_COUNT_DELTA;
131 }
132 else
133 {
134
135 /* When the number of free sectors is low, simply pick the block that has the most number of obsolete sectors. */
136 erase_count_threshold = LX_ALL_ONES;
137 }
138
139 /* Loop through the blocks to attempt to find the mapped logical sector. */
140 for (i = 0; i < nor_flash -> lx_nor_flash_total_blocks; i++)
141 {
142
143 /* Read the erase count of this block. */
144 #ifdef LX_DIRECT_READ
145
146 /* Read the word directly. */
147 erase_count = *(block_word_ptr);
148 #else
149 status = _lx_nor_flash_driver_read(nor_flash, block_word_ptr, &erase_count, 1);
150
151 /* Check for an error from flash driver. Drivers should never return an error.. */
152 if (status)
153 {
154
155 /* Call system error handler. */
156 _lx_nor_flash_system_error(nor_flash, status);
157
158 /* Return the error. */
159 return(status);
160 }
161 #endif
162
163 /* Update the system minimum and maximum erase counts. */
164 if (erase_count < min_system_block_erase_count)
165 min_system_block_erase_count = erase_count;
166 if (erase_count > max_system_block_erase_count)
167 max_system_block_erase_count = erase_count;
168
169 /* Compute the number of obsolete and mapped sectors for this block. */
170 obsolete_sectors = 0;
171 mapped_sectors = 0;
172
173 /* Setup a pointer to the mapped list. */
174 list_word_ptr = block_word_ptr + nor_flash -> lx_nor_flash_block_physical_sector_mapping_offset;
175
176 /* Loop through the mapped list for this block. */
177 for (j = 0; j < nor_flash -> lx_nor_flash_physical_sectors_per_block; j++)
178 {
179
180 /* Read the current mapping entry. */
181 #ifdef LX_DIRECT_READ
182
183 /* Read the word directly. */
184 list_word = *(list_word_ptr);
185 #else
186 status = _lx_nor_flash_driver_read(nor_flash, list_word_ptr, &list_word, 1);
187
188 /* Check for an error from flash driver. Drivers should never return an error.. */
189 if (status)
190 {
191
192 /* Call system error handler. */
193 _lx_nor_flash_system_error(nor_flash, status);
194
195 /* Return the error. */
196 return(status);
197 }
198 #endif
199
200 /* Determine if the entry hasn't been used. */
201 if (list_word == LX_NOR_PHYSICAL_SECTOR_FREE)
202 {
203
204 /* Since allocations are done sequentially in the block, we know nothing
205 else exists after this point. */
206 break;
207 }
208
209 /* Is this entry obsolete? */
210 if ((list_word & LX_NOR_PHYSICAL_SECTOR_VALID) == 0)
211 {
212
213 /* Increment the number of obsolete sectors. */
214 obsolete_sectors++;
215 }
216 else
217 {
218
219 /* Increment the number of mapped sectors. */
220 mapped_sectors++;
221 }
222
223 /* Move the list pointer ahead. */
224 list_word_ptr++;
225 }
226
227 /* Determine if we have a block with a new maximum number of obsolete sectors. */
228 if ((obsolete_sectors > max_obsolete_sectors) && (erase_count <= erase_count_threshold))
229 {
230
231 /* Update the new maximum obsolete sectors and related information. */
232 max_obsolete_sectors = obsolete_sectors;
233 max_obsolete_block = i;
234 max_obsolete_erase_count = erase_count;
235 max_obsolete_mapped_count = mapped_sectors;
236 }
237 else if ((max_obsolete_sectors) && (obsolete_sectors == max_obsolete_sectors) && (erase_count <= erase_count_threshold))
238 {
239
240 /* Another block has the same number of obsolete sectors. Does this new block have a smaller erase
241 count? */
242 if (erase_count < max_obsolete_erase_count)
243 {
244
245 /* Yes, erase the block with the smaller erase count. */
246 max_obsolete_sectors = obsolete_sectors;
247 max_obsolete_block = i;
248 max_obsolete_erase_count = erase_count;
249 max_obsolete_mapped_count = mapped_sectors;
250 }
251 }
252
253 /* Determine if we have a new minimum erase count. */
254 if (erase_count < min_block_erase_count)
255 {
256
257 /* Update the new minimum erase count and related information. */
258 min_block_erase_count = erase_count;
259 min_block_erase = i;
260 min_block_obsolete_count = obsolete_sectors;
261 min_block_mapped_count = mapped_sectors;
262 }
263
264 /* Move to the next block. */
265 block_word_ptr = block_word_ptr + nor_flash -> lx_nor_flash_words_per_block;
266 }
267
268 /* Determine if we can erase the block with the most obsolete sectors. */
269 if (max_obsolete_sectors)
270 {
271
272 /* Erase the block with the most obsolete sectors. */
273 *return_erase_block = max_obsolete_block;
274 *return_erase_count = max_obsolete_erase_count;
275 *return_obsolete_sectors = max_obsolete_sectors;
276 *return_mapped_sectors = max_obsolete_mapped_count;
277 }
278 else
279 {
280
281 /* Otherwise, choose the block with the smallest erase count. */
282 *return_erase_block = min_block_erase;
283 *return_erase_count = min_block_erase_count;
284 *return_obsolete_sectors = min_block_obsolete_count;
285 *return_mapped_sectors = min_block_mapped_count;
286 }
287
288 /* Update the overall minimum and maximum erase count. */
289 nor_flash -> lx_nor_flash_minimum_erase_count = min_system_block_erase_count;
290 nor_flash -> lx_nor_flash_maximum_erase_count = max_system_block_erase_count;
291
292 /* Return success. */
293 return(LX_SUCCESS);
294 }
295
296
