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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
23f62689 PO |
2 | /* |
3 | * Functions for incremental construction of fcx enabled I/O control blocks. | |
4 | * | |
5 | * Copyright IBM Corp. 2008 | |
6 | * Author(s): Peter Oberparleiter <peter.oberparleiter@de.ibm.com> | |
7 | */ | |
8 | ||
9 | #include <linux/kernel.h> | |
10 | #include <linux/types.h> | |
11 | #include <linux/string.h> | |
12 | #include <linux/errno.h> | |
13 | #include <linux/err.h> | |
14 | #include <linux/module.h> | |
15 | #include <asm/fcx.h> | |
16 | #include <asm/itcw.h> | |
17 | ||
18 | /** | |
19 | * struct itcw - incremental tcw helper data type | |
20 | * | |
21 | * This structure serves as a handle for the incremental construction of a | |
22 | * tcw and associated tccb, tsb, data tidaw-list plus an optional interrogate | |
23 | * tcw and associated data. The data structures are contained inside a single | |
24 | * contiguous buffer provided by the user. | |
25 | * | |
26 | * The itcw construction functions take care of overall data integrity: | |
27 | * - reset unused fields to zero | |
28 | * - fill in required pointers | |
29 | * - ensure required alignment for data structures | |
30 | * - prevent data structures to cross 4k-byte boundary where required | |
31 | * - calculate tccb-related length fields | |
32 | * - optionally provide ready-made interrogate tcw and associated structures | |
33 | * | |
34 | * Restrictions apply to the itcws created with these construction functions: | |
35 | * - tida only supported for data address, not for tccb | |
36 | * - only contiguous tidaw-lists (no ttic) | |
37 | * - total number of bytes required per itcw may not exceed 4k bytes | |
38 | * - either read or write operation (may not work with r=0 and w=0) | |
39 | * | |
40 | * Example: | |
41 | * struct itcw *itcw; | |
42 | * void *buffer; | |
43 | * size_t size; | |
44 | * | |
45 | * size = itcw_calc_size(1, 2, 0); | |
c2f0e8c8 | 46 | * buffer = kmalloc(size, GFP_KERNEL | GFP_DMA); |
23f62689 PO |
47 | * if (!buffer) |
48 | * return -ENOMEM; | |
49 | * itcw = itcw_init(buffer, size, ITCW_OP_READ, 1, 2, 0); | |
50 | * if (IS_ERR(itcw)) | |
51 | * return PTR_ER(itcw); | |
52 | * itcw_add_dcw(itcw, 0x2, 0, NULL, 0, 72); | |
53 | * itcw_add_tidaw(itcw, 0, 0x30000, 20); | |
54 | * itcw_add_tidaw(itcw, 0, 0x40000, 52); | |
55 | * itcw_finalize(itcw); | |
56 | * | |
57 | */ | |
58 | struct itcw { | |
59 | struct tcw *tcw; | |
60 | struct tcw *intrg_tcw; | |
61 | int num_tidaws; | |
62 | int max_tidaws; | |
63 | int intrg_num_tidaws; | |
64 | int intrg_max_tidaws; | |
65 | }; | |
66 | ||
67 | /** | |
68 | * itcw_get_tcw - return pointer to tcw associated with the itcw | |
69 | * @itcw: address of the itcw | |
70 | * | |
71 | * Return pointer to the tcw associated with the itcw. | |
72 | */ | |
73 | struct tcw *itcw_get_tcw(struct itcw *itcw) | |
74 | { | |
75 | return itcw->tcw; | |
76 | } | |
77 | EXPORT_SYMBOL(itcw_get_tcw); | |
78 | ||
79 | /** | |
80 | * itcw_calc_size - return the size of an itcw with the given parameters | |
81 | * @intrg: if non-zero, add an interrogate tcw | |
82 | * @max_tidaws: maximum number of tidaws to be used for data addressing or zero | |
83 | * if no tida is to be used. | |
84 | * @intrg_max_tidaws: maximum number of tidaws to be used for data addressing | |
85 | * by the interrogate tcw, if specified | |
86 | * | |
87 | * Calculate and return the number of bytes required to hold an itcw with the | |
88 | * given parameters and assuming tccbs with maximum size. | |
89 | * | |
90 | * Note that the resulting size also contains bytes needed for alignment | |
91 | * padding as well as padding to ensure that data structures don't cross a | |
92 | * 4k-boundary where required. | |
93 | */ | |
94 | size_t itcw_calc_size(int intrg, int max_tidaws, int intrg_max_tidaws) | |
95 | { | |
96 | size_t len; | |
9062014c | 97 | int cross_count; |
23f62689 PO |
98 | |
99 | /* Main data. */ | |
100 | len = sizeof(struct itcw); | |
101 | len += /* TCW */ sizeof(struct tcw) + /* TCCB */ TCCB_MAX_SIZE + | |
102 | /* TSB */ sizeof(struct tsb) + | |
103 | /* TIDAL */ max_tidaws * sizeof(struct tidaw); | |
104 | /* Interrogate data. */ | |
105 | if (intrg) { | |
106 | len += /* TCW */ sizeof(struct tcw) + /* TCCB */ TCCB_MAX_SIZE + | |
107 | /* TSB */ sizeof(struct tsb) + | |
108 | /* TIDAL */ intrg_max_tidaws * sizeof(struct tidaw); | |
109 | } | |
9062014c | 110 | |
23f62689 PO |
111 | /* Maximum required alignment padding. */ |
112 | len += /* Initial TCW */ 63 + /* Interrogate TCCB */ 7; | |
9062014c SW |
113 | |
114 | /* TIDAW lists may not cross a 4k boundary. To cross a | |
115 | * boundary we need to add a TTIC TIDAW. We need to reserve | |
116 | * one additional TIDAW for a TTIC that we may need to add due | |
117 | * to the placement of the data chunk in memory, and a further | |
118 | * TIDAW for each page boundary that the TIDAW list may cross | |
119 | * due to it's own size. | |
120 | */ | |
121 | if (max_tidaws) { | |
122 | cross_count = 1 + ((max_tidaws * sizeof(struct tidaw) - 1) | |
123 | >> PAGE_SHIFT); | |
124 | len += cross_count * sizeof(struct tidaw); | |
125 | } | |
126 | if (intrg_max_tidaws) { | |
127 | cross_count = 1 + ((intrg_max_tidaws * sizeof(struct tidaw) - 1) | |
128 | >> PAGE_SHIFT); | |
129 | len += cross_count * sizeof(struct tidaw); | |
130 | } | |
23f62689 PO |
131 | return len; |
132 | } | |
133 | EXPORT_SYMBOL(itcw_calc_size); | |
134 | ||
135 | #define CROSS4K(x, l) (((x) & ~4095) != ((x + l) & ~4095)) | |
136 | ||
137 | static inline void *fit_chunk(addr_t *start, addr_t end, size_t len, | |
138 | int align, int check_4k) | |
139 | { | |
140 | addr_t addr; | |
141 | ||
142 | addr = ALIGN(*start, align); | |
143 | if (check_4k && CROSS4K(addr, len)) { | |
144 | addr = ALIGN(addr, 4096); | |
145 | addr = ALIGN(addr, align); | |
146 | } | |
147 | if (addr + len > end) | |
148 | return ERR_PTR(-ENOSPC); | |
149 | *start = addr + len; | |
150 | return (void *) addr; | |
151 | } | |
152 | ||
153 | /** | |
154 | * itcw_init - initialize incremental tcw data structure | |
155 | * @buffer: address of buffer to use for data structures | |
156 | * @size: number of bytes in buffer | |
157 | * @op: %ITCW_OP_READ for a read operation tcw, %ITCW_OP_WRITE for a write | |
158 | * operation tcw | |
159 | * @intrg: if non-zero, add and initialize an interrogate tcw | |
160 | * @max_tidaws: maximum number of tidaws to be used for data addressing or zero | |
161 | * if no tida is to be used. | |
162 | * @intrg_max_tidaws: maximum number of tidaws to be used for data addressing | |
163 | * by the interrogate tcw, if specified | |
164 | * | |
165 | * Prepare the specified buffer to be used as an incremental tcw, i.e. a | |
166 | * helper data structure that can be used to construct a valid tcw by | |
167 | * successive calls to other helper functions. Note: the buffer needs to be | |
168 | * located below the 2G address limit. The resulting tcw has the following | |
169 | * restrictions: | |
170 | * - no tccb tidal | |
171 | * - input/output tidal is contiguous (no ttic) | |
172 | * - total data should not exceed 4k | |
173 | * - tcw specifies either read or write operation | |
174 | * | |
175 | * On success, return pointer to the resulting incremental tcw data structure, | |
176 | * ERR_PTR otherwise. | |
177 | */ | |
178 | struct itcw *itcw_init(void *buffer, size_t size, int op, int intrg, | |
179 | int max_tidaws, int intrg_max_tidaws) | |
180 | { | |
181 | struct itcw *itcw; | |
182 | void *chunk; | |
183 | addr_t start; | |
184 | addr_t end; | |
9062014c | 185 | int cross_count; |
23f62689 PO |
186 | |
187 | /* Check for 2G limit. */ | |
188 | start = (addr_t) buffer; | |
189 | end = start + size; | |
190 | if (end > (1 << 31)) | |
191 | return ERR_PTR(-EINVAL); | |
192 | memset(buffer, 0, size); | |
193 | /* ITCW. */ | |
194 | chunk = fit_chunk(&start, end, sizeof(struct itcw), 1, 0); | |
195 | if (IS_ERR(chunk)) | |
196 | return chunk; | |
197 | itcw = chunk; | |
9062014c SW |
198 | /* allow for TTIC tidaws that may be needed to cross a page boundary */ |
199 | cross_count = 0; | |
200 | if (max_tidaws) | |
201 | cross_count = 1 + ((max_tidaws * sizeof(struct tidaw) - 1) | |
202 | >> PAGE_SHIFT); | |
203 | itcw->max_tidaws = max_tidaws + cross_count; | |
204 | cross_count = 0; | |
205 | if (intrg_max_tidaws) | |
206 | cross_count = 1 + ((intrg_max_tidaws * sizeof(struct tidaw) - 1) | |
207 | >> PAGE_SHIFT); | |
208 | itcw->intrg_max_tidaws = intrg_max_tidaws + cross_count; | |
23f62689 PO |
209 | /* Main TCW. */ |
210 | chunk = fit_chunk(&start, end, sizeof(struct tcw), 64, 0); | |
211 | if (IS_ERR(chunk)) | |
212 | return chunk; | |
213 | itcw->tcw = chunk; | |
214 | tcw_init(itcw->tcw, (op == ITCW_OP_READ) ? 1 : 0, | |
215 | (op == ITCW_OP_WRITE) ? 1 : 0); | |
216 | /* Interrogate TCW. */ | |
217 | if (intrg) { | |
218 | chunk = fit_chunk(&start, end, sizeof(struct tcw), 64, 0); | |
219 | if (IS_ERR(chunk)) | |
220 | return chunk; | |
221 | itcw->intrg_tcw = chunk; | |
222 | tcw_init(itcw->intrg_tcw, 1, 0); | |
223 | tcw_set_intrg(itcw->tcw, itcw->intrg_tcw); | |
224 | } | |
225 | /* Data TIDAL. */ | |
226 | if (max_tidaws > 0) { | |
227 | chunk = fit_chunk(&start, end, sizeof(struct tidaw) * | |
9062014c | 228 | itcw->max_tidaws, 16, 0); |
23f62689 PO |
229 | if (IS_ERR(chunk)) |
230 | return chunk; | |
231 | tcw_set_data(itcw->tcw, chunk, 1); | |
232 | } | |
233 | /* Interrogate data TIDAL. */ | |
234 | if (intrg && (intrg_max_tidaws > 0)) { | |
235 | chunk = fit_chunk(&start, end, sizeof(struct tidaw) * | |
9062014c | 236 | itcw->intrg_max_tidaws, 16, 0); |
23f62689 PO |
237 | if (IS_ERR(chunk)) |
238 | return chunk; | |
239 | tcw_set_data(itcw->intrg_tcw, chunk, 1); | |
240 | } | |
241 | /* TSB. */ | |
242 | chunk = fit_chunk(&start, end, sizeof(struct tsb), 8, 0); | |
243 | if (IS_ERR(chunk)) | |
244 | return chunk; | |
245 | tsb_init(chunk); | |
246 | tcw_set_tsb(itcw->tcw, chunk); | |
247 | /* Interrogate TSB. */ | |
248 | if (intrg) { | |
249 | chunk = fit_chunk(&start, end, sizeof(struct tsb), 8, 0); | |
250 | if (IS_ERR(chunk)) | |
251 | return chunk; | |
252 | tsb_init(chunk); | |
253 | tcw_set_tsb(itcw->intrg_tcw, chunk); | |
254 | } | |
255 | /* TCCB. */ | |
256 | chunk = fit_chunk(&start, end, TCCB_MAX_SIZE, 8, 0); | |
257 | if (IS_ERR(chunk)) | |
258 | return chunk; | |
259 | tccb_init(chunk, TCCB_MAX_SIZE, TCCB_SAC_DEFAULT); | |
260 | tcw_set_tccb(itcw->tcw, chunk); | |
261 | /* Interrogate TCCB. */ | |
262 | if (intrg) { | |
263 | chunk = fit_chunk(&start, end, TCCB_MAX_SIZE, 8, 0); | |
264 | if (IS_ERR(chunk)) | |
265 | return chunk; | |
266 | tccb_init(chunk, TCCB_MAX_SIZE, TCCB_SAC_INTRG); | |
267 | tcw_set_tccb(itcw->intrg_tcw, chunk); | |
268 | tccb_add_dcw(chunk, TCCB_MAX_SIZE, DCW_CMD_INTRG, 0, NULL, | |
269 | sizeof(struct dcw_intrg_data), 0); | |
270 | tcw_finalize(itcw->intrg_tcw, 0); | |
271 | } | |
272 | return itcw; | |
273 | } | |
274 | EXPORT_SYMBOL(itcw_init); | |
275 | ||
276 | /** | |
277 | * itcw_add_dcw - add a dcw to the itcw | |
278 | * @itcw: address of the itcw | |
279 | * @cmd: the dcw command | |
280 | * @flags: flags for the dcw | |
281 | * @cd: address of control data for this dcw or NULL if none is required | |
282 | * @cd_count: number of control data bytes for this dcw | |
283 | * @count: number of data bytes for this dcw | |
284 | * | |
285 | * Add a new dcw to the specified itcw by writing the dcw information specified | |
286 | * by @cmd, @flags, @cd, @cd_count and @count to the tca of the tccb. Return | |
287 | * a pointer to the newly added dcw on success or -%ENOSPC if the new dcw | |
288 | * would exceed the available space. | |
289 | * | |
290 | * Note: the tcal field of the tccb header will be updated to reflect added | |
291 | * content. | |
292 | */ | |
293 | struct dcw *itcw_add_dcw(struct itcw *itcw, u8 cmd, u8 flags, void *cd, | |
294 | u8 cd_count, u32 count) | |
295 | { | |
296 | return tccb_add_dcw(tcw_get_tccb(itcw->tcw), TCCB_MAX_SIZE, cmd, | |
297 | flags, cd, cd_count, count); | |
298 | } | |
299 | EXPORT_SYMBOL(itcw_add_dcw); | |
300 | ||
301 | /** | |
302 | * itcw_add_tidaw - add a tidaw to the itcw | |
303 | * @itcw: address of the itcw | |
304 | * @flags: flags for the new tidaw | |
305 | * @addr: address value for the new tidaw | |
306 | * @count: count value for the new tidaw | |
307 | * | |
308 | * Add a new tidaw to the input/output data tidaw-list of the specified itcw | |
309 | * (depending on the value of the r-flag and w-flag). Return a pointer to | |
310 | * the new tidaw on success or -%ENOSPC if the new tidaw would exceed the | |
311 | * available space. | |
312 | * | |
9062014c SW |
313 | * Note: TTIC tidaws are automatically added when needed, so explicitly calling |
314 | * this interface with the TTIC flag is not supported. The last-tidaw flag | |
315 | * for the last tidaw in the list will be set by itcw_finalize. | |
23f62689 PO |
316 | */ |
317 | struct tidaw *itcw_add_tidaw(struct itcw *itcw, u8 flags, void *addr, u32 count) | |
318 | { | |
9062014c SW |
319 | struct tidaw *following; |
320 | ||
23f62689 PO |
321 | if (itcw->num_tidaws >= itcw->max_tidaws) |
322 | return ERR_PTR(-ENOSPC); | |
9062014c SW |
323 | /* |
324 | * Is the tidaw, which follows the one we are about to fill, on the next | |
325 | * page? Then we have to insert a TTIC tidaw first, that points to the | |
326 | * tidaw on the new page. | |
327 | */ | |
328 | following = ((struct tidaw *) tcw_get_data(itcw->tcw)) | |
329 | + itcw->num_tidaws + 1; | |
330 | if (itcw->num_tidaws && !((unsigned long) following & ~PAGE_MASK)) { | |
331 | tcw_add_tidaw(itcw->tcw, itcw->num_tidaws++, | |
332 | TIDAW_FLAGS_TTIC, following, 0); | |
333 | if (itcw->num_tidaws >= itcw->max_tidaws) | |
334 | return ERR_PTR(-ENOSPC); | |
335 | } | |
23f62689 PO |
336 | return tcw_add_tidaw(itcw->tcw, itcw->num_tidaws++, flags, addr, count); |
337 | } | |
338 | EXPORT_SYMBOL(itcw_add_tidaw); | |
339 | ||
340 | /** | |
341 | * itcw_set_data - set data address and tida flag of the itcw | |
342 | * @itcw: address of the itcw | |
343 | * @addr: the data address | |
344 | * @use_tidal: zero of the data address specifies a contiguous block of data, | |
345 | * non-zero if it specifies a list if tidaws. | |
346 | * | |
347 | * Set the input/output data address of the itcw (depending on the value of the | |
348 | * r-flag and w-flag). If @use_tidal is non-zero, the corresponding tida flag | |
349 | * is set as well. | |
350 | */ | |
351 | void itcw_set_data(struct itcw *itcw, void *addr, int use_tidal) | |
352 | { | |
353 | tcw_set_data(itcw->tcw, addr, use_tidal); | |
354 | } | |
355 | EXPORT_SYMBOL(itcw_set_data); | |
356 | ||
357 | /** | |
358 | * itcw_finalize - calculate length and count fields of the itcw | |
359 | * @itcw: address of the itcw | |
360 | * | |
361 | * Calculate tcw input-/output-count and tccbl fields and add a tcat the tccb. | |
362 | * In case input- or output-tida is used, the tidaw-list must be stored in | |
363 | * continuous storage (no ttic). The tcal field in the tccb must be | |
364 | * up-to-date. | |
365 | */ | |
366 | void itcw_finalize(struct itcw *itcw) | |
367 | { | |
368 | tcw_finalize(itcw->tcw, itcw->num_tidaws); | |
369 | } | |
370 | EXPORT_SYMBOL(itcw_finalize); |