1 | // SPDX-License-Identifier: GPL-2.0 |
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/io.h> |
13 | #include <linux/errno.h> |
14 | #include <linux/err.h> |
15 | #include <linux/module.h> |
16 | #include <asm/fcx.h> |
17 | #include <asm/itcw.h> |
18 | |
19 | /* |
20 | * struct itcw - incremental tcw helper data type |
21 | * |
22 | * This structure serves as a handle for the incremental construction of a |
23 | * tcw and associated tccb, tsb, data tidaw-list plus an optional interrogate |
24 | * tcw and associated data. The data structures are contained inside a single |
25 | * contiguous buffer provided by the user. |
26 | * |
27 | * The itcw construction functions take care of overall data integrity: |
28 | * - reset unused fields to zero |
29 | * - fill in required pointers |
30 | * - ensure required alignment for data structures |
31 | * - prevent data structures to cross 4k-byte boundary where required |
32 | * - calculate tccb-related length fields |
33 | * - optionally provide ready-made interrogate tcw and associated structures |
34 | * |
35 | * Restrictions apply to the itcws created with these construction functions: |
36 | * - tida only supported for data address, not for tccb |
37 | * - only contiguous tidaw-lists (no ttic) |
38 | * - total number of bytes required per itcw may not exceed 4k bytes |
39 | * - either read or write operation (may not work with r=0 and w=0) |
40 | * |
41 | * Example: |
42 | * struct itcw *itcw; |
43 | * void *buffer; |
44 | * size_t size; |
45 | * |
46 | * size = itcw_calc_size(1, 2, 0); |
47 | * buffer = kmalloc(size, GFP_KERNEL | GFP_DMA); |
48 | * if (!buffer) |
49 | * return -ENOMEM; |
50 | * itcw = itcw_init(buffer, size, ITCW_OP_READ, 1, 2, 0); |
51 | * if (IS_ERR(itcw)) |
52 | * return PTR_ER(itcw); |
53 | * itcw_add_dcw(itcw, 0x2, 0, NULL, 0, 72); |
54 | * itcw_add_tidaw(itcw, 0, 0x30000, 20); |
55 | * itcw_add_tidaw(itcw, 0, 0x40000, 52); |
56 | * itcw_finalize(itcw); |
57 | * |
58 | */ |
59 | struct itcw { |
60 | struct tcw *tcw; |
61 | struct tcw *intrg_tcw; |
62 | int num_tidaws; |
63 | int max_tidaws; |
64 | int intrg_num_tidaws; |
65 | int intrg_max_tidaws; |
66 | }; |
67 | |
68 | /** |
69 | * itcw_get_tcw - return pointer to tcw associated with the itcw |
70 | * @itcw: address of the itcw |
71 | * |
72 | * Return pointer to the tcw associated with the itcw. |
73 | */ |
74 | struct tcw *itcw_get_tcw(struct itcw *itcw) |
75 | { |
76 | return itcw->tcw; |
77 | } |
78 | EXPORT_SYMBOL(itcw_get_tcw); |
79 | |
80 | /** |
81 | * itcw_calc_size - return the size of an itcw with the given parameters |
82 | * @intrg: if non-zero, add an interrogate tcw |
83 | * @max_tidaws: maximum number of tidaws to be used for data addressing or zero |
84 | * if no tida is to be used. |
85 | * @intrg_max_tidaws: maximum number of tidaws to be used for data addressing |
86 | * by the interrogate tcw, if specified |
87 | * |
88 | * Calculate and return the number of bytes required to hold an itcw with the |
89 | * given parameters and assuming tccbs with maximum size. |
90 | * |
91 | * Note that the resulting size also contains bytes needed for alignment |
92 | * padding as well as padding to ensure that data structures don't cross a |
93 | * 4k-boundary where required. |
94 | */ |
95 | size_t itcw_calc_size(int intrg, int max_tidaws, int intrg_max_tidaws) |
96 | { |
97 | size_t len; |
98 | int cross_count; |
99 | |
100 | /* Main data. */ |
101 | len = sizeof(struct itcw); |
102 | len += /* TCW */ sizeof(struct tcw) + /* TCCB */ TCCB_MAX_SIZE + |
103 | /* TSB */ sizeof(struct tsb) + |
104 | /* TIDAL */ max_tidaws * sizeof(struct tidaw); |
105 | /* Interrogate data. */ |
106 | if (intrg) { |
107 | len += /* TCW */ sizeof(struct tcw) + /* TCCB */ TCCB_MAX_SIZE + |
108 | /* TSB */ sizeof(struct tsb) + |
109 | /* TIDAL */ intrg_max_tidaws * sizeof(struct tidaw); |
110 | } |
111 | |
112 | /* Maximum required alignment padding. */ |
113 | len += /* Initial TCW */ 63 + /* Interrogate TCCB */ 7; |
114 | |
115 | /* TIDAW lists may not cross a 4k boundary. To cross a |
116 | * boundary we need to add a TTIC TIDAW. We need to reserve |
117 | * one additional TIDAW for a TTIC that we may need to add due |
118 | * to the placement of the data chunk in memory, and a further |
119 | * TIDAW for each page boundary that the TIDAW list may cross |
120 | * due to it's own size. |
121 | */ |
122 | if (max_tidaws) { |
123 | cross_count = 1 + ((max_tidaws * sizeof(struct tidaw) - 1) |
124 | >> PAGE_SHIFT); |
125 | len += cross_count * sizeof(struct tidaw); |
126 | } |
127 | if (intrg_max_tidaws) { |
128 | cross_count = 1 + ((intrg_max_tidaws * sizeof(struct tidaw) - 1) |
129 | >> PAGE_SHIFT); |
130 | len += cross_count * sizeof(struct tidaw); |
131 | } |
132 | return len; |
133 | } |
134 | EXPORT_SYMBOL(itcw_calc_size); |
135 | |
136 | #define CROSS4K(x, l) (((x) & ~4095) != ((x + l) & ~4095)) |
137 | |
138 | static inline void *fit_chunk(addr_t *start, addr_t end, size_t len, |
139 | int align, int check_4k) |
140 | { |
141 | addr_t addr; |
142 | |
143 | addr = ALIGN(*start, align); |
144 | if (check_4k && CROSS4K(addr, len)) { |
145 | addr = ALIGN(addr, 4096); |
146 | addr = ALIGN(addr, align); |
147 | } |
148 | if (addr + len > end) |
149 | return ERR_PTR(error: -ENOSPC); |
150 | *start = addr + len; |
151 | return (void *) addr; |
152 | } |
153 | |
154 | /** |
155 | * itcw_init - initialize incremental tcw data structure |
156 | * @buffer: address of buffer to use for data structures |
157 | * @size: number of bytes in buffer |
158 | * @op: %ITCW_OP_READ for a read operation tcw, %ITCW_OP_WRITE for a write |
159 | * operation tcw |
160 | * @intrg: if non-zero, add and initialize an interrogate tcw |
161 | * @max_tidaws: maximum number of tidaws to be used for data addressing or zero |
162 | * if no tida is to be used. |
163 | * @intrg_max_tidaws: maximum number of tidaws to be used for data addressing |
164 | * by the interrogate tcw, if specified |
165 | * |
166 | * Prepare the specified buffer to be used as an incremental tcw, i.e. a |
167 | * helper data structure that can be used to construct a valid tcw by |
168 | * successive calls to other helper functions. Note: the buffer needs to be |
169 | * located below the 2G address limit. The resulting tcw has the following |
170 | * restrictions: |
171 | * - no tccb tidal |
172 | * - input/output tidal is contiguous (no ttic) |
173 | * - total data should not exceed 4k |
174 | * - tcw specifies either read or write operation |
175 | * |
176 | * On success, return pointer to the resulting incremental tcw data structure, |
177 | * ERR_PTR otherwise. |
178 | */ |
179 | struct itcw *itcw_init(void *buffer, size_t size, int op, int intrg, |
180 | int max_tidaws, int intrg_max_tidaws) |
181 | { |
182 | struct itcw *itcw; |
183 | void *chunk; |
184 | addr_t start; |
185 | addr_t end; |
186 | int cross_count; |
187 | |
188 | /* Check for 2G limit. */ |
189 | start = (addr_t) buffer; |
190 | end = start + size; |
191 | if ((virt_to_phys(address: buffer) + size) > (1 << 31)) |
192 | return ERR_PTR(error: -EINVAL); |
193 | memset(buffer, 0, size); |
194 | /* ITCW. */ |
195 | chunk = fit_chunk(&start, end, sizeof(struct itcw), 1, 0); |
196 | if (IS_ERR(ptr: chunk)) |
197 | return chunk; |
198 | itcw = chunk; |
199 | /* allow for TTIC tidaws that may be needed to cross a page boundary */ |
200 | cross_count = 0; |
201 | if (max_tidaws) |
202 | cross_count = 1 + ((max_tidaws * sizeof(struct tidaw) - 1) |
203 | >> PAGE_SHIFT); |
204 | itcw->max_tidaws = max_tidaws + cross_count; |
205 | cross_count = 0; |
206 | if (intrg_max_tidaws) |
207 | cross_count = 1 + ((intrg_max_tidaws * sizeof(struct tidaw) - 1) |
208 | >> PAGE_SHIFT); |
209 | itcw->intrg_max_tidaws = intrg_max_tidaws + cross_count; |
210 | /* Main TCW. */ |
211 | chunk = fit_chunk(&start, end, sizeof(struct tcw), 64, 0); |
212 | if (IS_ERR(ptr: chunk)) |
213 | return chunk; |
214 | itcw->tcw = chunk; |
215 | tcw_init(itcw->tcw, (op == ITCW_OP_READ) ? 1 : 0, |
216 | (op == ITCW_OP_WRITE) ? 1 : 0); |
217 | /* Interrogate TCW. */ |
218 | if (intrg) { |
219 | chunk = fit_chunk(&start, end, sizeof(struct tcw), 64, 0); |
220 | if (IS_ERR(ptr: chunk)) |
221 | return chunk; |
222 | itcw->intrg_tcw = chunk; |
223 | tcw_init(itcw->intrg_tcw, 1, 0); |
224 | tcw_set_intrg(itcw->tcw, itcw->intrg_tcw); |
225 | } |
226 | /* Data TIDAL. */ |
227 | if (max_tidaws > 0) { |
228 | chunk = fit_chunk(&start, end, sizeof(struct tidaw) * |
229 | itcw->max_tidaws, 16, 0); |
230 | if (IS_ERR(ptr: chunk)) |
231 | return chunk; |
232 | tcw_set_data(itcw->tcw, chunk, 1); |
233 | } |
234 | /* Interrogate data TIDAL. */ |
235 | if (intrg && (intrg_max_tidaws > 0)) { |
236 | chunk = fit_chunk(&start, end, sizeof(struct tidaw) * |
237 | itcw->intrg_max_tidaws, 16, 0); |
238 | if (IS_ERR(ptr: chunk)) |
239 | return chunk; |
240 | tcw_set_data(itcw->intrg_tcw, chunk, 1); |
241 | } |
242 | /* TSB. */ |
243 | chunk = fit_chunk(&start, end, sizeof(struct tsb), 8, 0); |
244 | if (IS_ERR(ptr: chunk)) |
245 | return chunk; |
246 | tsb_init(chunk); |
247 | tcw_set_tsb(itcw->tcw, chunk); |
248 | /* Interrogate TSB. */ |
249 | if (intrg) { |
250 | chunk = fit_chunk(&start, end, sizeof(struct tsb), 8, 0); |
251 | if (IS_ERR(ptr: chunk)) |
252 | return chunk; |
253 | tsb_init(chunk); |
254 | tcw_set_tsb(itcw->intrg_tcw, chunk); |
255 | } |
256 | /* TCCB. */ |
257 | chunk = fit_chunk(&start, end, TCCB_MAX_SIZE, 8, 0); |
258 | if (IS_ERR(ptr: chunk)) |
259 | return chunk; |
260 | tccb_init(chunk, TCCB_MAX_SIZE, TCCB_SAC_DEFAULT); |
261 | tcw_set_tccb(itcw->tcw, chunk); |
262 | /* Interrogate TCCB. */ |
263 | if (intrg) { |
264 | chunk = fit_chunk(&start, end, TCCB_MAX_SIZE, 8, 0); |
265 | if (IS_ERR(ptr: chunk)) |
266 | return chunk; |
267 | tccb_init(chunk, TCCB_MAX_SIZE, TCCB_SAC_INTRG); |
268 | tcw_set_tccb(itcw->intrg_tcw, chunk); |
269 | tccb_add_dcw(chunk, TCCB_MAX_SIZE, DCW_CMD_INTRG, 0, NULL, |
270 | sizeof(struct dcw_intrg_data), 0); |
271 | tcw_finalize(itcw->intrg_tcw, 0); |
272 | } |
273 | return itcw; |
274 | } |
275 | EXPORT_SYMBOL(itcw_init); |
276 | |
277 | /** |
278 | * itcw_add_dcw - add a dcw to the itcw |
279 | * @itcw: address of the itcw |
280 | * @cmd: the dcw command |
281 | * @flags: flags for the dcw |
282 | * @cd: address of control data for this dcw or NULL if none is required |
283 | * @cd_count: number of control data bytes for this dcw |
284 | * @count: number of data bytes for this dcw |
285 | * |
286 | * Add a new dcw to the specified itcw by writing the dcw information specified |
287 | * by @cmd, @flags, @cd, @cd_count and @count to the tca of the tccb. Return |
288 | * a pointer to the newly added dcw on success or -%ENOSPC if the new dcw |
289 | * would exceed the available space. |
290 | * |
291 | * Note: the tcal field of the tccb header will be updated to reflect added |
292 | * content. |
293 | */ |
294 | struct dcw *itcw_add_dcw(struct itcw *itcw, u8 cmd, u8 flags, void *cd, |
295 | u8 cd_count, u32 count) |
296 | { |
297 | return tccb_add_dcw(tcw_get_tccb(itcw->tcw), TCCB_MAX_SIZE, cmd, |
298 | flags, cd, cd_count, count); |
299 | } |
300 | EXPORT_SYMBOL(itcw_add_dcw); |
301 | |
302 | /** |
303 | * itcw_add_tidaw - add a tidaw to the itcw |
304 | * @itcw: address of the itcw |
305 | * @flags: flags for the new tidaw |
306 | * @addr: address value for the new tidaw |
307 | * @count: count value for the new tidaw |
308 | * |
309 | * Add a new tidaw to the input/output data tidaw-list of the specified itcw |
310 | * (depending on the value of the r-flag and w-flag). Return a pointer to |
311 | * the new tidaw on success or -%ENOSPC if the new tidaw would exceed the |
312 | * available space. |
313 | * |
314 | * Note: TTIC tidaws are automatically added when needed, so explicitly calling |
315 | * this interface with the TTIC flag is not supported. The last-tidaw flag |
316 | * for the last tidaw in the list will be set by itcw_finalize. |
317 | */ |
318 | struct tidaw *itcw_add_tidaw(struct itcw *itcw, u8 flags, void *addr, u32 count) |
319 | { |
320 | struct tidaw *following; |
321 | |
322 | if (itcw->num_tidaws >= itcw->max_tidaws) |
323 | return ERR_PTR(error: -ENOSPC); |
324 | /* |
325 | * Is the tidaw, which follows the one we are about to fill, on the next |
326 | * page? Then we have to insert a TTIC tidaw first, that points to the |
327 | * tidaw on the new page. |
328 | */ |
329 | following = ((struct tidaw *) tcw_get_data(itcw->tcw)) |
330 | + itcw->num_tidaws + 1; |
331 | if (itcw->num_tidaws && !((unsigned long) following & ~PAGE_MASK)) { |
332 | tcw_add_tidaw(itcw->tcw, itcw->num_tidaws++, |
333 | TIDAW_FLAGS_TTIC, following, 0); |
334 | if (itcw->num_tidaws >= itcw->max_tidaws) |
335 | return ERR_PTR(error: -ENOSPC); |
336 | } |
337 | return tcw_add_tidaw(itcw->tcw, itcw->num_tidaws++, flags, addr, count); |
338 | } |
339 | EXPORT_SYMBOL(itcw_add_tidaw); |
340 | |
341 | /** |
342 | * itcw_set_data - set data address and tida flag of the itcw |
343 | * @itcw: address of the itcw |
344 | * @addr: the data address |
345 | * @use_tidal: zero of the data address specifies a contiguous block of data, |
346 | * non-zero if it specifies a list if tidaws. |
347 | * |
348 | * Set the input/output data address of the itcw (depending on the value of the |
349 | * r-flag and w-flag). If @use_tidal is non-zero, the corresponding tida flag |
350 | * is set as well. |
351 | */ |
352 | void itcw_set_data(struct itcw *itcw, void *addr, int use_tidal) |
353 | { |
354 | tcw_set_data(itcw->tcw, addr, use_tidal); |
355 | } |
356 | EXPORT_SYMBOL(itcw_set_data); |
357 | |
358 | /** |
359 | * itcw_finalize - calculate length and count fields of the itcw |
360 | * @itcw: address of the itcw |
361 | * |
362 | * Calculate tcw input-/output-count and tccbl fields and add a tcat the tccb. |
363 | * In case input- or output-tida is used, the tidaw-list must be stored in |
364 | * continuous storage (no ttic). The tcal field in the tccb must be |
365 | * up-to-date. |
366 | */ |
367 | void itcw_finalize(struct itcw *itcw) |
368 | { |
369 | tcw_finalize(itcw->tcw, itcw->num_tidaws); |
370 | } |
371 | EXPORT_SYMBOL(itcw_finalize); |
372 | |