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/export.h>
10 #include <linux/kernel.h>
11 #include <linux/types.h>
12 #include <linux/string.h>
13 #include <linux/io.h>
14 #include <linux/errno.h>
15 #include <linux/err.h>
16 #include <linux/module.h>
17 #include <asm/fcx.h>
18 #include <asm/itcw.h>
19
20 /*
21 * struct itcw - incremental tcw helper data type
22 *
23 * This structure serves as a handle for the incremental construction of a
24 * tcw and associated tccb, tsb, data tidaw-list plus an optional interrogate
25 * tcw and associated data. The data structures are contained inside a single
26 * contiguous buffer provided by the user.
27 *
28 * The itcw construction functions take care of overall data integrity:
29 * - reset unused fields to zero
30 * - fill in required pointers
31 * - ensure required alignment for data structures
32 * - prevent data structures to cross 4k-byte boundary where required
33 * - calculate tccb-related length fields
34 * - optionally provide ready-made interrogate tcw and associated structures
35 *
36 * Restrictions apply to the itcws created with these construction functions:
37 * - tida only supported for data address, not for tccb
38 * - only contiguous tidaw-lists (no ttic)
39 * - total number of bytes required per itcw may not exceed 4k bytes
40 * - either read or write operation (may not work with r=0 and w=0)
41 *
42 * Example:
43 * struct itcw *itcw;
44 * void *buffer;
45 * size_t size;
46 *
47 * size = itcw_calc_size(1, 2, 0);
48 * buffer = kmalloc(size, GFP_KERNEL | GFP_DMA);
49 * if (!buffer)
50 * return -ENOMEM;
51 * itcw = itcw_init(buffer, size, ITCW_OP_READ, 1, 2, 0);
52 * if (IS_ERR(itcw))
53 * return PTR_ER(itcw);
54 * itcw_add_dcw(itcw, 0x2, 0, NULL, 0, 72);
55 * itcw_add_tidaw(itcw, 0, 0x30000, 20);
56 * itcw_add_tidaw(itcw, 0, 0x40000, 52);
57 * itcw_finalize(itcw);
58 *
59 */
60 struct itcw {
61 struct tcw *tcw;
62 struct tcw *intrg_tcw;
63 int num_tidaws;
64 int max_tidaws;
65 int intrg_num_tidaws;
66 int intrg_max_tidaws;
67 };
68
69 /**
70 * itcw_get_tcw - return pointer to tcw associated with the itcw
71 * @itcw: address of the itcw
72 *
73 * Return pointer to the tcw associated with the itcw.
74 */
itcw_get_tcw(struct itcw * itcw)75 struct tcw *itcw_get_tcw(struct itcw *itcw)
76 {
77 return itcw->tcw;
78 }
79 EXPORT_SYMBOL(itcw_get_tcw);
80
81 /**
82 * itcw_calc_size - return the size of an itcw with the given parameters
83 * @intrg: if non-zero, add an interrogate tcw
84 * @max_tidaws: maximum number of tidaws to be used for data addressing or zero
85 * if no tida is to be used.
86 * @intrg_max_tidaws: maximum number of tidaws to be used for data addressing
87 * by the interrogate tcw, if specified
88 *
89 * Calculate and return the number of bytes required to hold an itcw with the
90 * given parameters and assuming tccbs with maximum size.
91 *
92 * Note that the resulting size also contains bytes needed for alignment
93 * padding as well as padding to ensure that data structures don't cross a
94 * 4k-boundary where required.
95 */
itcw_calc_size(int intrg,int max_tidaws,int intrg_max_tidaws)96 size_t itcw_calc_size(int intrg, int max_tidaws, int intrg_max_tidaws)
97 {
98 size_t len;
99 int cross_count;
100
101 /* Main data. */
102 len = sizeof(struct itcw);
103 len += /* TCW */ sizeof(struct tcw) + /* TCCB */ TCCB_MAX_SIZE +
104 /* TSB */ sizeof(struct tsb) +
105 /* TIDAL */ max_tidaws * sizeof(struct tidaw);
106 /* Interrogate data. */
107 if (intrg) {
108 len += /* TCW */ sizeof(struct tcw) + /* TCCB */ TCCB_MAX_SIZE +
109 /* TSB */ sizeof(struct tsb) +
110 /* TIDAL */ intrg_max_tidaws * sizeof(struct tidaw);
111 }
112
113 /* Maximum required alignment padding. */
114 len += /* Initial TCW */ 63 + /* Interrogate TCCB */ 7;
115
116 /* TIDAW lists may not cross a 4k boundary. To cross a
117 * boundary we need to add a TTIC TIDAW. We need to reserve
118 * one additional TIDAW for a TTIC that we may need to add due
119 * to the placement of the data chunk in memory, and a further
120 * TIDAW for each page boundary that the TIDAW list may cross
121 * due to it's own size.
122 */
123 if (max_tidaws) {
124 cross_count = 1 + ((max_tidaws * sizeof(struct tidaw) - 1)
125 >> PAGE_SHIFT);
126 len += cross_count * sizeof(struct tidaw);
127 }
128 if (intrg_max_tidaws) {
129 cross_count = 1 + ((intrg_max_tidaws * sizeof(struct tidaw) - 1)
130 >> PAGE_SHIFT);
131 len += cross_count * sizeof(struct tidaw);
132 }
133 return len;
134 }
135 EXPORT_SYMBOL(itcw_calc_size);
136
137 #define CROSS4K(x, l) (((x) & ~4095) != ((x + l) & ~4095))
138
fit_chunk(addr_t * start,addr_t end,size_t len,int align,int check_4k)139 static inline void *fit_chunk(addr_t *start, addr_t end, size_t len,
140 int align, int check_4k)
141 {
142 addr_t addr;
143
144 addr = ALIGN(*start, align);
145 if (check_4k && CROSS4K(addr, len)) {
146 addr = ALIGN(addr, 4096);
147 addr = ALIGN(addr, align);
148 }
149 if (addr + len > end)
150 return ERR_PTR(-ENOSPC);
151 *start = addr + len;
152 return (void *) addr;
153 }
154
155 /**
156 * itcw_init - initialize incremental tcw data structure
157 * @buffer: address of buffer to use for data structures
158 * @size: number of bytes in buffer
159 * @op: %ITCW_OP_READ for a read operation tcw, %ITCW_OP_WRITE for a write
160 * operation tcw
161 * @intrg: if non-zero, add and initialize an interrogate tcw
162 * @max_tidaws: maximum number of tidaws to be used for data addressing or zero
163 * if no tida is to be used.
164 * @intrg_max_tidaws: maximum number of tidaws to be used for data addressing
165 * by the interrogate tcw, if specified
166 *
167 * Prepare the specified buffer to be used as an incremental tcw, i.e. a
168 * helper data structure that can be used to construct a valid tcw by
169 * successive calls to other helper functions. Note: the buffer needs to be
170 * located below the 2G address limit. The resulting tcw has the following
171 * restrictions:
172 * - no tccb tidal
173 * - input/output tidal is contiguous (no ttic)
174 * - total data should not exceed 4k
175 * - tcw specifies either read or write operation
176 *
177 * On success, return pointer to the resulting incremental tcw data structure,
178 * ERR_PTR otherwise.
179 */
itcw_init(void * buffer,size_t size,int op,int intrg,int max_tidaws,int intrg_max_tidaws)180 struct itcw *itcw_init(void *buffer, size_t size, int op, int intrg,
181 int max_tidaws, int intrg_max_tidaws)
182 {
183 struct itcw *itcw;
184 void *chunk;
185 addr_t start;
186 addr_t end;
187 int cross_count;
188
189 /* Check for 2G limit. */
190 start = (addr_t) buffer;
191 end = start + size;
192 if ((virt_to_phys(buffer) + size) > (1 << 31))
193 return ERR_PTR(-EINVAL);
194 memset(buffer, 0, size);
195 /* ITCW. */
196 chunk = fit_chunk(&start, end, sizeof(struct itcw), 1, 0);
197 if (IS_ERR(chunk))
198 return chunk;
199 itcw = chunk;
200 /* allow for TTIC tidaws that may be needed to cross a page boundary */
201 cross_count = 0;
202 if (max_tidaws)
203 cross_count = 1 + ((max_tidaws * sizeof(struct tidaw) - 1)
204 >> PAGE_SHIFT);
205 itcw->max_tidaws = max_tidaws + cross_count;
206 cross_count = 0;
207 if (intrg_max_tidaws)
208 cross_count = 1 + ((intrg_max_tidaws * sizeof(struct tidaw) - 1)
209 >> PAGE_SHIFT);
210 itcw->intrg_max_tidaws = intrg_max_tidaws + cross_count;
211 /* Main TCW. */
212 chunk = fit_chunk(&start, end, sizeof(struct tcw), 64, 0);
213 if (IS_ERR(chunk))
214 return chunk;
215 itcw->tcw = chunk;
216 tcw_init(itcw->tcw, (op == ITCW_OP_READ) ? 1 : 0,
217 (op == ITCW_OP_WRITE) ? 1 : 0);
218 /* Interrogate TCW. */
219 if (intrg) {
220 chunk = fit_chunk(&start, end, sizeof(struct tcw), 64, 0);
221 if (IS_ERR(chunk))
222 return chunk;
223 itcw->intrg_tcw = chunk;
224 tcw_init(itcw->intrg_tcw, 1, 0);
225 tcw_set_intrg(itcw->tcw, itcw->intrg_tcw);
226 }
227 /* Data TIDAL. */
228 if (max_tidaws > 0) {
229 chunk = fit_chunk(&start, end, sizeof(struct tidaw) *
230 itcw->max_tidaws, 16, 0);
231 if (IS_ERR(chunk))
232 return chunk;
233 tcw_set_data(itcw->tcw, chunk, 1);
234 }
235 /* Interrogate data TIDAL. */
236 if (intrg && (intrg_max_tidaws > 0)) {
237 chunk = fit_chunk(&start, end, sizeof(struct tidaw) *
238 itcw->intrg_max_tidaws, 16, 0);
239 if (IS_ERR(chunk))
240 return chunk;
241 tcw_set_data(itcw->intrg_tcw, chunk, 1);
242 }
243 /* TSB. */
244 chunk = fit_chunk(&start, end, sizeof(struct tsb), 8, 0);
245 if (IS_ERR(chunk))
246 return chunk;
247 tsb_init(chunk);
248 tcw_set_tsb(itcw->tcw, chunk);
249 /* Interrogate TSB. */
250 if (intrg) {
251 chunk = fit_chunk(&start, end, sizeof(struct tsb), 8, 0);
252 if (IS_ERR(chunk))
253 return chunk;
254 tsb_init(chunk);
255 tcw_set_tsb(itcw->intrg_tcw, chunk);
256 }
257 /* TCCB. */
258 chunk = fit_chunk(&start, end, TCCB_MAX_SIZE, 8, 0);
259 if (IS_ERR(chunk))
260 return chunk;
261 tccb_init(chunk, TCCB_MAX_SIZE, TCCB_SAC_DEFAULT);
262 tcw_set_tccb(itcw->tcw, chunk);
263 /* Interrogate TCCB. */
264 if (intrg) {
265 chunk = fit_chunk(&start, end, TCCB_MAX_SIZE, 8, 0);
266 if (IS_ERR(chunk))
267 return chunk;
268 tccb_init(chunk, TCCB_MAX_SIZE, TCCB_SAC_INTRG);
269 tcw_set_tccb(itcw->intrg_tcw, chunk);
270 tccb_add_dcw(chunk, TCCB_MAX_SIZE, DCW_CMD_INTRG, 0, NULL,
271 sizeof(struct dcw_intrg_data), 0);
272 tcw_finalize(itcw->intrg_tcw, 0);
273 }
274 return itcw;
275 }
276 EXPORT_SYMBOL(itcw_init);
277
278 /**
279 * itcw_add_dcw - add a dcw to the itcw
280 * @itcw: address of the itcw
281 * @cmd: the dcw command
282 * @flags: flags for the dcw
283 * @cd: address of control data for this dcw or NULL if none is required
284 * @cd_count: number of control data bytes for this dcw
285 * @count: number of data bytes for this dcw
286 *
287 * Add a new dcw to the specified itcw by writing the dcw information specified
288 * by @cmd, @flags, @cd, @cd_count and @count to the tca of the tccb. Return
289 * a pointer to the newly added dcw on success or -%ENOSPC if the new dcw
290 * would exceed the available space.
291 *
292 * Note: the tcal field of the tccb header will be updated to reflect added
293 * content.
294 */
itcw_add_dcw(struct itcw * itcw,u8 cmd,u8 flags,void * cd,u8 cd_count,u32 count)295 struct dcw *itcw_add_dcw(struct itcw *itcw, u8 cmd, u8 flags, void *cd,
296 u8 cd_count, u32 count)
297 {
298 return tccb_add_dcw(tcw_get_tccb(itcw->tcw), TCCB_MAX_SIZE, cmd,
299 flags, cd, cd_count, count);
300 }
301 EXPORT_SYMBOL(itcw_add_dcw);
302
303 /**
304 * itcw_add_tidaw - add a tidaw to the itcw
305 * @itcw: address of the itcw
306 * @flags: flags for the new tidaw
307 * @addr: address value for the new tidaw
308 * @count: count value for the new tidaw
309 *
310 * Add a new tidaw to the input/output data tidaw-list of the specified itcw
311 * (depending on the value of the r-flag and w-flag). Return a pointer to
312 * the new tidaw on success or -%ENOSPC if the new tidaw would exceed the
313 * available space.
314 *
315 * Note: TTIC tidaws are automatically added when needed, so explicitly calling
316 * this interface with the TTIC flag is not supported. The last-tidaw flag
317 * for the last tidaw in the list will be set by itcw_finalize.
318 */
itcw_add_tidaw(struct itcw * itcw,u8 flags,void * addr,u32 count)319 struct tidaw *itcw_add_tidaw(struct itcw *itcw, u8 flags, void *addr, u32 count)
320 {
321 struct tidaw *following;
322
323 if (itcw->num_tidaws >= itcw->max_tidaws)
324 return ERR_PTR(-ENOSPC);
325 /*
326 * Is the tidaw, which follows the one we are about to fill, on the next
327 * page? Then we have to insert a TTIC tidaw first, that points to the
328 * tidaw on the new page.
329 */
330 following = ((struct tidaw *) tcw_get_data(itcw->tcw))
331 + itcw->num_tidaws + 1;
332 if (itcw->num_tidaws && !((unsigned long) following & ~PAGE_MASK)) {
333 tcw_add_tidaw(itcw->tcw, itcw->num_tidaws++,
334 TIDAW_FLAGS_TTIC, following, 0);
335 if (itcw->num_tidaws >= itcw->max_tidaws)
336 return ERR_PTR(-ENOSPC);
337 }
338 return tcw_add_tidaw(itcw->tcw, itcw->num_tidaws++, flags, addr, count);
339 }
340 EXPORT_SYMBOL(itcw_add_tidaw);
341
342 /**
343 * itcw_set_data - set data address and tida flag of the itcw
344 * @itcw: address of the itcw
345 * @addr: the data address
346 * @use_tidal: zero of the data address specifies a contiguous block of data,
347 * non-zero if it specifies a list if tidaws.
348 *
349 * Set the input/output data address of the itcw (depending on the value of the
350 * r-flag and w-flag). If @use_tidal is non-zero, the corresponding tida flag
351 * is set as well.
352 */
itcw_set_data(struct itcw * itcw,void * addr,int use_tidal)353 void itcw_set_data(struct itcw *itcw, void *addr, int use_tidal)
354 {
355 tcw_set_data(itcw->tcw, addr, use_tidal);
356 }
357 EXPORT_SYMBOL(itcw_set_data);
358
359 /**
360 * itcw_finalize - calculate length and count fields of the itcw
361 * @itcw: address of the itcw
362 *
363 * Calculate tcw input-/output-count and tccbl fields and add a tcat the tccb.
364 * In case input- or output-tida is used, the tidaw-list must be stored in
365 * continuous storage (no ttic). The tcal field in the tccb must be
366 * up-to-date.
367 */
itcw_finalize(struct itcw * itcw)368 void itcw_finalize(struct itcw *itcw)
369 {
370 tcw_finalize(itcw->tcw, itcw->num_tidaws);
371 }
372 EXPORT_SYMBOL(itcw_finalize);
373