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 */
itcw_get_tcw(struct itcw * itcw)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 */
itcw_calc_size(int intrg,int max_tidaws,int intrg_max_tidaws)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
fit_chunk(addr_t * start,addr_t end,size_t len,int align,int check_4k)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(-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 */
itcw_init(void * buffer,size_t size,int op,int intrg,int max_tidaws,int intrg_max_tidaws)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(buffer) + size) > (1 << 31))
192 return ERR_PTR(-EINVAL);
193 memset(buffer, 0, size);
194 /* ITCW. */
195 chunk = fit_chunk(&start, end, sizeof(struct itcw), 1, 0);
196 if (IS_ERR(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(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(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(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(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(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(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(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(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 */
itcw_add_dcw(struct itcw * itcw,u8 cmd,u8 flags,void * cd,u8 cd_count,u32 count)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 */
itcw_add_tidaw(struct itcw * itcw,u8 flags,void * addr,u32 count)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(-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(-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 */
itcw_set_data(struct itcw * itcw,void * addr,int use_tidal)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 */
itcw_finalize(struct itcw * itcw)367 void itcw_finalize(struct itcw *itcw)
368 {
369 tcw_finalize(itcw->tcw, itcw->num_tidaws);
370 }
371 EXPORT_SYMBOL(itcw_finalize);
372