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Peter Oberparleiter23f62682008-07-14 09:58:52 +02001/*
2 * Functions for incremental construction of fcx enabled I/O control blocks.
3 *
4 * Copyright IBM Corp. 2008
5 * Author(s): Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
6 */
7
8#include <linux/kernel.h>
9#include <linux/types.h>
10#include <linux/string.h>
11#include <linux/errno.h>
12#include <linux/err.h>
13#include <linux/module.h>
14#include <asm/fcx.h>
15#include <asm/itcw.h>
16
17/**
18 * struct itcw - incremental tcw helper data type
19 *
20 * This structure serves as a handle for the incremental construction of a
21 * tcw and associated tccb, tsb, data tidaw-list plus an optional interrogate
22 * tcw and associated data. The data structures are contained inside a single
23 * contiguous buffer provided by the user.
24 *
25 * The itcw construction functions take care of overall data integrity:
26 * - reset unused fields to zero
27 * - fill in required pointers
28 * - ensure required alignment for data structures
29 * - prevent data structures to cross 4k-byte boundary where required
30 * - calculate tccb-related length fields
31 * - optionally provide ready-made interrogate tcw and associated structures
32 *
33 * Restrictions apply to the itcws created with these construction functions:
34 * - tida only supported for data address, not for tccb
35 * - only contiguous tidaw-lists (no ttic)
36 * - total number of bytes required per itcw may not exceed 4k bytes
37 * - either read or write operation (may not work with r=0 and w=0)
38 *
39 * Example:
40 * struct itcw *itcw;
41 * void *buffer;
42 * size_t size;
43 *
44 * size = itcw_calc_size(1, 2, 0);
Heiko Carstensc2f0e8c2010-06-08 18:58:09 +020045 * buffer = kmalloc(size, GFP_KERNEL | GFP_DMA);
Peter Oberparleiter23f62682008-07-14 09:58:52 +020046 * if (!buffer)
47 * return -ENOMEM;
48 * itcw = itcw_init(buffer, size, ITCW_OP_READ, 1, 2, 0);
49 * if (IS_ERR(itcw))
50 * return PTR_ER(itcw);
51 * itcw_add_dcw(itcw, 0x2, 0, NULL, 0, 72);
52 * itcw_add_tidaw(itcw, 0, 0x30000, 20);
53 * itcw_add_tidaw(itcw, 0, 0x40000, 52);
54 * itcw_finalize(itcw);
55 *
56 */
57struct itcw {
58 struct tcw *tcw;
59 struct tcw *intrg_tcw;
60 int num_tidaws;
61 int max_tidaws;
62 int intrg_num_tidaws;
63 int intrg_max_tidaws;
64};
65
66/**
67 * itcw_get_tcw - return pointer to tcw associated with the itcw
68 * @itcw: address of the itcw
69 *
70 * Return pointer to the tcw associated with the itcw.
71 */
72struct tcw *itcw_get_tcw(struct itcw *itcw)
73{
74 return itcw->tcw;
75}
76EXPORT_SYMBOL(itcw_get_tcw);
77
78/**
79 * itcw_calc_size - return the size of an itcw with the given parameters
80 * @intrg: if non-zero, add an interrogate tcw
81 * @max_tidaws: maximum number of tidaws to be used for data addressing or zero
82 * if no tida is to be used.
83 * @intrg_max_tidaws: maximum number of tidaws to be used for data addressing
84 * by the interrogate tcw, if specified
85 *
86 * Calculate and return the number of bytes required to hold an itcw with the
87 * given parameters and assuming tccbs with maximum size.
88 *
89 * Note that the resulting size also contains bytes needed for alignment
90 * padding as well as padding to ensure that data structures don't cross a
91 * 4k-boundary where required.
92 */
93size_t itcw_calc_size(int intrg, int max_tidaws, int intrg_max_tidaws)
94{
95 size_t len;
Stefan Weinhuber90620142011-01-05 12:48:01 +010096 int cross_count;
Peter Oberparleiter23f62682008-07-14 09:58:52 +020097
98 /* Main data. */
99 len = sizeof(struct itcw);
100 len += /* TCW */ sizeof(struct tcw) + /* TCCB */ TCCB_MAX_SIZE +
101 /* TSB */ sizeof(struct tsb) +
102 /* TIDAL */ max_tidaws * sizeof(struct tidaw);
103 /* Interrogate data. */
104 if (intrg) {
105 len += /* TCW */ sizeof(struct tcw) + /* TCCB */ TCCB_MAX_SIZE +
106 /* TSB */ sizeof(struct tsb) +
107 /* TIDAL */ intrg_max_tidaws * sizeof(struct tidaw);
108 }
Stefan Weinhuber90620142011-01-05 12:48:01 +0100109
Peter Oberparleiter23f62682008-07-14 09:58:52 +0200110 /* Maximum required alignment padding. */
111 len += /* Initial TCW */ 63 + /* Interrogate TCCB */ 7;
Stefan Weinhuber90620142011-01-05 12:48:01 +0100112
113 /* TIDAW lists may not cross a 4k boundary. To cross a
114 * boundary we need to add a TTIC TIDAW. We need to reserve
115 * one additional TIDAW for a TTIC that we may need to add due
116 * to the placement of the data chunk in memory, and a further
117 * TIDAW for each page boundary that the TIDAW list may cross
118 * due to it's own size.
119 */
120 if (max_tidaws) {
121 cross_count = 1 + ((max_tidaws * sizeof(struct tidaw) - 1)
122 >> PAGE_SHIFT);
123 len += cross_count * sizeof(struct tidaw);
124 }
125 if (intrg_max_tidaws) {
126 cross_count = 1 + ((intrg_max_tidaws * sizeof(struct tidaw) - 1)
127 >> PAGE_SHIFT);
128 len += cross_count * sizeof(struct tidaw);
129 }
Peter Oberparleiter23f62682008-07-14 09:58:52 +0200130 return len;
131}
132EXPORT_SYMBOL(itcw_calc_size);
133
134#define CROSS4K(x, l) (((x) & ~4095) != ((x + l) & ~4095))
135
136static inline void *fit_chunk(addr_t *start, addr_t end, size_t len,
137 int align, int check_4k)
138{
139 addr_t addr;
140
141 addr = ALIGN(*start, align);
142 if (check_4k && CROSS4K(addr, len)) {
143 addr = ALIGN(addr, 4096);
144 addr = ALIGN(addr, align);
145 }
146 if (addr + len > end)
147 return ERR_PTR(-ENOSPC);
148 *start = addr + len;
149 return (void *) addr;
150}
151
152/**
153 * itcw_init - initialize incremental tcw data structure
154 * @buffer: address of buffer to use for data structures
155 * @size: number of bytes in buffer
156 * @op: %ITCW_OP_READ for a read operation tcw, %ITCW_OP_WRITE for a write
157 * operation tcw
158 * @intrg: if non-zero, add and initialize an interrogate tcw
159 * @max_tidaws: maximum number of tidaws to be used for data addressing or zero
160 * if no tida is to be used.
161 * @intrg_max_tidaws: maximum number of tidaws to be used for data addressing
162 * by the interrogate tcw, if specified
163 *
164 * Prepare the specified buffer to be used as an incremental tcw, i.e. a
165 * helper data structure that can be used to construct a valid tcw by
166 * successive calls to other helper functions. Note: the buffer needs to be
167 * located below the 2G address limit. The resulting tcw has the following
168 * restrictions:
169 * - no tccb tidal
170 * - input/output tidal is contiguous (no ttic)
171 * - total data should not exceed 4k
172 * - tcw specifies either read or write operation
173 *
174 * On success, return pointer to the resulting incremental tcw data structure,
175 * ERR_PTR otherwise.
176 */
177struct itcw *itcw_init(void *buffer, size_t size, int op, int intrg,
178 int max_tidaws, int intrg_max_tidaws)
179{
180 struct itcw *itcw;
181 void *chunk;
182 addr_t start;
183 addr_t end;
Stefan Weinhuber90620142011-01-05 12:48:01 +0100184 int cross_count;
Peter Oberparleiter23f62682008-07-14 09:58:52 +0200185
186 /* Check for 2G limit. */
187 start = (addr_t) buffer;
188 end = start + size;
189 if (end > (1 << 31))
190 return ERR_PTR(-EINVAL);
191 memset(buffer, 0, size);
192 /* ITCW. */
193 chunk = fit_chunk(&start, end, sizeof(struct itcw), 1, 0);
194 if (IS_ERR(chunk))
195 return chunk;
196 itcw = chunk;
Stefan Weinhuber90620142011-01-05 12:48:01 +0100197 /* allow for TTIC tidaws that may be needed to cross a page boundary */
198 cross_count = 0;
199 if (max_tidaws)
200 cross_count = 1 + ((max_tidaws * sizeof(struct tidaw) - 1)
201 >> PAGE_SHIFT);
202 itcw->max_tidaws = max_tidaws + cross_count;
203 cross_count = 0;
204 if (intrg_max_tidaws)
205 cross_count = 1 + ((intrg_max_tidaws * sizeof(struct tidaw) - 1)
206 >> PAGE_SHIFT);
207 itcw->intrg_max_tidaws = intrg_max_tidaws + cross_count;
Peter Oberparleiter23f62682008-07-14 09:58:52 +0200208 /* Main TCW. */
209 chunk = fit_chunk(&start, end, sizeof(struct tcw), 64, 0);
210 if (IS_ERR(chunk))
211 return chunk;
212 itcw->tcw = chunk;
213 tcw_init(itcw->tcw, (op == ITCW_OP_READ) ? 1 : 0,
214 (op == ITCW_OP_WRITE) ? 1 : 0);
215 /* Interrogate TCW. */
216 if (intrg) {
217 chunk = fit_chunk(&start, end, sizeof(struct tcw), 64, 0);
218 if (IS_ERR(chunk))
219 return chunk;
220 itcw->intrg_tcw = chunk;
221 tcw_init(itcw->intrg_tcw, 1, 0);
222 tcw_set_intrg(itcw->tcw, itcw->intrg_tcw);
223 }
224 /* Data TIDAL. */
225 if (max_tidaws > 0) {
226 chunk = fit_chunk(&start, end, sizeof(struct tidaw) *
Stefan Weinhuber90620142011-01-05 12:48:01 +0100227 itcw->max_tidaws, 16, 0);
Peter Oberparleiter23f62682008-07-14 09:58:52 +0200228 if (IS_ERR(chunk))
229 return chunk;
230 tcw_set_data(itcw->tcw, chunk, 1);
231 }
232 /* Interrogate data TIDAL. */
233 if (intrg && (intrg_max_tidaws > 0)) {
234 chunk = fit_chunk(&start, end, sizeof(struct tidaw) *
Stefan Weinhuber90620142011-01-05 12:48:01 +0100235 itcw->intrg_max_tidaws, 16, 0);
Peter Oberparleiter23f62682008-07-14 09:58:52 +0200236 if (IS_ERR(chunk))
237 return chunk;
238 tcw_set_data(itcw->intrg_tcw, chunk, 1);
239 }
240 /* TSB. */
241 chunk = fit_chunk(&start, end, sizeof(struct tsb), 8, 0);
242 if (IS_ERR(chunk))
243 return chunk;
244 tsb_init(chunk);
245 tcw_set_tsb(itcw->tcw, chunk);
246 /* Interrogate TSB. */
247 if (intrg) {
248 chunk = fit_chunk(&start, end, sizeof(struct tsb), 8, 0);
249 if (IS_ERR(chunk))
250 return chunk;
251 tsb_init(chunk);
252 tcw_set_tsb(itcw->intrg_tcw, chunk);
253 }
254 /* TCCB. */
255 chunk = fit_chunk(&start, end, TCCB_MAX_SIZE, 8, 0);
256 if (IS_ERR(chunk))
257 return chunk;
258 tccb_init(chunk, TCCB_MAX_SIZE, TCCB_SAC_DEFAULT);
259 tcw_set_tccb(itcw->tcw, chunk);
260 /* Interrogate TCCB. */
261 if (intrg) {
262 chunk = fit_chunk(&start, end, TCCB_MAX_SIZE, 8, 0);
263 if (IS_ERR(chunk))
264 return chunk;
265 tccb_init(chunk, TCCB_MAX_SIZE, TCCB_SAC_INTRG);
266 tcw_set_tccb(itcw->intrg_tcw, chunk);
267 tccb_add_dcw(chunk, TCCB_MAX_SIZE, DCW_CMD_INTRG, 0, NULL,
268 sizeof(struct dcw_intrg_data), 0);
269 tcw_finalize(itcw->intrg_tcw, 0);
270 }
271 return itcw;
272}
273EXPORT_SYMBOL(itcw_init);
274
275/**
276 * itcw_add_dcw - add a dcw to the itcw
277 * @itcw: address of the itcw
278 * @cmd: the dcw command
279 * @flags: flags for the dcw
280 * @cd: address of control data for this dcw or NULL if none is required
281 * @cd_count: number of control data bytes for this dcw
282 * @count: number of data bytes for this dcw
283 *
284 * Add a new dcw to the specified itcw by writing the dcw information specified
285 * by @cmd, @flags, @cd, @cd_count and @count to the tca of the tccb. Return
286 * a pointer to the newly added dcw on success or -%ENOSPC if the new dcw
287 * would exceed the available space.
288 *
289 * Note: the tcal field of the tccb header will be updated to reflect added
290 * content.
291 */
292struct dcw *itcw_add_dcw(struct itcw *itcw, u8 cmd, u8 flags, void *cd,
293 u8 cd_count, u32 count)
294{
295 return tccb_add_dcw(tcw_get_tccb(itcw->tcw), TCCB_MAX_SIZE, cmd,
296 flags, cd, cd_count, count);
297}
298EXPORT_SYMBOL(itcw_add_dcw);
299
300/**
301 * itcw_add_tidaw - add a tidaw to the itcw
302 * @itcw: address of the itcw
303 * @flags: flags for the new tidaw
304 * @addr: address value for the new tidaw
305 * @count: count value for the new tidaw
306 *
307 * Add a new tidaw to the input/output data tidaw-list of the specified itcw
308 * (depending on the value of the r-flag and w-flag). Return a pointer to
309 * the new tidaw on success or -%ENOSPC if the new tidaw would exceed the
310 * available space.
311 *
Stefan Weinhuber90620142011-01-05 12:48:01 +0100312 * Note: TTIC tidaws are automatically added when needed, so explicitly calling
313 * this interface with the TTIC flag is not supported. The last-tidaw flag
314 * for the last tidaw in the list will be set by itcw_finalize.
Peter Oberparleiter23f62682008-07-14 09:58:52 +0200315 */
316struct tidaw *itcw_add_tidaw(struct itcw *itcw, u8 flags, void *addr, u32 count)
317{
Stefan Weinhuber90620142011-01-05 12:48:01 +0100318 struct tidaw *following;
319
Peter Oberparleiter23f62682008-07-14 09:58:52 +0200320 if (itcw->num_tidaws >= itcw->max_tidaws)
321 return ERR_PTR(-ENOSPC);
Stefan Weinhuber90620142011-01-05 12:48:01 +0100322 /*
323 * Is the tidaw, which follows the one we are about to fill, on the next
324 * page? Then we have to insert a TTIC tidaw first, that points to the
325 * tidaw on the new page.
326 */
327 following = ((struct tidaw *) tcw_get_data(itcw->tcw))
328 + itcw->num_tidaws + 1;
329 if (itcw->num_tidaws && !((unsigned long) following & ~PAGE_MASK)) {
330 tcw_add_tidaw(itcw->tcw, itcw->num_tidaws++,
331 TIDAW_FLAGS_TTIC, following, 0);
332 if (itcw->num_tidaws >= itcw->max_tidaws)
333 return ERR_PTR(-ENOSPC);
334 }
Peter Oberparleiter23f62682008-07-14 09:58:52 +0200335 return tcw_add_tidaw(itcw->tcw, itcw->num_tidaws++, flags, addr, count);
336}
337EXPORT_SYMBOL(itcw_add_tidaw);
338
339/**
340 * itcw_set_data - set data address and tida flag of the itcw
341 * @itcw: address of the itcw
342 * @addr: the data address
343 * @use_tidal: zero of the data address specifies a contiguous block of data,
344 * non-zero if it specifies a list if tidaws.
345 *
346 * Set the input/output data address of the itcw (depending on the value of the
347 * r-flag and w-flag). If @use_tidal is non-zero, the corresponding tida flag
348 * is set as well.
349 */
350void itcw_set_data(struct itcw *itcw, void *addr, int use_tidal)
351{
352 tcw_set_data(itcw->tcw, addr, use_tidal);
353}
354EXPORT_SYMBOL(itcw_set_data);
355
356/**
357 * itcw_finalize - calculate length and count fields of the itcw
358 * @itcw: address of the itcw
359 *
360 * Calculate tcw input-/output-count and tccbl fields and add a tcat the tccb.
361 * In case input- or output-tida is used, the tidaw-list must be stored in
362 * continuous storage (no ttic). The tcal field in the tccb must be
363 * up-to-date.
364 */
365void itcw_finalize(struct itcw *itcw)
366{
367 tcw_finalize(itcw->tcw, itcw->num_tidaws);
368}
369EXPORT_SYMBOL(itcw_finalize);