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(-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(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 */ 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(-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 */ 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