1 /* 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); 45 * buffer = kmalloc(size, GFP_KERNEL | GFP_DMA); 46 * 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 */ 57 struct 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 */ 72 struct tcw *itcw_get_tcw(struct itcw *itcw) 73 { 74 return itcw->tcw; 75 } 76 EXPORT_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 */ 93 size_t itcw_calc_size(int intrg, int max_tidaws, int intrg_max_tidaws) 94 { 95 size_t len; 96 97 /* Main data. */ 98 len = sizeof(struct itcw); 99 len += /* TCW */ sizeof(struct tcw) + /* TCCB */ TCCB_MAX_SIZE + 100 /* TSB */ sizeof(struct tsb) + 101 /* TIDAL */ max_tidaws * sizeof(struct tidaw); 102 /* Interrogate data. */ 103 if (intrg) { 104 len += /* TCW */ sizeof(struct tcw) + /* TCCB */ TCCB_MAX_SIZE + 105 /* TSB */ sizeof(struct tsb) + 106 /* TIDAL */ intrg_max_tidaws * sizeof(struct tidaw); 107 } 108 /* Maximum required alignment padding. */ 109 len += /* Initial TCW */ 63 + /* Interrogate TCCB */ 7; 110 /* Maximum padding for structures that may not cross 4k boundary. */ 111 if ((max_tidaws > 0) || (intrg_max_tidaws > 0)) 112 len += max(max_tidaws, intrg_max_tidaws) * 113 sizeof(struct tidaw) - 1; 114 return len; 115 } 116 EXPORT_SYMBOL(itcw_calc_size); 117 118 #define CROSS4K(x, l) (((x) & ~4095) != ((x + l) & ~4095)) 119 120 static inline void *fit_chunk(addr_t *start, addr_t end, size_t len, 121 int align, int check_4k) 122 { 123 addr_t addr; 124 125 addr = ALIGN(*start, align); 126 if (check_4k && CROSS4K(addr, len)) { 127 addr = ALIGN(addr, 4096); 128 addr = ALIGN(addr, align); 129 } 130 if (addr + len > end) 131 return ERR_PTR(-ENOSPC); 132 *start = addr + len; 133 return (void *) addr; 134 } 135 136 /** 137 * itcw_init - initialize incremental tcw data structure 138 * @buffer: address of buffer to use for data structures 139 * @size: number of bytes in buffer 140 * @op: %ITCW_OP_READ for a read operation tcw, %ITCW_OP_WRITE for a write 141 * operation tcw 142 * @intrg: if non-zero, add and initialize an interrogate tcw 143 * @max_tidaws: maximum number of tidaws to be used for data addressing or zero 144 * if no tida is to be used. 145 * @intrg_max_tidaws: maximum number of tidaws to be used for data addressing 146 * by the interrogate tcw, if specified 147 * 148 * Prepare the specified buffer to be used as an incremental tcw, i.e. a 149 * helper data structure that can be used to construct a valid tcw by 150 * successive calls to other helper functions. Note: the buffer needs to be 151 * located below the 2G address limit. The resulting tcw has the following 152 * restrictions: 153 * - no tccb tidal 154 * - input/output tidal is contiguous (no ttic) 155 * - total data should not exceed 4k 156 * - tcw specifies either read or write operation 157 * 158 * On success, return pointer to the resulting incremental tcw data structure, 159 * ERR_PTR otherwise. 160 */ 161 struct itcw *itcw_init(void *buffer, size_t size, int op, int intrg, 162 int max_tidaws, int intrg_max_tidaws) 163 { 164 struct itcw *itcw; 165 void *chunk; 166 addr_t start; 167 addr_t end; 168 169 /* Check for 2G limit. */ 170 start = (addr_t) buffer; 171 end = start + size; 172 if (end > (1 << 31)) 173 return ERR_PTR(-EINVAL); 174 memset(buffer, 0, size); 175 /* ITCW. */ 176 chunk = fit_chunk(&start, end, sizeof(struct itcw), 1, 0); 177 if (IS_ERR(chunk)) 178 return chunk; 179 itcw = chunk; 180 itcw->max_tidaws = max_tidaws; 181 itcw->intrg_max_tidaws = intrg_max_tidaws; 182 /* Main TCW. */ 183 chunk = fit_chunk(&start, end, sizeof(struct tcw), 64, 0); 184 if (IS_ERR(chunk)) 185 return chunk; 186 itcw->tcw = chunk; 187 tcw_init(itcw->tcw, (op == ITCW_OP_READ) ? 1 : 0, 188 (op == ITCW_OP_WRITE) ? 1 : 0); 189 /* Interrogate TCW. */ 190 if (intrg) { 191 chunk = fit_chunk(&start, end, sizeof(struct tcw), 64, 0); 192 if (IS_ERR(chunk)) 193 return chunk; 194 itcw->intrg_tcw = chunk; 195 tcw_init(itcw->intrg_tcw, 1, 0); 196 tcw_set_intrg(itcw->tcw, itcw->intrg_tcw); 197 } 198 /* Data TIDAL. */ 199 if (max_tidaws > 0) { 200 chunk = fit_chunk(&start, end, sizeof(struct tidaw) * 201 max_tidaws, 16, 1); 202 if (IS_ERR(chunk)) 203 return chunk; 204 tcw_set_data(itcw->tcw, chunk, 1); 205 } 206 /* Interrogate data TIDAL. */ 207 if (intrg && (intrg_max_tidaws > 0)) { 208 chunk = fit_chunk(&start, end, sizeof(struct tidaw) * 209 intrg_max_tidaws, 16, 1); 210 if (IS_ERR(chunk)) 211 return chunk; 212 tcw_set_data(itcw->intrg_tcw, chunk, 1); 213 } 214 /* TSB. */ 215 chunk = fit_chunk(&start, end, sizeof(struct tsb), 8, 0); 216 if (IS_ERR(chunk)) 217 return chunk; 218 tsb_init(chunk); 219 tcw_set_tsb(itcw->tcw, chunk); 220 /* Interrogate TSB. */ 221 if (intrg) { 222 chunk = fit_chunk(&start, end, sizeof(struct tsb), 8, 0); 223 if (IS_ERR(chunk)) 224 return chunk; 225 tsb_init(chunk); 226 tcw_set_tsb(itcw->intrg_tcw, chunk); 227 } 228 /* TCCB. */ 229 chunk = fit_chunk(&start, end, TCCB_MAX_SIZE, 8, 0); 230 if (IS_ERR(chunk)) 231 return chunk; 232 tccb_init(chunk, TCCB_MAX_SIZE, TCCB_SAC_DEFAULT); 233 tcw_set_tccb(itcw->tcw, chunk); 234 /* Interrogate TCCB. */ 235 if (intrg) { 236 chunk = fit_chunk(&start, end, TCCB_MAX_SIZE, 8, 0); 237 if (IS_ERR(chunk)) 238 return chunk; 239 tccb_init(chunk, TCCB_MAX_SIZE, TCCB_SAC_INTRG); 240 tcw_set_tccb(itcw->intrg_tcw, chunk); 241 tccb_add_dcw(chunk, TCCB_MAX_SIZE, DCW_CMD_INTRG, 0, NULL, 242 sizeof(struct dcw_intrg_data), 0); 243 tcw_finalize(itcw->intrg_tcw, 0); 244 } 245 return itcw; 246 } 247 EXPORT_SYMBOL(itcw_init); 248 249 /** 250 * itcw_add_dcw - add a dcw to the itcw 251 * @itcw: address of the itcw 252 * @cmd: the dcw command 253 * @flags: flags for the dcw 254 * @cd: address of control data for this dcw or NULL if none is required 255 * @cd_count: number of control data bytes for this dcw 256 * @count: number of data bytes for this dcw 257 * 258 * Add a new dcw to the specified itcw by writing the dcw information specified 259 * by @cmd, @flags, @cd, @cd_count and @count to the tca of the tccb. Return 260 * a pointer to the newly added dcw on success or -%ENOSPC if the new dcw 261 * would exceed the available space. 262 * 263 * Note: the tcal field of the tccb header will be updated to reflect added 264 * content. 265 */ 266 struct dcw *itcw_add_dcw(struct itcw *itcw, u8 cmd, u8 flags, void *cd, 267 u8 cd_count, u32 count) 268 { 269 return tccb_add_dcw(tcw_get_tccb(itcw->tcw), TCCB_MAX_SIZE, cmd, 270 flags, cd, cd_count, count); 271 } 272 EXPORT_SYMBOL(itcw_add_dcw); 273 274 /** 275 * itcw_add_tidaw - add a tidaw to the itcw 276 * @itcw: address of the itcw 277 * @flags: flags for the new tidaw 278 * @addr: address value for the new tidaw 279 * @count: count value for the new tidaw 280 * 281 * Add a new tidaw to the input/output data tidaw-list of the specified itcw 282 * (depending on the value of the r-flag and w-flag). Return a pointer to 283 * the new tidaw on success or -%ENOSPC if the new tidaw would exceed the 284 * available space. 285 * 286 * Note: the tidaw-list is assumed to be contiguous with no ttics. The 287 * last-tidaw flag for the last tidaw in the list will be set by itcw_finalize. 288 */ 289 struct tidaw *itcw_add_tidaw(struct itcw *itcw, u8 flags, void *addr, u32 count) 290 { 291 if (itcw->num_tidaws >= itcw->max_tidaws) 292 return ERR_PTR(-ENOSPC); 293 return tcw_add_tidaw(itcw->tcw, itcw->num_tidaws++, flags, addr, count); 294 } 295 EXPORT_SYMBOL(itcw_add_tidaw); 296 297 /** 298 * itcw_set_data - set data address and tida flag of the itcw 299 * @itcw: address of the itcw 300 * @addr: the data address 301 * @use_tidal: zero of the data address specifies a contiguous block of data, 302 * non-zero if it specifies a list if tidaws. 303 * 304 * Set the input/output data address of the itcw (depending on the value of the 305 * r-flag and w-flag). If @use_tidal is non-zero, the corresponding tida flag 306 * is set as well. 307 */ 308 void itcw_set_data(struct itcw *itcw, void *addr, int use_tidal) 309 { 310 tcw_set_data(itcw->tcw, addr, use_tidal); 311 } 312 EXPORT_SYMBOL(itcw_set_data); 313 314 /** 315 * itcw_finalize - calculate length and count fields of the itcw 316 * @itcw: address of the itcw 317 * 318 * Calculate tcw input-/output-count and tccbl fields and add a tcat the tccb. 319 * In case input- or output-tida is used, the tidaw-list must be stored in 320 * continuous storage (no ttic). The tcal field in the tccb must be 321 * up-to-date. 322 */ 323 void itcw_finalize(struct itcw *itcw) 324 { 325 tcw_finalize(itcw->tcw, itcw->num_tidaws); 326 } 327 EXPORT_SYMBOL(itcw_finalize); 328