1 // SPDX-License-Identifier: GPL-2.0
20  * struct itcw - incremental tcw helper data type
23  * tcw and associated tccb, tsb, data tidaw-list plus an optional interrogate
25  * contiguous buffer provided by the user.
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
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)
49  *	return -ENOMEM;
69  * itcw_get_tcw - return pointer to tcw associated with the itcw
76 	return itcw->tcw;  in itcw_get_tcw()
81  * itcw_calc_size - return the size of an itcw with the given parameters
82  * @intrg: if non-zero, add an interrogate tcw
93  * 4k-boundary where required.
123 		cross_count = 1 + ((max_tidaws * sizeof(struct tidaw) - 1)  in itcw_calc_size()
128 		cross_count = 1 + ((intrg_max_tidaws * sizeof(struct tidaw) - 1)  in itcw_calc_size()
149 		return ERR_PTR(-ENOSPC);  in fit_chunk()
155  * itcw_init - initialize incremental tcw data structure
160  * @intrg: if non-zero, add and initialize an interrogate tcw
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
192 		return ERR_PTR(-EINVAL);  in itcw_init()
202 		cross_count = 1 + ((max_tidaws * sizeof(struct tidaw) - 1)  in itcw_init()
204 	itcw->max_tidaws = max_tidaws + cross_count;  in itcw_init()
207 		cross_count = 1 + ((intrg_max_tidaws * sizeof(struct tidaw) - 1)  in itcw_init()
209 	itcw->intrg_max_tidaws = intrg_max_tidaws + cross_count;  in itcw_init()
214 	itcw->tcw = chunk;  in itcw_init()
215 	tcw_init(itcw->tcw, (op == ITCW_OP_READ) ? 1 : 0,  in itcw_init()
222 		itcw->intrg_tcw = chunk;  in itcw_init()
223 		tcw_init(itcw->intrg_tcw, 1, 0);  in itcw_init()
224 		tcw_set_intrg(itcw->tcw, itcw->intrg_tcw);  in itcw_init()
229 				  itcw->max_tidaws, 16, 0);  in itcw_init()
232 		tcw_set_data(itcw->tcw, chunk, 1);  in itcw_init()
237 				  itcw->intrg_max_tidaws, 16, 0);  in itcw_init()
240 		tcw_set_data(itcw->intrg_tcw, chunk, 1);  in itcw_init()
247 	tcw_set_tsb(itcw->tcw, chunk);  in itcw_init()
254 		tcw_set_tsb(itcw->intrg_tcw, chunk);  in itcw_init()
261 	tcw_set_tccb(itcw->tcw, chunk);  in itcw_init()
268 		tcw_set_tccb(itcw->intrg_tcw, chunk);  in itcw_init()
271 		tcw_finalize(itcw->intrg_tcw, 0);  in itcw_init()
278  * itcw_add_dcw - add a dcw to the itcw
288  * a pointer to the newly added dcw on success or -%ENOSPC if the new dcw
297 	return tccb_add_dcw(tcw_get_tccb(itcw->tcw), TCCB_MAX_SIZE, cmd,  in itcw_add_dcw()
303  * itcw_add_tidaw - add a tidaw to the itcw
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
315  * this interface with the TTIC flag is not supported. The last-tidaw flag
322 	if (itcw->num_tidaws >= itcw->max_tidaws)  in itcw_add_tidaw()
323 		return ERR_PTR(-ENOSPC);  in itcw_add_tidaw()
329 	following = ((struct tidaw *) tcw_get_data(itcw->tcw))  in itcw_add_tidaw()
330 		+ itcw->num_tidaws + 1;  in itcw_add_tidaw()
331 	if (itcw->num_tidaws && !((unsigned long) following & ~PAGE_MASK)) {  in itcw_add_tidaw()
332 		tcw_add_tidaw(itcw->tcw, itcw->num_tidaws++,  in itcw_add_tidaw()
334 		if (itcw->num_tidaws >= itcw->max_tidaws)  in itcw_add_tidaw()
335 			return ERR_PTR(-ENOSPC);  in itcw_add_tidaw()
337 	return tcw_add_tidaw(itcw->tcw, itcw->num_tidaws++, flags, addr, count);  in itcw_add_tidaw()
342  * itcw_set_data - set data address and tida flag of the itcw
345  * @use_tidal: zero of the data address specifies a contiguous block of data,
346  * non-zero if it specifies a list if tidaws.
349  * r-flag and w-flag). If @use_tidal is non-zero, the corresponding tida flag
354 	tcw_set_data(itcw->tcw, addr, use_tidal);  in itcw_set_data()
359  * itcw_finalize - calculate length and count fields of the itcw
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
365  * up-to-date.
369 	tcw_finalize(itcw->tcw, itcw->num_tidaws);  in itcw_finalize()