| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Functions for incremental construction of fcx enabled I/O control blocks. |
| * |
| * Copyright IBM Corp. 2008 |
| * Author(s): Peter Oberparleiter <peter.oberparleiter@de.ibm.com> |
| */ |
| |
| #include <linux/kernel.h> |
| #include <linux/types.h> |
| #include <linux/string.h> |
| #include <linux/errno.h> |
| #include <linux/err.h> |
| #include <linux/module.h> |
| #include <asm/fcx.h> |
| #include <asm/itcw.h> |
| |
| /* |
| * struct itcw - incremental tcw helper data type |
| * |
| * This structure serves as a handle for the incremental construction of a |
| * tcw and associated tccb, tsb, data tidaw-list plus an optional interrogate |
| * tcw and associated data. The data structures are contained inside a single |
| * contiguous buffer provided by the user. |
| * |
| * The itcw construction functions take care of overall data integrity: |
| * - reset unused fields to zero |
| * - fill in required pointers |
| * - ensure required alignment for data structures |
| * - prevent data structures to cross 4k-byte boundary where required |
| * - calculate tccb-related length fields |
| * - optionally provide ready-made interrogate tcw and associated structures |
| * |
| * Restrictions apply to the itcws created with these construction functions: |
| * - tida only supported for data address, not for tccb |
| * - only contiguous tidaw-lists (no ttic) |
| * - total number of bytes required per itcw may not exceed 4k bytes |
| * - either read or write operation (may not work with r=0 and w=0) |
| * |
| * Example: |
| * struct itcw *itcw; |
| * void *buffer; |
| * size_t size; |
| * |
| * size = itcw_calc_size(1, 2, 0); |
| * buffer = kmalloc(size, GFP_KERNEL | GFP_DMA); |
| * if (!buffer) |
| * return -ENOMEM; |
| * itcw = itcw_init(buffer, size, ITCW_OP_READ, 1, 2, 0); |
| * if (IS_ERR(itcw)) |
| * return PTR_ER(itcw); |
| * itcw_add_dcw(itcw, 0x2, 0, NULL, 0, 72); |
| * itcw_add_tidaw(itcw, 0, 0x30000, 20); |
| * itcw_add_tidaw(itcw, 0, 0x40000, 52); |
| * itcw_finalize(itcw); |
| * |
| */ |
| struct itcw { |
| struct tcw *tcw; |
| struct tcw *intrg_tcw; |
| int num_tidaws; |
| int max_tidaws; |
| int intrg_num_tidaws; |
| int intrg_max_tidaws; |
| }; |
| |
| /** |
| * itcw_get_tcw - return pointer to tcw associated with the itcw |
| * @itcw: address of the itcw |
| * |
| * Return pointer to the tcw associated with the itcw. |
| */ |
| struct tcw *itcw_get_tcw(struct itcw *itcw) |
| { |
| return itcw->tcw; |
| } |
| EXPORT_SYMBOL(itcw_get_tcw); |
| |
| /** |
| * itcw_calc_size - return the size of an itcw with the given parameters |
| * @intrg: if non-zero, add an interrogate tcw |
| * @max_tidaws: maximum number of tidaws to be used for data addressing or zero |
| * if no tida is to be used. |
| * @intrg_max_tidaws: maximum number of tidaws to be used for data addressing |
| * by the interrogate tcw, if specified |
| * |
| * Calculate and return the number of bytes required to hold an itcw with the |
| * given parameters and assuming tccbs with maximum size. |
| * |
| * Note that the resulting size also contains bytes needed for alignment |
| * padding as well as padding to ensure that data structures don't cross a |
| * 4k-boundary where required. |
| */ |
| size_t itcw_calc_size(int intrg, int max_tidaws, int intrg_max_tidaws) |
| { |
| size_t len; |
| int cross_count; |
| |
| /* Main data. */ |
| len = sizeof(struct itcw); |
| len += /* TCW */ sizeof(struct tcw) + /* TCCB */ TCCB_MAX_SIZE + |
| /* TSB */ sizeof(struct tsb) + |
| /* TIDAL */ max_tidaws * sizeof(struct tidaw); |
| /* Interrogate data. */ |
| if (intrg) { |
| len += /* TCW */ sizeof(struct tcw) + /* TCCB */ TCCB_MAX_SIZE + |
| /* TSB */ sizeof(struct tsb) + |
| /* TIDAL */ intrg_max_tidaws * sizeof(struct tidaw); |
| } |
| |
| /* Maximum required alignment padding. */ |
| len += /* Initial TCW */ 63 + /* Interrogate TCCB */ 7; |
| |
| /* TIDAW lists may not cross a 4k boundary. To cross a |
| * boundary we need to add a TTIC TIDAW. We need to reserve |
| * one additional TIDAW for a TTIC that we may need to add due |
| * to the placement of the data chunk in memory, and a further |
| * TIDAW for each page boundary that the TIDAW list may cross |
| * due to it's own size. |
| */ |
| if (max_tidaws) { |
| cross_count = 1 + ((max_tidaws * sizeof(struct tidaw) - 1) |
| >> PAGE_SHIFT); |
| len += cross_count * sizeof(struct tidaw); |
| } |
| if (intrg_max_tidaws) { |
| cross_count = 1 + ((intrg_max_tidaws * sizeof(struct tidaw) - 1) |
| >> PAGE_SHIFT); |
| len += cross_count * sizeof(struct tidaw); |
| } |
| return len; |
| } |
| EXPORT_SYMBOL(itcw_calc_size); |
| |
| #define CROSS4K(x, l) (((x) & ~4095) != ((x + l) & ~4095)) |
| |
| static inline void *fit_chunk(addr_t *start, addr_t end, size_t len, |
| int align, int check_4k) |
| { |
| addr_t addr; |
| |
| addr = ALIGN(*start, align); |
| if (check_4k && CROSS4K(addr, len)) { |
| addr = ALIGN(addr, 4096); |
| addr = ALIGN(addr, align); |
| } |
| if (addr + len > end) |
| return ERR_PTR(-ENOSPC); |
| *start = addr + len; |
| return (void *) addr; |
| } |
| |
| /** |
| * itcw_init - initialize incremental tcw data structure |
| * @buffer: address of buffer to use for data structures |
| * @size: number of bytes in buffer |
| * @op: %ITCW_OP_READ for a read operation tcw, %ITCW_OP_WRITE for a write |
| * operation tcw |
| * @intrg: if non-zero, add and initialize an interrogate tcw |
| * @max_tidaws: maximum number of tidaws to be used for data addressing or zero |
| * if no tida is to be used. |
| * @intrg_max_tidaws: maximum number of tidaws to be used for data addressing |
| * by the interrogate tcw, if specified |
| * |
| * Prepare the specified buffer to be used as an incremental tcw, i.e. a |
| * helper data structure that can be used to construct a valid tcw by |
| * successive calls to other helper functions. Note: the buffer needs to be |
| * located below the 2G address limit. The resulting tcw has the following |
| * restrictions: |
| * - no tccb tidal |
| * - input/output tidal is contiguous (no ttic) |
| * - total data should not exceed 4k |
| * - tcw specifies either read or write operation |
| * |
| * On success, return pointer to the resulting incremental tcw data structure, |
| * ERR_PTR otherwise. |
| */ |
| struct itcw *itcw_init(void *buffer, size_t size, int op, int intrg, |
| int max_tidaws, int intrg_max_tidaws) |
| { |
| struct itcw *itcw; |
| void *chunk; |
| addr_t start; |
| addr_t end; |
| int cross_count; |
| |
| /* Check for 2G limit. */ |
| start = (addr_t) buffer; |
| end = start + size; |
| if (end > (1 << 31)) |
| return ERR_PTR(-EINVAL); |
| memset(buffer, 0, size); |
| /* ITCW. */ |
| chunk = fit_chunk(&start, end, sizeof(struct itcw), 1, 0); |
| if (IS_ERR(chunk)) |
| return chunk; |
| itcw = chunk; |
| /* allow for TTIC tidaws that may be needed to cross a page boundary */ |
| cross_count = 0; |
| if (max_tidaws) |
| cross_count = 1 + ((max_tidaws * sizeof(struct tidaw) - 1) |
| >> PAGE_SHIFT); |
| itcw->max_tidaws = max_tidaws + cross_count; |
| cross_count = 0; |
| if (intrg_max_tidaws) |
| cross_count = 1 + ((intrg_max_tidaws * sizeof(struct tidaw) - 1) |
| >> PAGE_SHIFT); |
| itcw->intrg_max_tidaws = intrg_max_tidaws + cross_count; |
| /* Main TCW. */ |
| chunk = fit_chunk(&start, end, sizeof(struct tcw), 64, 0); |
| if (IS_ERR(chunk)) |
| return chunk; |
| itcw->tcw = chunk; |
| tcw_init(itcw->tcw, (op == ITCW_OP_READ) ? 1 : 0, |
| (op == ITCW_OP_WRITE) ? 1 : 0); |
| /* Interrogate TCW. */ |
| if (intrg) { |
| chunk = fit_chunk(&start, end, sizeof(struct tcw), 64, 0); |
| if (IS_ERR(chunk)) |
| return chunk; |
| itcw->intrg_tcw = chunk; |
| tcw_init(itcw->intrg_tcw, 1, 0); |
| tcw_set_intrg(itcw->tcw, itcw->intrg_tcw); |
| } |
| /* Data TIDAL. */ |
| if (max_tidaws > 0) { |
| chunk = fit_chunk(&start, end, sizeof(struct tidaw) * |
| itcw->max_tidaws, 16, 0); |
| if (IS_ERR(chunk)) |
| return chunk; |
| tcw_set_data(itcw->tcw, chunk, 1); |
| } |
| /* Interrogate data TIDAL. */ |
| if (intrg && (intrg_max_tidaws > 0)) { |
| chunk = fit_chunk(&start, end, sizeof(struct tidaw) * |
| itcw->intrg_max_tidaws, 16, 0); |
| if (IS_ERR(chunk)) |
| return chunk; |
| tcw_set_data(itcw->intrg_tcw, chunk, 1); |
| } |
| /* TSB. */ |
| chunk = fit_chunk(&start, end, sizeof(struct tsb), 8, 0); |
| if (IS_ERR(chunk)) |
| return chunk; |
| tsb_init(chunk); |
| tcw_set_tsb(itcw->tcw, chunk); |
| /* Interrogate TSB. */ |
| if (intrg) { |
| chunk = fit_chunk(&start, end, sizeof(struct tsb), 8, 0); |
| if (IS_ERR(chunk)) |
| return chunk; |
| tsb_init(chunk); |
| tcw_set_tsb(itcw->intrg_tcw, chunk); |
| } |
| /* TCCB. */ |
| chunk = fit_chunk(&start, end, TCCB_MAX_SIZE, 8, 0); |
| if (IS_ERR(chunk)) |
| return chunk; |
| tccb_init(chunk, TCCB_MAX_SIZE, TCCB_SAC_DEFAULT); |
| tcw_set_tccb(itcw->tcw, chunk); |
| /* Interrogate TCCB. */ |
| if (intrg) { |
| chunk = fit_chunk(&start, end, TCCB_MAX_SIZE, 8, 0); |
| if (IS_ERR(chunk)) |
| return chunk; |
| tccb_init(chunk, TCCB_MAX_SIZE, TCCB_SAC_INTRG); |
| tcw_set_tccb(itcw->intrg_tcw, chunk); |
| tccb_add_dcw(chunk, TCCB_MAX_SIZE, DCW_CMD_INTRG, 0, NULL, |
| sizeof(struct dcw_intrg_data), 0); |
| tcw_finalize(itcw->intrg_tcw, 0); |
| } |
| return itcw; |
| } |
| EXPORT_SYMBOL(itcw_init); |
| |
| /** |
| * itcw_add_dcw - add a dcw to the itcw |
| * @itcw: address of the itcw |
| * @cmd: the dcw command |
| * @flags: flags for the dcw |
| * @cd: address of control data for this dcw or NULL if none is required |
| * @cd_count: number of control data bytes for this dcw |
| * @count: number of data bytes for this dcw |
| * |
| * Add a new dcw to the specified itcw by writing the dcw information specified |
| * by @cmd, @flags, @cd, @cd_count and @count to the tca of the tccb. Return |
| * a pointer to the newly added dcw on success or -%ENOSPC if the new dcw |
| * would exceed the available space. |
| * |
| * Note: the tcal field of the tccb header will be updated to reflect added |
| * content. |
| */ |
| struct dcw *itcw_add_dcw(struct itcw *itcw, u8 cmd, u8 flags, void *cd, |
| u8 cd_count, u32 count) |
| { |
| return tccb_add_dcw(tcw_get_tccb(itcw->tcw), TCCB_MAX_SIZE, cmd, |
| flags, cd, cd_count, count); |
| } |
| EXPORT_SYMBOL(itcw_add_dcw); |
| |
| /** |
| * itcw_add_tidaw - add a tidaw to the itcw |
| * @itcw: address of the itcw |
| * @flags: flags for the new tidaw |
| * @addr: address value for the new tidaw |
| * @count: count value for the new tidaw |
| * |
| * Add a new tidaw to the input/output data tidaw-list of the specified itcw |
| * (depending on the value of the r-flag and w-flag). Return a pointer to |
| * the new tidaw on success or -%ENOSPC if the new tidaw would exceed the |
| * available space. |
| * |
| * Note: TTIC tidaws are automatically added when needed, so explicitly calling |
| * this interface with the TTIC flag is not supported. The last-tidaw flag |
| * for the last tidaw in the list will be set by itcw_finalize. |
| */ |
| struct tidaw *itcw_add_tidaw(struct itcw *itcw, u8 flags, void *addr, u32 count) |
| { |
| struct tidaw *following; |
| |
| if (itcw->num_tidaws >= itcw->max_tidaws) |
| return ERR_PTR(-ENOSPC); |
| /* |
| * Is the tidaw, which follows the one we are about to fill, on the next |
| * page? Then we have to insert a TTIC tidaw first, that points to the |
| * tidaw on the new page. |
| */ |
| following = ((struct tidaw *) tcw_get_data(itcw->tcw)) |
| + itcw->num_tidaws + 1; |
| if (itcw->num_tidaws && !((unsigned long) following & ~PAGE_MASK)) { |
| tcw_add_tidaw(itcw->tcw, itcw->num_tidaws++, |
| TIDAW_FLAGS_TTIC, following, 0); |
| if (itcw->num_tidaws >= itcw->max_tidaws) |
| return ERR_PTR(-ENOSPC); |
| } |
| return tcw_add_tidaw(itcw->tcw, itcw->num_tidaws++, flags, addr, count); |
| } |
| EXPORT_SYMBOL(itcw_add_tidaw); |
| |
| /** |
| * itcw_set_data - set data address and tida flag of the itcw |
| * @itcw: address of the itcw |
| * @addr: the data address |
| * @use_tidal: zero of the data address specifies a contiguous block of data, |
| * non-zero if it specifies a list if tidaws. |
| * |
| * Set the input/output data address of the itcw (depending on the value of the |
| * r-flag and w-flag). If @use_tidal is non-zero, the corresponding tida flag |
| * is set as well. |
| */ |
| void itcw_set_data(struct itcw *itcw, void *addr, int use_tidal) |
| { |
| tcw_set_data(itcw->tcw, addr, use_tidal); |
| } |
| EXPORT_SYMBOL(itcw_set_data); |
| |
| /** |
| * itcw_finalize - calculate length and count fields of the itcw |
| * @itcw: address of the itcw |
| * |
| * Calculate tcw input-/output-count and tccbl fields and add a tcat the tccb. |
| * In case input- or output-tida is used, the tidaw-list must be stored in |
| * continuous storage (no ttic). The tcal field in the tccb must be |
| * up-to-date. |
| */ |
| void itcw_finalize(struct itcw *itcw) |
| { |
| tcw_finalize(itcw->tcw, itcw->num_tidaws); |
| } |
| EXPORT_SYMBOL(itcw_finalize); |