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Diffstat (limited to '')
| -rw-r--r-- | drivers/s390/cio/itcw.c | 370 |
1 files changed, 370 insertions, 0 deletions
diff --git a/drivers/s390/cio/itcw.c b/drivers/s390/cio/itcw.c new file mode 100644 index 000000000..19e463633 --- /dev/null +++ b/drivers/s390/cio/itcw.c @@ -0,0 +1,370 @@ +// 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); |