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