// 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 <[email protected]>
*/
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/io.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 ((virt_to_phys(buffer) + size) > (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);
Codebase Browser
linux