/*
* core.c
* ------
* This module contains code to probe the FPGA for its installed cores.
*
* Author: Paul Selkirk, Rob Austein
* Copyright (c) 2015-2017, NORDUnet A/S All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* - Neither the name of the NORDUnet nor the names of its contributors may
* be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include "hal.h"
#include "hal_internal.h"
/*
* POSIX function whose declaration gets lost somewhere in the twisty
* corridors of glibc's "Feature Test Macro" system.
*/
extern size_t strnlen(const char *, size_t);
/*
* Structure of our internal database is private, in case we want to
* change representation (array, tree, list of lists, whatever) at
* some later date without having to change the public API.
*/
struct hal_core {
hal_core_info_t info;
int busy;
hal_core_lru_t lru;
struct hal_core *next;
};
#if defined(HAL_STATIC_CORE_STATE_BLOCKS) && HAL_STATIC_CORE_STATE_BLOCKS > 0
static hal_core_t core_table[HAL_STATIC_CORE_STATE_BLOCKS];
#else
#error HAL_STATIC_CORE_STATE_BLOCKS must be defined as a positive integer
#endif
/*
* Check whether a core's name matches a particular string. This is a
* bit nasty due to non-null-terminated fixed-length names.
*/
static inline int name_matches(const hal_core_t *const core, const char * const name)
{
return (core != NULL && name != NULL && *name != '\0' &&
strncmp(name, core->info.name, strnlen(name, sizeof(core->info.name))) == 0);
}
/*
* Probe the FPGA and build our internal database.
*
* At the moment this knows far more than it should about pecularities
* of certain cores. In theory at least some of this will be fixed
* soon on the Verilog side. Adding a core-length word to the core
* header sure would make this simpler.
*/
#define CORE_MIN 0
#define CORE_MAX 0x10000
#define CORE_SIZE 0x100
static hal_core_t *head = NULL;
static hal_core_lru_t lru = 0;
static inline hal_core_t *probe_cores(void)
{
/* Extra space to leave after particular cores. Yummy. */
static const struct { const char *name; hal_addr_t extra; } gaps[] = {
{ "csprng", 11 * CORE_SIZE }, /* empty slots after csprng */
{ "modexps6", 3 * CORE_SIZE }, /* ModexpS6 uses four slots */
{ "modexpa7", 7 * CORE_SIZE }, /* ModexpA7 uses eight slots */
};
if (offsetof(hal_core_t, info) != 0)
return NULL; /* Paranoia, see hal.h */
if (head != NULL)
return head;
hal_core_t **tail = &head;
hal_error_t err = HAL_OK;
hal_addr_t addr;
int n;
for (addr = CORE_MIN, n = 0;
addr < CORE_MAX && n < HAL_STATIC_CORE_STATE_BLOCKS;
addr += CORE_SIZE, n++) {
hal_core_t *core = &core_table[n];
memset(core, 0, sizeof(*core));
core->info.base = addr;
if ((err = hal_io_read(core, ADDR_NAME0, (uint8_t *) core->info.name, 8)) != HAL_OK ||
(err = hal_io_read(core, ADDR_VERSION, (uint8_t *) core->info.version, 4)) != HAL_OK)
goto fail;
if (core->info.name[0] == 0x00 || core->info.name[0] == 0xff)
continue;
for (size_t i = 0; i < sizeof(gaps)/sizeof(*gaps); i++) {
if (name_matches(core, gaps[i].name)) {
addr += gaps[i].extra;
break;
}
}
*tail = core;
tail = &core->next;
}
return head;
fail:
memset(core_table, 0, sizeof(core_table));
return NULL;
}
void hal_core_reset_table(void)
{
head = NULL;
memset(core_table, 0, sizeof(core_table));
}
hal_core_t * hal_core_iterate(hal_core_t *core)
{
return core == NULL ? probe_cores() : core->next;
}
hal_core_t *hal_core_find(const char *name, hal_core_t *core)
{
for (core = hal_core_iterate(core); core != NULL; core = core->next)
if (name_matches(core, name))
return core;
return NULL;
}
/*
* If caller specifies a non-NULL core value, we fail unless that core
* is available and has the right name and lru values.
*
* If caller specifies a NULL core value, we take any free core with
* the right name.
*
* Modification of lru field is handled by the jacket routines, to
* avoid premature updates.
*/
static hal_error_t hal_core_alloc_no_wait(const char *name, hal_core_t **pcore, hal_core_lru_t *pomace)
{
if (name == NULL || pcore == NULL || (*pcore != NULL && pomace == NULL))
return HAL_ERROR_BAD_ARGUMENTS;
hal_error_t err = HAL_ERROR_CORE_NOT_FOUND;
hal_core_t *core = *pcore;
hal_core_t *best = NULL;
uint32_t age = 0;
hal_critical_section_start();
/*
* User wants to reuse previous core, grab that core or or bust.
* Never return CORE_BUSY in this case, because busy implies
* somebody else has touched it. Checking the name in this case
* isn't strictly necessary, but it's cheap insurance.
*/
if (core != NULL) {
if (core->busy || core->lru != *pomace)
err = HAL_ERROR_CORE_REASSIGNED;
else if (!name_matches(core, name))
err = HAL_ERROR_CORE_NOT_FOUND;
else {
core->busy = 1;
err = HAL_OK;
}
}
/*
* User just wants a core with the right name, search for least recently used matching core.
*/
else {
for (core = hal_core_find(name, NULL); core != NULL; core = hal_core_find(name, core)) {
if (core->busy && err == HAL_ERROR_CORE_NOT_FOUND) {
err = HAL_ERROR_CORE_BUSY;
}
else if (!core->busy && (lru - core->lru) >= age) {
best = core;
age = (lru - core->lru);
}
}
if (best != NULL) {
*pcore = best;
best->busy = 1;
err = HAL_OK;
}
}
hal_critical_section_end();
return err;
}
hal_error_t hal_core_alloc(const char *name, hal_core_t **pcore, hal_core_lru_t *pomace)
{
hal_error_t err;
while ((err = hal_core_alloc_no_wait(name, pcore, pomace)) == HAL_ERROR_CORE_BUSY)
hal_task_yield();
if (err != HAL_OK)
return err;
(*pcore)->lru = ++lru;
if (pomace != NULL)
*pomace = (*pcore)->lru;
return HAL_OK;
}
hal_error_t hal_core_alloc2(const char *name1, hal_core_t **pcore1, hal_core_lru_t *pomace1,
const char *name2, hal_core_t **pcore2, hal_core_lru_t *pomace2)
{
const int clear = pcore1 != NULL && *pcore1 == NULL;
for (;;) {
hal_error_t err = hal_core_alloc_no_wait(name1, pcore1, pomace1);
switch (err) {
case HAL_OK:
break;
case HAL_ERROR_CORE_BUSY:
hal_task_yield();
continue;
default:
return err;
}
if ((err = hal_core_alloc_no_wait(name2, pcore2, pomace2)) == HAL_OK)
break;
hal_core_free(*pcore1); /* hal_core_free does a yield, so we don't need to do another one */
if (clear) /* put *pcore1 back as we found it */
*pcore1 = NULL;
if (err != HAL_ERROR_CORE_BUSY)
return err;
}
(*pcore1)->lru = ++lru;
(*pcore2)->lru = ++lru;
if (pomace1 != NULL)
*pomace1 = (*pcore1)->lru;
if (pomace2 != NULL)
*pomace2 = (*pcore2)->lru;
return HAL_OK;
}
void hal_core_free(hal_core_t *core)
{
if (core != NULL) {
hal_critical_section_start();
core->busy = 0;
hal_critical_section_end();
hal_task_yield();
}
}
/*
* Local variables:
* indent-tabs-mode: nil
* End:
*/
