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/*
* Copyright (c) 2014, ARM Limited and Contributors. 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 ARM 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 <stddef.h>
#include <assert.h>
#include "io_storage.h"
#include "io_driver.h"
#define MAX_DEVICES(plat_data) \
(sizeof((plat_data)->devices)/sizeof((plat_data)->devices[0]))
/* Storage for a fixed maximum number of IO entities, definable by platform */
static struct io_entity entity_pool[MAX_IO_HANDLES];
/* Simple way of tracking used storage - each entry is NULL or a pointer to an
* entity */
static struct io_entity *entity_map[MAX_IO_HANDLES];
/* Track number of allocated entities */
static unsigned int entity_count;
/* Used to keep a reference to platform-specific data */
static struct io_plat_data *platform_data;
#if DEBUG /* Extra validation functions only used in debug builds */
/* Return a boolean value indicating whether a device connector is valid */
static int is_valid_dev_connector(const struct io_dev_connector *dev_con)
{
int result = (dev_con != NULL) && (dev_con->dev_open != NULL);
return result;
}
/* Return a boolean value indicating whether a device handle is valid */
static int is_valid_dev(io_dev_handle handle)
{
const struct io_dev_info *dev = handle;
int result = (dev != NULL) && (dev->funcs != NULL) &&
(dev->funcs->type != NULL) &&
(dev->funcs->type() < IO_TYPE_MAX);
return result;
}
/* Return a boolean value indicating whether an IO entity is valid */
static int is_valid_entity(io_handle handle)
{
const struct io_entity *entity = handle;
int result = (entity != NULL) && (is_valid_dev(entity->dev_handle));
return result;
}
/* Return a boolean value indicating whether a seek mode is valid */
static int is_valid_seek_mode(io_seek_mode mode)
{
return ((mode != IO_SEEK_INVALID) && (mode < IO_SEEK_MAX));
}
#endif /* End of debug-only validation functions */
/* Open a connection to a specific device */
static int dev_open(const struct io_dev_connector *dev_con, void *dev_spec,
struct io_dev_info **dev_info)
{
int result = IO_FAIL;
assert(dev_info != NULL);
assert(is_valid_dev_connector(dev_con));
result = dev_con->dev_open(dev_spec, dev_info);
return result;
}
/* Set a handle to track an entity */
static void set_handle(io_handle *handle, struct io_entity *entity)
{
assert(handle != NULL);
*handle = entity;
}
/* Locate an entity in the pool, specified by address */
static int find_first_entity(struct io_entity *entity, unsigned int *index_out)
{
int result = IO_FAIL;
for (int index = 0; index < MAX_IO_HANDLES; ++index) {
if (entity_map[index] == entity) {
result = IO_SUCCESS;
*index_out = index;
break;
}
}
return result;
}
/* Allocate an entity from the pool and return a pointer to it */
static int allocate_entity(struct io_entity **entity)
{
int result = IO_FAIL;
assert(entity != NULL);
if (entity_count < MAX_IO_HANDLES) {
unsigned int index = 0;
result = find_first_entity(NULL, &index);
assert(result == IO_SUCCESS);
*entity = entity_map[index] = &entity_pool[index];
++entity_count;
} else
result = IO_RESOURCES_EXHAUSTED;
return result;
}
/* Release an entity back to the pool */
static int free_entity(struct io_entity *entity)
{
int result = IO_FAIL;
unsigned int index = 0;
assert(entity != NULL);
result = find_first_entity(entity, &index);
if (result == IO_SUCCESS) {
entity_map[index] = NULL;
--entity_count;
}
return result;
}
/* Exported API */
/* Initialise the IO layer */
void io_init(struct io_plat_data *data)
{
assert(data != NULL);
platform_data = data;
}
/* Register a device driver */
int io_register_device(struct io_dev_info *dev_info)
{
int result = IO_FAIL;
assert(dev_info != NULL);
assert(platform_data != NULL);
unsigned int dev_count = platform_data->dev_count;
if (dev_count < MAX_DEVICES(platform_data)) {
platform_data->devices[dev_count] = dev_info;
platform_data->dev_count++;
result = IO_SUCCESS;
} else {
result = IO_RESOURCES_EXHAUSTED;
}
return result;
}
/* Open a connection to an IO device */
int io_dev_open(struct io_dev_connector *dev_con, void *dev_spec,
io_dev_handle *handle)
{
int result = IO_FAIL;
assert(handle != NULL);
result = dev_open(dev_con, dev_spec, handle);
return result;
}
/* Initialise an IO device explicitly - to permit lazy initialisation or
* re-initialisation */
int io_dev_init(struct io_dev_info *dev_handle, const void *init_params)
{
int result = IO_FAIL;
assert(dev_handle != NULL);
assert(is_valid_dev(dev_handle));
struct io_dev_info *dev = dev_handle;
if (dev->funcs->dev_init != NULL) {
result = dev->funcs->dev_init(dev, init_params);
} else {
/* Absence of registered function implies NOP here */
result = IO_SUCCESS;
}
return result;
}
/* TODO: Consider whether an explicit "shutdown" API should be included */
/* Close a connection to a device */
int io_dev_close(io_dev_handle dev_handle)
{
int result = IO_FAIL;
assert(dev_handle != NULL);
assert(is_valid_dev(dev_handle));
struct io_dev_info *dev = dev_handle;
if (dev->funcs->dev_close != NULL) {
result = dev->funcs->dev_close(dev);
} else {
/* Absence of registered function implies NOP here */
result = IO_SUCCESS;
}
return result;
}
/* Synchronous operations */
/* Open an IO entity */
int io_open(io_dev_handle dev_handle, const void *spec, io_handle *handle)
{
int result = IO_FAIL;
assert((spec != NULL) && (handle != NULL));
assert(is_valid_dev(dev_handle));
struct io_dev_info *dev = dev_handle;
struct io_entity *entity;
result = allocate_entity(&entity);
if (result == IO_SUCCESS) {
assert(dev->funcs->open != NULL);
result = dev->funcs->open(dev, spec, entity);
if (result == IO_SUCCESS) {
entity->dev_handle = dev_handle;
set_handle(handle, entity);
} else
free_entity(entity);
}
return result;
}
/* Seek to a specific position in an IO entity */
int io_seek(io_handle handle, io_seek_mode mode, ssize_t offset)
{
int result = IO_FAIL;
assert(is_valid_entity(handle) && is_valid_seek_mode(mode));
struct io_entity *entity = handle;
struct io_dev_info *dev = entity->dev_handle;
if (dev->funcs->seek != NULL)
result = dev->funcs->seek(entity, mode, offset);
else
result = IO_NOT_SUPPORTED;
return result;
}
/* Determine the length of an IO entity */
int io_size(io_handle handle, size_t *length)
{
int result = IO_FAIL;
assert(is_valid_entity(handle) && (length != NULL));
struct io_entity *entity = handle;
struct io_dev_info *dev = entity->dev_handle;
if (dev->funcs->size != NULL)
result = dev->funcs->size(entity, length);
else
result = IO_NOT_SUPPORTED;
return result;
}
/* Read data from an IO entity */
int io_read(io_handle handle, void *buffer, size_t length, size_t *length_read)
{
int result = IO_FAIL;
assert(is_valid_entity(handle) && (buffer != NULL));
struct io_entity *entity = handle;
struct io_dev_info *dev = entity->dev_handle;
if (dev->funcs->read != NULL)
result = dev->funcs->read(entity, buffer, length, length_read);
else
result = IO_NOT_SUPPORTED;
return result;
}
/* Write data to an IO entity */
int io_write(io_handle handle, const void *buffer, size_t length,
size_t *length_written)
{
int result = IO_FAIL;
assert(is_valid_entity(handle) && (buffer != NULL));
struct io_entity *entity = handle;
struct io_dev_info *dev = entity->dev_handle;
if (dev->funcs->write != NULL) {
result = dev->funcs->write(entity, buffer, length,
length_written);
} else
result = IO_NOT_SUPPORTED;
return result;
}
/* Close an IO entity */
int io_close(io_handle handle)
{
int result = IO_FAIL;
assert(is_valid_entity(handle));
struct io_entity *entity = handle;
struct io_dev_info *dev = entity->dev_handle;
if (dev->funcs->close != NULL)
result = dev->funcs->close(entity);
else {
/* Absence of registered function implies NOP here */
result = IO_SUCCESS;
}
/* Ignore improbable free_entity failure */
(void)free_entity(entity);
return result;
}