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/*
* Copyright (c) 2014-2017, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <assert.h>
#include <io_driver.h>
#include <io_storage.h>
#include <platform_def.h>
#include <stddef.h>
/* Storage for a fixed maximum number of IO entities, definable by platform */
static io_entity_t entity_pool[MAX_IO_HANDLES];
/* Simple way of tracking used storage - each entry is NULL or a pointer to an
* entity */
static io_entity_t *entity_map[MAX_IO_HANDLES];
/* Track number of allocated entities */
static unsigned int entity_count;
/* Array of fixed maximum of registered devices, definable by platform */
static const io_dev_info_t *devices[MAX_IO_DEVICES];
/* Number of currently registered devices */
static unsigned int dev_count;
/* Extra validation functions only used when asserts are enabled */
#if ENABLE_ASSERTIONS
/* Return a boolean value indicating whether a device connector is valid */
static int is_valid_dev_connector(const io_dev_connector_t *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(const uintptr_t dev_handle)
{
const io_dev_info_t *dev = (io_dev_info_t *)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(const uintptr_t handle)
{
const io_entity_t *entity = (io_entity_t *)handle;
int result = (entity != NULL) &&
(is_valid_dev((uintptr_t)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_t mode)
{
return ((mode != IO_SEEK_INVALID) && (mode < IO_SEEK_MAX));
}
#endif /* ENABLE_ASSERTIONS */
/* End of extra validation functions only used when asserts are enabled */
/* Open a connection to a specific device */
static int dev_open(const io_dev_connector_t *dev_con, const uintptr_t dev_spec,
io_dev_info_t **dev_info)
{
int result;
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(uintptr_t *handle, io_entity_t *entity)
{
assert(handle != NULL);
*handle = (uintptr_t)entity;
}
/* Locate an entity in the pool, specified by address */
static int find_first_entity(const io_entity_t *entity, unsigned int *index_out)
{
int result = -ENOENT;
for (int index = 0; index < MAX_IO_HANDLES; ++index) {
if (entity_map[index] == entity) {
result = 0;
*index_out = index;
break;
}
}
return result;
}
/* Allocate an entity from the pool and return a pointer to it */
static int allocate_entity(io_entity_t **entity)
{
int result = -ENOMEM;
assert(entity != NULL);
if (entity_count < MAX_IO_HANDLES) {
unsigned int index = 0;
result = find_first_entity(NULL, &index);
assert(result == 0);
*entity = entity_map[index] = &entity_pool[index];
++entity_count;
}
return result;
}
/* Release an entity back to the pool */
static int free_entity(const io_entity_t *entity)
{
int result;
unsigned int index = 0;
assert(entity != NULL);
result = find_first_entity(entity, &index);
if (result == 0) {
entity_map[index] = NULL;
--entity_count;
}
return result;
}
/* Exported API */
/* Register a device driver */
int io_register_device(const io_dev_info_t *dev_info)
{
int result = -ENOMEM;
assert(dev_info != NULL);
if (dev_count < MAX_IO_DEVICES) {
devices[dev_count] = dev_info;
dev_count++;
result = 0;
}
return result;
}
/* Open a connection to an IO device */
int io_dev_open(const io_dev_connector_t *dev_con, const uintptr_t dev_spec,
uintptr_t *handle)
{
int result;
assert(handle != NULL);
result = dev_open(dev_con, dev_spec, (io_dev_info_t **)handle);
return result;
}
/* Initialise an IO device explicitly - to permit lazy initialisation or
* re-initialisation */
int io_dev_init(uintptr_t dev_handle, const uintptr_t init_params)
{
int result = 0;
assert(dev_handle != (uintptr_t)NULL);
assert(is_valid_dev(dev_handle));
io_dev_info_t *dev = (io_dev_info_t *)dev_handle;
/* Absence of registered function implies NOP here */
if (dev->funcs->dev_init != NULL) {
result = dev->funcs->dev_init(dev, init_params);
}
return result;
}
/* TODO: Consider whether an explicit "shutdown" API should be included */
/* Close a connection to a device */
int io_dev_close(uintptr_t dev_handle)
{
int result = 0;
assert(dev_handle != (uintptr_t)NULL);
assert(is_valid_dev(dev_handle));
io_dev_info_t *dev = (io_dev_info_t *)dev_handle;
/* Absence of registered function implies NOP here */
if (dev->funcs->dev_close != NULL) {
result = dev->funcs->dev_close(dev);
}
return result;
}
/* Synchronous operations */
/* Open an IO entity */
int io_open(uintptr_t dev_handle, const uintptr_t spec, uintptr_t *handle)
{
int result;
assert((spec != (uintptr_t)NULL) && (handle != NULL));
assert(is_valid_dev(dev_handle));
io_dev_info_t *dev = (io_dev_info_t *)dev_handle;
io_entity_t *entity;
result = allocate_entity(&entity);
if (result == 0) {
assert(dev->funcs->open != NULL);
result = dev->funcs->open(dev, spec, entity);
if (result == 0) {
entity->dev_handle = dev;
set_handle(handle, entity);
} else
free_entity(entity);
}
return result;
}
/* Seek to a specific position in an IO entity */
int io_seek(uintptr_t handle, io_seek_mode_t mode, ssize_t offset)
{
int result = -ENODEV;
assert(is_valid_entity(handle) && is_valid_seek_mode(mode));
io_entity_t *entity = (io_entity_t *)handle;
io_dev_info_t *dev = entity->dev_handle;
if (dev->funcs->seek != NULL)
result = dev->funcs->seek(entity, mode, offset);
return result;
}
/* Determine the length of an IO entity */
int io_size(uintptr_t handle, size_t *length)
{
int result = -ENODEV;
assert(is_valid_entity(handle) && (length != NULL));
io_entity_t *entity = (io_entity_t *)handle;
io_dev_info_t *dev = entity->dev_handle;
if (dev->funcs->size != NULL)
result = dev->funcs->size(entity, length);
return result;
}
/* Read data from an IO entity */
int io_read(uintptr_t handle,
uintptr_t buffer,
size_t length,
size_t *length_read)
{
int result = -ENODEV;
assert(is_valid_entity(handle) && (buffer != (uintptr_t)NULL));
io_entity_t *entity = (io_entity_t *)handle;
io_dev_info_t *dev = entity->dev_handle;
if (dev->funcs->read != NULL)
result = dev->funcs->read(entity, buffer, length, length_read);
return result;
}
/* Write data to an IO entity */
int io_write(uintptr_t handle,
const uintptr_t buffer,
size_t length,
size_t *length_written)
{
int result = -ENODEV;
assert(is_valid_entity(handle) && (buffer != (uintptr_t)NULL));
io_entity_t *entity = (io_entity_t *)handle;
io_dev_info_t *dev = entity->dev_handle;
if (dev->funcs->write != NULL) {
result = dev->funcs->write(entity, buffer, length,
length_written);
}
return result;
}
/* Close an IO entity */
int io_close(uintptr_t handle)
{
int result = 0;
assert(is_valid_entity(handle));
io_entity_t *entity = (io_entity_t *)handle;
io_dev_info_t *dev = entity->dev_handle;
/* Absence of registered function implies NOP here */
if (dev->funcs->close != NULL)
result = dev->funcs->close(entity);
/* Ignore improbable free_entity failure */
(void)free_entity(entity);
return result;
}