aosp12/external/arm-trusted-firmware/drivers/io/io_memmap.c

252 lines
6.2 KiB
C

/*
* Copyright (c) 2014-2020, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <assert.h>
#include <string.h>
#include <platform_def.h>
#include <common/debug.h>
#include <drivers/io/io_driver.h>
#include <drivers/io/io_memmap.h>
#include <drivers/io/io_storage.h>
#include <lib/utils.h>
/* As we need to be able to keep state for seek, only one file can be open
* at a time. Make this a structure and point to the entity->info. When we
* can malloc memory we can change this to support more open files.
*/
typedef struct {
/* Use the 'in_use' flag as any value for base and file_pos could be
* valid.
*/
int in_use;
uintptr_t base;
unsigned long long file_pos;
unsigned long long size;
} memmap_file_state_t;
static memmap_file_state_t current_memmap_file = {0};
/* Identify the device type as memmap */
static io_type_t device_type_memmap(void)
{
return IO_TYPE_MEMMAP;
}
/* Memmap device functions */
static int memmap_dev_open(const uintptr_t dev_spec, io_dev_info_t **dev_info);
static int memmap_block_open(io_dev_info_t *dev_info, const uintptr_t spec,
io_entity_t *entity);
static int memmap_block_seek(io_entity_t *entity, int mode,
signed long long offset);
static int memmap_block_len(io_entity_t *entity, size_t *length);
static int memmap_block_read(io_entity_t *entity, uintptr_t buffer,
size_t length, size_t *length_read);
static int memmap_block_write(io_entity_t *entity, const uintptr_t buffer,
size_t length, size_t *length_written);
static int memmap_block_close(io_entity_t *entity);
static int memmap_dev_close(io_dev_info_t *dev_info);
static const io_dev_connector_t memmap_dev_connector = {
.dev_open = memmap_dev_open
};
static const io_dev_funcs_t memmap_dev_funcs = {
.type = device_type_memmap,
.open = memmap_block_open,
.seek = memmap_block_seek,
.size = memmap_block_len,
.read = memmap_block_read,
.write = memmap_block_write,
.close = memmap_block_close,
.dev_init = NULL,
.dev_close = memmap_dev_close,
};
/* No state associated with this device so structure can be const */
static io_dev_info_t memmap_dev_info = {
.funcs = &memmap_dev_funcs,
.info = (uintptr_t)NULL
};
/* Open a connection to the memmap device */
static int memmap_dev_open(const uintptr_t dev_spec __unused,
io_dev_info_t **dev_info)
{
assert(dev_info != NULL);
*dev_info = &memmap_dev_info;
return 0;
}
/* Close a connection to the memmap device */
static int memmap_dev_close(io_dev_info_t *dev_info)
{
/* NOP */
/* TODO: Consider tracking open files and cleaning them up here */
return 0;
}
/* Open a file on the memmap device */
static int memmap_block_open(io_dev_info_t *dev_info, const uintptr_t spec,
io_entity_t *entity)
{
int result = -ENOMEM;
const io_block_spec_t *block_spec = (io_block_spec_t *)spec;
/* Since we need to track open state for seek() we only allow one open
* spec at a time. When we have dynamic memory we can malloc and set
* entity->info.
*/
if (current_memmap_file.in_use == 0) {
assert(block_spec != NULL);
assert(entity != NULL);
current_memmap_file.in_use = 1;
current_memmap_file.base = block_spec->offset;
/* File cursor offset for seek and incremental reads etc. */
current_memmap_file.file_pos = 0;
current_memmap_file.size = block_spec->length;
entity->info = (uintptr_t)&current_memmap_file;
result = 0;
} else {
WARN("A Memmap device is already active. Close first.\n");
}
return result;
}
/* Seek to a particular file offset on the memmap device */
static int memmap_block_seek(io_entity_t *entity, int mode,
signed long long offset)
{
int result = -ENOENT;
memmap_file_state_t *fp;
/* We only support IO_SEEK_SET for the moment. */
if (mode == IO_SEEK_SET) {
assert(entity != NULL);
fp = (memmap_file_state_t *) entity->info;
/* Assert that new file position is valid */
assert((offset >= 0) &&
((unsigned long long)offset < fp->size));
/* Reset file position */
fp->file_pos = (unsigned long long)offset;
result = 0;
}
return result;
}
/* Return the size of a file on the memmap device */
static int memmap_block_len(io_entity_t *entity, size_t *length)
{
assert(entity != NULL);
assert(length != NULL);
*length = (size_t)((memmap_file_state_t *)entity->info)->size;
return 0;
}
/* Read data from a file on the memmap device */
static int memmap_block_read(io_entity_t *entity, uintptr_t buffer,
size_t length, size_t *length_read)
{
memmap_file_state_t *fp;
unsigned long long pos_after;
assert(entity != NULL);
assert(length_read != NULL);
fp = (memmap_file_state_t *) entity->info;
/* Assert that file position is valid for this read operation */
pos_after = fp->file_pos + length;
assert((pos_after >= fp->file_pos) && (pos_after <= fp->size));
memcpy((void *)buffer,
(void *)((uintptr_t)(fp->base + fp->file_pos)), length);
*length_read = length;
/* Set file position after read */
fp->file_pos = pos_after;
return 0;
}
/* Write data to a file on the memmap device */
static int memmap_block_write(io_entity_t *entity, const uintptr_t buffer,
size_t length, size_t *length_written)
{
memmap_file_state_t *fp;
unsigned long long pos_after;
assert(entity != NULL);
assert(length_written != NULL);
fp = (memmap_file_state_t *) entity->info;
/* Assert that file position is valid for this write operation */
pos_after = fp->file_pos + length;
assert((pos_after >= fp->file_pos) && (pos_after <= fp->size));
memcpy((void *)((uintptr_t)(fp->base + fp->file_pos)),
(void *)buffer, length);
*length_written = length;
/* Set file position after write */
fp->file_pos = pos_after;
return 0;
}
/* Close a file on the memmap device */
static int memmap_block_close(io_entity_t *entity)
{
assert(entity != NULL);
entity->info = 0;
/* This would be a mem free() if we had malloc.*/
zeromem((void *)&current_memmap_file, sizeof(current_memmap_file));
return 0;
}
/* Exported functions */
/* Register the memmap driver with the IO abstraction */
int register_io_dev_memmap(const io_dev_connector_t **dev_con)
{
int result;
assert(dev_con != NULL);
result = io_register_device(&memmap_dev_info);
if (result == 0)
*dev_con = &memmap_dev_connector;
return result;
}