/*
* Copyright (c) 2016-2017, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <assert.h>
#include <errno.h>
#include <string.h>
#include <platform_def.h>
#include <common/debug.h>
#include <drivers/io/io_block.h>
#include <drivers/io/io_driver.h>
#include <drivers/io/io_storage.h>
#include <lib/utils.h>
typedef struct {
io_block_dev_spec_t *dev_spec;
uintptr_t base;
size_t file_pos;
size_t size;
} block_dev_state_t;
#define is_power_of_2(x) ((x != 0) && ((x & (x - 1)) == 0))
io_type_t device_type_block(void);
static int block_open(io_dev_info_t *dev_info, const uintptr_t spec,
io_entity_t *entity);
static int block_seek(io_entity_t *entity, int mode, ssize_t offset);
static int block_read(io_entity_t *entity, uintptr_t buffer, size_t length,
size_t *length_read);
static int block_write(io_entity_t *entity, const uintptr_t buffer,
size_t length, size_t *length_written);
static int block_close(io_entity_t *entity);
static int block_dev_open(const uintptr_t dev_spec, io_dev_info_t **dev_info);
static int block_dev_close(io_dev_info_t *dev_info);
static const io_dev_connector_t block_dev_connector = {
.dev_open = block_dev_open
};
static const io_dev_funcs_t block_dev_funcs = {
.type = device_type_block,
.open = block_open,
.seek = block_seek,
.size = NULL,
.read = block_read,
.write = block_write,
.close = block_close,
.dev_init = NULL,
.dev_close = block_dev_close,
};
static block_dev_state_t state_pool[MAX_IO_BLOCK_DEVICES];
static io_dev_info_t dev_info_pool[MAX_IO_BLOCK_DEVICES];
/* Track number of allocated block state */
static unsigned int block_dev_count;
io_type_t device_type_block(void)
{
return IO_TYPE_BLOCK;
}
/* Locate a block state in the pool, specified by address */
static int find_first_block_state(const io_block_dev_spec_t *dev_spec,
unsigned int *index_out)
{
unsigned int index;
int result = -ENOENT;
for (index = 0U; index < MAX_IO_BLOCK_DEVICES; ++index) {
/* dev_spec is used as identifier since it's unique */
if (state_pool[index].dev_spec == dev_spec) {
result = 0;
*index_out = index;
break;
}
}
return result;
}
/* Allocate a device info from the pool and return a pointer to it */
static int allocate_dev_info(io_dev_info_t **dev_info)
{
int result = -ENOMEM;
assert(dev_info != NULL);
if (block_dev_count < MAX_IO_BLOCK_DEVICES) {
unsigned int index = 0;
result = find_first_block_state(NULL, &index);
assert(result == 0);
/* initialize dev_info */
dev_info_pool[index].funcs = &block_dev_funcs;
dev_info_pool[index].info = (uintptr_t)&state_pool[index];
*dev_info = &dev_info_pool[index];
++block_dev_count;
}
return result;
}
/* Release a device info to the pool */
static int free_dev_info(io_dev_info_t *dev_info)
{
int result;
unsigned int index = 0;
block_dev_state_t *state;
assert(dev_info != NULL);
state = (block_dev_state_t *)dev_info->info;
result = find_first_block_state(state->dev_spec, &index);
if (result == 0) {
/* free if device info is valid */
zeromem(state, sizeof(block_dev_state_t));
zeromem(dev_info, sizeof(io_dev_info_t));
--block_dev_count;
}
return result;
}
static int block_open(io_dev_info_t *dev_info, const uintptr_t spec,
io_entity_t *entity)
{
block_dev_state_t *cur;
io_block_spec_t *region;
assert((dev_info->info != (uintptr_t)NULL) &&
(spec != (uintptr_t)NULL) &&
(entity->info == (uintptr_t)NULL));
region = (io_block_spec_t *)spec;
cur = (block_dev_state_t *)dev_info->info;
assert(((region->offset % cur->dev_spec->block_size) == 0) &&
((region->length % cur->dev_spec->block_size) == 0));
cur->base = region->offset;
cur->size = region->length;
cur->file_pos = 0;
entity->info = (uintptr_t)cur;
return 0;
}
/* parameter offset is relative address at here */
static int block_seek(io_entity_t *entity, int mode, ssize_t offset)
{
block_dev_state_t *cur;
assert(entity->info != (uintptr_t)NULL);
cur = (block_dev_state_t *)entity->info;
assert((offset >= 0) && (offset < cur->size));
switch (mode) {
case IO_SEEK_SET:
cur->file_pos = offset;
break;
case IO_SEEK_CUR:
cur->file_pos += offset;
break;
default:
return -EINVAL;
}
assert(cur->file_pos < cur->size);
return 0;
}
/*
* This function allows the caller to read any number of bytes
* from any position. It hides from the caller that the low level
* driver only can read aligned blocks of data. For this reason
* we need to handle the use case where the first byte to be read is not
* aligned to start of the block, the last byte to be read is also not
* aligned to the end of a block, and there are zero or more blocks-worth
* of data in between.
*
* In such a case we need to read more bytes than requested (i.e. full
* blocks) and strip-out the leading bytes (aka skip) and the trailing
* bytes (aka padding). See diagram below
*
* cur->file_pos ------------
* |
* cur->base |
* | |
* v v<---- length ---->
* --------------------------------------------------------------
* | | block#1 | | block#n |
* | block#0 | + | ... | + |
* | | <- skip -> + | | + <- padding ->|
* ------------------------+----------------------+--------------
* ^ ^
* | |
* v iteration#1 iteration#n v
* --------------------------------------------------
* | | | |
* |<---- request ---->| ... |<----- request ---->|
* | | | |
* --------------------------------------------------
* / / | |
* / / | |
* / / | |
* / / | |
* / / | |
* / / | |
* / / | |
* / / | |
* / / | |
* / / | |
* <---- request ------> <------ request ----->
* --------------------- -----------------------
* | | | | | |
* |<-skip->|<-nbytes->| -------->|<-nbytes->|<-padding->|
* | | | | | | |
* --------------------- | -----------------------
* ^ \ \ | | |
* | \ \ | | |
* | \ \ | | |
* buf->offset \ \ buf->offset | |
* \ \ | |
* \ \ | |
* \ \ | |
* \ \ | |
* \ \ | |
* \ \ | |
* \ \ | |
* --------------------------------
* | | | |
* buffer-------------->| | ... | |
* | | | |
* --------------------------------
* <-count#1->| |
* <---------- count#n -------->
* <---------- length ---------->
*
* Additionally, the IO driver has an underlying buffer that is at least
* one block-size and may be big enough to allow.
*/
static int block_read(io_entity_t *entity, uintptr_t buffer, size_t length,
size_t *length_read)
{
block_dev_state_t *cur;
io_block_spec_t *buf;
io_block_ops_t *ops;
int lba;
size_t block_size, left;
size_t nbytes; /* number of bytes read in one iteration */
size_t request; /* number of requested bytes in one iteration */
size_t count; /* number of bytes already read */
/*
* number of leading bytes from start of the block
* to the first byte to be read
*/
size_t skip;
/*
* number of trailing bytes between the last byte
* to be read and the end of the block
*/
size_t padding;
assert(entity->info != (uintptr_t)NULL);
cur = (block_dev_state_t *)entity->info;
ops = &(cur->dev_spec->ops);
buf = &(cur->dev_spec->buffer);
block_size = cur->dev_spec->block_size;
assert((length <= cur->size) &&
(length > 0) &&
(ops->read != 0));
/*
* We don't know the number of bytes that we are going
* to read in every iteration, because it will depend
* on the low level driver.
*/
count = 0;
for (left = length; left > 0; left -= nbytes) {
/*
* We must only request operations aligned to the block
* size. Therefore if file_pos is not block-aligned,
* we have to request the operation to start at the
* previous block boundary and skip the leading bytes. And
* similarly, the number of bytes requested must be a
* block size multiple
*/
skip = cur->file_pos & (block_size - 1);
/*
* Calculate the block number containing file_pos
* - e.g. block 3.
*/
lba = (cur->file_pos + cur->base) / block_size;
if (skip + left > buf->length) {
/*
* The underlying read buffer is too small to
* read all the required data - limit to just
* fill the buffer, and then read again.
*/
request = buf->length;
} else {
/*
* The underlying read buffer is big enough to
* read all the required data. Calculate the
* number of bytes to read to align with the
* block size.
*/
request = skip + left;
request = (request + (block_size - 1)) & ~(block_size - 1);
}
request = ops->read(lba, buf->offset, request);
if (request <= skip) {
/*
* We couldn't read enough bytes to jump over
* the skip bytes, so we should have to read
* again the same block, thus generating
* the same error.
*/
return -EIO;
}
/*
* Need to remove skip and padding bytes,if any, from
* the read data when copying to the user buffer.
*/
nbytes = request - skip;
padding = (nbytes > left) ? nbytes - left : 0;
nbytes -= padding;
memcpy((void *)(buffer + count),
(void *)(buf->offset + skip),
nbytes);
cur->file_pos += nbytes;
count += nbytes;
}
assert(count == length);
*length_read = count;
return 0;
}
/*
* This function allows the caller to write any number of bytes
* from any position. It hides from the caller that the low level
* driver only can write aligned blocks of data.
* See comments for block_read for more details.
*/
static int block_write(io_entity_t *entity, const uintptr_t buffer,
size_t length, size_t *length_written)
{
block_dev_state_t *cur;
io_block_spec_t *buf;
io_block_ops_t *ops;
int lba;
size_t block_size, left;
size_t nbytes; /* number of bytes read in one iteration */
size_t request; /* number of requested bytes in one iteration */
size_t count; /* number of bytes already read */
/*
* number of leading bytes from start of the block
* to the first byte to be read
*/
size_t skip;
/*
* number of trailing bytes between the last byte
* to be read and the end of the block
*/
size_t padding;
assert(entity->info != (uintptr_t)NULL);
cur = (block_dev_state_t *)entity->info;
ops = &(cur->dev_spec->ops);
buf = &(cur->dev_spec->buffer);
block_size = cur->dev_spec->block_size;
assert((length <= cur->size) &&
(length > 0) &&
(ops->read != 0) &&
(ops->write != 0));
/*
* We don't know the number of bytes that we are going
* to write in every iteration, because it will depend
* on the low level driver.
*/
count = 0;
for (left = length; left > 0; left -= nbytes) {
/*
* We must only request operations aligned to the block
* size. Therefore if file_pos is not block-aligned,
* we have to request the operation to start at the
* previous block boundary and skip the leading bytes. And
* similarly, the number of bytes requested must be a
* block size multiple
*/
skip = cur->file_pos & (block_size - 1);
/*
* Calculate the block number containing file_pos
* - e.g. block 3.
*/
lba = (cur->file_pos + cur->base) / block_size;
if (skip + left > buf->length) {
/*
* The underlying read buffer is too small to
* read all the required data - limit to just
* fill the buffer, and then read again.
*/
request = buf->length;
} else {
/*
* The underlying read buffer is big enough to
* read all the required data. Calculate the
* number of bytes to read to align with the
* block size.
*/
request = skip + left;
request = (request + (block_size - 1)) & ~(block_size - 1);
}
/*
* The number of bytes that we are going to write
* from the user buffer will depend of the size
* of the current request.
*/
nbytes = request - skip;
padding = (nbytes > left) ? nbytes - left : 0;
nbytes -= padding;
/*
* If we have skip or padding bytes then we have to preserve
* some content and it means that we have to read before
* writing
*/
if (skip > 0 || padding > 0) {
request = ops->read(lba, buf->offset, request);
/*
* The read may return size less than
* requested. Round down to the nearest block
* boundary
*/
request &= ~(block_size-1);
if (request <= skip) {
/*
* We couldn't read enough bytes to jump over
* the skip bytes, so we should have to read
* again the same block, thus generating
* the same error.
*/
return -EIO;
}
nbytes = request - skip;
padding = (nbytes > left) ? nbytes - left : 0;
nbytes -= padding;
}
memcpy((void *)(buf->offset + skip),
(void *)(buffer + count),
nbytes);
request = ops->write(lba, buf->offset, request);
if (request <= skip)
return -EIO;
/*
* And the previous write operation may modify the size
* of the request, so again, we have to calculate the
* number of bytes that we consumed from the user
* buffer
*/
nbytes = request - skip;
padding = (nbytes > left) ? nbytes - left : 0;
nbytes -= padding;
cur->file_pos += nbytes;
count += nbytes;
}
assert(count == length);
*length_written = count;
return 0;
}
static int block_close(io_entity_t *entity)
{
entity->info = (uintptr_t)NULL;
return 0;
}
static int block_dev_open(const uintptr_t dev_spec, io_dev_info_t **dev_info)
{
block_dev_state_t *cur;
io_block_spec_t *buffer;
io_dev_info_t *info;
size_t block_size;
int result;
assert(dev_info != NULL);
result = allocate_dev_info(&info);
if (result)
return -ENOENT;
cur = (block_dev_state_t *)info->info;
/* dev_spec is type of io_block_dev_spec_t. */
cur->dev_spec = (io_block_dev_spec_t *)dev_spec;
buffer = &(cur->dev_spec->buffer);
block_size = cur->dev_spec->block_size;
assert((block_size > 0) &&
(is_power_of_2(block_size) != 0) &&
((buffer->offset % block_size) == 0) &&
((buffer->length % block_size) == 0));
*dev_info = info; /* cast away const */
(void)block_size;
(void)buffer;
return 0;
}
static int block_dev_close(io_dev_info_t *dev_info)
{
return free_dev_info(dev_info);
}
/* Exported functions */
/* Register the Block driver with the IO abstraction */
int register_io_dev_block(const io_dev_connector_t **dev_con)
{
int result;
assert(dev_con != NULL);
/*
* Since dev_info isn't really used in io_register_device, always
* use the same device info at here instead.
*/
result = io_register_device(&dev_info_pool[0]);
if (result == 0)
*dev_con = &block_dev_connector;
return result;
}
