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/*
* Copyright (C) 2017-2024 Alibaba Group Holding Limited
*
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the License); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an AS IS BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <rtthread.h>
#include <rtdevice.h>
#define DBG_TAG "drv.ramdisk"
#define DBG_LVL DBG_INFO
#include <rtdbg.h>
#define RAMDISK_SECTOR_SIZE 512
#define RAMDISK_SIZE (8 * 1024 * 1024)
#define RAMDISK_SECTOR_NR (RAMDISK_SIZE / RAMDISK_SECTOR_SIZE)
static struct rt_device _ramdisk_dev;
static rt_uint8_t *_ramdisk_data;
static rt_ssize_t _ramdisk_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
{
if (pos + size > RAMDISK_SECTOR_NR)
{
return 0;
}
rt_memcpy(buffer, _ramdisk_data + pos * RAMDISK_SECTOR_SIZE, size * RAMDISK_SECTOR_SIZE);
return size;
}
static rt_ssize_t _ramdisk_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
{
if (pos + size > RAMDISK_SECTOR_NR)
{
return 0;
}
rt_memcpy(_ramdisk_data + pos * RAMDISK_SECTOR_SIZE, buffer, size * RAMDISK_SECTOR_SIZE);
return size;
}
static rt_err_t _ramdisk_control(rt_device_t dev, int cmd, void *args)
{
if (cmd == RT_DEVICE_CTRL_BLK_GETGEOME)
{
struct rt_device_blk_geometry *geometry = (struct rt_device_blk_geometry *)args;
if (geometry == RT_NULL)
{
return -RT_ERROR;
}
geometry->bytes_per_sector = RAMDISK_SECTOR_SIZE;
geometry->block_size = RAMDISK_SECTOR_SIZE;
geometry->sector_count = RAMDISK_SECTOR_NR;
}
return RT_EOK;
}
#ifdef RT_USING_DEVICE_OPS
static const struct rt_device_ops ramdisk_ops = {
RT_NULL,
RT_NULL,
RT_NULL,
_ramdisk_read,
_ramdisk_write,
_ramdisk_control,
};
#endif
int rt_hw_ramdisk_init(void)
{
rt_device_t dev = &_ramdisk_dev;
_ramdisk_data = rt_malloc(RAMDISK_SIZE);
if (_ramdisk_data == RT_NULL)
{
LOG_E("no memory for the ramdisk");
return -RT_ENOMEM;
}
rt_memset(_ramdisk_data, 0, RAMDISK_SIZE);
dev->type = RT_Device_Class_Block;
#ifdef RT_USING_DEVICE_OPS
dev->ops = &ramdisk_ops;
#else
dev->read = _ramdisk_read;
dev->write = _ramdisk_write;
dev->control = _ramdisk_control;
#endif
return rt_device_register(dev, "ramdisk0", RT_DEVICE_FLAG_RDWR | RT_DEVICE_FLAG_STANDALONE);
}
INIT_DEVICE_EXPORT(rt_hw_ramdisk_init);
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