90 lines
2.5 KiB
C
90 lines
2.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* The Virtual DVB test driver serves as a reference DVB driver and helps
|
|
* validate the existing APIs in the media subsystem. It can also aid
|
|
* developers working on userspace applications.
|
|
*
|
|
* Copyright (C) 2020 Daniel W. S. Almeida
|
|
*/
|
|
#define pr_fmt(fmt) KBUILD_MODNAME ":%s, %d: " fmt, __func__, __LINE__
|
|
|
|
#include <linux/printk.h>
|
|
#include <linux/ratelimit.h>
|
|
#include <linux/string.h>
|
|
#include <linux/types.h>
|
|
|
|
#include "vidtv_common.h"
|
|
|
|
/**
|
|
* vidtv_memcpy() - wrapper routine to be used by MPEG-TS
|
|
* generator, in order to avoid going past the
|
|
* output buffer.
|
|
* @to: Starting element to where a MPEG-TS packet will
|
|
* be copied.
|
|
* @to_offset: Starting position of the @to buffer to be filled.
|
|
* @to_size: Size of the @to buffer.
|
|
* @from: Starting element of the buffer to be copied.
|
|
* @len: Number of elements to be copy from @from buffer
|
|
* into @to+ @to_offset buffer.
|
|
*
|
|
* Note:
|
|
* Real digital TV demod drivers should not have memcpy
|
|
* wrappers. We use it here because emulating MPEG-TS
|
|
* generation at kernelspace requires some extra care.
|
|
*
|
|
* Return:
|
|
* Returns the number of bytes written
|
|
*/
|
|
u32 vidtv_memcpy(void *to,
|
|
size_t to_offset,
|
|
size_t to_size,
|
|
const void *from,
|
|
size_t len)
|
|
{
|
|
if (unlikely(to_offset + len > to_size)) {
|
|
pr_err_ratelimited("overflow detected, skipping. Try increasing the buffer size. Needed %zu, had %zu\n",
|
|
to_offset + len,
|
|
to_size);
|
|
return 0;
|
|
}
|
|
|
|
memcpy(to + to_offset, from, len);
|
|
return len;
|
|
}
|
|
|
|
/**
|
|
* vidtv_memset() - wrapper routine to be used by MPEG-TS
|
|
* generator, in order to avoid going past the
|
|
* output buffer.
|
|
* @to: Starting element to set
|
|
* @to_offset: Starting position of the @to buffer to be filled.
|
|
* @to_size: Size of the @to buffer.
|
|
* @c: The value to set the memory to.
|
|
* @len: Number of elements to be copy from @from buffer
|
|
* into @to+ @to_offset buffer.
|
|
*
|
|
* Note:
|
|
* Real digital TV demod drivers should not have memset
|
|
* wrappers. We use it here because emulating MPEG-TS
|
|
* generation at kernelspace requires some extra care.
|
|
*
|
|
* Return:
|
|
* Returns the number of bytes written
|
|
*/
|
|
u32 vidtv_memset(void *to,
|
|
size_t to_offset,
|
|
size_t to_size,
|
|
const int c,
|
|
size_t len)
|
|
{
|
|
if (unlikely(to_offset + len > to_size)) {
|
|
pr_err_ratelimited("overflow detected, skipping. Try increasing the buffer size. Needed %zu, had %zu\n",
|
|
to_offset + len,
|
|
to_size);
|
|
return 0;
|
|
}
|
|
|
|
memset(to + to_offset, c, len);
|
|
return len;
|
|
}
|