1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * The Virtual DVB test driver serves as a reference DVB driver and helps
4*4882a593Smuzhiyun * validate the existing APIs in the media subsystem. It can also aid
5*4882a593Smuzhiyun * developers working on userspace applications.
6*4882a593Smuzhiyun *
7*4882a593Smuzhiyun * Copyright (C) 2020 Daniel W. S. Almeida
8*4882a593Smuzhiyun */
9*4882a593Smuzhiyun #define pr_fmt(fmt) KBUILD_MODNAME ":%s, %d: " fmt, __func__, __LINE__
10*4882a593Smuzhiyun
11*4882a593Smuzhiyun #include <linux/printk.h>
12*4882a593Smuzhiyun #include <linux/ratelimit.h>
13*4882a593Smuzhiyun #include <linux/string.h>
14*4882a593Smuzhiyun #include <linux/types.h>
15*4882a593Smuzhiyun
16*4882a593Smuzhiyun #include "vidtv_common.h"
17*4882a593Smuzhiyun
18*4882a593Smuzhiyun /**
19*4882a593Smuzhiyun * vidtv_memcpy() - wrapper routine to be used by MPEG-TS
20*4882a593Smuzhiyun * generator, in order to avoid going past the
21*4882a593Smuzhiyun * output buffer.
22*4882a593Smuzhiyun * @to: Starting element to where a MPEG-TS packet will
23*4882a593Smuzhiyun * be copied.
24*4882a593Smuzhiyun * @to_offset: Starting position of the @to buffer to be filled.
25*4882a593Smuzhiyun * @to_size: Size of the @to buffer.
26*4882a593Smuzhiyun * @from: Starting element of the buffer to be copied.
27*4882a593Smuzhiyun * @len: Number of elements to be copy from @from buffer
28*4882a593Smuzhiyun * into @to+ @to_offset buffer.
29*4882a593Smuzhiyun *
30*4882a593Smuzhiyun * Note:
31*4882a593Smuzhiyun * Real digital TV demod drivers should not have memcpy
32*4882a593Smuzhiyun * wrappers. We use it here because emulating MPEG-TS
33*4882a593Smuzhiyun * generation at kernelspace requires some extra care.
34*4882a593Smuzhiyun *
35*4882a593Smuzhiyun * Return:
36*4882a593Smuzhiyun * Returns the number of bytes written
37*4882a593Smuzhiyun */
vidtv_memcpy(void * to,size_t to_offset,size_t to_size,const void * from,size_t len)38*4882a593Smuzhiyun u32 vidtv_memcpy(void *to,
39*4882a593Smuzhiyun size_t to_offset,
40*4882a593Smuzhiyun size_t to_size,
41*4882a593Smuzhiyun const void *from,
42*4882a593Smuzhiyun size_t len)
43*4882a593Smuzhiyun {
44*4882a593Smuzhiyun if (unlikely(to_offset + len > to_size)) {
45*4882a593Smuzhiyun pr_err_ratelimited("overflow detected, skipping. Try increasing the buffer size. Needed %zu, had %zu\n",
46*4882a593Smuzhiyun to_offset + len,
47*4882a593Smuzhiyun to_size);
48*4882a593Smuzhiyun return 0;
49*4882a593Smuzhiyun }
50*4882a593Smuzhiyun
51*4882a593Smuzhiyun memcpy(to + to_offset, from, len);
52*4882a593Smuzhiyun return len;
53*4882a593Smuzhiyun }
54*4882a593Smuzhiyun
55*4882a593Smuzhiyun /**
56*4882a593Smuzhiyun * vidtv_memset() - wrapper routine to be used by MPEG-TS
57*4882a593Smuzhiyun * generator, in order to avoid going past the
58*4882a593Smuzhiyun * output buffer.
59*4882a593Smuzhiyun * @to: Starting element to set
60*4882a593Smuzhiyun * @to_offset: Starting position of the @to buffer to be filled.
61*4882a593Smuzhiyun * @to_size: Size of the @to buffer.
62*4882a593Smuzhiyun * @c: The value to set the memory to.
63*4882a593Smuzhiyun * @len: Number of elements to be copy from @from buffer
64*4882a593Smuzhiyun * into @to+ @to_offset buffer.
65*4882a593Smuzhiyun *
66*4882a593Smuzhiyun * Note:
67*4882a593Smuzhiyun * Real digital TV demod drivers should not have memset
68*4882a593Smuzhiyun * wrappers. We use it here because emulating MPEG-TS
69*4882a593Smuzhiyun * generation at kernelspace requires some extra care.
70*4882a593Smuzhiyun *
71*4882a593Smuzhiyun * Return:
72*4882a593Smuzhiyun * Returns the number of bytes written
73*4882a593Smuzhiyun */
vidtv_memset(void * to,size_t to_offset,size_t to_size,const int c,size_t len)74*4882a593Smuzhiyun u32 vidtv_memset(void *to,
75*4882a593Smuzhiyun size_t to_offset,
76*4882a593Smuzhiyun size_t to_size,
77*4882a593Smuzhiyun const int c,
78*4882a593Smuzhiyun size_t len)
79*4882a593Smuzhiyun {
80*4882a593Smuzhiyun if (unlikely(to_offset + len > to_size)) {
81*4882a593Smuzhiyun pr_err_ratelimited("overflow detected, skipping. Try increasing the buffer size. Needed %zu, had %zu\n",
82*4882a593Smuzhiyun to_offset + len,
83*4882a593Smuzhiyun to_size);
84*4882a593Smuzhiyun return 0;
85*4882a593Smuzhiyun }
86*4882a593Smuzhiyun
87*4882a593Smuzhiyun memset(to + to_offset, c, len);
88*4882a593Smuzhiyun return len;
89*4882a593Smuzhiyun }
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