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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /drivers/media/test-drivers/vidtv/vidtv_common.c | |
parent | Initial commit. (diff) | |
download | linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip |
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/media/test-drivers/vidtv/vidtv_common.c')
-rw-r--r-- | drivers/media/test-drivers/vidtv/vidtv_common.c | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/drivers/media/test-drivers/vidtv/vidtv_common.c b/drivers/media/test-drivers/vidtv/vidtv_common.c new file mode 100644 index 000000000..63b3055bd --- /dev/null +++ b/drivers/media/test-drivers/vidtv/vidtv_common.c @@ -0,0 +1,89 @@ +// 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; +} |