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 000000000000..63b3055bd715
--- /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;
+}