1 files changed, 43 insertions, 0 deletions
diff --git a/drivers/sound/synth.c b/drivers/sound/synth.c
new file mode 100644
index 0000000000..c9de62b516
--- /dev/null
+++ b/drivers/sound/synth.c
@@ -0,0 +1,43 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2012 Samsung Electronics, R. Chandrasekar <rcsekar@samsung.com>
+ * Copyright (C) 2021 Ahmad Fatoum
+ */
+
+#include <common.h>
+#include <linux/fixp-arith.h>
+#include <linux/math64.h>
+#include <sound.h>
+
+void __synth_sin(unsigned freq, s16 amplitude, s16 *stream,
+		 unsigned sample_rate, unsigned nsamples)
+{
+    int64_t v = 0;
+    int i = 0;
+
+    for (i = 0; i < nsamples; i++) {
+	    /* Assume RHS sign extension, true for GCC */
+	    stream[i] = (fixp_sin32(div_s64(v * 360, sample_rate)) * (int64_t)amplitude) >> 31;
+	    v += freq;
+    }
+}
+
+void __synth_square(unsigned freq, s16 amplitude, s16 *stream,
+		    unsigned sample_rate, unsigned nsamples)
+{
+	unsigned period = freq ? sample_rate / freq : 0;
+	int half = period / 2;
+
+	while (nsamples) {
+		int i;
+
+		for (i = 0; nsamples && i < half; i++) {
+			nsamples--;
+			*stream++ = amplitude;
+		}
+		for (i = 0; nsamples && i < period - half; i++) {
+			nsamples--;
+			*stream++ = -amplitude;
+		}
+	}
+}