1 files changed, 67 insertions, 0 deletions
diff --git a/src/target/firmware/layer1/agc.c b/src/target/firmware/layer1/agc.c
new file mode 100644
index 00000000..aa4af5e1
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+++ b/src/target/firmware/layer1/agc.c
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+/* AFC (Automatic Gain Control) Implementation */
+
+/* (C) 2010 by Harald Welte <laforge@gnumonks.org>
+ *
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+
+#include <stdint.h>
+#include <stdio.h>
+
+#include <debug.h>
+#include <gsm.h>
+#include <rffe.h>
+
+#include <layer1/agc.h>
+#include <calypso/dsp.h>
+
+/* This is a value that has been measured on the C123 by Harald: 71dBm,
+   it is the difference between the input level at the antenna and what
+   the DSP reports, subtracted by the total gain of the TRF6151 */
+#define SYSTEM_INHERENT_GAIN	71
+
+/* compute the input level present at the antenna based on a baseband
+ * power measurement of the DSP at baseband */
+int16_t agc_inp_dbm8_by_pm(int16_t pm)
+{
+	/* pm is in 1/8 dBm at baseband */
+	int16_t total_gain_dbm8;
+
+	/* compute total current gain */
+	total_gain_dbm8 = (SYSTEM_INHERENT_GAIN + rffe_get_gain()) * 8;
+
+	/* subtract gain from power measurement at baseband level */
+	return pm - total_gain_dbm8;
+}
+
+uint8_t agc_il_by_dbm8(int16_t dbm8)
+{
+	uint16_t il;
+
+	/* convert from 1/8 dBm to l1c format: [220..0] in -1/2dBm unit */
+	if (dbm8 >= 0)
+		il = 0;
+	else
+		il = -dbm8;
+
+	/* saturate */
+	if (il > 4 * 255)
+		il = 4 * 255;
+
+	return (uint8_t)(il >> 2);
+}