nrf51: Add Bluetooth LE test code for the radio

Implement support for Direct Test Modet packets.

BUG=None
BRANCH=None
CQ-DEPEND=CL:361960
TEST=use hci commands to send and receive test packets.

Change-Id: Idc12812fb88319ba6f8aad4396a175e3299211b8
Signed-off-by: Myles Watson <mylesgw@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/362143
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Reviewed-by: Levi Oliver <levio@google.com>

3 files changed, 226 insertions, 0 deletions

diff --git a/chip/nrf51/build.mk b/chip/nrf51/build.mk
index 69a2e3ed41..5680f10d91 100644
--- a/chip/nrf51/build.mk
+++ b/chip/nrf51/build.mk
@@ -14,6 +14,7 @@ chip-y+=gpio.o system.o uart.o
 chip-y+=jtag.o watchdog.o ppi.o
 
 chip-$(CONFIG_BLUETOOTH_LE)+=radio.o bluetooth_le.o
+chip-$(CONFIG_BLUETOOTH_LE_RADIO_TEST)+=radio_test.o
 chip-$(CONFIG_COMMON_TIMER)+=hwtimer.o clock.o
 chip-$(CONFIG_I2C)+=i2c.o
 chip-$(HAS_TASK_KEYSCAN)+=keyboard_raw.o
diff --git a/chip/nrf51/radio_test.c b/chip/nrf51/radio_test.c
new file mode 100644
index 0000000000..bcad7466e9
--- /dev/null
+++ b/chip/nrf51/radio_test.c
@@ -0,0 +1,184 @@
+/* Copyright 2016 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "bluetooth_le.h" /* chan2freq */
+#include "btle_hci_int.h"
+#include "console.h"
+#include "radio.h"
+#include "radio_test.h"
+#include "registers.h"
+#include "timer.h"
+#include "util.h"
+
+#define BLE_TEST_TYPE_PRBS9   0
+#define BLE_TEST_TYPE_F0      1
+#define BLE_TEST_TYPE_AA      2
+#define BLE_TEST_TYPE_PRBS15  3
+#define BLE_TEST_TYPE_FF      4
+#define BLE_TEST_TYPE_00      5
+#define BLE_TEST_TYPE_0F      6
+#define BLE_TEST_TYPE_55      7
+
+#define BLE_TEST_TYPES_IMPLEMENTED 0xf6 /* No PRBS yet */
+
+static struct nrf51_ble_packet_t rx_packet;
+static struct nrf51_ble_packet_t tx_packet;
+static uint32_t rx_end;
+
+static int test_in_progress;
+
+void ble_test_stop(void)
+{
+	test_in_progress = 0;
+}
+
+static uint32_t prbs_lfsr;
+static uint32_t prbs_poly;
+
+/*
+ * This is a Galois LFSR, the polynomial is the counterpart of the Fibonacci
+ * LFSR in the doc.  It requires fewer XORs to implement in software.
+ * This also means that the initial value is different.
+ */
+static uint8_t prbs_next_byte(void)
+{
+	int i;
+	int lsb;
+	uint8_t rv = 0;
+
+	for (i = 0; i < 8; i++) {
+		lsb = prbs_lfsr & 1;
+		rv |= lsb << i;
+		prbs_lfsr = prbs_lfsr >> 1;
+		if (lsb)
+			prbs_lfsr ^= prbs_poly;
+	}
+	return rv;
+}
+
+void ble_test_fill_tx_packet(int type, int len)
+{
+	int i;
+
+	tx_packet.s0 = type & 0xf;
+	tx_packet.length = len;
+
+	switch (type) {
+	case BLE_TEST_TYPE_PRBS9:
+		prbs_lfsr = 0xf;
+		prbs_poly = 0x108;
+		for (i = 0; i < len; i++)
+			tx_packet.payload[i] = prbs_next_byte();
+		break;
+	case BLE_TEST_TYPE_PRBS15:
+		prbs_lfsr = 0xf;
+		prbs_poly = 0x6000;
+		for (i = 0; i < len; i++)
+			tx_packet.payload[i] = prbs_next_byte();
+		break;
+	case BLE_TEST_TYPE_F0:
+		memset(tx_packet.payload, 0xF0, len);
+		break;
+	case BLE_TEST_TYPE_AA:
+		memset(tx_packet.payload, 0xAA, len);
+		break;
+	case BLE_TEST_TYPE_FF:
+		memset(tx_packet.payload, 0xFF, len);
+		break;
+	case BLE_TEST_TYPE_00:
+		memset(tx_packet.payload, 0x00, len);
+		break;
+	case BLE_TEST_TYPE_0F:
+		memset(tx_packet.payload, 0x0F, len);
+		break;
+	case BLE_TEST_TYPE_55:
+		memset(tx_packet.payload, 0x55, len);
+		break;
+	default:
+		break;
+	}
+}
+
+static int ble_test_init(int chan)
+{
+	int rv = radio_init(BLE_1MBIT);
+
+	if (rv)
+		return HCI_ERR_Hardware_Failure;
+
+	if (chan > BLE_MAX_TEST_CHANNEL || chan < BLE_MIN_TEST_CHANNEL)
+		return HCI_ERR_Invalid_HCI_Command_Parameters;
+
+	NRF51_RADIO_CRCCNF = 3 | (1 << 8); /* 3-byte, skip address */
+	/* x^24 + x^10 + x^9 + x^6 + x^4 + x^3 + x + 1 */
+	/* 0x1_0000_0000_0000_0110_0101_1011 */
+	NRF51_RADIO_CRCPOLY = 0x100065B;
+	NRF51_RADIO_CRCINIT = 0x555555;
+
+	NRF51_RADIO_TXPOWER = NRF51_RADIO_TXPOWER_0_DBM;
+
+	/* The testing address is the inverse of the advertising address. */
+	NRF51_RADIO_BASE0 = (~BLE_ADV_ACCESS_ADDRESS) << 8;
+
+	NRF51_RADIO_PREFIX0 = (~BLE_ADV_ACCESS_ADDRESS) >> 24;
+
+	NRF51_RADIO_TXADDRESS = 0;
+	NRF51_RADIO_RXADDRESSES = 1;
+
+	NRF51_RADIO_PCNF0 = NRF51_RADIO_PCNF0_TEST;
+
+	NRF51_RADIO_PCNF1 = NRF51_RADIO_PCNF1_TEST;
+
+	NRF51_RADIO_FREQUENCY = NRF51_RADIO_FREQUENCY_VAL(2*chan + 2402);
+
+	test_in_progress = 1;
+	return rv;
+}
+
+int ble_test_rx_init(int chan)
+{
+	NRF51_RADIO_PACKETPTR = (uint32_t)&rx_packet;
+	return ble_test_init(chan);
+}
+
+int ble_test_tx_init(int chan, int len, int type)
+{
+	if (((1 << type) & BLE_TEST_TYPES_IMPLEMENTED) == 0 ||
+			(len < 0 || len > BLE_MAX_TEST_PAYLOAD_OCTETS))
+		return HCI_ERR_Invalid_HCI_Command_Parameters;
+
+	ble_test_fill_tx_packet(type, len);
+	NRF51_RADIO_PACKETPTR = (uint32_t)&tx_packet;
+
+	return ble_test_init(chan);
+}
+
+void ble_test_tx(void)
+{
+	NRF51_RADIO_END = 0;
+	NRF51_RADIO_TXEN = 1;
+}
+
+int ble_test_rx(void)
+{
+	int retries = 100;
+
+	NRF51_RADIO_END = 0;
+	NRF51_RADIO_RXEN = 1;
+
+	do {
+		retries--;
+		if (retries <= 0) {
+			radio_disable();
+			return EC_ERROR_TIMEOUT;
+		}
+		usleep(100);
+	} while (!NRF51_RADIO_END);
+
+	rx_end = get_time().le.lo;
+
+	return EC_SUCCESS;
+}
+
diff --git a/chip/nrf51/radio_test.h b/chip/nrf51/radio_test.h
new file mode 100644
index 0000000000..b70a22d69a
--- /dev/null
+++ b/chip/nrf51/radio_test.h
@@ -0,0 +1,41 @@
+/* Copyright 2016 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+/*
+ * Radio test interface for NRF51
+ *
+ * These functions implement parts of the Direct Test Mode functionality in
+ * the Bluetooth Spec.
+ */
+
+#ifndef __NRF51_RADIO_TEST_H
+#define __NRF51_RADIO_TEST_H
+
+#define BLE_MAX_TEST_PAYLOAD_OCTETS       37
+#define BLE_MAX_TEST_CHANNEL              39
+#define BLE_MIN_TEST_CHANNEL              0
+
+#define NRF51_RADIO_PCNF0_TEST NRF51_RADIO_PCNF0_ADV
+
+#define BLE_TEST_WHITEN           0
+
+#define NRF51_RADIO_PCNF1_TEST \
+	NRF51_RADIO_PCNF1_VAL(BLE_MAX_TEST_PAYLOAD_OCTETS, \
+			      EXTRA_RECEIVE_BYTES, \
+			      BLE_ACCESS_ADDRESS_BYTES - 1, \
+			      BLE_TEST_WHITEN)
+
+/*
+ * Prepare the radio for transmitting packets.  The value of chan must be
+ * between 0 and 39 inclusive.  The maximum length is 37.
+ */
+
+int ble_test_tx_init(int chan, int type, int len);
+int ble_test_rx_init(int chan);
+void ble_test_tx(void);
+int ble_test_rx(void);
+void ble_test_stop(void);
+
+#endif /* __NRF51_RADIO_TEST_H */