nrf51: Add generic radio support

Add functions to initialize and disable the radio.
Add packet definitions.
Update the spelling of the FICR_OVERRIDEEN register.

BUG=None
BRANCH=None
TEST=make buildall -j

Change-Id: I3a9e500d0f177b6ce77a3b6ed6a42acd4f49eb7e
Signed-off-by: Myles Watson <mylesgw@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/362175
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Reviewed-by: Levi Oliver <levio@google.com>

4 files changed, 99 insertions, 4 deletions

diff --git a/chip/nrf51/build.mk b/chip/nrf51/build.mk
index db64c6f618..88509bba3c 100644
--- a/chip/nrf51/build.mk
+++ b/chip/nrf51/build.mk
@@ -13,6 +13,7 @@ CFLAGS_CPU+=-march=armv6-m -mcpu=cortex-m0
 chip-y+=gpio.o system.o uart.o
 chip-y+=jtag.o watchdog.o ppi.o
 
+chip-$(CONFIG_BLUETOOTH_LE)+=radio.o
 chip-$(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.c b/chip/nrf51/radio.c
new file mode 100644
index 0000000000..af9d029a0d
--- /dev/null
+++ b/chip/nrf51/radio.c
@@ -0,0 +1,59 @@
+/* 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 "radio.h"
+
+int radio_disable(void)
+{
+	int timeout = 10000;
+
+	NRF51_RADIO_DISABLED = 0;
+	NRF51_RADIO_DISABLE = 1;
+
+	while (!NRF51_RADIO_DISABLED && timeout > 0)
+		timeout--;
+
+	if (timeout == 0)
+		return EC_ERROR_TIMEOUT;
+
+	return EC_SUCCESS;
+}
+
+int radio_init(enum nrf51_radio_mode_t mode)
+{
+	int err_code = radio_disable();
+
+	if (mode == BLE_1MBIT) {
+		NRF51_RADIO_MODE = NRF51_RADIO_MODE_BLE_1MBIT;
+
+		NRF51_RADIO_TIFS = 150;	/* Bluetooth 4.1 Vol 6 pg 58 4.1 */
+
+		/*
+		 * BLE never sends or receives two packets in a row.
+		 * Enabling the radio means we want to transmit or receive.
+		 * After transmission, disable as quickly as possible.
+		 */
+		NRF51_RADIO_SHORTS = NRF51_RADIO_SHORTS_READY_START |
+				NRF51_RADIO_SHORTS_END_DISABLE;
+
+		/* Use factory parameters if available */
+		if (!(NRF51_FICR_OVERRIDEEN & NRF51_FICR_OVERRIDEEN_BLE_BIT_N)
+		    ) {
+			int i;
+
+			for (i = 0; i < 4; i++) {
+				NRF51_RADIO_OVERRIDE(i) =
+					NRF51_FICR_BLE_1MBIT(i);
+			}
+			NRF51_RADIO_OVERRIDE(4) = NRF51_FICR_BLE_1MBIT(4) |
+				NRF51_RADIO_OVERRIDE_EN;
+		}
+	} else {
+		return EC_ERROR_UNIMPLEMENTED;
+	}
+
+	return err_code;
+}
+
diff --git a/chip/nrf51/radio.h b/chip/nrf51/radio.h
new file mode 100644
index 0000000000..43232202f2
--- /dev/null
+++ b/chip/nrf51/radio.h
@@ -0,0 +1,35 @@
+/* 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 interface for Chrome EC */
+
+#ifndef __NRF51_RADIO_H
+#define __NRF51_RADIO_H
+
+#include "common.h"
+#include "registers.h"
+
+#ifndef NRF51_RADIO_MAX_PAYLOAD
+	#define NRF51_RADIO_MAX_PAYLOAD 253
+#endif
+
+#define RADIO_DONE (NRF51_RADIO_END == 1)
+
+enum nrf51_radio_mode_t {
+	BLE_1MBIT = NRF51_RADIO_MODE_BLE_1MBIT,
+};
+
+struct nrf51_radio_packet_t {
+	uint8_t s0; /* First byte */
+	uint8_t length; /* Length field */
+	uint8_t s1; /* Bits after length */
+	uint8_t payload[NRF51_RADIO_MAX_PAYLOAD];
+} __packed;
+
+int radio_init(enum nrf51_radio_mode_t mode);
+
+int radio_disable(void);
+
+#endif  /* __NRF51_RADIO_H */
diff --git a/chip/nrf51/registers.h b/chip/nrf51/registers.h
index ebf49b4a93..3f60828fa1 100644
--- a/chip/nrf51/registers.h
+++ b/chip/nrf51/registers.h
@@ -100,15 +100,15 @@
 #define NRF51_FICR_IR(n)               REG32(NRF51_FICR_BASE + 0x090 + ((n)*4))
 #define NRF51_FICR_DEVICEADDRTYPE      REG32(NRF51_FICR_BASE + 0x0A0)
 #define NRF51_FICR_DEVICEADDR(n)       REG32(NRF51_FICR_BASE + 0x0A4 + ((n)*4))
-#define NRF51_FICR_OVERRIDDEN          REG32(NRF51_FICR_BASE + 0x0AC)
+#define NRF51_FICR_OVERRIDEEN          REG32(NRF51_FICR_BASE + 0x0AC)
 #define NRF51_FICR_BLE_1MBIT(n)        REG32(NRF51_FICR_BASE + 0x0EC + ((n)*4))
 
 /* DEVICEADDRTYPE */
 #define NRF51_FICR_DEVICEADDRTYPE_RANDOM      1
 
-/* OVERRIDDEN */
-#define NRF51_FICR_OVERRIDDEN_NRF_BIT_N       1
-#define NRF51_FICR_OVERRIDDEN_BLE_BIT_N       8
+/* OVERRIDEEN */
+#define NRF51_FICR_OVERRIDEEN_NRF_BIT_N       1
+#define NRF51_FICR_OVERRIDEEN_BLE_BIT_N       8
 
 /*
  * UICR