From 76e4c820e526947e6ca91edd2477e932efed3f91 Mon Sep 17 00:00:00 2001
From: Oleg Hahm <oleg@hobbykeller.org>
Date: Mon, 18 May 2015 21:19:03 +0200
Subject: [PATCH] ng_netconf: ng_at86rf2xx: set retransmissions

Introduces a netconf option to configure the maximum amount of
retransmissions and implements this for the at86rf2xx radios.
---
 drivers/include/ng_at86rf2xx.h                | 21 +++++++++++++++++++
 .../include/ng_at86rf2xx_registers.h          |  9 ++++++++
 drivers/ng_at86rf2xx/ng_at86rf2xx_getset.c    | 14 +++++++++++++
 drivers/ng_at86rf2xx/ng_at86rf2xx_netdev.c    | 14 +++++++++++++
 sys/include/net/ng_netconf.h                  |  2 ++
 5 files changed, 60 insertions(+)

diff --git a/drivers/include/ng_at86rf2xx.h b/drivers/include/ng_at86rf2xx.h
index 83bbbff5db..22291b3276 100644
--- a/drivers/include/ng_at86rf2xx.h
+++ b/drivers/include/ng_at86rf2xx.h
@@ -316,6 +316,27 @@ int16_t ng_at86rf2xx_get_txpower(ng_at86rf2xx_t *dev);
  */
 void ng_at86rf2xx_set_txpower(ng_at86rf2xx_t *dev, int16_t txpower);
 
+/**
+ * @brief   Get the maximum number of retransmissions
+ *
+ * @param[in] dev           device to read from
+ *
+ * @return                  configured number of retransmissions
+ */
+uint8_t ng_at86rf2xx_get_max_retries(ng_at86rf2xx_t *dev);
+
+/**
+ * @brief   Set the maximum number of retransmissions
+ *
+ * This setting specifies the number of attempts to retransmit a frame, when it
+ * was not acknowledged by the recipient, before the transaction gets cancelled.
+ * The maximum value is 7.
+ *
+ * @param[in] dev           device to write to
+ * @param[in] max           the maximum number of retransmissions
+ */
+void ng_at86rf2xx_set_max_retries(ng_at86rf2xx_t *dev, uint8_t max);
+
 /**
  * @brief   Enable or disable driver specific options
  *
diff --git a/drivers/ng_at86rf2xx/include/ng_at86rf2xx_registers.h b/drivers/ng_at86rf2xx/include/ng_at86rf2xx_registers.h
index 73630f67ee..94c328a6da 100644
--- a/drivers/ng_at86rf2xx/include/ng_at86rf2xx_registers.h
+++ b/drivers/ng_at86rf2xx/include/ng_at86rf2xx_registers.h
@@ -291,6 +291,15 @@ extern "C" {
 #define NG_AT86RF2XX_TIMING__RESET_TO_TRX_OFF                   (37)
 /** @} */
 
+/**
+ * @brief   Bitfield definitions for the XAH_CTRL_0 register
+ * @{
+ */
+#define NG_AT86RF2XX_XAH_CTRL_0__MAX_FRAME_RETRIES              (0xF0)
+#define NG_AT86RF2XX_XAH_CTRL_0__MAX_CSMA_RETRIES               (0x0E)
+#define NG_AT86RF2XX_XAH_CTRL_0__SLOTTED_OPERATION              (0x01)
+/** @} */
+
 /**
  * @brief   Bitfield definitions for the XAH_CTRL_1 register
  * @{
diff --git a/drivers/ng_at86rf2xx/ng_at86rf2xx_getset.c b/drivers/ng_at86rf2xx/ng_at86rf2xx_getset.c
index 25a918db6c..0394cd3590 100644
--- a/drivers/ng_at86rf2xx/ng_at86rf2xx_getset.c
+++ b/drivers/ng_at86rf2xx/ng_at86rf2xx_getset.c
@@ -235,6 +235,20 @@ void ng_at86rf2xx_set_txpower(ng_at86rf2xx_t *dev, int16_t txpower)
 #endif
 }
 
+uint8_t ng_at86rf2xx_get_max_retries(ng_at86rf2xx_t *dev)
+{
+    return (ng_at86rf2xx_reg_read(dev, NG_AT86RF2XX_REG__XAH_CTRL_0) >> 4);
+}
+
+void ng_at86rf2xx_set_max_retries(ng_at86rf2xx_t *dev, uint8_t max)
+{
+    max = (max > 7) ? 7 : max;
+    uint8_t tmp = ng_at86rf2xx_reg_read(dev, NG_AT86RF2XX_REG__XAH_CTRL_0);
+    tmp &= ~(NG_AT86RF2XX_XAH_CTRL_0__MAX_FRAME_RETRIES);
+    tmp |= (max << 4);
+    ng_at86rf2xx_reg_write(dev, NG_AT86RF2XX_REG__XAH_CTRL_0, tmp);
+}
+
 void ng_at86rf2xx_set_option(ng_at86rf2xx_t *dev, uint16_t option, bool state)
 {
     uint8_t tmp;
diff --git a/drivers/ng_at86rf2xx/ng_at86rf2xx_netdev.c b/drivers/ng_at86rf2xx/ng_at86rf2xx_netdev.c
index cec284c901..87ded51896 100644
--- a/drivers/ng_at86rf2xx/ng_at86rf2xx_netdev.c
+++ b/drivers/ng_at86rf2xx/ng_at86rf2xx_netdev.c
@@ -445,6 +445,13 @@ static int _get(ng_netdev_t *device, ng_netconf_opt_t opt,
             }
             return sizeof(ng_netconf_enable_t);
 
+        case NETCONF_OPT_RETRANS:
+            if (max_len < sizeof(uint8_t)) {
+                return -EOVERFLOW;
+            }
+            *((uint8_t *)val) = ng_at86rf2xx_get_max_retries(dev);
+            return sizeof(uint8_t);
+
         case NETCONF_OPT_PROMISCUOUSMODE:
             if (dev->options & NG_AT86RF2XX_OPT_PROMISCUOUS) {
                 *((ng_netconf_enable_t *)val) = NETCONF_ENABLE;
@@ -577,6 +584,13 @@ static int _set(ng_netdev_t *device, ng_netconf_opt_t opt,
                                     ((bool *)val)[0]);
             return sizeof(ng_netconf_enable_t);
 
+        case NETCONF_OPT_RETRANS:
+            if (len > sizeof(uint8_t)) {
+                return -EOVERFLOW;
+            }
+            ng_at86rf2xx_set_max_retries(dev, *((uint8_t *)val));
+            return sizeof(uint8_t);
+
         case NETCONF_OPT_PRELOADING:
             ng_at86rf2xx_set_option(dev, NG_AT86RF2XX_OPT_PRELOADING,
                                     ((bool *)val)[0]);
diff --git a/sys/include/net/ng_netconf.h b/sys/include/net/ng_netconf.h
index 167b221193..170cfcaa2e 100644
--- a/sys/include/net/ng_netconf.h
+++ b/sys/include/net/ng_netconf.h
@@ -72,6 +72,8 @@ typedef enum {
                                      *   the current state */
     NETCONF_OPT_AUTOACK,            /**< en/disable link layer auto ACKs or read
                                      *   the current state */
+    NETCONF_OPT_RETRANS,            /**< get/set the maximum number of
+                                         retransmissions. */
     NETCONF_OPT_PROTO,              /**< get/set the protocol for the layer
                                      *   as type ng_nettype_t. */
     NETCONF_OPT_STATE,              /**< get/set the state of network devices as