at86rf2xx: implement CSMA settings

drivers/at86rf2xx/at86rf2xx_getset.c

@@ -16,6 +16,7 @@
  * @author      Thomas Eichinger <thomas.eichinger@fu-berlin.de>
  * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
  * @author      Baptiste Clenet <bapclenet@gmail.com>
+ * @author      Daniel Krebs <github@daniel-krebs.net>
  *
  * @}
  */
@@ -254,6 +255,56 @@ void at86rf2xx_set_max_retries(at86rf2xx_t *dev, uint8_t max)
     at86rf2xx_reg_write(dev, AT86RF2XX_REG__XAH_CTRL_0, tmp);
 }
 
+uint8_t at86rf2xx_get_csma_max_retries(at86rf2xx_t *dev)
+{
+    uint8_t tmp;
+    tmp  = at86rf2xx_reg_read(dev, AT86RF2XX_REG__XAH_CTRL_0);
+    tmp &= AT86RF2XX_XAH_CTRL_0__MAX_CSMA_RETRIES;
+    tmp >>= 1;
+    return tmp;
+}
+
+void at86rf2xx_set_csma_max_retries(at86rf2xx_t *dev, int8_t retries)
+{
+    retries = (retries > 5) ? 5 : retries; /* valid values: 0-5 */
+    retries = (retries < 0) ? 7 : retries; /* max < 0 => disable CSMA (set to 7) */
+    DEBUG("[at86rf2xx] opt: Set CSMA retries to %u\n", retries);
+
+    uint8_t tmp = at86rf2xx_reg_read(dev, AT86RF2XX_REG__XAH_CTRL_0);
+    tmp &= ~(AT86RF2XX_XAH_CTRL_0__MAX_CSMA_RETRIES);
+    tmp |= (retries << 1);
+    at86rf2xx_reg_write(dev, AT86RF2XX_REG__XAH_CTRL_0, tmp);
+}
+
+void at86rf2xx_set_csma_backoff_exp(at86rf2xx_t *dev, uint8_t min, uint8_t max)
+{
+    max = (max > 8) ? 8 : max;
+    min = (min > max) ? max : min;
+    DEBUG("[at86rf2xx] opt: Set min BE=%u, max BE=%u\n", min, max);
+
+    at86rf2xx_reg_write(dev,
+            AT86RF2XX_REG__CSMA_BE,
+            (max << 4) | (min));
+}
+
+void at86rf2xx_set_csma_seed(at86rf2xx_t *dev, uint8_t entropy[2])
+{
+    if(entropy == NULL) {
+        DEBUG("[at86rf2xx] opt: CSMA seed entropy is nullpointer\n");
+        return;
+    }
+    DEBUG("[at86rf2xx] opt: Set CSMA seed to 0x%x 0x%x\n", entropy[0], entropy[1]);
+
+    at86rf2xx_reg_write(dev,
+                           AT86RF2XX_REG__CSMA_SEED_0,
+                           entropy[0]);
+
+    uint8_t tmp = at86rf2xx_reg_read(dev, AT86RF2XX_REG__CSMA_SEED_1);
+    tmp &= ~(AT86RF2XX_CSMA_SEED_1__CSMA_SEED_1);
+    tmp |= entropy[1] & AT86RF2XX_CSMA_SEED_1__CSMA_SEED_1;
+    at86rf2xx_reg_write(dev, AT86RF2XX_REG__CSMA_SEED_1, tmp);
+}
+
 void at86rf2xx_set_option(at86rf2xx_t *dev, uint16_t option, bool state)
 {
     uint8_t tmp;
@@ -266,8 +317,12 @@ void at86rf2xx_set_option(at86rf2xx_t *dev, uint16_t option, bool state)
         /* trigger option specific actions */
         switch (option) {
             case AT86RF2XX_OPT_CSMA:
-                DEBUG("[at86rf2xx] opt: enabling CSMA mode (NOT IMPLEMENTED)\n");
+                DEBUG("[at86rf2xx] opt: enabling CSMA mode" \
-                /* TODO: en/disable csma */
+                      "(4 retries, min BE: 3 max BE: 5)\n");
+                /* Initialize CSMA seed with hardware address */
+                at86rf2xx_set_csma_seed(dev, dev->addr_long);
+                at86rf2xx_set_csma_max_retries(dev, 4);
+                at86rf2xx_set_csma_backoff_exp(dev, 3, 5);
                 break;
             case AT86RF2XX_OPT_PROMISCUOUS:
                 DEBUG("[at86rf2xx] opt: enabling PROMISCUOUS mode\n");
@@ -302,8 +357,9 @@ void at86rf2xx_set_option(at86rf2xx_t *dev, uint16_t option, bool state)
         /* trigger option specific actions */
         switch (option) {
             case AT86RF2XX_OPT_CSMA:
-                DEBUG("[at86rf2xx] opt: disabling CSMA mode (NOT IMPLEMENTED)\n");
+                DEBUG("[at86rf2xx] opt: disabling CSMA mode\n");
-                /* TODO: en/disable csma */
+                /* setting retries to -1 means CSMA disabled */
+                at86rf2xx_set_csma_max_retries(dev, -1);
                 break;
             case AT86RF2XX_OPT_PROMISCUOUS:
                 DEBUG("[at86rf2xx] opt: disabling PROMISCUOUS mode\n");

drivers/at86rf2xx/at86rf2xx_netdev.c

@@ -528,6 +528,18 @@ static int _get(gnrc_netdev_t *device, netopt_t opt, void *val, size_t max_len)
                 !!(dev->options & AT86RF2XX_OPT_TELL_TX_END);
             return sizeof(netopt_enable_t);
 
+        case NETOPT_CSMA:
+            *((netopt_enable_t *)val) =
+                !!(dev->options & AT86RF2XX_OPT_CSMA);
+            return sizeof(netopt_enable_t);
+
+        case NETOPT_CSMA_RETRIES:
+            if (max_len < sizeof(uint8_t)) {
+                return -EOVERFLOW;
+            }
+            *((uint8_t *)val) = at86rf2xx_get_csma_max_retries(dev);
+            return sizeof(uint8_t);
+
         default:
             return -ENOTSUP;
     }
@@ -654,6 +666,23 @@ static int _set(gnrc_netdev_t *device, netopt_t opt, void *val, size_t len)
                                  ((bool *)val)[0]);
             return sizeof(netopt_enable_t);
 
+        case NETOPT_CSMA:
+            at86rf2xx_set_option(dev, AT86RF2XX_OPT_CSMA,
+                                    ((bool *)val)[0]);
+            return sizeof(netopt_enable_t);
+
+        case NETOPT_CSMA_RETRIES:
+            if( (len > sizeof(uint8_t)) ||
+                (*((uint8_t *)val) > 5) ) {
+                return -EOVERFLOW;
+            }
+            /* If CSMA is disabled, don't allow setting retries */
+            if( !(dev->options & AT86RF2XX_OPT_CSMA) ) {
+                return -ENOTSUP;
+            }
+            at86rf2xx_set_csma_max_retries(dev, *((uint8_t *)val));
+            return sizeof(uint8_t);
+
         default:
             return -ENOTSUP;
     }

drivers/at86rf2xx/include/at86rf2xx_registers.h

@@ -317,6 +317,7 @@ extern "C" {
 #define AT86RF2XX_CSMA_SEED_1__AACK_SET_PD                      (0x20)
 #define AT86RF2XX_CSMA_SEED_1__AACK_DIS_ACK                     (0x10)
 #define AT86RF2XX_CSMA_SEED_1__AACK_I_AM_COORD                  (0x08)
+#define AT86RF2XX_CSMA_SEED_1__CSMA_SEED_1                      (0x07)
 /** @} */
 
 /**

drivers/include/at86rf2xx.h

@@ -21,6 +21,7 @@
  * @author      Thomas Eichinger <thomas.eichinger@fu-berlin.de>
  * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
  * @author      Kaspar Schleiser <kaspar@schleiser.de>
+ * @author      Daniel Krebs <github@daniel-krebs.net>
  */
 
 #ifndef AT86RF2XX_H_
@@ -334,6 +335,48 @@ uint8_t at86rf2xx_get_max_retries(at86rf2xx_t *dev);
  */
 void at86rf2xx_set_max_retries(at86rf2xx_t *dev, uint8_t max);
 
+/**
+ * @brief   Get the maximum number of channel access attempts per frame (CSMA)
+ *
+ * @param[in] dev           device to read from
+ *
+ * @return                  configured number of retries
+ */
+uint8_t at86rf2xx_get_csma_max_retries(at86rf2xx_t *dev);
+
+/**
+ * @brief   Set the maximum number of channel access attempts per frame (CSMA)
+ *
+ * This setting specifies the number of attempts to access the channel to
+ * transmit a frame. If the channel is busy @p retries times, then frame
+ * transmission fails.
+ * Valid values: 0 to 5, -1 means CSMA disabled
+ *
+ * @param[in] dev           device to write to
+ * @param[in] max           the maximum number of retries
+ */
+void at86rf2xx_set_csma_max_retries(at86rf2xx_t *dev, int8_t retries);
+
+/**
+ * @brief   Set the min and max backoff exponent for CSMA/CA
+ *
+ * - Maximum BE: 0 - 8
+ * - Minimum BE: 0 - [max]
+ *
+ * @param[in] dev           device to write to
+ * @param[in] min           the minimum BE
+ * @param[in] max           the maximum BE
+ */
+void at86rf2xx_set_csma_backoff_exp(at86rf2xx_t *dev, uint8_t min, uint8_t max);
+
+/**
+ * @brief   Set seed for CSMA random backoff
+ *
+ * @param[in] dev           device to write to
+ * @param[in] entropy       11 bit of entropy as seed for random backoff
+ */
+void at86rf2xx_set_csma_seed(at86rf2xx_t *dev, uint8_t entropy[2]);
+
 /**
  * @brief   Enable or disable driver specific options
  *

sys/include/net/netopt.h

@@ -137,9 +137,31 @@ typedef enum {
      * @note not all transceivers may support this interrupt
      */
     NETOPT_TX_END_IRQ,
-    NETOPT_AUTOCCA,             /**< en/disable to check automatically
-                                 *   before sending the channel is clear. */
 
+    /**
+     * @brief Check automatically before sending if the channel is clear.
+     *
+     * This may be a hardware feature of the given transceiver, or might be
+     * otherwise implemented in software. If the device supports CSMA this
+     * option will enable CSMA with a certain set of parameters to emulate the
+     * desired behaviour.
+     *
+     * @note Be sure not to set NETCONF_OPT_CSMA simultaneously.
+     *
+     * TODO: How to get feedback?
+     */
+    NETOPT_AUTOCCA,
+
+    /**
+     * @brief en/disable CSMA/CA support
+     *
+     * If the device supports CSMA in hardware, this option enables it with
+     * default parameters. For further configuration refer to the other
+     * NETCONF_OPT_CSMA_* options.
+     */
+    NETOPT_CSMA,
+    NETOPT_CSMA_RETRIES,            /**< get/set the number of retries when
+                                         when channel is busy */
     /**
      * @brief read-only check for a wired interface.
      *

sys/net/crosslayer/netopt/netopt.c

@@ -46,6 +46,8 @@ static const char *_netopt_strmap[] = {
     [NETOPT_TX_START_IRQ]    = "NETOPT_TX_START_IRQ",
     [NETOPT_TX_END_IRQ]      = "NETOPT_TX_END_IRQ",
     [NETOPT_AUTOCCA]         = "NETOPT_AUTOCCA",
+    [NETOPT_CSMA]            = "NETOPT_CSMA",
+    [NETOPT_CSMA_RETRIES]    = "NETOPT_CSMA_RETRIES",
     [NETOPT_IS_WIRED]        = "NETOPT_IS_WIRED",
     [NETOPT_NUMOF]           = "NETOPT_NUMOF",
 };

sys/shell/commands/sc_netif.c

@@ -80,7 +80,8 @@ static void _set_usage(char *cmd_name)
          "       * \"addr_long\" - sets long address\n"
          "       * \"addr_short\" - alias for \"addr\"\n"
          "       * \"channel\" - sets the frequency channel\n"
-         "       * \"chan\" - alias for \"channel\""
+         "       * \"chan\" - alias for \"channel\"\n"
+         "       * \"csma_retries\" - set max. number of channel access attempts\n"
          "       * \"nid\" - sets the network identifier (or the PAN ID)\n"
          "       * \"pan\" - alias for \"nid\"\n"
          "       * \"pan_id\" - alias for \"nid\"\n"
@@ -96,7 +97,7 @@ static void _mtu_usage(char *cmd_name)
 
 static void _flag_usage(char *cmd_name)
 {
-    printf("usage: %s <if_id> [-]{promisc|autoack|preload|6lo|iphc}\n", cmd_name);
+    printf("usage: %s <if_id> [-]{promisc|autoack|csma|autocca|preload|6lo|iphc}\n", cmd_name);
 }
 
 static void _add_usage(char *cmd_name)
@@ -138,6 +139,10 @@ static void _print_netopt(netopt_t opt)
             printf("TX power [in dBm]");
             break;
 
+        case NETOPT_CSMA_RETRIES:
+            printf("CSMA retries");
+            break;
+
         default:
             /* we don't serve these options here */
             break;
@@ -176,6 +181,7 @@ static void _netif_list(kernel_pid_t dev)
     uint8_t hwaddr[MAX_ADDR_LEN];
     uint16_t u16;
     int16_t i16;
+    uint8_t u8;
     int res;
     netopt_state_t state;
     netopt_enable_t enable;
@@ -232,9 +238,19 @@ static void _netif_list(kernel_pid_t dev)
         printf("Long HWaddr: ");
         printf("%s ", gnrc_netif_addr_to_str(hwaddr_str, sizeof(hwaddr_str),
                                             hwaddr, res));
-        printf("\n           ");
     }
 
+    res = gnrc_netapi_get(dev, NETOPT_CSMA_RETRIES, 0, &u8, sizeof(u8));
+
+    if (res >= 0) {
+        res = gnrc_netapi_get(dev, NETOPT_CSMA, 0, &enable, sizeof(enable));
+        if ((res >= 0) && (enable == NETOPT_ENABLE)) {
+            printf(" CSMA Retries: %" PRIu8 " ", *((uint8_t*) &u8));
+        }
+    }
+
+    printf("\n           ");
+
     res = gnrc_netapi_get(dev, NETOPT_PROMISCUOUSMODE, 0, &enable, sizeof(enable));
 
     if ((res >= 0) && (enable == NETOPT_ENABLE)) {
@@ -263,6 +279,20 @@ static void _netif_list(kernel_pid_t dev)
         linebreak = true;
     }
 
+    res = gnrc_netapi_get(dev, NETOPT_CSMA, 0, &enable, sizeof(enable));
+
+    if ((res >= 0) && (enable == NETOPT_ENABLE)) {
+        printf("CSMA  ");
+        linebreak = true;
+    }
+
+    res = gnrc_netapi_get(dev, NETOPT_AUTOCCA, 0, &enable, sizeof(enable));
+
+    if ((res >= 0) && (enable == NETOPT_ENABLE)) {
+        printf("AUTOCCA  ");
+        linebreak = true;
+    }
+
 #ifdef MODULE_GNRC_IPV6_NETIF
     if (entry != NULL) {
         printf("MTU:%" PRIu16 "  ", entry->mtu);
@@ -401,6 +431,24 @@ static int _netif_set_i16(kernel_pid_t dev, netopt_t opt, char *i16_str)
     return 0;
 }
 
+static int _netif_set_u8(kernel_pid_t dev, netopt_t opt, char *u8_str)
+{
+    uint8_t val = (uint8_t)atoi(u8_str);
+
+    if (gnrc_netapi_set(dev, opt, 0, (uint8_t *)&val, sizeof(uint8_t)) < 0) {
+        printf("error: unable to set ");
+        _print_netopt(opt);
+        puts("");
+        return 1;
+    }
+
+    printf("success: set ");
+    _print_netopt(opt);
+    printf(" on interface %" PRIkernel_pid " to %i\n", dev, val);
+
+    return 0;
+}
+
 static int _netif_set_flag(kernel_pid_t dev, netopt_t opt,
                            netopt_enable_t set)
 {
@@ -498,6 +546,9 @@ static int _netif_set(char *cmd_name, kernel_pid_t dev, char *key, char *value)
     else if (strcmp("state", key) == 0) {
         return _netif_set_state(dev, value);
     }
+    else if (strcmp("csma_retries", key) == 0) {
+        return _netif_set_u8(dev, NETOPT_CSMA_RETRIES, value);
+    }
 
     _set_usage(cmd_name);
     return 1;
@@ -524,6 +575,12 @@ static int _netif_flag(char *cmd, kernel_pid_t dev, char *flag)
     else if (strcmp(flag, "raw") == 0) {
         return _netif_set_flag(dev, NETOPT_RAWMODE, set);
     }
+    else if (strcmp(flag, "csma") == 0) {
+        return _netif_set_flag(dev, NETOPT_CSMA, set);
+    }
+    else if (strcmp(flag, "autocca") == 0) {
+        return _netif_set_flag(dev, NETOPT_AUTOCCA, set);
+    }
     else if (strcmp(flag, "6lo") == 0) {
 #ifdef MODULE_GNRC_IPV6_NETIF
         gnrc_ipv6_netif_t *entry = gnrc_ipv6_netif_get(dev);