bladeRF: have it functional with libbladerf 2.0

Not much has been changed in the driver (that used libbladerf 1.0).
Some bugs have been fixed. Documentation has been added. A configuration
file has been added too, put in the directory ./configuration/bladeRF.

To use a bladeRF device, see documentation in targets/ARCH/BLADERF/README.

Only the BladeRF x40 has been tested.

Performance is not too bad at 5MHz, a bit worse at 10MHz and on the test
machine I used I face realtime problems at 20MHz when I push downlink
throughput.

So, there is still some work to do to have a good support of bladeRF.

targets/ARCH/BLADERF/README

+BladeRF documentation
+=====================
+
+As of 2018-11-06, the bladeRF support is not fully automatic and requires
+some manual settings before use. This documentation is the ultimate source
+of information. If something described in this file does not work or does
+not correspond to the reality, then contact us so we can fix the problems
+and update this documentation.
+
+1. Install bladeRF 2.0 libraries.
+
+    As of now, it's better to install from source.
+    So, do not run: ./build_oai -I -w BLADERF
+    (That is: do not include '-w BLADERF'.)
+
+    Instead, follow the instructions at: https://github.com/Nuand/bladeRF
+
+    If you already had some bladeRF software installed using automatic
+    methods, first remove it by hand ('apt-get purge bladeRF' or something
+    similar, you can get the list of installed bladeRF packages by running
+    'dpkg -l|grep -i blade', remove them all).
+
+2. Update the device.
+
+    Download the latest FX3 firmware and FPGA images from Nuand's website.
+    As of writing, this is:
+
+        https://github.com/Nuand/bladeRF/wiki
+
+    That points to the following pages.
+    For FX3:
+
+        http://www.nuand.com/fx3_images/
+
+    For FPGA:
+
+        http://www.nuand.com/fpga_images/
+
+    Install FX3 firmware:
+
+        sudo bladeRF-cli -f bladeRF_fw_latest.img
+
+    Install FPGA image (this is for BladeRF x40):
+
+        sudo bladeRF-cli -L hostedx40-latest.rbf
+
+    Retrieve calibration information:
+
+        sudo bladeRF-cli -i
+        info
+
+    That outputs the serial number of your device.
+
+    Go to:
+
+        https://www.nuand.com/calibration
+
+    And enter your serial number.
+    The website tells you to run something like:
+
+        sudo bladeRF-cli -i
+        flash_init_cal 40 0x9271
+
+    Actual values depend on your device and serial number.
+
+3. Calibrate the bladeRF device.
+
+    We will work with band 7 on 2.68GHz with a bandwidth of 5 MHz (25 RBs).
+
+    Plug the bladeRF device, then run:
+
+        sudo bladeRF-cli -i
+        set frequency tx 2680000000
+        set frequency rx 2560000000
+        set gain rx 60
+        set gain tx 60
+        set bandwidth 5000000
+        set samplerate 7680000
+        cal lms
+        cal lms
+        cal lms
+        cal dc rxtx
+        cal dc rxtx
+        cal dc rxtx
+
+4. Tune the RX gain using the enb tracer.
+
+    Run the softmodem and the 'enb' tracer. For instructions, see:
+
+        https://gitlab.eurecom.fr/oai/openairinterface5g/wikis/T/basic
+
+    In the enb window, check the 'input signal'. You should see some blue
+    signal as seen at:
+
+        https://gitlab.eurecom.fr/oai/openairinterface5g/wikis/T/enb
+
+    (the 'Time signal power' plot).
+
+    The level should be around 30.
+
+    If it's not around 30 then edit your configuration file and modify
+    the value 'max_rxgain' in the section 'RUs'.
+
+    The configuration file to use is:
+
+        configuration/bladeRF/enb-band7-5mhz.conf
+
+    In the configuration file, you also need to set the correct values for:
+
+        - tracking_area_code
+        - plmn_list: mcc, mnc, mnc_length
+        - mme_ip_address: this is the IP address used by the computer running
+          the softmodem to connect to the EPC
+        - NETWORK_INTERFACES: all the ENB*ADDRESS* variables have to point
+          to the IP address of the EPC machine
+
+5. You're good to go.
+
+    You can now connect a UE and pass some traffic. If everything is well
+    configured you can expect more than 16 Mb/s of throughput in the downlink
+    using iperf and more than 8 Mb/s in the uplink. Looking at the logs, you
+    should find lines containing 'PHR 40' and 'CQI 15'. If your values are
+    lower then your setup may need some adjustments.
+
+6. In case of problems.
+
+    If the performance of the softmodem is very bad, you can stop it and
+    run the calibration again, without setting the parameters (frequencies,
+    gains, etc.). Just run:
+
+        sudo bladeRF-cli -i
+        cal lms
+        cal dc rxtx
+
+    That may help.
+
+    Be sure to use proper radio equipment (duplexer, antennas, clean
+    environment without interferences).

targets/ARCH/BLADERF/USERSPACE/LIB/bladerf_lib.c

@@ -116,15 +116,6 @@ int trx_brf_start(openair0_device *device) {
     abort();
   }
 
-  if ((status=bladerf_calibrate_dc(brf->dev, BLADERF_MODULE_TX)) != 0) {
-    fprintf(stderr,"Failed to calibrate TX DC: %s\n", bladerf_strerror(status));
-    abort();
-  }
-  if ((status=bladerf_calibrate_dc(brf->dev, BLADERF_MODULE_RX)) != 0) {
-    fprintf(stderr,"Failed to calibrate RX DC: %s\n", bladerf_strerror(status));
-    abort();
-  }
-
   return 0;
 }
 
@@ -235,8 +226,6 @@ static int trx_brf_read(openair0_device *device, openair0_timestamp *ptimestamp,
  * \param device the hardware to use
  */
 void trx_brf_end(openair0_device *device) {
-abort();
-
   int status;
   brf_state_t *brf = (brf_state_t*)device->priv;
   // Disable RX module, shutting down our underlying RX stream
@@ -247,6 +236,7 @@ abort();
     fprintf(stderr, "Failed to disable TX module: %s\n",  bladerf_strerror(status));
   }
   bladerf_close(brf->dev);
+  exit(1);
 }
 
 /*! \brief print the BladeRF statistics  
@@ -362,6 +352,8 @@ void set_rx_gain_offset(openair0_config_t *openair0_cfg, int chain_index) {
  */
 void calibrate_rf(openair0_device *device) {
 
+  /* TODO: this function does not seem to work. Disabled until fixed. */
+  return;
 
   brf_state_t *brf = (brf_state_t *)device->priv;
   openair0_timestamp ptimestamp;
@@ -1005,6 +997,12 @@ int device_init(openair0_device *device, openair0_config_t *openair0_cfg) {
   // RX  
   // Example of CLI output: RX Frequency: 2539999999Hz
   
+
+  if ((status=bladerf_set_gain_mode(brf->dev, BLADERF_MODULE_RX, BLADERF_GAIN_MGC))) {
+    fprintf(stderr, "[BRF] Failed to disable AGC\n");
+    brf_error(status);
+  }
+
   if ((status=bladerf_set_frequency(brf->dev, BLADERF_MODULE_RX, (unsigned int) openair0_cfg->rx_freq[0])) != 0){
     fprintf(stderr,"Failed to set RX frequency: %s\n",bladerf_strerror(status));
     brf_error(status);
@@ -1096,17 +1094,14 @@ int device_init(openair0_device *device, openair0_config_t *openair0_cfg) {
 
   // calibrate 
     
- if ((status=bladerf_calibrate_dc(brf->dev, BLADERF_MODULE_TX)) != 0) {
-    fprintf(stderr,"Failed to calibrate TX DC: %s\n", bladerf_strerror(status));
+  if ((status=bladerf_calibrate_dc(brf->dev, BLADERF_DC_CAL_LPF_TUNING)) != 0 ||
+      (status=bladerf_calibrate_dc(brf->dev, BLADERF_DC_CAL_TX_LPF)) != 0 ||
+      (status=bladerf_calibrate_dc(brf->dev, BLADERF_DC_CAL_RX_LPF)) != 0 ||
+      (status=bladerf_calibrate_dc(brf->dev, BLADERF_DC_CAL_RXVGA2)) != 0) {
+    fprintf(stderr, "[BRF] error calibrating\n");
     brf_error(status);
-  } else 
-    printf("[BRF] TX module calibrated DC \n");
- 
-  if ((status=bladerf_calibrate_dc(brf->dev, BLADERF_MODULE_RX)) != 0) {
-    fprintf(stderr,"Failed to calibrate RX DC: %s\n", bladerf_strerror(status));
-    brf_error(status);
-  }else 
-    printf("[BRF] RX module calibrated DC \n");
+  } else
+    printf("[BRF] calibration OK\n");
   
   bladerf_log_set_verbosity(get_brf_log_level(openair0_cfg->log_level));
   
@@ -1146,8 +1141,8 @@ int device_init(openair0_device *device, openair0_config_t *openair0_cfg) {
  * \returns 0 on success
  */
 int brf_error(int status) {
-  
-  //exit(-1);
+  fprintf(stderr, "[BRF] brf_error: %s\n", bladerf_strerror(status));
+  exit(-1);
   return status; // or status error code
 }
 
@@ -1190,7 +1185,7 @@ struct bladerf * open_bladerf_from_serial(const char *serial) {
 int get_brf_log_level(int log_level){
 
   int level=BLADERF_LOG_LEVEL_INFO;
-  return  BLADERF_LOG_LEVEL_DEBUG; // BLADERF_LOG_LEVEL_VERBOSE;// BLADERF_LOG_LEVEL_DEBUG; //
+  return  BLADERF_LOG_LEVEL_INFO;
   switch(log_level) {
   case LOG_DEBUG:
     level=BLADERF_LOG_LEVEL_DEBUG;