Merge branch 'ashish/fpga-busy-bugfix' into maint

10 files changed, 220 insertions, 63 deletions

diff --git a/firmware/x300/x300/x300_defs.h b/firmware/x300/x300/x300_defs.h
index 02c3d4808..65c5d5a23 100644
--- a/firmware/x300/x300/x300_defs.h
+++ b/firmware/x300/x300/x300_defs.h
@@ -1,10 +1,10 @@
 
-// Copyright 2012 Ettus Research LLC
+// Copyright 2014 Ettus Research LLC
 
-#ifndef INCLUDED_B250_DEFS_H
-#define INCLUDED_B250_DEFS_H
+#ifndef INCLUDED_X300_DEFS_H
+#define INCLUDED_X300_DEFS_H
 
-#define CPU_CLOCK 175000000
+#define CPU_CLOCK 166666667
 #define MAIN_RAM_BASE 0x0000
 #define PKT_RAM0_BASE 0x8000
 #define XGE0_BASE 0xC000
@@ -72,4 +72,4 @@ static const int BL_DATA        = 1;
 #define ETH_FRAMER_DST_UDP_MAC 6
 #define ETH_FRAMER_DST_MAC_LO 7
 
-#endif /* INCLUDED_B250_DEFS_H */
+#endif /* INCLUDED_X300_DEFS_H */
diff --git a/host/include/uhd/transport/nirio/niriok_proxy.h b/host/include/uhd/transport/nirio/niriok_proxy.h
index a6b6183d1..ca6a4ba02 100644
--- a/host/include/uhd/transport/nirio/niriok_proxy.h
+++ b/host/include/uhd/transport/nirio/niriok_proxy.h
@@ -126,6 +126,8 @@ namespace uhd { namespace niusrprio
         nirio_status unmap_fifo_memory(
             nirio_driver_iface::rio_mmap_t& map);
 
+        nirio_status stop_all_fifos();
+
         nirio_quirks& get_rio_quirks() {
             return _rio_quirks;
         }
diff --git a/host/include/uhd/transport/nirio/niusrprio_session.h b/host/include/uhd/transport/nirio/niusrprio_session.h
index c9a61ae76..c84bc75d0 100644
--- a/host/include/uhd/transport/nirio/niusrprio_session.h
+++ b/host/include/uhd/transport/nirio/niusrprio_session.h
@@ -37,31 +37,31 @@ public:
     typedef uhd::usrprio_rpc::usrprio_device_info device_info;
     typedef uhd::usrprio_rpc::usrprio_device_info_vtr device_info_vtr;
 
-	static nirio_status enumerate(
+    static nirio_status enumerate(
         const std::string& rpc_port_name,
         device_info_vtr& device_info_vtr);
 
-	niusrprio_session(
+    niusrprio_session(
         const std::string& resource_name,
         const std::string& port_name);
-	virtual ~niusrprio_session();
+    virtual ~niusrprio_session();
 
-	nirio_status open(
+    nirio_status open(
         nifpga_lvbitx::sptr lvbitx,
         bool force_download = false);
 
-	void close(bool skip_reset = false);
+    void close(bool skip_reset = false);
 
-	nirio_status reset();
+    nirio_status reset();
 
-	template<typename data_t>
-	nirio_status create_tx_fifo(
-		const char* fifo_name,
-		boost::shared_ptr< nirio_fifo<data_t> >& fifo)
-	{
+    template<typename data_t>
+    nirio_status create_tx_fifo(
+        const char* fifo_name,
+        boost::shared_ptr< nirio_fifo<data_t> >& fifo)
+    {
         if (!_session_open) return NiRio_Status_ResourceNotInitialized;
         return _resource_manager.create_tx_fifo(fifo_name, fifo);
-	}
+    }
 
     template<typename data_t>
     nirio_status create_tx_fifo(
@@ -73,13 +73,13 @@ public:
     }
 
     template<typename data_t>
-	nirio_status create_rx_fifo(
-		const char* fifo_name,
-		boost::shared_ptr< nirio_fifo<data_t> >& fifo)
-	{
+    nirio_status create_rx_fifo(
+        const char* fifo_name,
+        boost::shared_ptr< nirio_fifo<data_t> >& fifo)
+    {
         if (!_session_open) return NiRio_Status_ResourceNotInitialized;
         return _resource_manager.create_rx_fifo(fifo_name, fifo);
-	}
+    }
 
     template<typename data_t>
     nirio_status create_rx_fifo(
@@ -90,9 +90,9 @@ public:
         return create_rx_fifo(_lvbitx->get_input_fifo_names()[fifo_instance], fifo);
     }
 
-	niriok_proxy& get_kernel_proxy() {
-	    return _riok_proxy;
-	}
+    niriok_proxy& get_kernel_proxy() {
+        return _riok_proxy;
+    }
 
     nirio_status download_bitstream_to_flash(const std::string& bitstream_path);
 
@@ -102,21 +102,22 @@ public:
         const std::string& rpc_port_name);
 
 private:
-	nirio_status _verify_signature();
-	std::string _read_bitstream_checksum();
-	nirio_status _write_bitstream_checksum(const std::string& checksum);
-	nirio_status _wait_for_device_available();
-
-	std::string								_resource_name;
-	nifpga_lvbitx::sptr                     _lvbitx;
-    std::string                             _interface_path;
-    bool                                    _session_open;
-	niriok_proxy			                _riok_proxy;
-	nirio_resource_manager	                _resource_manager;
-    usrprio_rpc::usrprio_rpc_client         _rpc_client;
-	boost::recursive_mutex                  _session_mutex;
-
-	static const uint32_t SESSION_LOCK_TIMEOUT_IN_MS    = 3000;
+    nirio_status _verify_signature();
+    std::string _read_bitstream_checksum();
+    nirio_status _write_bitstream_checksum(const std::string& checksum);
+    nirio_status _ensure_fpga_ready();
+
+    std::string                     _resource_name;
+    nifpga_lvbitx::sptr             _lvbitx;
+    std::string                     _interface_path;
+    bool                            _session_open;
+    niriok_proxy                    _riok_proxy;
+    nirio_resource_manager          _resource_manager;
+    usrprio_rpc::usrprio_rpc_client _rpc_client;
+    boost::recursive_mutex          _session_mutex;
+
+    static const uint32_t FPGA_READY_TIMEOUT_IN_MS      = 1000;
+    static const uint32_t SESSION_LOCK_TIMEOUT_IN_MS    = 3000;
     static const uint32_t SESSION_LOCK_RETRY_INT_IN_MS  = 500;
 };
 
diff --git a/host/lib/transport/nirio/niriok_proxy.cpp b/host/lib/transport/nirio/niriok_proxy.cpp
index 031623c9a..ac8faf0a4 100644
--- a/host/lib/transport/nirio/niriok_proxy.cpp
+++ b/host/lib/transport/nirio/niriok_proxy.cpp
@@ -293,6 +293,16 @@ namespace uhd { namespace niusrprio
     {
         return nirio_driver_iface::rio_munmap(map);
     }
+
+    nirio_status niriok_proxy::stop_all_fifos()
+    {
+        nirio_driver_iface::nirio_syncop_in_params_t in = {};
+        nirio_driver_iface::nirio_syncop_out_params_t out = {};
+
+        in.function = nirio_driver_iface::NIRIO_FUNC::FIFO_STOP_ALL;
+
+        return sync_operation(&in, sizeof(in), &out, sizeof(out));
+    }
 }}
 
 #ifdef __GNUC__
diff --git a/host/lib/transport/nirio/niusrprio_session.cpp b/host/lib/transport/nirio/niusrprio_session.cpp
index a07bc4fdf..97d764736 100644
--- a/host/lib/transport/nirio/niusrprio_session.cpp
+++ b/host/lib/transport/nirio/niusrprio_session.cpp
@@ -77,6 +77,8 @@ nirio_status niusrprio_session::open(
         std::string lvbitx_checksum(_lvbitx->get_bitstream_checksum());
         boost::uint16_t download_fpga = (force_download || (_read_bitstream_checksum() != lvbitx_checksum)) ? 1 : 0;
 
+        nirio_status_chain(_ensure_fpga_ready(), status);
+
         nirio_status_chain(_rpc_client.niusrprio_open_session(
             _resource_name, bitfile_path, signature, download_fpga), status);
         _session_open = nirio_status_not_fatal(status);
@@ -196,4 +198,59 @@ nirio_status niusrprio_session::_write_bitstream_checksum(const std::string& che
     return status;
 }
 
+nirio_status niusrprio_session::_ensure_fpga_ready()
+{
+    nirio_status status = NiRio_Status_Success;
+    niriok_scoped_addr_space(_riok_proxy, BUS_INTERFACE, status);
+
+    //Verify that the Ettus FPGA loaded in the device. This may not be true if the
+    //user is switching to UHD after using LabVIEW FPGA. In that case skip this check.
+    boost::uint32_t pcie_fpga_signature = 0;
+    nirio_status_chain(_riok_proxy.peek(FPGA_PCIE_SIG_REG, pcie_fpga_signature), status);
+    //@TODO: Remove X300 specific constants for future products
+    if (pcie_fpga_signature != FPGA_X3xx_SIG_VALUE) {
+        return status;
+    }
+
+    boost::uint32_t reg_data = 0xffffffff;
+    nirio_status_chain(_riok_proxy.peek(FPGA_STATUS_REG, reg_data), status);
+    if (nirio_status_not_fatal(status) && (reg_data & FPGA_STATUS_DMA_ACTIVE_MASK))
+    {
+        //In case this session was re-initialized *immediately* after the previous
+        //there is a small chance that the server is still finishing up cleaning up
+        //the DMA FIFOs. We currently don't have any feedback from the driver regarding
+        //this state so just wait.
+        boost::this_thread::sleep(boost::posix_time::milliseconds(FPGA_READY_TIMEOUT_IN_MS));
+
+        //Disable all FIFOs in the FPGA
+        for (size_t i = 0; i < _lvbitx->get_input_fifo_count(); i++) {
+            _riok_proxy.poke(PCIE_RX_DMA_REG(DMA_CTRL_STATUS_REG, i), DMA_CTRL_DISABLED);
+        }
+        for (size_t i = 0; i < _lvbitx->get_output_fifo_count(); i++) {
+            _riok_proxy.poke(PCIE_TX_DMA_REG(DMA_CTRL_STATUS_REG, i), DMA_CTRL_DISABLED);
+        }
+
+        //Disable all FIFOs in the kernel driver
+        _riok_proxy.stop_all_fifos();
+
+        boost::posix_time::ptime start_time = boost::posix_time::microsec_clock::local_time();
+        boost::posix_time::time_duration elapsed;
+        do {
+            boost::this_thread::sleep(boost::posix_time::milliseconds(10)); //Avoid flooding the bus
+            elapsed = boost::posix_time::microsec_clock::local_time() - start_time;
+            nirio_status_chain(_riok_proxy.peek(FPGA_STATUS_REG, reg_data), status);
+        } while (
+            nirio_status_not_fatal(status) &&
+            (reg_data & FPGA_STATUS_DMA_ACTIVE_MASK) &&
+            elapsed.total_milliseconds() < FPGA_READY_TIMEOUT_IN_MS);
+
+        nirio_status_chain(_riok_proxy.peek(FPGA_STATUS_REG, reg_data), status);
+        if (nirio_status_not_fatal(status) && (reg_data & FPGA_STATUS_DMA_ACTIVE_MASK)) {
+            return NiRio_Status_FifoReserved;
+        }
+    }
+
+    return status;
+}
+
 }}
diff --git a/host/lib/transport/nirio_zero_copy.cpp b/host/lib/transport/nirio_zero_copy.cpp
index c3c8a9368..3bb822720 100644
--- a/host/lib/transport/nirio_zero_copy.cpp
+++ b/host/lib/transport/nirio_zero_copy.cpp
@@ -24,6 +24,7 @@
 #include <uhd/utils/atomic.hpp>
 #include <boost/format.hpp>
 #include <boost/make_shared.hpp>
+#include <boost/date_time/posix_time/posix_time.hpp>
 #include <boost/thread/thread.hpp> //sleep
 #include <vector>
 #include <algorithm>    // std::max
@@ -143,6 +144,12 @@ public:
         nirio_status status = 0;
         size_t actual_depth = 0, actual_size = 0;
 
+        //Disable DMA streams in case last shutdown was unclean (cleanup, so don't status chain)
+        _proxy().poke(PCIE_TX_DMA_REG(DMA_CTRL_STATUS_REG, _fifo_instance), DMA_CTRL_DISABLED);
+        _proxy().poke(PCIE_RX_DMA_REG(DMA_CTRL_STATUS_REG, _fifo_instance), DMA_CTRL_DISABLED);
+
+        _wait_until_stream_ready();
+
         //Configure frame width
         nirio_status_chain(
             _proxy().poke(PCIE_TX_DMA_REG(DMA_FRAME_SIZE_REG, _fifo_instance),
@@ -152,14 +159,14 @@ public:
             _proxy().poke(PCIE_RX_DMA_REG(DMA_FRAME_SIZE_REG, _fifo_instance),
                           static_cast<uint32_t>(_xport_params.recv_frame_size/sizeof(fifo_data_t))),
             status);
-        //Config 32-bit word flipping and Reset DMA streams
+        //Config 32-bit word flipping and enable DMA streams
         nirio_status_chain(
             _proxy().poke(PCIE_TX_DMA_REG(DMA_CTRL_STATUS_REG, _fifo_instance),
-                          DMA_CTRL_SW_BUF_U32 | DMA_CTRL_RESET),
+                          DMA_CTRL_SW_BUF_U32 | DMA_CTRL_ENABLED),
             status);
         nirio_status_chain(
             _proxy().poke(PCIE_RX_DMA_REG(DMA_CTRL_STATUS_REG, _fifo_instance),
-                          DMA_CTRL_SW_BUF_U32 | DMA_CTRL_RESET),
+                          DMA_CTRL_SW_BUF_U32 | DMA_CTRL_ENABLED),
             status);
 
         //Create FIFOs
@@ -189,10 +196,6 @@ public:
             nirio_status_chain(_send_fifo->start(), status);
 
             if (nirio_status_not_fatal(status)) {
-                //Flush RX kernel buffers in case some cruft was
-                //left behind from the last run
-                _flush_rx_buff();
-
                 //allocate re-usable managed receive buffers
                 for (size_t i = 0; i < get_num_recv_frames(); i++){
                     _mrb_pool.push_back(boost::shared_ptr<nirio_zero_copy_mrb>(new nirio_zero_copy_mrb(
@@ -216,9 +219,9 @@ public:
     {
         _proxy().get_rio_quirks().remove_tx_fifo(_fifo_instance);
 
-        //Reset DMA streams (Teardown, so don't status chain)
-        _proxy().poke(PCIE_TX_DMA_REG(DMA_CTRL_STATUS_REG, _fifo_instance), DMA_CTRL_RESET);
-        _proxy().poke(PCIE_RX_DMA_REG(DMA_CTRL_STATUS_REG, _fifo_instance), DMA_CTRL_RESET);
+        //Disable DMA streams (cleanup, so don't status chain)
+        _proxy().poke(PCIE_TX_DMA_REG(DMA_CTRL_STATUS_REG, _fifo_instance), DMA_CTRL_DISABLED);
+        _proxy().poke(PCIE_RX_DMA_REG(DMA_CTRL_STATUS_REG, _fifo_instance), DMA_CTRL_DISABLED);
 
         _flush_rx_buff();
 
@@ -284,6 +287,47 @@ private:
         }
     }
 
+    UHD_INLINE void _wait_until_stream_ready()
+    {
+        static const uint32_t TIMEOUT_IN_MS = 100;
+
+        uint32_t reg_data = 0xffffffff;
+        bool tx_busy = true, rx_busy = true;
+        boost::posix_time::ptime start_time;
+        boost::posix_time::time_duration elapsed;
+        nirio_status status = NiRio_Status_Success;
+
+        nirio_status_chain(_proxy().peek(
+            PCIE_TX_DMA_REG(DMA_CTRL_STATUS_REG, _fifo_instance), reg_data), status);
+        tx_busy = (reg_data & DMA_STATUS_BUSY);
+        nirio_status_chain(_proxy().peek(
+            PCIE_RX_DMA_REG(DMA_CTRL_STATUS_REG, _fifo_instance), reg_data), status);
+        rx_busy = (reg_data & DMA_STATUS_BUSY);
+
+        if (nirio_status_not_fatal(status) && (tx_busy || rx_busy)) {
+            start_time = boost::posix_time::microsec_clock::local_time();
+            do {
+                boost::this_thread::sleep(boost::posix_time::microsec(50)); //Avoid flooding the bus
+                elapsed = boost::posix_time::microsec_clock::local_time() - start_time;
+                nirio_status_chain(_proxy().peek(
+                    PCIE_TX_DMA_REG(DMA_CTRL_STATUS_REG, _fifo_instance), reg_data), status);
+                tx_busy = (reg_data & DMA_STATUS_BUSY);
+                nirio_status_chain(_proxy().peek(
+                    PCIE_RX_DMA_REG(DMA_CTRL_STATUS_REG, _fifo_instance), reg_data), status);
+                rx_busy = (reg_data & DMA_STATUS_BUSY);
+            } while (
+                nirio_status_not_fatal(status) &&
+                (tx_busy || rx_busy) &&
+                elapsed.total_milliseconds() < TIMEOUT_IN_MS);
+
+            if (tx_busy || rx_busy) {
+                nirio_status_chain(NiRio_Status_FpgaBusy, status);
+            }
+
+            nirio_status_to_exception(status, "Could not create nirio_zero_copy transport.");
+        }
+    }
+
     //memory management -> buffers and fifos
     niusrprio::niusrprio_session::sptr _fpga_session;
     uint32_t _fifo_instance;
diff --git a/host/lib/usrp/x300/x300_fw_common.h b/host/lib/usrp/x300/x300_fw_common.h
index 632391644..0bbaee319 100644
--- a/host/lib/usrp/x300/x300_fw_common.h
+++ b/host/lib/usrp/x300/x300_fw_common.h
@@ -31,7 +31,7 @@ extern "C" {
 
 #define X300_FW_COMPAT_MAJOR 3
 #define X300_FW_COMPAT_MINOR 0
-#define X300_FPGA_COMPAT_MAJOR 4
+#define X300_FPGA_COMPAT_MAJOR 6
 
 //shared memory sections - in between the stack and the program space
 #define X300_FW_SHMEM_BASE 0x6000
diff --git a/host/lib/usrp/x300/x300_impl.cpp b/host/lib/usrp/x300/x300_impl.cpp
index 6a9de1f30..e931b7983 100644
--- a/host/lib/usrp/x300/x300_impl.cpp
+++ b/host/lib/usrp/x300/x300_impl.cpp
@@ -135,6 +135,12 @@ static device_addrs_t x300_find_with_addr(const device_addr_t &hint)
     return addrs;
 }
 
+//We need a zpu xport registry to ensure synchronization between the static finder method
+//and the instances of the x300_impl class.
+typedef uhd::dict< std::string, boost::weak_ptr<wb_iface> > pcie_zpu_iface_registry_t;
+UHD_SINGLETON_FCN(pcie_zpu_iface_registry_t, get_pcie_zpu_iface_registry)
+static boost::mutex pcie_zpu_iface_registry_mutex;
+
 static device_addrs_t x300_find_pcie(const device_addr_t &hint, bool explicit_query)
 {
     std::string rpc_port_name(NIUSRPRIO_DEFAULT_RPC_PORT);
@@ -167,17 +173,30 @@ static device_addrs_t x300_find_pcie(const device_addr_t &hint, bool explicit_qu
         }
 
         niriok_proxy kernel_proxy;
-        kernel_proxy.open(dev_info.interface_path);
 
         //Attempt to read the name from the EEPROM and perform filtering.
         //This operation can throw due to compatibility mismatch.
         try
         {
-            //This call could throw an exception if the user is switching to using UHD
+            //This block could throw an exception if the user is switching to using UHD
             //after LabVIEW FPGA. In that case, skip reading the name and serial and pick
             //a default FPGA flavor. During make, a new image will be loaded and everything
             //will be OK
-            wb_iface::sptr zpu_ctrl = x300_make_ctrl_iface_pcie(kernel_proxy);
+
+            wb_iface::sptr zpu_ctrl;
+
+            //Hold on to the registry mutex as long as zpu_ctrl is alive
+            //to prevent any use by different threads while enumerating
+            boost::mutex::scoped_lock(pcie_zpu_iface_registry_mutex);
+
+            if (get_pcie_zpu_iface_registry().has_key(resource_d)) {
+                zpu_ctrl = get_pcie_zpu_iface_registry()[resource_d].lock();
+            } else {
+                kernel_proxy.open(dev_info.interface_path);
+                zpu_ctrl = x300_make_ctrl_iface_pcie(kernel_proxy);
+                //We don't put this zpu_ctrl in the registry because we need
+                //a persistent niriok_proxy associated with the object
+            }
             if (x300_impl::is_claimed(zpu_ctrl)) continue; //claimed by another process
 
             //Attempt to autodetect the FPGA type
@@ -465,7 +484,13 @@ void x300_impl::setup_mb(const size_t mb_i, const uhd::device_addr_t &dev_addr)
     //create basic communication
     UHD_MSG(status) << "Setup basic communication..." << std::endl;
     if (mb.xport_path == "nirio") {
-        mb.zpu_ctrl = x300_make_ctrl_iface_pcie(mb.rio_fpga_interface->get_kernel_proxy());
+        boost::mutex::scoped_lock(pcie_zpu_iface_registry_mutex);
+        if (get_pcie_zpu_iface_registry().has_key(mb.addr)) {
+            throw uhd::assertion_error("Someone else has a ZPU transport to the device open. Internal error!");
+        } else {
+            mb.zpu_ctrl = x300_make_ctrl_iface_pcie(mb.rio_fpga_interface->get_kernel_proxy());
+            get_pcie_zpu_iface_registry()[mb.addr] = boost::weak_ptr<wb_iface>(mb.zpu_ctrl);
+        }
     } else {
         mb.zpu_ctrl = x300_make_ctrl_iface_enet(udp_simple::make_connected(mb.addr,
                     BOOST_STRINGIZE(X300_FW_COMMS_UDP_PORT)));
@@ -834,8 +859,14 @@ x300_impl::~x300_impl(void)
 
             //kill the claimer task and unclaim the device
             mb.claimer_task.reset();
-            mb.zpu_ctrl->poke32(SR_ADDR(X300_FW_SHMEM_BASE, X300_FW_SHMEM_CLAIM_TIME), 0);
-            mb.zpu_ctrl->poke32(SR_ADDR(X300_FW_SHMEM_BASE, X300_FW_SHMEM_CLAIM_SRC), 0);
+            {   //Critical section
+                boost::mutex::scoped_lock(pcie_zpu_iface_registry_mutex);
+                mb.zpu_ctrl->poke32(SR_ADDR(X300_FW_SHMEM_BASE, X300_FW_SHMEM_CLAIM_TIME), 0);
+                mb.zpu_ctrl->poke32(SR_ADDR(X300_FW_SHMEM_BASE, X300_FW_SHMEM_CLAIM_SRC), 0);
+                //If the process is killed, the entire registry will disappear so we
+                //don't need to worry about unclean shutdowns here.
+                get_pcie_zpu_iface_registry().pop(mb.addr);
+            }
         }
     }
     catch(...)
@@ -1461,13 +1492,18 @@ void x300_impl::set_fp_gpio(gpio_core_200::sptr gpio, const std::string &attr, c
 
 void x300_impl::claimer_loop(wb_iface::sptr iface)
 {
-    iface->poke32(SR_ADDR(X300_FW_SHMEM_BASE, X300_FW_SHMEM_CLAIM_TIME), time(NULL));
-    iface->poke32(SR_ADDR(X300_FW_SHMEM_BASE, X300_FW_SHMEM_CLAIM_SRC), get_process_hash());
-    boost::this_thread::sleep(boost::posix_time::milliseconds(1500)); //1.5 seconds
+    {   //Critical section
+        boost::mutex::scoped_lock(claimer_mutex);
+        iface->poke32(SR_ADDR(X300_FW_SHMEM_BASE, X300_FW_SHMEM_CLAIM_TIME), time(NULL));
+        iface->poke32(SR_ADDR(X300_FW_SHMEM_BASE, X300_FW_SHMEM_CLAIM_SRC), get_process_hash());
+    }
+    boost::this_thread::sleep(boost::posix_time::milliseconds(1000)); //1 second
 }
 
 bool x300_impl::is_claimed(wb_iface::sptr iface)
 {
+    boost::mutex::scoped_lock(claimer_mutex);
+
     //If timed out then device is definitely unclaimed
     if (iface->peek32(SR_ADDR(X300_FW_SHMEM_BASE, X300_FW_SHMEM_CLAIM_STATUS)) == 0)
         return false;
diff --git a/host/lib/usrp/x300/x300_impl.hpp b/host/lib/usrp/x300/x300_impl.hpp
index 4b3efc845..90aed2fdb 100644
--- a/host/lib/usrp/x300/x300_impl.hpp
+++ b/host/lib/usrp/x300/x300_impl.hpp
@@ -53,7 +53,7 @@
 static const std::string X300_FW_FILE_NAME  = "usrp_x300_fw.bin";
 
 static const double X300_DEFAULT_TICK_RATE      = 200e6;        //Hz
-static const double X300_BUS_CLOCK_RATE         = 175e6;        //Hz
+static const double X300_BUS_CLOCK_RATE         = 166.666667e6; //Hz
 
 static const size_t X300_TX_HW_BUFF_SIZE        = 0x90000;      //576KiB
 static const size_t X300_TX_FC_RESPONSE_FREQ    = 8;            //per flow-control window
@@ -152,6 +152,7 @@ public:
     bool recv_async_msg(uhd::async_metadata_t &, double);
 
     // used by x300_find_with_addr to find X300 devices.
+    static boost::mutex claimer_mutex;  //All claims and checks in this process are serialized
     static bool is_claimed(uhd::wb_iface::sptr);
 
     enum x300_mboard_t {
diff --git a/host/lib/usrp/x300/x300_regs.hpp b/host/lib/usrp/x300/x300_regs.hpp
index fb1786deb..cf1e33695 100644
--- a/host/lib/usrp/x300/x300_regs.hpp
+++ b/host/lib/usrp/x300/x300_regs.hpp
@@ -124,9 +124,12 @@ static const uint32_t FPGA_PCIE_SIG_REG     = PCIE_FPGA_REG(0x0000);
 static const uint32_t FPGA_CNTR_LO_REG      = PCIE_FPGA_REG(0x0004);
 static const uint32_t FPGA_CNTR_HI_REG      = PCIE_FPGA_REG(0x0008);
 static const uint32_t FPGA_CNTR_FREQ_REG    = PCIE_FPGA_REG(0x000C);
+static const uint32_t FPGA_STATUS_REG       = PCIE_FPGA_REG(0x0020);
 static const uint32_t FPGA_USR_SIG_REG_BASE = PCIE_FPGA_REG(0x0030);
 static const uint32_t FPGA_USR_SIG_REG_SIZE = 16;
 
+static const uint32_t FPGA_STATUS_DMA_ACTIVE_MASK = 0x3F3F0000;
+
 static const uint32_t PCIE_TX_DMA_REG_BASE  = PCIE_FPGA_REG(0x0200);
 static const uint32_t PCIE_RX_DMA_REG_BASE  = PCIE_FPGA_REG(0x0400);
 
@@ -139,12 +142,15 @@ static const uint32_t DMA_PKT_COUNT_REG     = 0xC;
 #define PCIE_TX_DMA_REG(REG, CHAN)          (PCIE_TX_DMA_REG_BASE + (CHAN*DMA_REG_GRP_SIZE) + REG)
 #define PCIE_RX_DMA_REG(REG, CHAN)          (PCIE_RX_DMA_REG_BASE + (CHAN*DMA_REG_GRP_SIZE) + REG)
 
-static const uint32_t DMA_CTRL_RESET        = 1;
+static const uint32_t DMA_CTRL_DISABLED     = 0x00000000;
+static const uint32_t DMA_CTRL_ENABLED      = 0x00000002;
+static const uint32_t DMA_CTRL_CLEAR_STB    = 0x00000001;
 static const uint32_t DMA_CTRL_SW_BUF_U64   = (3 << 4);
 static const uint32_t DMA_CTRL_SW_BUF_U32   = (2 << 4);
 static const uint32_t DMA_CTRL_SW_BUF_U16   = (1 << 4);
 static const uint32_t DMA_CTRL_SW_BUF_U8    = (0 << 4);
-static const uint32_t DMA_STATUS_ERROR      = 1;
+static const uint32_t DMA_STATUS_ERROR      = 0x00000001;
+static const uint32_t DMA_STATUS_BUSY       = 0x00000002;
 
 static const uint32_t PCIE_ROUTER_REG_BASE  = PCIE_FPGA_REG(0x0500);
 #define PCIE_ROUTER_REG(X)                  (PCIE_ROUTER_REG_BASE + X)