3 files changed, 43 insertions, 19 deletions
diff --git a/host/lib/usrp/cores/spi_core_4000.cpp b/host/lib/usrp/cores/spi_core_4000.cpp
index 1d72dd88d..55486d6c8 100644
--- a/host/lib/usrp/cores/spi_core_4000.cpp
+++ b/host/lib/usrp/cores/spi_core_4000.cpp
@@ -25,6 +25,7 @@ public:
         const size_t spi_transaction_cfg,
         const size_t spi_transaction_go,
         const size_t spi_status,
+        const size_t spi_controller_info,
         const mapper_sptr port_mapper)
         : _poke32(std::move(poke32_fn))
         , _peek32(std::move(peek32_fn))
@@ -32,6 +33,7 @@ public:
         , _spi_transaction_cfg(spi_transaction_cfg)
         , _spi_transaction_go(spi_transaction_go)
         , _spi_status(spi_status)
+        , _spi_ctrl_info(spi_controller_info)
         , _port_mapper(port_mapper)
     {
     }
@@ -39,12 +41,17 @@ public:
     void set_spi_slave_config(
         const std::vector<uhd::features::spi_slave_config_t>& ssc) override
     {
-        if (ssc.size() > 4) {
-            throw uhd::value_error(
-                "Passed more than 4 SPI slaves. Maximum number of SPI slaves is 4.");
+        const size_t num_slaves_allowed = _peek32(_spi_ctrl_info) & 0xF;
+        if (ssc.size() > num_slaves_allowed) {
+            throw uhd::value_error("Number of configurations passed ("
+                                   + std::to_string(ssc.size())
+                                   + ") exceeds the maximum number allowed by "
+                                     "the bitfile per radio block. Maximum number: "
+                                   + std::to_string(num_slaves_allowed));
         }
 
         _spi_slave_config = ssc;
+        _slave_ctrl_cache.assign(_spi_slave_config.size(), 0);
     }
 
     uint32_t transact_spi(const int which_slave,
@@ -135,8 +142,9 @@ private:
     const size_t _spi_transaction_cfg;
     const size_t _spi_transaction_go;
     const size_t _spi_status;
+    const size_t _spi_ctrl_info;
     const mapper_sptr _port_mapper;
-    std::vector<uint32_t> _slave_ctrl_cache{0, 0, 0, 0};
+    std::vector<uint32_t> _slave_ctrl_cache;
     uint32_t _transaction_cfg_cache = 0;
     std::mutex _mutex;
     std::vector<uhd::features::spi_slave_config_t> _spi_slave_config;
@@ -161,6 +169,7 @@ spi_core_4000::sptr spi_core_4000::make(spi_core_4000::poke32_fn_t&& poke32_fn,
     const size_t spi_transaction_cfg,
     const size_t spi_transaction_go,
     const size_t spi_status,
+    const size_t spi_controller_info,
     const mapper_sptr port_mapper)
 {
     return std::make_shared<spi_core_4000_impl>(std::move(poke32_fn),
@@ -169,6 +178,7 @@ spi_core_4000::sptr spi_core_4000::make(spi_core_4000::poke32_fn_t&& poke32_fn,
         spi_transaction_cfg,
         spi_transaction_go,
         spi_status,
+        spi_controller_info,
         port_mapper);
 }
 
diff --git a/host/lib/usrp/x400/x400_radio_control.cpp b/host/lib/usrp/x400/x400_radio_control.cpp
index ef2d6bd21..59207d486 100644
--- a/host/lib/usrp/x400/x400_radio_control.cpp
+++ b/host/lib/usrp/x400/x400_radio_control.cpp
@@ -191,20 +191,32 @@ x400_radio_control_impl::x400_radio_control_impl(make_args_ptr make_args)
 
         auto gpio_port_mapper = std::shared_ptr<uhd::mapper::gpio_port_mapper>(
             new uhd::rfnoc::x400::x400_gpio_port_mapping);
-        auto spicore = uhd::cores::spi_core_4000::make(
-            [this](const uint32_t addr, const uint32_t data) {
-                regs().poke32(addr, data, get_command_time(0));
-            },
-            [this](
-                const uint32_t addr) { return regs().peek32(addr, get_command_time(0)); },
-            x400_regs::SPI_SLAVE_CFG,
-            x400_regs::SPI_TRANSACTION_CFG_REG,
-            x400_regs::SPI_TRANSACTION_GO_REG,
-            x400_regs::SPI_STATUS_REG,
-            gpio_port_mapper);
-
-        _spi_getter_iface = std::make_shared<x400_spi_getter>(spicore);
-        register_feature(_spi_getter_iface);
+
+        // Check if SPI is available as GPIO source, otherwise don't register
+        // SPI_GETTER_IFace
+        auto gpio_srcs = _mb_control->get_gpio_srcs("GPIO0");
+        if (std::count(gpio_srcs.begin(), gpio_srcs.end(), "DB0_SPI") > 0) {
+            auto spicore = uhd::cores::spi_core_4000::make(
+                [this](const uint32_t addr, const uint32_t data) {
+                    regs().poke32(addr, data, get_command_time(0));
+                },
+                [this](const uint32_t addr) {
+                    return regs().peek32(addr, get_command_time(0));
+                },
+                x400_regs::SPI_SLAVE_CFG,
+                x400_regs::SPI_TRANSACTION_CFG_REG,
+                x400_regs::SPI_TRANSACTION_GO_REG,
+                x400_regs::SPI_STATUS_REG,
+                x400_regs::SPI_CONTROLLER_INFO_REG,
+                gpio_port_mapper);
+
+            _spi_getter_iface = std::make_shared<x400_spi_getter>(spicore);
+            register_feature(_spi_getter_iface);
+        } else {
+            UHD_LOG_INFO("x400_radio_control",
+                "SPI functionality not available in this FPGA image. Please update to at "
+                "least version 7.7 to use SPI.");
+        }
     }
 }
 
@@ -816,5 +828,4 @@ std::string x400_radio_control_impl::get_dboard_fe_from_chan(
 
 UHD_RFNOC_BLOCK_REGISTER_FOR_DEVICE_DIRECT(
     x400_radio_control, RADIO_BLOCK, X400, "Radio", true, "radio_clk", "ctrl_clk")
-
 }} // namespace uhd::rfnoc
diff --git a/host/lib/usrp/x400/x400_radio_control.hpp b/host/lib/usrp/x400/x400_radio_control.hpp
index cd45291bc..7fcf9a12a 100644
--- a/host/lib/usrp/x400/x400_radio_control.hpp
+++ b/host/lib/usrp/x400/x400_radio_control.hpp
@@ -54,6 +54,9 @@ constexpr uint32_t SPI_TRANSACTION_GO_REG = SPI_SLAVE_CFG + 0x0014;
 //! Base address for SPI_STATUS Register
 constexpr uint32_t SPI_STATUS_REG = SPI_SLAVE_CFG + 0x0018;
 
+//! Base address for SPI_CONTROLLER_INFO Register
+constexpr uint32_t SPI_CONTROLLER_INFO_REG = SPI_SLAVE_CFG + 0x001C;
+
 } // namespace x400_regs
 
 class x400_radio_control_impl : public radio_control_impl