DATA_DIR override with environment variable (#333)

CMakeLists.txt

@@ -92,6 +92,7 @@ set(OPENFPGALOADER_SOURCE
 	src/anlogicBitParser.cpp
 	src/anlogicCable.cpp
 	src/ch552_jtag.cpp
+	src/common.cpp
 	src/dfu.cpp
 	src/dfuFileParser.cpp
 	src/dirtyJtag.cpp
@@ -140,6 +141,7 @@ set(OPENFPGALOADER_HEADERS
 	src/anlogicBitParser.hpp
 	src/anlogicCable.hpp
 	src/ch552_jtag.hpp
+	src/common.hpp
 	src/cxxopts.hpp
 	src/dfu.hpp
 	src/dfuFileParser.hpp

README.md

@@ -124,3 +124,21 @@ for any corresponding short options.
 
 Report bugs to <gwenhael.goavec-merou@trabucayre.com>.
 ```
+
+By default **spiOverJtag** are search into `${CMAKE_INSTALL_FULL_DATAROOTDIR}`
+(*/usr/local/share/* by default). It's possible to change this behaviour by
+using an environment variable:
+
+```bash
+export OPENFPGALOADER_SOJ_DIR=/somewhere
+openFPGALoader xxxx
+```
+
+or
+
+```
+OPENFPGALOADER_SOJ_DIR=/somewhere openFPGALoader xxxx
+```
+
+`OPENFPGALOADER_SOJ_DIR` must point to directory containing **spiOverJtag**
+bitstreams.

doc/guide/advanced.rst

@@ -82,3 +82,20 @@ Writing to an arbitrary address in flash memory
 
 With FPGA using an external SPI flash (*xilinx*, *lattice ECP5/nexus/ice40*, *anlogic*, *efinix*) option ``-o`` allows
 one to write raw binary file to an arbitrary adress in FLASH.
+
+Using an alternative directory for *spiOverJtag*
+================================================
+
+By setting ``OPENFPGALOADER_SOJ_DIR`` it's possible to override default
+*spiOverJtag* bitstreams directory:
+
+.. code-block:: bash
+
+    export OPENFPGALOADER_SOJ_DIR=/somewhere
+    openFPGALoader xxxx
+
+or
+
+.. code-block:: bash
+
+    OPENFPGALOADER_SOJ_DIR=/somewhere openFPGALoader xxxx

src/altera.cpp

@@ -9,6 +9,7 @@
 
 #include <string>
 
+#include "common.hpp"
 #include "jtag.hpp"
 #include "device.hpp"
 #include "epcq.hpp"
@@ -181,12 +182,11 @@ bool Altera::load_bridge()
 			return false;
 		}
 
-		// DATA_DIR is defined at compile time.
-		bitname = DATA_DIR "/openFPGALoader/spiOverJtag_";
+		bitname = get_shell_env_var("OPENFPGALOADER_SOJ_DIR", DATA_DIR "/openFPGALoader");
 #ifdef HAS_ZLIB
-		bitname += _device_package + ".rbf.gz";
+		bitname += "/spiOverJtag_" + _device_package + ".rbf.gz";
 #else
-		bitname += _device_package + ".rbf";
+		bitname += "/spiOverJtag_" + _device_package + ".rbf";
 #endif
 	}
 

src/common.cpp

@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: Apache-2.0
+/*
+ * Copyright (C) 2023 Gwenhael Goavec-Merou <gwenhael.goavec-merou@trabucayre.com>
+ */
+
+
+#include "common.hpp"
+
+#include <string>
+#include <cstdlib>
+
+/*!
+ * \brief return shell environment variable value
+ * \param[in] key: variable name
+ * \return variable value or ""
+ */
+const std::string get_shell_env_var(const char* key,
+		const char *def_val) noexcept {
+	const char* ret = std::getenv(key);
+	return std::string(ret ? ret : def_val);
+}

src/common.hpp

@@ -0,0 +1,20 @@
+// SPDX-License-Identifier: Apache-2.0
+/*
+ * Copyright (C) 2023 Gwenhael Goavec-Merou <gwenhael.goavec-merou@trabucayre.com>
+ */
+
+#ifndef SRC_COMMON_HPP_
+#define SRC_COMMON_HPP_
+
+#include <string>
+
+/*!
+ * \brief return shell environment variable value
+ * \param[in] key: variable name
+ * \param[in] def_val: value to return when not found
+ * \return variable value or def_val
+ */
+const std::string get_shell_env_var(const char* key,
+	const char *def_val="") noexcept;
+
+#endif  // SRC_COMMON_HPP_

src/xilinx.cpp

@@ -13,6 +13,7 @@
 
 #include "jtag.hpp"
 #include "bitparser.hpp"
+#include "common.hpp"
 #include "configBitstreamParser.hpp"
 #include "jedParser.hpp"
 #include "mcsParser.hpp"
@@ -468,9 +469,8 @@ bool Xilinx::load_bridge()
 			return false;
 		}
 
-		// DATA_DIR is defined at compile time.
-		bitname = DATA_DIR "/openFPGALoader/spiOverJtag_";
-		bitname += _device_package + ".bit.gz";
+		bitname = get_shell_env_var("OPENFPGALOADER_SOJ_DIR", DATA_DIR "/openFPGALoader");
+		bitname += "/spiOverJtag_" + _device_package + ".bit.gz";
 	}
 
 #if defined (_WIN64) || defined (_WIN32)