Decrease bootloader flash usage

Added more to the discard section in the bootloader linker files for
RP2040 and RP3250 based boards. Added the linker .map file generation to
the build_bootloader.py script.

lib/BlueSCSI_platform_RP2MCU/rp2040_btldr.ld

@@ -44,7 +44,38 @@ SECTIONS
         __flash_binary_start = .;
     } > FLASH
 
+    /* Discard code that is not used in bootloader mode to
+    * reduce the flash usage.
+    */
+    /DISCARD/ : {
+
+        *scanf*(*)
+        *strtod*(*)
+        *libipv4.a:*(*)
+        *liblwip*.a:*(*)
+        *libBlueSCSI_audio_RP2MCU.a:*(*)
+        *libAdafruit*.a:*(*)
+        *libWire.a:*(*)
+        *libSPI.a:*(*)
+        *libBlueSCSI_platform_RP2MCU.a:BlueSCSI_platform_network.cpp.o*(*)
+        *libFrameworkArduino.a:cyw43_wrappers.cpp.o*(*)
+
+        /* gt */
+        *BlueSCSI_tape.cpp.o*(*)
+        *BlueSCSI_mode.cpp.o*(*)
+        *BlueSCSI_blink.cpp.o*(*)
+        *BlueSCSI_buffer_control.cpp.o*(*)
+        *uiDiskUtils.cpp.o*(*)
+        *SDNavigator.cpp.o*(*)
+    }
+
     .text : {
+        cyw43_digitalWrite = 0;
+        cyw43_digitalRead = 0;
+        cyw43_pinMode = 0;
+        init_cyw43_wifi = bootloader_main;
+        platform_poll = 0;
+
         __logical_binary_start = .;
         KEEP (*(.btldr_vectors))
         KEEP (*(.binary_info_header))

lib/BlueSCSI_platform_RP2MCU/rp23xx_btldr.ld

@@ -45,7 +45,41 @@ SECTIONS
         __flash_binary_start = .;
     } > FLASH
 
+    /* Discard code that is not used in bootloader mode to
+    * reduce the flash usage.
+    */
+    /DISCARD/ : {
+
+        *scanf*(*)
+        *strtod*(*)
+        *libipv4.a:*(*)
+        *liblwip*.a:*(*)
+        *libBlueSCSI_audio_RP2MCU.a:*(*)
+        *libAdafruit*.a:*(*)
+        *libWire.a:*(*)
+        *libSPI.a:*(*)
+        *libBlueSCSI_UI_RP2MCU.a:*(*)
+        *libBlueSCSI_platform_RP2MCU.a:BlueSCSI_platform_network.cpp.o*(*)
+        *libFrameworkArduino.a:cyw43_wrappers.cpp.o*(*)
+
+        /* gt */
+        *BlueSCSI_tape.cpp.o*(*)
+        *BlueSCSI_mode.cpp.o*(*)
+        *BlueSCSI_blink.cpp.o*(*)
+        *BlueSCSI_buffer_control.cpp.o*(*)
+        *uiDiskUtils.cpp.o*(*)
+        *SDNavigator.cpp.o*(*)
+    }
+
     .text : {
+        cyw43_digitalWrite = 0;
+        cyw43_digitalRead = 0;
+        cyw43_pinMode = 0;
+        init_cyw43_wifi = bootloader_main;
+        setPendingImageLoad = 0;
+        platform_poll = 0;
+
+
         __logical_binary_start = .;
         KEEP (*(.btldr_vectors))
         KEEP (*(.binary_info_header))

src/build_bootloader.py

@@ -58,7 +58,7 @@ if env2.GetProjectOption("ldscript_bootloader"):
     env2.Replace(LDSCRIPT_PATH = env2.GetProjectOption("ldscript_bootloader"))
     env2['LINKFLAGS'] = [a for a in env2['LINKFLAGS'] if not a.startswith('-T') and not a.endswith('.ld')]
     env2.Append(LINKFLAGS="-T" + env2.GetProjectOption("ldscript_bootloader"))
-
+    env2.Append(LINKFLAGS="-Wl,-Map=\"" + os.path.join("$BUILD_DIR", "bootloader.map") + "\"")
 # Build bootloader.elf
 bootloader_elf = env2.Program(
     os.path.join("$BUILD_DIR", "bootloader.elf"),