armcm_boot: Use armcm_main() instead of main() to start board code

The main() function has a special meaning to gcc and using it can
result in different code generation.  Use armcm_main() to avoid that.

Also, invoke SystemInit() from the board specific armcm_main() code.
This gives the board code more control over board initialization.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

6 files changed, 27 insertions, 25 deletions

diff --git a/src/atsam/main.c b/src/atsam/main.c
index 580ad770..843b5034 100644
--- a/src/atsam/main.c
+++ b/src/atsam/main.c
@@ -4,6 +4,7 @@
 //
 // This file may be distributed under the terms of the GNU GPLv3 license.
 
+#include "board/armcm_boot.h" // armcm_main
 #include "board/irq.h" // irq_disable
 #include "board/usb_cdc.h" // usb_request_bootloader
 #include "command.h" // DECL_COMMAND_FLAGS
@@ -110,11 +111,11 @@ matrix_init(void)
                               | MATRIX_SCFG_DEFMSTR_TYPE(1));
 }
 
-// Main entry point
-int
-main(void)
+// Main entry point - called from armcm_boot.c:ResetHandler()
+void
+armcm_main(void)
 {
+    SystemInit();
     matrix_init();
     sched_main();
-    return 0;
 }
diff --git a/src/atsamd/main.c b/src/atsamd/main.c
index a5b7196b..d3943e6a 100644
--- a/src/atsamd/main.c
+++ b/src/atsamd/main.c
@@ -4,12 +4,14 @@
 //
 // This file may be distributed under the terms of the GNU GPLv3 license.
 
+#include "board/armcm_boot.h" // armcm_main
+#include "internal.h" // SystemInit
 #include "sched.h" // sched_main
 
-// Main entry point
-int
-main(void)
+// Main entry point - called from armcm_boot.c:ResetHandler()
+void
+armcm_main(void)
 {
+    SystemInit();
     sched_main();
-    return 0;
 }
diff --git a/src/generic/armcm_boot.c b/src/generic/armcm_boot.c
index ad7461ca..261fb912 100644
--- a/src/generic/armcm_boot.c
+++ b/src/generic/armcm_boot.c
@@ -6,8 +6,8 @@
 
 #include "armcm_boot.h" // DECL_ARMCM_IRQ
 #include "autoconf.h" // CONFIG_MCU
-#include "board/internal.h" // SystemInit
 #include "command.h" // DECL_CONSTANT_STR
+#include "misc.h" // dynmem_start
 
 // Export MCU type
 DECL_CONSTANT_STR("MCU", CONFIG_MCU);
@@ -37,14 +37,10 @@ ResetHandler(void)
     // Initializing the C library isn't needed...
     //__libc_init_array();
 
-    // Initialize the machine
-    SystemInit();
+    // Run the main board specific code
+    armcm_main();
 
-    // Run the main code
-    extern int main(void);
-    main();
-
-    // The main() call should not return
+    // The armcm_main() call should not return
     for (;;)
         ;
 }
diff --git a/src/generic/armcm_boot.h b/src/generic/armcm_boot.h
index a0bfd3f4..7bd982ce 100644
--- a/src/generic/armcm_boot.h
+++ b/src/generic/armcm_boot.h
@@ -3,6 +3,8 @@
 
 #include "ctr.h" // DECL_CTR_INT
 
+void armcm_main(void);
+
 // Declare an IRQ handler
 #define DECL_ARMCM_IRQ(FUNC, NUM)                                       \
     DECL_CTR_INT("DECL_ARMCM_IRQ " __stringify(FUNC), 1, CTR_INT(NUM))
diff --git a/src/lpc176x/main.c b/src/lpc176x/main.c
index 79001e72..7f19f8c0 100644
--- a/src/lpc176x/main.c
+++ b/src/lpc176x/main.c
@@ -4,6 +4,7 @@
 //
 // This file may be distributed under the terms of the GNU GPLv3 license.
 
+#include "board/armcm_boot.h" // armcm_main
 #include "internal.h" // enable_pclock
 #include "sched.h" // sched_main
 
@@ -56,10 +57,10 @@ enable_pclock(uint32_t pclk)
     }
 }
 
-// Main entry point
-int
-main(void)
+// Main entry point - called from armcm_boot.c:ResetHandler()
+void
+armcm_main(void)
 {
+    SystemInit();
     sched_main();
-    return 0;
 }
diff --git a/src/stm32/main.c b/src/stm32/main.c
index 7c46d4b5..5cf7dfd1 100644
--- a/src/stm32/main.c
+++ b/src/stm32/main.c
@@ -4,15 +4,15 @@
 //
 // This file may be distributed under the terms of the GNU GPLv3 license.
 
+#include "board/armcm_boot.h" // armcm_main
 #include "internal.h" // clock_setup
 #include "sched.h" // sched_main
 
-// Main entry point
-int
-main(void)
+// Main entry point - called from armcm_boot.c:ResetHandler()
+void
+armcm_main(void)
 {
+    SystemInit();
     clock_setup();
-
     sched_main();
-    return 0;
 }