Copy code to ITCM_RAM

betaflight · Jul 10, 2017 · ff01735 · ff01735
1 parent 7a8a2d1
commit ff01735
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Showing 3 changed files with 12 additions and 1 deletion.
diff --git a/src/main/fc/fc_init.c b/src/main/fc/fc_init.c
@@ -240,6 +240,12 @@ void spiPreInit(void)
 
 void init(void)
 {
+    /* Load functions into ITCM RAM */ 
+    extern unsigned char critical_code_start; 
+    extern unsigned char critical_code_end; 
+    extern unsigned char critical_code; 
+    memcpy(&critical_code_start, &critical_code, (int) (&critical_code_end - &critical_code_start));
+
 #ifdef USE_HAL_DRIVER
     HAL_Init();
 #endif

diff --git a/src/main/target/link/stm32_flash_f722.ld b/src/main/target/link/stm32_flash_f722.ld
@@ -22,8 +22,9 @@ ENTRY(Reset_Handler)
 /* Specify the memory areas */
 MEMORY
 {
+    ITCM_ISR (rx)     : ORIGIN = 0x00000000, LENGTH = 1K
+    ITCM_RAM (rx)     : ORIGIN = 0x00000400, LENGTH = 15K
 
-    ITCM_RAM (rx)     : ORIGIN = 0x00000000, LENGTH = 16K
     ITCMFL (rx)       : ORIGIN = 0x00200000, LENGTH = 16K 
     ITCMFL1 (rx)      : ORIGIN = 0x00208000, LENGTH = 480K 
 

diff --git a/src/main/target/link/stm32_flash_f7_split.ld b/src/main/target/link/stm32_flash_f7_split.ld
@@ -35,12 +35,16 @@ SECTIONS
   } >FLASH
 
   /* Critical program code goes into ITCM RAM */
+  /* Copy specific fast-executing code to ITCM RAM */ 
+  critical_code = LOADADDR(.critical_code); 
   .critical_code :
   {
     . = ALIGN(4);
+    critical_code_start = .; 
     *(.critical_code)
     *(.critical_code*)
     . = ALIGN(4);
+    critical_code_end = .; 
   } >ITCM_RAM AT >FLASH1
 
   /* The program code and other data goes into FLASH */