mk450: x and y axis basic implementation

[cortex-from-scratch] / ivt.c

diff --git a/ivt.c b/ivt.c
index b3854f1..a271487 100644 (file)
--- a/ivt.c
+++ b/ivt.c
@@ -5,14 +5,32 @@
  * Initial version 
  * 
  * $DESCRIPTION$
+ * Set up of basic exceptions and interrupts. These interrupts
+ * don't do much, except for halting the system. 
+ * ivt_set_gate(interrupt nr, function, priority) can be used
+ * later to define more appropriate handling. See timer (timer.c) 
+ * or serial or (uart.c) handling for non-trivial examples.
+ *
+ * The actual code is not much, but there are a lot of details
+ * to consider. Besides that, in case more control is desired over
+ * entering and exiting interrupts (what is pushed on the stack) 
+ * A so-called naked function can be used. See below for more
+ * details.
  * 
+ *
  * */
 
 #include <stdbool.h>
 #include <stddef.h>
 #include <stdint.h>
-#include <stm32.h>
-#include <mmap.h>
+
+#include <sys/robsys.h>
+#include <sys/mmap.h>
+
+#include <lib/stdio.h>
+#include <lib/string.h>
+#include <lib/regfunc.h>
+#include <lib/tinyprintf.h>
 
 /* 
  * These values are pushed on the stack just before
@@ -22,7 +40,7 @@
  * gives me a little bit more control over the caller
  *
  * The following register are pushed to the stack
- * in reverse order
+ * in reverse order:
  *
  * */
 struct interrupt_frame {
@@ -39,68 +57,72 @@ struct interrupt_frame {
 
 /* 
  * Vector table, each entry contains an interrupt
- * service routine:  
- *
+ * service routine: 
  * interrupt vector 1-15: processor exceptions
  * interrupt vector 16-92: irq0 - irq ..
+ * Vector table needs to be aligned in memory.
  * */
-
 uint32_t __attribute__((aligned(0x100))) ivt[92];
 
-/* each message corresponds to each and every exception. 
- * We get the correct message by accessing
- *  exception_message[interrupt_number] 
- *  exception_message[0] is not used (=MSP)*/
-
+/* Each message corresponds to each and every exception. */
 char * exception_message(uint8_t intnr) {
 
-       char * messages[] = {
-           "--",
-           "RESET",
-           "NMI",
-           "HARD FAULT",
-           "MEMMANAGE FAULT",
-           "BUS FAULT",
-           "USAGE FAULT",
-           "RESERVED",
-           "SVC",
-           "DEBUG MONITOR",
-           "RESERVED",
-           "RESERVED",
-           "RESERVED",
-           "RESERVED",
-           "PENDSV",
-           "SYSTICK",
-           "IRQ1",
-           "IRQ2",
-           "IRQ3",
-           "IRQ4",
-           // add more if needed
-       };
-
-       if (intnr < 20) // TODO: strlen
-               return messages[intnr];
-
-       return NULL;
+char * messages[] = {
+    "--",
+    "RESET",
+    "NMI",
+    "HARD FAULT",
+    "MEMMANAGE FAULT",
+    "BUS FAULT",
+    "USAGE FAULT",
+    "RESERVED",
+    "SVC",
+    "DEBUG MONITOR",
+    "RESERVED",
+    "RESERVED",
+    "RESERVED",
+    "RESERVED",
+    "PENDSV",
+    "SYSTICK",
+    "IRQ1",
+    "IRQ2",
+    "IRQ3",
+    "IRQ4",
+    // add more if needed
+};
+
+if (intnr < 20) // TODO: strlen
+       return messages[intnr];
+
+return "UNKNOWN";
 }
 
 void ivt_set_gate(unsigned char num, void * isr(), short pri) {
 
        ivt[num] = (uint32_t) isr;
-       *NVIC_ISER0 = (1 << ((uint32_t)(num) & 0x1F));
-       /* Priorities */
+//     if (num <= 32)
+//             *NVIC_ISER0 = (1 << ((uint32_t)(num) & 0x1F));
+       /* TODO: Priorities */
 }
 
 
-/* Dummy interrupt */
-// __attribute__ ((interrupt)) 
-void * dummy_isr(/* struct interrupt_frame * frame */) {
+/* Dummy interrupt: comment out the comment to use a naked
+ * function */
+
+__attribute__ ((interrupt)) 
+void * dummy_isr( struct interrupt_frame * frame ) {
 
        uint8_t nr = *SCB_VTOR_ST & 0xFF;
-       
-       uart_puts("EXCEPTION: ");
-       uart_puts(exception_message(nr));
-       uart_puts("\nSYSTEM HALTED\n");
+       printf("EXCEPTION: %s\n", exception_message(nr));
+       printf("STACK TRACE:\n");
+       printf("R0:%p\n",frame->r0);
+       printf("R1:%p\n",frame->r1);
+       printf("R2:%p\n",frame->r2);
+       printf("R3:%p\n",frame->r3);
+       printf("R12:%p\n",frame->r12);
+       printf("LR:%p\n",frame->lr);
+       printf("PC:%p\n",frame->pc);
+       printf("PSR:%p\n",frame->psr);
        
        for(;;);
 }
@@ -108,24 +130,24 @@ void * dummy_isr(/* struct interrupt_frame * frame */) {
 /* Initialize interrupt vector  */
 void ivt_init() {
 
-       /* clear entiry IVT, in SRAM location for SRAM + .data (in .bss section) */
+       /* clear entire IVT location in memory  */
        memset(&ivt, 0, (sizeof(uint32_t) * 92));
 
-       // stack top is loaded from the first entry table on boot/reset
-       // don't need to relocate or init this here
+       /* The reset, NMI and hardfault handlers are originally
+        * defined in the assembly start up and can be 
+        * reused or overwritten. 
+       *  */
        extern void * reset,  * nmi, * hardfault;
 
+       // set dummy handlers 
        for (int i = 1; i <= 64 ; i++) {
                ivt_set_gate(i, dummy_isr, 0);
        }
 
-
-       /* the vector table starts at 0x0. Since the address 0x0 point to 
-        * bootcode, it is on ROM or FLASH. The vector table can be
+       /* The vector table is intially at 0x0. The vector table can be
         * relocated to other memory locations. We can do this by setting 
         * a register in the NVIC called the vector table offset register */
 
-       //*SCB_VTOR = (volatile uint32_t) &ivt; 
-       regw_u32(SCB_VTOR, (uint32_t) &ivt, 0, OWRITE);
+       rwrite(SCB_VTOR, (uint32_t) &ivt);
 
 }