For stm32f4discovery

Makefile.include

@@ -0,0 +1,4 @@
+ifeq ($(CPU),stm32f407vgt6)
+  export USEMODULE += stm32f4xxstdperi
+  export UNDEF += $(BINDIR)syscalls.o
+endif

stm32f407vgt6/atom.c

@@ -4,152 +4,16 @@
  *  Created on: 10.08.2012
  *      Author: pfeiffer
  */
-#include "sched.h"
+#include "atomic.h"
 #include "cpu.h"
 
-extern void sched_task_exit(void);
-void sched_task_return(void);
-
-unsigned int atomic_set_return(unsigned int* p, unsigned int uiVal) {
-	//unsigned int cspr = disableIRQ();		//crashes
-	dINT();
-	unsigned int uiOldVal = *p;
-	*p = uiVal;
-	//restoreIRQ(cspr);						//crashes
-	eINT();
-	return uiOldVal;
-}
-
-void cpu_switch_context_exit(void){
-    sched_run();
-    sched_task_return();
-}
-
-
-void thread_yield(void) {
-	asm("svc 0x01\n");
-}
-
-
-__attribute__((naked))
-void SVC_Handler(void)
+unsigned int atomic_set_return(unsigned int *p, unsigned int uiVal)
 {
-	save_context();
-	asm("bl sched_run");
-	/* call scheduler update active_thread variable with pdc of next thread
-	 * the thread that has higest priority and is in PENDING state */
-	restore_context();
-}
-
- /* kernel functions */
-void ctx_switch(void)
-{
-	/* Save return address on stack */
-	/* stmfd   sp!, {lr} */
-
-	/* disable interrupts */
-	/* mov     lr, #NOINT|SVCMODE */
-	/* msr     CPSR_c, lr */
-	/* cpsid 	i */
-
-	/* save other register */
-	asm("nop");
-
-	asm("mov r12, sp");
-	asm("stmfd r12!, {r4-r11}");
-
-	/* save user mode stack pointer in *active_thread */
-	asm("ldr     r1, =active_thread"); /* r1 = &active_thread */
-	asm("ldr     r1, [r1]"); /* r1 = *r1 = active_thread */
-	asm("str     r12, [r1]"); /* store stack pointer in tasks pdc*/
-
-	sched_task_return();
-}
-/* call scheduler so active_thread points to the next task */
-void sched_task_return(void)
-{
-	/* load pdc->stackpointer in r0 */
-	asm("ldr     r0, =active_thread"); /* r0 = &active_thread */
-	asm("ldr     r0, [r0]"); /* r0 = *r0 = active_thread */
-	asm("ldr     sp, [r0]"); /* sp = r0  restore stack pointer*/
-	asm("pop		{r4}"); /* skip exception return */
-	asm(" pop		{r4-r11}");
-	asm(" pop		{r0-r3,r12,lr}"); /* simulate register restor from stack */
-//	asm("pop 		{r4}"); /*foo*/
-	asm("pop		{pc}");
-}
-/*
- * cortex m4 knows stacks and handles register backups
- *
- * so use different stack frame layout
- *
- *
- * with float storage
- * ------------------------------------------------------------------------------------------------------------------------------------
- * | R0 | R1 | R2 | R3 | LR | PC | xPSR | S0 | S1 | S2 | S3 | S4 | S5 | S6 | S7 | S8 | S9 | S10 | S11 | S12 | S13 | S14 | S15 | FPSCR |
- * ------------------------------------------------------------------------------------------------------------------------------------
- *
- * without
- *
- * --------------------------------------
- * | R0 | R1 | R2 | R3 | LR | PC | xPSR |
- * --------------------------------------
- *
- *
- */
-char * thread_stack_init(void * task_func, void * stack_start, int stack_size ) {
-	unsigned int * stk;
-	stk = (unsigned int *) (stack_start + stack_size);
-
-	/* marker */
-	stk--;
-	*stk = 0x77777777;
-
-	//FIXME FPSCR
-	stk--;
-	*stk = (unsigned int) 0;
-
-	//S0 - S15
-	for (int i = 15; i >= 0; i--) {
-		stk--;
-		*stk = i;
-	}
-
-	//FIXME xPSR
-	stk--;
-	*stk = (unsigned int) 0x01000200;
-
-	//program counter
-	stk--;
-	*stk = (unsigned int) task_func;
-
-	/* link register */
-	stk--;
-	*stk = (unsigned int) 0x0;
-
-	/* r12 */
-	stk--;
-	*stk = (unsigned int) 0;
-
-	/* r0 - r3 */
-	for (int i = 3; i >= 0; i--) {
-		stk--;
-		*stk = i;
-	}
-
-	/* r11 - r4 */
-	for (int i = 11; i >= 4; i--) {
-		stk--;
-		*stk = i;
-	}
-
-	/* foo */
-	/*stk--;
-	*stk = (unsigned int) 0xDEADBEEF;*/
-
-	/* lr means exception return code  */
-	stk--;
-	*stk = (unsigned int) 0xfffffff9; // return to taskmode main stack pointer
-
-	return (char*) stk;
+    //unsigned int cspr = disableIRQ();		//crashes
+    dINT();
+    unsigned int uiOldVal = *p;
+    *p = uiVal;
+    //restoreIRQ(cspr);						//crashes
+    eINT();
+    return uiOldVal;
 }

stm32f407vgt6/cpu.c

@@ -5,37 +5,152 @@
  *      Author: pfeiffer
  */
 
-#include "stdint.h"
-#include "stm32f4xx_tim.h"
+#include <stdint.h>
 
-void stm32f4_pclk_scale(uint32_t source, uint32_t target, uint32_t* pclksel, uint32_t* prescale)
+#include "stm32f4xx.h"
+
+#include "cpu.h"
+#include "sched.h"
+
+extern void sched_task_exit(void);
+
+static inline void save_context(void);
+static inline void restore_context(void);
+
+__attribute__((always_inline))
+static inline void save_context(void)
+{
+    /* {r0-r3,r12,LR,PC,xPSR} are saved automatically on exception entry */
+
+    asm("ldr    r1, =active_thread");
+    /* load address of currend pdc */
+    asm("ldr    r1, [r1]");
+    /* deref pdc */
+    asm("cmp    r1, #0");
+    /* active_thread exists */
+    asm("ittt   ne");
+    /*if active_thread != NULL */
+    asm("pushne {r4-r11}");
+    /* save unsaved registers */
+    /*vstmdb    sp!, {s16-s31}    */ //FIXME save fpu registers if needed
+    asm("pushne {LR}");
+    /* save exception return value */
+    asm("strne  sp, [r1]");
+    /* write sp to pdc->sp means current threads stack pointer */
+}
+
+__attribute__((always_inline))
+static inline void restore_context(void)
 {
-	uint32_t pclkdiv;
-	*prescale = source / target;
-
-	if( (*prescale % 4) == 0 ) {
-		*pclksel = TIM_CKD_DIV4;
-		pclkdiv = 4;
-	} else if( (*prescale % 2) == 0 ) {
-		*pclksel = TIM_CKD_DIV2;
-		pclkdiv = 2;
-	} else {
-		*pclksel = TIM_CKD_DIV1;
-		pclkdiv = 1;
-	}
-	*prescale /= pclkdiv;
-
-	if( *prescale % 2 )
-		(*prescale)++;
+    asm("ldr    r0, =active_thread");
+    /* load address of currend pdc */
+    asm("ldr    r0, [r0]");
+    /* deref pdc */
+    asm("ldr    sp, [r0]");
+    /* load pdc->sp to sp register */
+
+    asm("pop    {r0}");
+    /* restore exception retrun value from stack */
+    /*pop       {s16-s31}        */ //FIXME load fpu register if needed depends on r0 exret
+    asm("pop    {r4-r11}");
+    /* load unloaded register */
+    //    asm("pop         {r4}"); /*foo*/
+    asm("bx     r0");                /* load exception return value to pc causes end of exception*/
+    /* {r0-r3,r12,LR,PC,xPSR} are restored automatically on exception return */
 }
 
+void cpu_switch_context_exit(void)
+{
+    __pendSV();
+    __enable_irq();
+}
+
+void thread_yield(void)
+{
+    __pendSV();
+}
+
+__attribute__((naked))
+void PendSV_Handler(void)
+{
+    save_context();
+    sched_run();
+    restore_context();
+}
+
+/*
+ * cortex m4 knows stacks and handles register backups
+ *
+ * so use different stack frame layout
+ *
+ *
+ * with float storage
+ * ------------------------------------------------------------------------------------------------------------------------------------
+ * | R0 | R1 | R2 | R3 | LR | PC | xPSR | S0 | S1 | S2 | S3 | S4 | S5 | S6 | S7 | S8 | S9 | S10 | S11 | S12 | S13 | S14 | S15 | FPSCR |
+ * ------------------------------------------------------------------------------------------------------------------------------------
+ *
+ * without
+ *
+ * --------------------------------------
+ * | R0 | R1 | R2 | R3 | LR | PC | xPSR |
+ * --------------------------------------
+ *
+ *
+ */
+char *thread_stack_init(void *task_func, void *stack_start, uint32_t stack_size)
+{
+    uint32_t *stk;
+    stk = (uint32_t *)(stack_start + stack_size);
+
+    /* marker */
+    stk--;
+    *stk = 0x77777777;
+
+    //FIXME FPSCR
+    stk--;
+    *stk = (uint32_t) 0;
+
+    //S0 - S15
+    for (int i = 15; i >= 0; i--) {
+        stk--;
+        *stk = i;
+    }
+
+    //FIXME xPSR
+    stk--;
+    *stk = (uint32_t) 0x01000200;
+
+    //program counter
+    stk--;
+    *stk = (uint32_t) task_func;
+
+    /* link register */
+    stk--;
+    *stk = (uint32_t) sched_task_exit;
+
+    /* r12 */
+    stk--;
+    *stk = (uint32_t) 0;
+
+    /* r0 - r3 */
+    for (int i = 3; i >= 0; i--) {
+        stk--;
+        *stk = i;
+    }
+
+    /* r11 - r4 */
+    for (int i = 11; i >= 4; i--) {
+        stk--;
+        *stk = i;
+    }
 
-void cpu_clock_scale(uint32_t source, uint32_t target, uint32_t* prescale) {
-    uint32_t pclksel;
+    /* foo */
+    /*stk--;
+    *stk = (uint32_t) 0xDEADBEEF;*/
 
-    stm32f4_pclk_scale(source, target, &pclksel, prescale);
+    /* lr means exception return code  */
+    stk--;
+    *stk = (uint32_t) 0xfffffff9; // return to taskmode main stack pointer
 
-    //PCLKSEL0 = (PCLKSEL0 & ~(BIT2|BIT3)) | (pclksel << 2); 		// timer 0
-    //PCLKSEL0 = (PCLKSEL0 & ~(BIT4|BIT5)) | (pclksel << 4); 		// timer 1
-    //PCLKSEL1 = (PCLKSEL1 & ~(BIT12|BIT13)) | (pclksel << 12);	// timer 2
+    return (char *) stk;
 }

stm32f407vgt6/include/cpu-conf.h

@@ -71,6 +71,8 @@ and the mailinglist (subscription via web site)
 #define KERNEL_CONF_STACKSIZE_DEFAULT	2500
 #endif
 
+#define KERNEL_CONF_STACKSIZE_PRINTF	4096
+
 #define KERNEL_CONF_STACKSIZE_IDLE		500
 /** @} */