Merge branch "preempt" in "trunk".

[bertos.git] / bertos / cpu / arm / drv / adc_at91.c

diff --git a/bertos/cpu/arm/drv/adc_at91.c b/bertos/cpu/arm/drv/adc_at91.c
index bb6a8d11ffd1409fe86d557a86d31e6d233714f1..7fd50ddf24eae8ff05fe80a0f3b21953720de41e 100644 (file)
--- a/bertos/cpu/arm/drv/adc_at91.c
+++ b/bertos/cpu/arm/drv/adc_at91.c
@@ -84,7 +84,7 @@
         * ADC ISR.
         * Simply signal the adc process that convertion is complete.
         */
-       static void ISR_FUNC adc_conversion_end_irq(void)
+       static DECLARE_ISR(adc_conversion_end_irq)
        {
                sig_signal(adc_process, SIG_ADC_COMPLETE);
 
@@ -126,13 +126,13 @@ void adc_hw_select_ch(uint8_t ch)
 /**
  * Start an ADC convertion.
  * If a kernel is present, preempt until convertion is complete, otherwise
- * a busy wait on ADCS bit is done.
+ * a busy wait on ADC_DRDY bit is done.
  */
 uint16_t adc_hw_read(void)
 {
-       ASSERT(!(ADC_SR & ADC_EOC_MASK));
-
        #if CONFIG_KERN
+               /* Ensure ADC is not already in use by another process */
+               ASSERT(adc_process == NULL);
                adc_process = proc_current();
        #endif
 
@@ -143,13 +143,19 @@ uint16_t adc_hw_read(void)
                // Ensure IRQs enabled.
                IRQ_ASSERT_ENABLED();
                sig_wait(SIG_ADC_COMPLETE);
+
+               /* Prevent race condition in case of preemptive kernel */
+               uint16_t ret = ADC_LCDR;
+               MEMORY_BARRIER;
+               adc_process = NULL;
+               return ret;
        #else
                //Wait in polling until is done
                while (!(ADC_SR & BV(ADC_DRDY)));
-       #endif
 
-       //Return the last converted data
-       return(ADC_LCDR);
+               //Return the last converted data
+               return(ADC_LCDR);
+       #endif
 }
 
 /**