stmhal: Turn off DMA clocks when idle for 100 msec

Turning on each DMA block increases the current consumption
by about 8 mA. This code adds an idle timer for each DMA
block and turns off the clocks when no streams are in use
for 128 msec. Having a small timeout allows for improved
performance when back-to-back transfers are being performed.

The 128 msec is basically a guess.

1 files changed, 5 insertions, 0 deletions

diff --git a/stmhal/stm32_it.c b/stmhal/stm32_it.c
index 14049fe6d..8a00c1469 100644
--- a/stmhal/stm32_it.c
+++ b/stmhal/stm32_it.c
@@ -77,6 +77,7 @@
 #include "uart.h"
 #include "storage.h"
 #include "can.h"
+#include "dma.h"
 
 extern void __fatal_error(const char*);
 extern PCD_HandleTypeDef pcd_handle;
@@ -267,6 +268,10 @@ void SysTick_Handler(void) {
     // the COUNTFLAG bit, which makes the logic in sys_tick_get_microseconds
     // work properly.
     SysTick->CTRL;
+
+    if (DMA_IDLE_ENABLED() && DMA_IDLE_TICK(uwTick)) {
+        dma_idle_handler(); 
+    }
 }
 
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