From 05a8141139187940c2fc7031442d2c06f0193f93 Mon Sep 17 00:00:00 2001
From: mikeller <github@ike.ch>
Date: Thu, 24 Aug 2017 04:34:10 +1200
Subject: [PATCH] Enable only DMA for channels that are used.

---
 src/main/drivers/pwm_output.c           | 3 ---
 src/main/drivers/pwm_output.h           | 1 +
 src/main/drivers/pwm_output_dshot.c     | 5 ++++-
 src/main/drivers/pwm_output_dshot_hal.c | 1 +
 4 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/main/drivers/pwm_output.c b/src/main/drivers/pwm_output.c
index 067be78fc3..9ace87f45e 100644
--- a/src/main/drivers/pwm_output.c
+++ b/src/main/drivers/pwm_output.c
@@ -397,9 +397,6 @@ void pwmWriteDshotCommand(uint8_t index, uint8_t motorCount, uint8_t command)
                     motorDmaOutput_t *const motor = getMotorDmaOutput(i);
                     motor->requestTelemetry = true;
                     pwmWriteDshotInt(i, command);
-                } else {
-                    // Needed to avoid DMA errors
-                    pwmWriteDshotInt(i, DSHOT_CMD_MOTOR_STOP);
                 }
             }
 
diff --git a/src/main/drivers/pwm_output.h b/src/main/drivers/pwm_output.h
index 6e3e8c9065..1d5929686c 100644
--- a/src/main/drivers/pwm_output.h
+++ b/src/main/drivers/pwm_output.h
@@ -107,6 +107,7 @@ typedef struct {
     const timerHardware_t *timerHardware;
     uint16_t value;
     uint16_t timerDmaSource;
+    motorDmaTimer_t *timer;
     volatile bool requestTelemetry;
 #if defined(STM32F3) || defined(STM32F4) || defined(STM32F7)
     uint32_t dmaBuffer[DSHOT_DMA_BUFFER_SIZE];
diff --git a/src/main/drivers/pwm_output_dshot.c b/src/main/drivers/pwm_output_dshot.c
index ff38430937..8bd18a2864 100644
--- a/src/main/drivers/pwm_output_dshot.c
+++ b/src/main/drivers/pwm_output_dshot.c
@@ -66,6 +66,7 @@ void pwmWriteDshotInt(uint8_t index, uint16_t value)
 
     uint8_t bufferSize = loadDmaBuffer(motor, packet);
 
+    motor->timer->timerDmaSources |= motor->timerDmaSource;
     DMA_SetCurrDataCounter(motor->timerHardware->dmaRef, bufferSize);
     DMA_Cmd(motor->timerHardware->dmaRef, ENABLE);
 }
@@ -77,6 +78,7 @@ void pwmCompleteDshotMotorUpdate(uint8_t motorCount)
     for (int i = 0; i < dmaMotorTimerCount; i++) {
         TIM_SetCounter(dmaMotorTimers[i].timer, 0);
         TIM_DMACmd(dmaMotorTimers[i].timer, dmaMotorTimers[i].timerDmaSources, ENABLE);
+        dmaMotorTimers[i].timerDmaSources = 0;
     }
 }
 
@@ -138,7 +140,8 @@ void pwmDshotMotorHardwareConfig(const timerHardware_t *timerHardware, uint8_t m
     timerOCInit(timer, timerHardware->channel, &TIM_OCInitStructure);
     timerOCPreloadConfig(timer, timerHardware->channel, TIM_OCPreload_Enable);
     motor->timerDmaSource = timerDmaSource(timerHardware->channel);
-    dmaMotorTimers[timerIndex].timerDmaSources |= motor->timerDmaSource;
+    motor->timer = &dmaMotorTimers[timerIndex];
+    motor->timer->timerDmaSources &= ~motor->timerDmaSource;
 
     TIM_CCxCmd(timer, timerHardware->channel, TIM_CCx_Enable);
 
diff --git a/src/main/drivers/pwm_output_dshot_hal.c b/src/main/drivers/pwm_output_dshot_hal.c
index c4a65cfed4..a382154a0e 100644
--- a/src/main/drivers/pwm_output_dshot_hal.c
+++ b/src/main/drivers/pwm_output_dshot_hal.c
@@ -115,6 +115,7 @@ void pwmDshotMotorHardwareConfig(const timerHardware_t *timerHardware, uint8_t m
     }
 
     motor->timerDmaSource = timerDmaSource(timerHardware->channel);
+    motor->timer = &dmaMotorTimers[timerIndex];
     dmaMotorTimers[timerIndex].timerDmaSources |= motor->timerDmaSource;
 
     /* Set the parameters to be configured */