From 264a7c8ef979c357cccdd67fbbbc6f88cd66991e Mon Sep 17 00:00:00 2001
From: Joshua DeWeese <jdeweese@primecontrols.com>
Date: Fri, 7 Oct 2022 15:35:47 -0400
Subject: [PATCH] cpu/stm32/periph/dma: fix DMA2 on STMF3 families

As it was, the calculation of DMA2's IRQ number was inccrorect for some
STM families. The implmentation alocates streams numbers 0 to 7 for the
first DMA controller and 8 and up for the second DMA controller. This
offset of +8 was not accounted for when IRQ's of the second DMA
controller was calculated. This patch corrects this.
---
 cpu/stm32/include/periph/cpu_dma.h |  2 +-
 cpu/stm32/periph/dma.c             | 14 ++++++++++----
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/cpu/stm32/include/periph/cpu_dma.h b/cpu/stm32/include/periph/cpu_dma.h
index 74dd58e8cd..bcdfc1ce95 100644
--- a/cpu/stm32/include/periph/cpu_dma.h
+++ b/cpu/stm32/include/periph/cpu_dma.h
@@ -38,7 +38,7 @@ typedef struct {
      *  - 8: DAM2 / Stream0
      *  - ...
      *  - 15: DMA2 / Stream7
-     * STM32F0/1/L0/1/4:
+     * STM32F0/1/3/L0/1/4:
      *  - 0: DMA1 / Channel1
      *  - ...
      *  - 4: DMA1 / Channel5
diff --git a/cpu/stm32/periph/dma.c b/cpu/stm32/periph/dma.c
index c61106f6b8..8f4d7b9f43 100644
--- a/cpu/stm32/periph/dma.c
+++ b/cpu/stm32/periph/dma.c
@@ -193,22 +193,28 @@ static IRQn_Type dma_get_irqn(int stream)
         return ((IRQn_Type)((int)DMA1_Channel1_IRQn + stream));
     }
 #if defined(DMA2_BASE)
+    /* stream 7 is invalid for these CPU families */
+    else if (stream == 7) {
+        return -1;
+    }
 #if defined(CPU_FAM_STM32F1)
     else if (stream < 11) {
 #else
     else if (stream < 13 ) {
 #endif
-        return ((IRQn_Type)((int)DMA2_Channel1_IRQn + stream));
+        /* magic number 8 is first DMA2 stream */
+        return ((IRQn_Type)((int)DMA2_Channel1_IRQn + stream - 8));
     }
-#if !defined(CPU_FAM_STM32L1)
+#if !defined(CPU_FAM_STM32L1) && !defined(CPU_FAM_STM32F3)
     else {
 #if defined(CPU_FAM_STM32F1)
         return (DMA2_Channel4_5_IRQn);
 #else
-        return ((IRQn_Type)((int)DMA2_Channel6_IRQn + stream));
+        /* magic number 13 is 8 (first DMA2 stream) + 5 (Channel6) */
+        return ((IRQn_Type)((int)DMA2_Channel6_IRQn + stream - 13));
 #endif
     }
-#endif /* !defined(CPU_FAM_STM32L1) */
+#endif /* !defined(CPU_FAM_STM32L1) && !defined(CPU_FAM_STM32F3) */
 #endif /* defined(DMA2_BASE) */
 #endif