STM32F7: default CONFIG_STM32F7_DMACAPABLE to 'n'. STM32F7 does not have CCM RAM but DTCM, so this option does not need to enabled. DTCM RAM is DMA-able through CPU AHBS bus.

arch/arm/src/stm32f7/Kconfig

@@ -1884,8 +1884,7 @@ config STM32F7_DTCM_PROCFS
 config STM32F7_DMACAPABLE
 	bool "Workaround non-DMA capable memory"
 	depends on ARCH_DMA
-	default y if !STM32F7_CCMEXCLUDE
-	default n if STM32F7_CCMEXCLUDE
+	default n
 	---help---
 		This option enables the DMA interface stm32_dmacapable that can be
 		used to check if it is possible to do DMA from the selected address.

arch/arm/src/stm32f7/stm32_ethernet.c

@@ -635,8 +635,8 @@ struct stm32_ethmac_s
  * 1. Be a multiple of the D-Cache line size.  This requirement is assured
  *    by the definition of RXDMA buffer size above.
  * 2. Be aligned a D-Cache line boundaries, and
- * 3. Be positioned in DMA-able memory (*NOT* DTCM memory).  This must
- *    be managed by logic in the linker script file.
+ * 3. Be positioned in DMA-able memory.  This must be managed by logic
+ *    in the linker script file.
  *
  * These DMA buffers are defined sequentially here to best assure optimal
  * packing of the buffers.

arch/arm/src/stm32f7/stm32_serial.c

@@ -383,8 +383,7 @@ static const struct uart_ops_s g_uart_dma_ops =
  * 1. Be a multiple of the D-Cache line size.  This requirement is assured
  *    by the definition of RXDMA buffer size above.
  * 2. Be aligned a D-Cache line boundaries, and
- * 3. Be positioned in DMA-able memory (*NOT* DTCM memory).  This must
- *    be managed by logic in the linker script file.
+ * 3. Be positioned in DMA-able memory.
  *
  * These DMA buffers are defined sequentially here to best assure optimal
  * packing of the buffers.