dma_mcux_lpc: Fix descriptor address conversion when used by DSP

The SDK FSL DMA driver converts descriptor addresses to DMA's address
space when linking descriptors. The Zephyr dma_mcux_lpc driver is
missing the inverse conversion when dereferencing the linked next
descriptor pointer.

This isn't a problem when this driver is used on the M33 core
of the MIMXRT595S because the M33 can access the address space
of the DMA (0x20000000+). But when the Fusion F1 DSP core uses
this driver, the DSP cannot access the DMA's address space
so the inverse conversion is needed.

Signed-off-by: Yicheng Li <[email protected]>

Author: yclistanford

drivers/dma/dma_mcux_lpc.c

@@ -13,6 +13,9 @@
 #include <zephyr/drivers/dma.h>
 #include <fsl_dma.h>
 #include <fsl_inputmux.h>
+#if defined(FSL_FEATURE_MEMORY_HAS_ADDRESS_OFFSET) && (FSL_FEATURE_MEMORY_HAS_ADDRESS_OFFSET == 1)
+#include "fsl_memory.h"
+#endif
 #include <zephyr/logging/log.h>
 #include <zephyr/irq.h>
 #include <zephyr/sys/barrier.h>
@@ -206,6 +209,14 @@ static int dma_mcux_lpc_queue_descriptors(struct channel_data *data,
 			 * is called from a reload function
 			 */
 			next_descriptor = data->curr_descriptor->linkToNextDesc;
+			/* The SDK converts next descriptor addresses to DMA's
+			 * address space when linking the descriptors, so
+			 * convert it back.
+			 */
+#if defined(FSL_FEATURE_MEMORY_HAS_ADDRESS_OFFSET) && (FSL_FEATURE_MEMORY_HAS_ADDRESS_OFFSET == 1)
+			next_descriptor = (void *)MEMORY_ConvertMemoryMapAddress(
+				(uint32_t)next_descriptor, kMEMORY_DMA2Local);
+#endif
 		}
 
 		/* SPI TX transfers need to queue a DMA descriptor to