diff --git a/drivers/soc/fsl/qe/qe_common.c b/drivers/soc/fsl/qe/qe_common.c
index 83e85e61669f5..84c90105e588b 100644
--- a/drivers/soc/fsl/qe/qe_common.c
+++ b/drivers/soc/fsl/qe/qe_common.c
@@ -32,7 +32,7 @@ static phys_addr_t muram_pbase;
 
 struct muram_block {
 	struct list_head head;
-	unsigned long start;
+	s32 start;
 	int size;
 };
 
@@ -110,13 +110,14 @@ out_muram:
  * @algo: algorithm for alloc.
  * @data: data for genalloc's algorithm.
  *
- * This function returns an offset into the muram area.
+ * This function returns a non-negative offset into the muram area, or
+ * a negative errno on failure.
  */
-static unsigned long cpm_muram_alloc_common(unsigned long size,
-		genpool_algo_t algo, void *data)
+static s32 cpm_muram_alloc_common(unsigned long size,
+				  genpool_algo_t algo, void *data)
 {
 	struct muram_block *entry;
-	unsigned long start;
+	s32 start;
 
 	if (!muram_pool && cpm_muram_init())
 		goto out2;
@@ -137,7 +138,7 @@ static unsigned long cpm_muram_alloc_common(unsigned long size,
 out1:
 	gen_pool_free(muram_pool, start, size);
 out2:
-	return (unsigned long)-ENOMEM;
+	return -ENOMEM;
 }
 
 /*
@@ -145,13 +146,14 @@ out2:
  * @size: number of bytes to allocate
  * @align: requested alignment, in bytes
  *
- * This function returns an offset into the muram area.
+ * This function returns a non-negative offset into the muram area, or
+ * a negative errno on failure.
  * Use cpm_dpram_addr() to get the virtual address of the area.
  * Use cpm_muram_free() to free the allocation.
  */
-unsigned long cpm_muram_alloc(unsigned long size, unsigned long align)
+s32 cpm_muram_alloc(unsigned long size, unsigned long align)
 {
-	unsigned long start;
+	s32 start;
 	unsigned long flags;
 	struct genpool_data_align muram_pool_data;
 
@@ -168,7 +170,7 @@ EXPORT_SYMBOL(cpm_muram_alloc);
  * cpm_muram_free - free a chunk of multi-user ram
  * @offset: The beginning of the chunk as returned by cpm_muram_alloc().
  */
-int cpm_muram_free(unsigned long offset)
+int cpm_muram_free(s32 offset)
 {
 	unsigned long flags;
 	int size;
@@ -194,13 +196,14 @@ EXPORT_SYMBOL(cpm_muram_free);
  * cpm_muram_alloc_fixed - reserve a specific region of multi-user ram
  * @offset: offset of allocation start address
  * @size: number of bytes to allocate
- * This function returns an offset into the muram area
+ * This function returns @offset if the area was available, a negative
+ * errno otherwise.
  * Use cpm_dpram_addr() to get the virtual address of the area.
  * Use cpm_muram_free() to free the allocation.
  */
-unsigned long cpm_muram_alloc_fixed(unsigned long offset, unsigned long size)
+s32 cpm_muram_alloc_fixed(unsigned long offset, unsigned long size)
 {
-	unsigned long start;
+	s32 start;
 	unsigned long flags;
 	struct genpool_data_fixed muram_pool_data_fixed;
 
diff --git a/include/soc/fsl/qe/qe.h b/include/soc/fsl/qe/qe.h
index c1036d16ed03b..2d35d5db16231 100644
--- a/include/soc/fsl/qe/qe.h
+++ b/include/soc/fsl/qe/qe.h
@@ -98,26 +98,26 @@ static inline void qe_reset(void) {}
 int cpm_muram_init(void);
 
 #if defined(CONFIG_CPM) || defined(CONFIG_QUICC_ENGINE)
-unsigned long cpm_muram_alloc(unsigned long size, unsigned long align);
-int cpm_muram_free(unsigned long offset);
-unsigned long cpm_muram_alloc_fixed(unsigned long offset, unsigned long size);
+s32 cpm_muram_alloc(unsigned long size, unsigned long align);
+int cpm_muram_free(s32 offset);
+s32 cpm_muram_alloc_fixed(unsigned long offset, unsigned long size);
 void __iomem *cpm_muram_addr(unsigned long offset);
 unsigned long cpm_muram_offset(void __iomem *addr);
 dma_addr_t cpm_muram_dma(void __iomem *addr);
 #else
-static inline unsigned long cpm_muram_alloc(unsigned long size,
-					    unsigned long align)
+static inline s32 cpm_muram_alloc(unsigned long size,
+				  unsigned long align)
 {
 	return -ENOSYS;
 }
 
-static inline int cpm_muram_free(unsigned long offset)
+static inline int cpm_muram_free(s32 offset)
 {
 	return -ENOSYS;
 }
 
-static inline unsigned long cpm_muram_alloc_fixed(unsigned long offset,
-						  unsigned long size)
+static inline s32 cpm_muram_alloc_fixed(unsigned long offset,
+					unsigned long size)
 {
 	return -ENOSYS;
 }
