[PATCH/RFC 2/6] dma-coherent: Add NO_DMA dummies for managed DMA API

From: Geert Uytterhoeven
Date: Tue Feb 06 2018 - 05:16:36 EST


Add dummies for dmam_{alloc,free}_coherent(), to allow compile-testing
if NO_DMA=y.

This prevents the following from showing up later:

ERROR: "dmam_alloc_coherent" [drivers/net/ethernet/arc/arc_emac.ko] undefined!
ERROR: "dmam_free_coherent" [drivers/net/ethernet/apm/xgene/xgene-enet.ko] undefined!
ERROR: "dmam_alloc_coherent" [drivers/net/ethernet/apm/xgene/xgene-enet.ko] undefined!
ERROR: "dmam_alloc_coherent" [drivers/mtd/nand/hisi504_nand.ko] undefined!
ERROR: "dmam_alloc_coherent" [drivers/mmc/host/dw_mmc.ko] undefined!

Signed-off-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
---
include/linux/dma-mapping.h | 9 +++++++++
1 file changed, 9 insertions(+)

diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index d78d7541f784875b..4d92956a4ddb8a5c 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -776,10 +776,19 @@ static inline void dma_deconfigure(struct device *dev) {}
/*
* Managed DMA API
*/
+#ifdef CONFIG_HAS_DMA
extern void *dmam_alloc_coherent(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp);
extern void dmam_free_coherent(struct device *dev, size_t size, void *vaddr,
dma_addr_t dma_handle);
+#else /* !CONFIG_HAS_DMA */
+static inline void *dmam_alloc_coherent(struct device *dev, size_t size,
+ dma_addr_t *dma_handle, gfp_t gfp)
+{ return NULL; }
+static inline void dmam_free_coherent(struct device *dev, size_t size,
+ void *vaddr, dma_addr_t dma_handle) { }
+#endif /* !CONFIG_HAS_DMA */
+
extern void *dmam_alloc_attrs(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp,
unsigned long attrs);
--
2.7.4