Subject: [PATCH 15/21] ARM: dma-mapping: always invalidate WT caches before DMA

From: Arnd Bergmann <[email-masked]>
Date: Mon, 27 Mar 2023 14:13:11 +0200

From: Arnd Bergmann <[email-masked]>

Most ARM CPUs can have write-back caches and that require
cache management to be done in the dma_sync_*_for_device()
operation. This is typically done in both writeback and
writethrough mode.

The cache-v4.S (arm720/740/7tdmi/9tdmi) and cache-v4wt.S
(arm920t, arm940t) implementations are the exception here,
and only do the cache management after the DMA is complete,
in the dma_sync_*_for_cpu() operation.

Change this for consistency with the other platforms. This
should have no user visible effect.

Signed-off-by: Arnd Bergmann <[email-masked]>
---
 arch/arm/mm/cache-v4.S   | 8 ++++----
 arch/arm/mm/cache-v4wt.S | 8 ++++----
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/arch/arm/mm/cache-v4.S b/arch/arm/mm/cache-v4.S
index 7787057e4990..e2b104876340 100644
--- a/arch/arm/mm/cache-v4.S
+++ b/arch/arm/mm/cache-v4.S
@@ -117,23 +117,23 @@ ENTRY(v4_dma_flush_range)
 	ret	lr
 
 /*
- *	dma_unmap_area(start, size, dir)
+ *	dma_map_area(start, size, dir)
  *	- start	- kernel virtual start address
  *	- size	- size of region
  *	- dir	- DMA direction
  */
-ENTRY(v4_dma_unmap_area)
+ENTRY(v4_dma_map_area)
 	teq	r2, #DMA_TO_DEVICE
 	bne	v4_dma_flush_range
 	/* FALLTHROUGH */
 
 /*
- *	dma_map_area(start, size, dir)
+ *	dma_unmap_area(start, size, dir)
  *	- start	- kernel virtual start address
  *	- size	- size of region
  *	- dir	- DMA direction
  */
-ENTRY(v4_dma_map_area)
+ENTRY(v4_dma_unmap_area)
 	ret	lr
 ENDPROC(v4_dma_unmap_area)
 ENDPROC(v4_dma_map_area)
diff --git a/arch/arm/mm/cache-v4wt.S b/arch/arm/mm/cache-v4wt.S
index 0b290c25a99d..652218752f88 100644
--- a/arch/arm/mm/cache-v4wt.S
+++ b/arch/arm/mm/cache-v4wt.S
@@ -172,24 +172,24 @@ v4wt_dma_inv_range:
 	.equ	v4wt_dma_flush_range, v4wt_dma_inv_range
 
 /*
- *	dma_unmap_area(start, size, dir)
+ *	dma_map_area(start, size, dir)
  *	- start	- kernel virtual start address
  *	- size	- size of region
  *	- dir	- DMA direction
  */
-ENTRY(v4wt_dma_unmap_area)
+ENTRY(v4wt_dma_map_area)
 	add	r1, r1, r0
 	teq	r2, #DMA_TO_DEVICE
 	bne	v4wt_dma_inv_range
 	/* FALLTHROUGH */
 
 /*
- *	dma_map_area(start, size, dir)
+ *	dma_unmap_area(start, size, dir)
  *	- start	- kernel virtual start address
  *	- size	- size of region
  *	- dir	- DMA direction
  */
-ENTRY(v4wt_dma_map_area)
+ENTRY(v4wt_dma_unmap_area)
 	ret	lr
 ENDPROC(v4wt_dma_unmap_area)
 ENDPROC(v4wt_dma_map_area)
-- 
2.39.2