arm64: remove __dma_*_area() aliases

The __dma_inv_area() and __dma_clean_area() aliases make cache.S harder
to navigate, but don't gain us anything in practice.

For clarity, let's remove them along with their redundant comments. The
only users are __dma_map_area() and __dma_unmap_area(), which need to be
position independent, and can call __pi_dcache_inval_poc() and
__pi_dcache_clean_poc() directly.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Fuad Tabba <tabba@google.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Will Deacon <will@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20211206124715.4101571-4-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Author: mrutland-arm

arch/arm64/mm/cache.S

@@ -140,15 +140,7 @@ SYM_FUNC_END(dcache_clean_pou)
  *	- start   - kernel start address of region
  *	- end     - kernel end address of region
  */
-SYM_FUNC_START_LOCAL(__dma_inv_area)
 SYM_FUNC_START_PI(dcache_inval_poc)
-	/* FALLTHROUGH */
-
-/*
- *	__dma_inv_area(start, end)
- *	- start   - virtual start address of region
- *	- end     - virtual end address of region
- */
 	dcache_line_size x2, x3
 	sub	x3, x2, #1
 	tst	x1, x3				// end cache line aligned?
@@ -167,7 +159,6 @@ SYM_FUNC_START_PI(dcache_inval_poc)
 	dsb	sy
 	ret
 SYM_FUNC_END_PI(dcache_inval_poc)
-SYM_FUNC_END(__dma_inv_area)
 
 /*
  *	dcache_clean_poc(start, end)
@@ -178,19 +169,10 @@ SYM_FUNC_END(__dma_inv_area)
  *	- start   - virtual start address of region
  *	- end     - virtual end address of region
  */
-SYM_FUNC_START_LOCAL(__dma_clean_area)
 SYM_FUNC_START_PI(dcache_clean_poc)
-	/* FALLTHROUGH */
-
-/*
- *	__dma_clean_area(start, end)
- *	- start   - virtual start address of region
- *	- end     - virtual end address of region
- */
 	dcache_by_line_op cvac, sy, x0, x1, x2, x3
 	ret
 SYM_FUNC_END_PI(dcache_clean_poc)
-SYM_FUNC_END(__dma_clean_area)
 
 /*
  *	dcache_clean_pop(start, end)
@@ -232,8 +214,8 @@ SYM_FUNC_END_PI(__dma_flush_area)
 SYM_FUNC_START_PI(__dma_map_area)
 	add	x1, x0, x1
 	cmp	w2, #DMA_FROM_DEVICE
-	b.eq	__dma_inv_area
-	b	__dma_clean_area
+	b.eq	__pi_dcache_inval_poc
+	b	__pi_dcache_clean_poc
 SYM_FUNC_END_PI(__dma_map_area)
 
 /*
@@ -245,6 +227,6 @@ SYM_FUNC_END_PI(__dma_map_area)
 SYM_FUNC_START_PI(__dma_unmap_area)
 	add	x1, x0, x1
 	cmp	w2, #DMA_TO_DEVICE
-	b.ne	__dma_inv_area
+	b.ne	__pi_dcache_inval_poc
 	ret
 SYM_FUNC_END_PI(__dma_unmap_area)