dma-direct: make uncached_kernel_address more general

Rename the symbol to arch_dma_set_uncached, and pass a size to it as
well as allow an error return.  That will allow reusing this hook for
in-place pagetable remapping.

As the in-place remap doesn't always require an explicit cache flush,
also detangle ARCH_HAS_DMA_PREP_COHERENT from ARCH_HAS_DMA_SET_UNCACHED.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>

9 files changed, 14 insertions, 12 deletions

diff --git a/arch/Kconfig b/arch/Kconfig
index 7994b239f155..090cfe0c82a7 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -248,11 +248,11 @@ config ARCH_HAS_SET_DIRECT_MAP
 	bool
 
 #
-# Select if arch has an uncached kernel segment and provides the
-# uncached_kernel_address symbol to use it
+# Select if the architecture provides the arch_dma_set_uncached symbol to
+# either provide an uncached segement alias for a DMA allocation, or
+# to remap the page tables in place.
 #
-config ARCH_HAS_UNCACHED_SEGMENT
-	select ARCH_HAS_DMA_PREP_COHERENT
+config ARCH_HAS_DMA_SET_UNCACHED
 	bool
 
 # Select if arch init_task must go in the __init_task_data section
diff --git a/arch/microblaze/Kconfig b/arch/microblaze/Kconfig
index 6a331bd57ea8..9606c244b5b8 100644
--- a/arch/microblaze/Kconfig
+++ b/arch/microblaze/Kconfig
@@ -8,7 +8,7 @@ config MICROBLAZE
 	select ARCH_HAS_GCOV_PROFILE_ALL
 	select ARCH_HAS_SYNC_DMA_FOR_CPU
 	select ARCH_HAS_SYNC_DMA_FOR_DEVICE
-	select ARCH_HAS_UNCACHED_SEGMENT if !MMU
+	select ARCH_HAS_DMA_SET_UNCACHED if !MMU
 	select ARCH_MIGHT_HAVE_PC_PARPORT
 	select ARCH_WANT_IPC_PARSE_VERSION
 	select BUILDTIME_TABLE_SORT
diff --git a/arch/microblaze/mm/consistent.c b/arch/microblaze/mm/consistent.c
index cede7c5e8135..e09b66e43cb6 100644
--- a/arch/microblaze/mm/consistent.c
+++ b/arch/microblaze/mm/consistent.c
@@ -40,7 +40,7 @@ void arch_dma_prep_coherent(struct page *page, size_t size)
 #define UNCACHED_SHADOW_MASK 0
 #endif /* CONFIG_XILINX_UNCACHED_SHADOW */
 
-void *uncached_kernel_address(void *ptr)
+void *arch_dma_set_uncached(void *ptr, size_t size)
 {
 	unsigned long addr = (unsigned long)ptr;
 
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 797d7f1ad5fe..489185db501e 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -1187,8 +1187,9 @@ config DMA_NONCOHERENT
 	# significant advantages.
 	#
 	select ARCH_HAS_DMA_WRITE_COMBINE
+	select ARCH_HAS_DMA_PREP_COHERENT
 	select ARCH_HAS_SYNC_DMA_FOR_DEVICE
-	select ARCH_HAS_UNCACHED_SEGMENT
+	select ARCH_HAS_DMA_SET_UNCACHED
 	select DMA_NONCOHERENT_MMAP
 	select DMA_NONCOHERENT_CACHE_SYNC
 	select NEED_DMA_MAP_STATE
diff --git a/arch/mips/mm/dma-noncoherent.c b/arch/mips/mm/dma-noncoherent.c
index 77dce28ad0a0..fcea92d95d86 100644
--- a/arch/mips/mm/dma-noncoherent.c
+++ b/arch/mips/mm/dma-noncoherent.c
@@ -49,7 +49,7 @@ void arch_dma_prep_coherent(struct page *page, size_t size)
 	dma_cache_wback_inv((unsigned long)page_address(page), size);
 }
 
-void *uncached_kernel_address(void *addr)
+void *arch_dma_set_uncached(void *addr, size_t size)
 {
 	return (void *)(__pa(addr) + UNCAC_BASE);
 }
diff --git a/arch/nios2/Kconfig b/arch/nios2/Kconfig
index 44b5da37e8bd..2fc4ed210b5f 100644
--- a/arch/nios2/Kconfig
+++ b/arch/nios2/Kconfig
@@ -2,9 +2,10 @@
 config NIOS2
 	def_bool y
 	select ARCH_32BIT_OFF_T
+	select ARCH_HAS_DMA_PREP_COHERENT
 	select ARCH_HAS_SYNC_DMA_FOR_CPU
 	select ARCH_HAS_SYNC_DMA_FOR_DEVICE
-	select ARCH_HAS_UNCACHED_SEGMENT
+	select ARCH_HAS_DMA_SET_UNCACHED
 	select ARCH_NO_SWAP
 	select TIMER_OF
 	select GENERIC_ATOMIC64
diff --git a/arch/nios2/mm/dma-mapping.c b/arch/nios2/mm/dma-mapping.c
index f30f2749257c..fd887d5f3f9a 100644
--- a/arch/nios2/mm/dma-mapping.c
+++ b/arch/nios2/mm/dma-mapping.c
@@ -67,7 +67,7 @@ void arch_dma_prep_coherent(struct page *page, size_t size)
 	flush_dcache_range(start, start + size);
 }
 
-void *uncached_kernel_address(void *ptr)
+void *arch_dma_set_uncached(void *ptr, size_t size)
 {
 	unsigned long addr = (unsigned long)ptr;
 
diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig
index 32ee759a3fda..de229424b659 100644
--- a/arch/xtensa/Kconfig
+++ b/arch/xtensa/Kconfig
@@ -6,7 +6,7 @@ config XTENSA
 	select ARCH_HAS_DMA_PREP_COHERENT if MMU
 	select ARCH_HAS_SYNC_DMA_FOR_CPU if MMU
 	select ARCH_HAS_SYNC_DMA_FOR_DEVICE if MMU
-	select ARCH_HAS_UNCACHED_SEGMENT if MMU
+	select ARCH_HAS_DMA_SET_UNCACHED if MMU
 	select ARCH_USE_QUEUED_RWLOCKS
 	select ARCH_USE_QUEUED_SPINLOCKS
 	select ARCH_WANT_FRAME_POINTERS
diff --git a/arch/xtensa/kernel/pci-dma.c b/arch/xtensa/kernel/pci-dma.c
index 6a685545d5c9..17c4384f8495 100644
--- a/arch/xtensa/kernel/pci-dma.c
+++ b/arch/xtensa/kernel/pci-dma.c
@@ -92,7 +92,7 @@ void arch_dma_prep_coherent(struct page *page, size_t size)
  * coherent DMA memory operations when CONFIG_MMU is not enabled.
  */
 #ifdef CONFIG_MMU
-void *uncached_kernel_address(void *p)
+void *arch_dma_set_uncached(void *p, size_t size)
 {
 	return p + XCHAL_KSEG_BYPASS_VADDR - XCHAL_KSEG_CACHED_VADDR;
 }