dma-direct: remove the cached_kernel_address hook

dma-direct now finds the kernel address for coherent allocations based
on the dma address, so the cached_kernel_address hooks is unused and
can be removed entirely.

Signed-off-by: Christoph Hellwig <[e-mail]>
Reviewed-by: Robin Murphy <[e-mail]>

arch/Kconfig

···
 
 #
 # Select if arch has an uncached kernel segment and provides the
-# uncached_kernel_address / cached_kernel_address symbols to use it
+# uncached_kernel_address symbol to use it
 #
 config ARCH_HAS_UNCACHED_SEGMENT
 	select ARCH_HAS_DMA_PREP_COHERENT

arch/microblaze/mm/consistent.c

···
 		pr_warn("ERROR: Your cache coherent area is CACHED!!!\n");
 	return (void *)addr;
 }
-
-void *cached_kernel_address(void *ptr)
-{
-	unsigned long addr = (unsigned long)ptr;
-
-	return (void *)(addr & ~UNCACHED_SHADOW_MASK);
-}
 #endif /* CONFIG_MMU */

arch/mips/mm/dma-noncoherent.c

···
 	return (void *)(__pa(addr) + UNCAC_BASE);
 }
 
-void *cached_kernel_address(void *addr)
-{
-	return __va(addr) - UNCAC_BASE;
-}
-
 static inline void dma_sync_virt(void *addr, size_t size,
 		enum dma_data_direction dir)
 {

arch/nios2/mm/dma-mapping.c

···
 
 	return (void *)ptr;
 }
-
-void *cached_kernel_address(void *ptr)
-{
-	unsigned long addr = (unsigned long)ptr;
-
-	addr &= ~CONFIG_NIOS2_IO_REGION_BASE;
-	addr |= CONFIG_NIOS2_KERNEL_REGION_BASE;
-
-	return (void *)ptr;
-}

arch/xtensa/kernel/pci-dma.c

···
 
 /*
  * Memory caching is platform-dependent in noMMU xtensa configurations.
- * The following two functions should be implemented in platform code
- * in order to enable coherent DMA memory operations when CONFIG_MMU is not
- * enabled.
+ * This function should be implemented in platform code in order to enable
+ * coherent DMA memory operations when CONFIG_MMU is not enabled.
  */
 #ifdef CONFIG_MMU
 void *uncached_kernel_address(void *p)
 {
 	return p + XCHAL_KSEG_BYPASS_VADDR - XCHAL_KSEG_CACHED_VADDR;
-}
-
-void *cached_kernel_address(void *p)
-{
-	return p + XCHAL_KSEG_CACHED_VADDR - XCHAL_KSEG_BYPASS_VADDR;
 }
 #endif /* CONFIG_MMU */

include/linux/dma-noncoherent.h

···
 #endif /* CONFIG_ARCH_HAS_DMA_PREP_COHERENT */
 
 void *uncached_kernel_address(void *addr);
-void *cached_kernel_address(void *addr);
 
 #endif /* _LINUX_DMA_NONCOHERENT_H */