riscv: split cache ops out of dma-noncoherent.c

The cache ops are also used by the pmem code which is unconditionally
built into the kernel.  Move them into a separate file that is built
based on the correct config option.

Fixes: fd96278 ("riscv: RISCV_NONSTANDARD_CACHE_OPS shouldn't depend on RISCV_DMA_NONCOHERENT")
Reported-by: kernel test robot <[email protected]>
Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Conor Dooley <[email protected]>
Tested-by: Conor Dooley <[email protected]>
Reviewed-by: Lad Prabhakar <[email protected]>
Tested-by: Lad Prabhakar <[email protected]> #
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Palmer Dabbelt <[email protected]>

Author: Christoph Hellwig

arch/riscv/mm/Makefile

@@ -36,3 +36,4 @@ endif
 
 obj-$(CONFIG_DEBUG_VIRTUAL) += physaddr.o
 obj-$(CONFIG_RISCV_DMA_NONCOHERENT) += dma-noncoherent.o
+obj-$(CONFIG_RISCV_NONSTANDARD_CACHE_OPS) += cache-ops.o

arch/riscv/mm/cache-ops.c

@@ -0,0 +1,17 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2021 Western Digital Corporation or its affiliates.
+ */
+
+#include <asm/dma-noncoherent.h>
+
+struct riscv_nonstd_cache_ops noncoherent_cache_ops __ro_after_init;
+
+void
+riscv_noncoherent_register_cache_ops(const struct riscv_nonstd_cache_ops *ops)
+{
+	if (!ops)
+		return;
+	noncoherent_cache_ops = *ops;
+}
+EXPORT_SYMBOL_GPL(riscv_noncoherent_register_cache_ops);

arch/riscv/mm/dma-noncoherent.c

@@ -15,12 +15,6 @@ static bool noncoherent_supported __ro_after_init;
 int dma_cache_alignment __ro_after_init = ARCH_DMA_MINALIGN;
 EXPORT_SYMBOL_GPL(dma_cache_alignment);
 
-struct riscv_nonstd_cache_ops noncoherent_cache_ops __ro_after_init = {
-	.wback = NULL,
-	.inv = NULL,
-	.wback_inv = NULL,
-};
-
 static inline void arch_dma_cache_wback(phys_addr_t paddr, size_t size)
 {
 	void *vaddr = phys_to_virt(paddr);
@@ -162,12 +156,3 @@ void __init riscv_set_dma_cache_alignment(void)
 	if (!noncoherent_supported)
 		dma_cache_alignment = 1;
 }
-
-void riscv_noncoherent_register_cache_ops(const struct riscv_nonstd_cache_ops *ops)
-{
-	if (!ops)
-		return;
-
-	noncoherent_cache_ops = *ops;
-}
-EXPORT_SYMBOL_GPL(riscv_noncoherent_register_cache_ops);