riscv: use the generic ioremap code

Use the generic ioremap code instead of providing a local version.
Note that this relies on the asm-generic no-op definition of
pgprot_noncached.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Paul Walmsley <paul.walmsley@sifive.com>
Tested-by: Paul Walmsley <paul.walmsley@sifive.com> # rv32, rv64 boot
Acked-by: Paul Walmsley <paul.walmsley@sifive.com> # arch/riscv

arch/riscv/Kconfig

@@ -30,6 +30,7 @@ config RISCV
 	select GENERIC_STRNLEN_USER
 	select GENERIC_SMP_IDLE_THREAD
 	select GENERIC_ATOMIC64 if !64BIT
+	select GENERIC_IOREMAP
 	select HAVE_ARCH_AUDITSYSCALL
 	select HAVE_ASM_MODVERSIONS
 	select HAVE_MEMBLOCK_NODE_MAP

arch/riscv/include/asm/io.h

@@ -15,9 +15,6 @@
 #include <asm/mmiowb.h>
 #include <asm/pgtable.h>
 
-extern void __iomem *ioremap(phys_addr_t offset, unsigned long size);
-extern void iounmap(volatile void __iomem *addr);
-
 /* Generic IO read/write.  These perform native-endian accesses. */
 #define __raw_writeb __raw_writeb
 static inline void __raw_writeb(u8 val, volatile void __iomem *addr)

arch/riscv/include/asm/pgtable.h

@@ -62,6 +62,12 @@
 
 #define PAGE_TABLE		__pgprot(_PAGE_TABLE)
 
+/*
+ * The RISC-V ISA doesn't yet specify how to query or modify PMAs, so we can't
+ * change the properties of memory regions.
+ */
+#define _PAGE_IOREMAP _PAGE_KERNEL
+
 extern pgd_t swapper_pg_dir[];
 
 /* MAP_PRIVATE permissions: xwr (copy-on-write) */

arch/riscv/mm/Makefile

@@ -8,7 +8,6 @@ endif
 obj-y += init.o
 obj-y += fault.o
 obj-y += extable.o
-obj-y += ioremap.o
 obj-y += cacheflush.o
 obj-y += context.o
 obj-y += sifive_l2_cache.o

arch/riscv/mm/ioremap.c

@@ -1,84 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-only
-/*
- * (C) Copyright 1995 1996 Linus Torvalds
- * (C) Copyright 2012 Regents of the University of California
- */
-
-#include <linux/export.h>
-#include <linux/mm.h>
-#include <linux/vmalloc.h>
-#include <linux/io.h>
-
-#include <asm/pgtable.h>
-
-/*
- * Remap an arbitrary physical address space into the kernel virtual
- * address space. Needed when the kernel wants to access high addresses
- * directly.
- *
- * NOTE! We need to allow non-page-aligned mappings too: we will obviously
- * have to convert them into an offset in a page-aligned mapping, but the
- * caller shouldn't need to know that small detail.
- */
-static void __iomem *__ioremap_caller(phys_addr_t addr, size_t size,
-	pgprot_t prot, void *caller)
-{
-	phys_addr_t last_addr;
-	unsigned long offset, vaddr;
-	struct vm_struct *area;
-
-	/* Disallow wrap-around or zero size */
-	last_addr = addr + size - 1;
-	if (!size || last_addr < addr)
-		return NULL;
-
-	/* Page-align mappings */
-	offset = addr & (~PAGE_MASK);
-	addr -= offset;
-	size = PAGE_ALIGN(size + offset);
-
-	area = get_vm_area_caller(size, VM_IOREMAP, caller);
-	if (!area)
-		return NULL;
-	vaddr = (unsigned long)area->addr;
-
-	if (ioremap_page_range(vaddr, vaddr + size, addr, prot)) {
-		free_vm_area(area);
-		return NULL;
-	}
-
-	return (void __iomem *)(vaddr + offset);
-}
-
-/*
- * ioremap     -   map bus memory into CPU space
- * @offset:    bus address of the memory
- * @size:      size of the resource to map
- *
- * ioremap performs a platform specific sequence of operations to
- * make bus memory CPU accessible via the readb/readw/readl/writeb/
- * writew/writel functions and the other mmio helpers. The returned
- * address is not guaranteed to be usable directly as a virtual
- * address.
- *
- * Must be freed with iounmap.
- */
-void __iomem *ioremap(phys_addr_t offset, unsigned long size)
-{
-	return __ioremap_caller(offset, size, PAGE_KERNEL,
-		__builtin_return_address(0));
-}
-EXPORT_SYMBOL(ioremap);
-
-
-/**
- * iounmap - Free a IO remapping
- * @addr: virtual address from ioremap_*
- *
- * Caller must ensure there is only one unmapping for the same pointer.
- */
-void iounmap(volatile void __iomem *addr)
-{
-	vunmap((void *)((unsigned long)addr & PAGE_MASK));
-}
-EXPORT_SYMBOL(iounmap);