arm64: Device specific operations

This patch adds several definitions for device communication, including
I/O accessors and ioremap(). The __raw_* accessors are implemented as
inline asm to avoid compiler generation of post-indexed accesses (less
efficient to emulate in a virtualised environment).

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Olof Johansson <olof@lixom.net>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>

1 files changed, 84 insertions, 0 deletions

diff --git a/arch/arm64/mm/ioremap.c b/arch/arm64/mm/ioremap.c
new file mode 100644
index 000000000000..1725cd6db37a
--- /dev/null
+++ b/arch/arm64/mm/ioremap.c
@@ -0,0 +1,84 @@
+/*
+ * Based on arch/arm/mm/ioremap.c
+ *
+ * (C) Copyright 1995 1996 Linus Torvalds
+ * Hacked for ARM by Phil Blundell <philb@gnu.org>
+ * Hacked to allow all architectures to build, and various cleanups
+ * by Russell King
+ * Copyright (C) 2012 ARM Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/export.h>
+#include <linux/mm.h>
+#include <linux/vmalloc.h>
+#include <linux/io.h>
+
+static void __iomem *__ioremap_caller(phys_addr_t phys_addr, size_t size,
+                                      pgprot_t prot, void *caller)
+{
+        unsigned long last_addr;
+        unsigned long offset = phys_addr & ~PAGE_MASK;
+        int err;
+        unsigned long addr;
+        struct vm_struct *area;
+
+        /*
+         * Page align the mapping address and size, taking account of any
+         * offset.
+         */
+        phys_addr &= PAGE_MASK;
+        size = PAGE_ALIGN(size + offset);
+
+        /*
+         * Don't allow wraparound, zero size or outside PHYS_MASK.
+         */
+        last_addr = phys_addr + size - 1;
+        if (!size || last_addr < phys_addr || (last_addr & ~PHYS_MASK))
+                return NULL;
+
+        /*
+         * Don't allow RAM to be mapped.
+         */
+        if (WARN_ON(pfn_valid(__phys_to_pfn(phys_addr))))
+                return NULL;
+
+        area = get_vm_area_caller(size, VM_IOREMAP, caller);
+        if (!area)
+                return NULL;
+        addr = (unsigned long)area->addr;
+
+        err = ioremap_page_range(addr, addr + size, phys_addr, prot);
+        if (err) {
+                vunmap((void *)addr);
+                return NULL;
+        }
+
+        return (void __iomem *)(offset + addr);
+}
+
+void __iomem *__ioremap(phys_addr_t phys_addr, size_t size, pgprot_t prot)
+{
+        return __ioremap_caller(phys_addr, size, prot,
+                                __builtin_return_address(0));
+}
+EXPORT_SYMBOL(__ioremap);
+
+void __iounmap(volatile void __iomem *io_addr)
+{
+        void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);
+
+        vunmap(addr);
+}
+EXPORT_SYMBOL(__iounmap);