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authorPaul Mundt <lethal@linux-sh.org>2009-04-02 12:31:16 +0900
committerPaul Mundt <lethal@linux-sh.org>2009-04-02 12:31:16 +0900
commiteeee7853c4ffaf5b9eb58f39708e3c78f66cee15 (patch)
tree55506c48a8e841573f1d869cd6e0fbfc6e8443e1 /arch/sh
parent8dafc34616282c1fd79d42a4353ee5322767d720 (diff)
sh: Add a command line option for disabling I/O trapping.
This adds a 'noiotrap' kernel command line option to permit disabling of I/O trapping. This is mostly useful for running on emulators where the physical device limitations are not an issue. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Diffstat (limited to 'arch/sh')
-rw-r--r--arch/sh/kernel/io_trapped.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/arch/sh/kernel/io_trapped.c b/arch/sh/kernel/io_trapped.c
index 39cd7f3aec7..c22853b059e 100644
--- a/arch/sh/kernel/io_trapped.c
+++ b/arch/sh/kernel/io_trapped.c
@@ -14,6 +14,7 @@
#include <linux/bitops.h>
#include <linux/vmalloc.h>
#include <linux/module.h>
+#include <linux/init.h>
#include <asm/system.h>
#include <asm/mmu_context.h>
#include <asm/uaccess.h>
@@ -32,6 +33,15 @@ EXPORT_SYMBOL_GPL(trapped_mem);
#endif
static DEFINE_SPINLOCK(trapped_lock);
+static int trapped_io_disable __read_mostly;
+
+static int __init trapped_io_setup(char *__unused)
+{
+ trapped_io_disable = 1;
+ return 1;
+}
+__setup("noiotrap", trapped_io_setup);
+
int register_trapped_io(struct trapped_io *tiop)
{
struct resource *res;
@@ -39,6 +49,9 @@ int register_trapped_io(struct trapped_io *tiop)
struct page *pages[TRAPPED_PAGES_MAX];
int k, n;
+ if (unlikely(trapped_io_disable))
+ return 0;
+
/* structure must be page aligned */
if ((unsigned long)tiop & (PAGE_SIZE - 1))
goto bad;