lib/ioremap.c: add huge I/O map capability interfaces

Add ioremap_pud_enabled() and ioremap_pmd_enabled(), which return 1 when
I/O mappings with pud/pmd are enabled on the kernel.

ioremap_huge_init() calls arch_ioremap_pud_supported() and
arch_ioremap_pmd_supported() to initialize the capabilities at boot-time.

A new kernel option "nohugeiomap" is also added, so that user can disable
the huge I/O map capabilities when necessary.

Signed-off-by: Toshi Kani <toshi.kani@hp.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Robert Elliott <Elliott@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 37 insertions, 0 deletions

diff --git a/lib/ioremap.c b/lib/ioremap.c
index 0c9216c48762..2008652c9a1f 100644
--- a/lib/ioremap.c
+++ b/lib/ioremap.c
@@ -13,6 +13,43 @@
 #include <asm/cacheflush.h>
 #include <asm/pgtable.h>
 
+#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
+int __read_mostly ioremap_pud_capable;
+int __read_mostly ioremap_pmd_capable;
+int __read_mostly ioremap_huge_disabled;
+
+static int __init set_nohugeiomap(char *str)
+{
+        ioremap_huge_disabled = 1;
+        return 0;
+}
+early_param("nohugeiomap", set_nohugeiomap);
+
+void __init ioremap_huge_init(void)
+{
+        if (!ioremap_huge_disabled) {
+                if (arch_ioremap_pud_supported())
+                        ioremap_pud_capable = 1;
+                if (arch_ioremap_pmd_supported())
+                        ioremap_pmd_capable = 1;
+        }
+}
+
+static inline int ioremap_pud_enabled(void)
+{
+        return ioremap_pud_capable;
+}
+
+static inline int ioremap_pmd_enabled(void)
+{
+        return ioremap_pmd_capable;
+}
+
+#else   /* !CONFIG_HAVE_ARCH_HUGE_VMAP */
+static inline int ioremap_pud_enabled(void) { return 0; }
+static inline int ioremap_pmd_enabled(void) { return 0; }
+#endif  /* CONFIG_HAVE_ARCH_HUGE_VMAP */
+
 static int ioremap_pte_range(pmd_t *pmd, unsigned long addr,
                 unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
 {