1 files changed, 44 insertions, 0 deletions
diff --git a/arch/sh/mm/uncached.c b/arch/sh/mm/uncached.c
new file mode 100644
index 000000000..bd1585e8e
--- /dev/null
+++ b/arch/sh/mm/uncached.c
@@ -0,0 +1,44 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/sizes.h>
+#include <asm/page.h>
+#include <asm/addrspace.h>
+
+/*
+ * This is the offset of the uncached section from its cached alias.
+ *
+ * Legacy platforms handle trivial transitions between cached and
+ * uncached segments by making use of the 1:1 mapping relationship in
+ * 512MB lowmem, others via a special uncached mapping.
+ *
+ * Default value only valid in 29 bit mode, in 32bit mode this will be
+ * updated by the early PMB initialization code.
+ */
+unsigned long cached_to_uncached = SZ_512M;
+unsigned long uncached_size = SZ_512M;
+unsigned long uncached_start, uncached_end;
+EXPORT_SYMBOL(uncached_start);
+EXPORT_SYMBOL(uncached_end);
+
+int virt_addr_uncached(unsigned long kaddr)
+{
+	return (kaddr >= uncached_start) && (kaddr < uncached_end);
+}
+EXPORT_SYMBOL(virt_addr_uncached);
+
+void __init uncached_init(void)
+{
+#if defined(CONFIG_29BIT) || !defined(CONFIG_MMU)
+	uncached_start = P2SEG;
+#else
+	uncached_start = memory_end;
+#endif
+	uncached_end = uncached_start + uncached_size;
+}
+
+void __init uncached_resize(unsigned long size)
+{
+	uncached_size = size;
+	uncached_end = uncached_start + uncached_size;
+}