1 files changed, 103 insertions, 0 deletions

diff --git a/include/asm-mips/highmem.h b/include/asm-mips/highmem.h
new file mode 100644
index 000000000000..f49930d947d4
--- /dev/null
+++ b/include/asm-mips/highmem.h
@@ -0,0 +1,103 @@
+/*
+ * highmem.h: virtual kernel memory mappings for high memory
+ *
+ * Used in CONFIG_HIGHMEM systems for memory pages which
+ * are not addressable by direct kernel virtual addresses.
+ *
+ * Copyright (C) 1999 Gerhard Wichert, Siemens AG
+ *                    Gerhard.Wichert@pdb.siemens.de
+ *
+ *
+ * Redesigned the x86 32-bit VM architecture to deal with
+ * up to 16 Terabyte physical memory. With current x86 CPUs
+ * we now support up to 64 Gigabytes physical RAM.
+ *
+ * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
+ */
+#ifndef _ASM_HIGHMEM_H
+#define _ASM_HIGHMEM_H
+
+#ifdef __KERNEL__
+
+#include <linux/config.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <asm/kmap_types.h>
+
+/* undef for production */
+#define HIGHMEM_DEBUG 1
+
+/* declarations for highmem.c */
+extern unsigned long highstart_pfn, highend_pfn;
+
+extern pte_t *kmap_pte;
+extern pgprot_t kmap_prot;
+extern pte_t *pkmap_page_table;
+
+/*
+ * Right now we initialize only a single pte table. It can be extended
+ * easily, subsequent pte tables have to be allocated in one physical
+ * chunk of RAM.
+ */
+#define PKMAP_BASE (0xfe000000UL)
+#define LAST_PKMAP 1024
+#define LAST_PKMAP_MASK (LAST_PKMAP-1)
+#define PKMAP_NR(virt)  ((virt-PKMAP_BASE) >> PAGE_SHIFT)
+#define PKMAP_ADDR(nr)  (PKMAP_BASE + ((nr) << PAGE_SHIFT))
+
+extern void * kmap_high(struct page *page);
+extern void kunmap_high(struct page *page);
+
+/*
+ * CONFIG_LIMITED_DMA is for systems with DMA limitations such as Momentum's
+ * Jaguar ATX.  This option exploits the highmem code in the kernel so is
+ * always enabled together with CONFIG_HIGHMEM but at this time doesn't
+ * actually add highmem functionality.
+ */
+
+#ifdef CONFIG_LIMITED_DMA
+
+/*
+ * These are the default functions for the no-highmem case from
+ * <linux/highmem.h>
+ */
+static inline void *kmap(struct page *page)
+{
+        might_sleep();
+        return page_address(page);
+}
+
+#define kunmap(page) do { (void) (page); } while (0)
+
+static inline void *kmap_atomic(struct page *page, enum km_type type)
+{
+        return page_address(page);
+}
+
+static inline void kunmap_atomic(void *kvaddr, enum km_type type) { }
+
+#define kmap_atomic_to_page(ptr) virt_to_page(ptr)
+
+#define flush_cache_kmaps()     do { } while (0)
+
+#else /* LIMITED_DMA */
+
+extern void *__kmap(struct page *page);
+extern void __kunmap(struct page *page);
+extern void *__kmap_atomic(struct page *page, enum km_type type);
+extern void __kunmap_atomic(void *kvaddr, enum km_type type);
+extern struct page *__kmap_atomic_to_page(void *ptr);
+
+#define kmap                    __kmap
+#define kunmap                  __kunmap
+#define kmap_atomic             __kmap_atomic
+#define kunmap_atomic           __kunmap_atomic
+#define kmap_atomic_to_page     __kmap_atomic_to_page
+
+#define flush_cache_kmaps()     flush_cache_all()
+
+#endif /* LIMITED_DMA */
+
+#endif /* __KERNEL__ */
+
+#endif /* _ASM_HIGHMEM_H */