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authorLinus Torvalds <torvalds@linux-foundation.org>2011-07-24 09:55:18 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-07-24 09:55:18 -0700
commitff0c4ad2c3a75ccfe6adca916e50804eb45bb2d9 (patch)
tree574f2d38793f7a08af73c40a96d6dc76af9c6f46 /arch/openrisc/include/asm/fixmap.h
parentfcda12e7f6d58d61997681a9d41779e3fd2ffc94 (diff)
parent19f9d392365113f74286b1721c7c032c12cf5abd (diff)
Merge branch 'for-upstream' of git://openrisc.net/jonas/linux
* 'for-upstream' of git://openrisc.net/jonas/linux: (24 commits) OpenRISC: Add MAINTAINERS entry OpenRISC: Miscellaneous OpenRISC: Library routines OpenRISC: Headers OpenRISC: Traps OpenRISC: Module support OpenRISC: GPIO OpenRISC: Scheduling/Process management OpenRISC: Idle/Power management OpenRISC: System calls OpenRISC: IRQ OpenRISC: Timekeeping OpenRISC: DMA OpenRISC: PTrace OpenRISC: Build infrastructure OpenRISC: Signal handling OpenRISC: Memory management OpenRISC: Device tree OpenRISC: Boot code iomap: make IOPORT/PCI mapping functions conditional ...
Diffstat (limited to 'arch/openrisc/include/asm/fixmap.h')
-rw-r--r--arch/openrisc/include/asm/fixmap.h87
1 files changed, 87 insertions, 0 deletions
diff --git a/arch/openrisc/include/asm/fixmap.h b/arch/openrisc/include/asm/fixmap.h
new file mode 100644
index 000000000000..52733416c1f3
--- /dev/null
+++ b/arch/openrisc/include/asm/fixmap.h
@@ -0,0 +1,87 @@
+/*
+ * OpenRISC Linux
+ *
+ * Linux architectural port borrowing liberally from similar works of
+ * others. All original copyrights apply as per the original source
+ * declaration.
+ *
+ * OpenRISC implementation:
+ * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
+ * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
+ * et al.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#ifndef __ASM_OPENRISC_FIXMAP_H
+#define __ASM_OPENRISC_FIXMAP_H
+
+/* Why exactly do we need 2 empty pages between the top of the fixed
+ * addresses and the top of virtual memory? Something is using that
+ * memory space but not sure what right now... If you find it, leave
+ * a comment here.
+ */
+#define FIXADDR_TOP ((unsigned long) (-2*PAGE_SIZE))
+
+#include <linux/kernel.h>
+#include <asm/page.h>
+
+/*
+ * On OpenRISC we use these special fixed_addresses for doing ioremap
+ * early in the boot process before memory initialization is complete.
+ * This is used, in particular, by the early serial console code.
+ *
+ * It's not really 'fixmap', per se, but fits loosely into the same
+ * paradigm.
+ */
+enum fixed_addresses {
+ /*
+ * FIX_IOREMAP entries are useful for mapping physical address
+ * space before ioremap() is useable, e.g. really early in boot
+ * before kmalloc() is working.
+ */
+#define FIX_N_IOREMAPS 32
+ FIX_IOREMAP_BEGIN,
+ FIX_IOREMAP_END = FIX_IOREMAP_BEGIN + FIX_N_IOREMAPS - 1,
+ __end_of_fixed_addresses
+};
+
+#define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
+/* FIXADDR_BOTTOM might be a better name here... */
+#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
+
+#define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT))
+#define __virt_to_fix(x) ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
+
+/*
+ * 'index to address' translation. If anyone tries to use the idx
+ * directly without tranlation, we catch the bug with a NULL-deference
+ * kernel oops. Illegal ranges of incoming indices are caught too.
+ */
+static __always_inline unsigned long fix_to_virt(const unsigned int idx)
+{
+ /*
+ * this branch gets completely eliminated after inlining,
+ * except when someone tries to use fixaddr indices in an
+ * illegal way. (such as mixing up address types or using
+ * out-of-range indices).
+ *
+ * If it doesn't get removed, the linker will complain
+ * loudly with a reasonably clear error message..
+ */
+ if (idx >= __end_of_fixed_addresses)
+ BUG();
+
+ return __fix_to_virt(idx);
+}
+
+static inline unsigned long virt_to_fix(const unsigned long vaddr)
+{
+ BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
+ return __virt_to_fix(vaddr);
+}
+
+#endif