Initial import

1 files changed, 159 insertions, 0 deletions

diff --git a/arch/powerpc/mm/40x_mmu.c b/arch/powerpc/mm/40x_mmu.c
new file mode 100644
index 000000000..581096751
--- /dev/null
+++ b/arch/powerpc/mm/40x_mmu.c
@@ -0,0 +1,159 @@
+/*
+ * This file contains the routines for initializing the MMU
+ * on the 4xx series of chips.
+ *  -- paulus
+ *
+ *  Derived from arch/ppc/mm/init.c:
+ *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
+ *
+ *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
+ *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
+ *    Copyright (C) 1996 Paul Mackerras
+ *
+ *  Derived from "arch/i386/mm/init.c"
+ *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
+ *
+ *  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.
+ *
+ */
+
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/ptrace.h>
+#include <linux/mman.h>
+#include <linux/mm.h>
+#include <linux/swap.h>
+#include <linux/stddef.h>
+#include <linux/vmalloc.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/highmem.h>
+#include <linux/memblock.h>
+
+#include <asm/pgalloc.h>
+#include <asm/prom.h>
+#include <asm/io.h>
+#include <asm/mmu_context.h>
+#include <asm/pgtable.h>
+#include <asm/mmu.h>
+#include <asm/uaccess.h>
+#include <asm/smp.h>
+#include <asm/bootx.h>
+#include <asm/machdep.h>
+#include <asm/setup.h>
+
+#include "mmu_decl.h"
+
+extern int __map_without_ltlbs;
+/*
+ * MMU_init_hw does the chip-specific initialization of the MMU hardware.
+ */
+void __init MMU_init_hw(void)
+{
+	/*
+	 * The Zone Protection Register (ZPR) defines how protection will
+	 * be applied to every page which is a member of a given zone. At
+	 * present, we utilize only two of the 4xx's zones.
+	 * The zone index bits (of ZSEL) in the PTE are used for software
+	 * indicators, except the LSB.  For user access, zone 1 is used,
+	 * for kernel access, zone 0 is used.  We set all but zone 1
+	 * to zero, allowing only kernel access as indicated in the PTE.
+	 * For zone 1, we set a 01 binary (a value of 10 will not work)
+	 * to allow user access as indicated in the PTE.  This also allows
+	 * kernel access as indicated in the PTE.
+	 */
+
+        mtspr(SPRN_ZPR, 0x10000000);
+
+	flush_instruction_cache();
+
+	/*
+	 * Set up the real-mode cache parameters for the exception vector
+	 * handlers (which are run in real-mode).
+	 */
+
+        mtspr(SPRN_DCWR, 0x00000000);	/* All caching is write-back */
+
+        /*
+	 * Cache instruction and data space where the exception
+	 * vectors and the kernel live in real-mode.
+	 */
+
+        mtspr(SPRN_DCCR, 0xFFFF0000);	/* 2GByte of data space at 0x0. */
+        mtspr(SPRN_ICCR, 0xFFFF0000);	/* 2GByte of instr. space at 0x0. */
+}
+
+#define LARGE_PAGE_SIZE_16M	(1<<24)
+#define LARGE_PAGE_SIZE_4M	(1<<22)
+
+unsigned long __init mmu_mapin_ram(unsigned long top)
+{
+	unsigned long v, s, mapped;
+	phys_addr_t p;
+
+	v = KERNELBASE;
+	p = 0;
+	s = total_lowmem;
+
+	if (__map_without_ltlbs)
+		return 0;
+
+	while (s >= LARGE_PAGE_SIZE_16M) {
+		pmd_t *pmdp;
+		unsigned long val = p | _PMD_SIZE_16M | _PAGE_EXEC | _PAGE_HWWRITE;
+
+		pmdp = pmd_offset(pud_offset(pgd_offset_k(v), v), v);
+		pmd_val(*pmdp++) = val;
+		pmd_val(*pmdp++) = val;
+		pmd_val(*pmdp++) = val;
+		pmd_val(*pmdp++) = val;
+
+		v += LARGE_PAGE_SIZE_16M;
+		p += LARGE_PAGE_SIZE_16M;
+		s -= LARGE_PAGE_SIZE_16M;
+	}
+
+	while (s >= LARGE_PAGE_SIZE_4M) {
+		pmd_t *pmdp;
+		unsigned long val = p | _PMD_SIZE_4M | _PAGE_EXEC | _PAGE_HWWRITE;
+
+		pmdp = pmd_offset(pud_offset(pgd_offset_k(v), v), v);
+		pmd_val(*pmdp) = val;
+
+		v += LARGE_PAGE_SIZE_4M;
+		p += LARGE_PAGE_SIZE_4M;
+		s -= LARGE_PAGE_SIZE_4M;
+	}
+
+	mapped = total_lowmem - s;
+
+	/* If the size of RAM is not an exact power of two, we may not
+	 * have covered RAM in its entirety with 16 and 4 MiB
+	 * pages. Consequently, restrict the top end of RAM currently
+	 * allocable so that calls to the MEMBLOCK to allocate PTEs for "tail"
+	 * coverage with normal-sized pages (or other reasons) do not
+	 * attempt to allocate outside the allowed range.
+	 */
+	memblock_set_current_limit(mapped);
+
+	return mapped;
+}
+
+void setup_initial_memory_limit(phys_addr_t first_memblock_base,
+				phys_addr_t first_memblock_size)
+{
+	/* We don't currently support the first MEMBLOCK not mapping 0
+	 * physical on those processors
+	 */
+	BUG_ON(first_memblock_base != 0);
+
+	/* 40x can only access 16MB at the moment (see head_40x.S) */
+	memblock_set_current_limit(min_t(u64, first_memblock_size, 0x00800000));
+}