powerpc: Merge enough to start building in arch/powerpc.

This creates the directory structure under arch/powerpc and a bunch
of Kconfig files.  It does a first-cut merge of arch/powerpc/mm,
arch/powerpc/lib and arch/powerpc/platforms/powermac.  This is enough
to build a 32-bit powermac kernel with ARCH=powerpc.

For now we are getting some unmerged files from arch/ppc/kernel and
arch/ppc/syslib, or arch/ppc64/kernel.  This makes some minor changes
to files in those directories and files outside arch/powerpc.

The boot directory is still not merged.  That's going to be interesting.

Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/mm/4xx_mmu.c b/arch/powerpc/mm/4xx_mmu.c
new file mode 100644
index 0000000..b7bcbc2
--- /dev/null
+++ b/arch/powerpc/mm/4xx_mmu.c
@@ -0,0 +1,141 @@
+/*
+ * 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
+ *  Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
+ *
+ *  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/config.h>
+#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 <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, 0xF0000000);	/* 512 MB of data space at 0x0. */
+        mtspr(SPRN_ICCR, 0xF0000000);	/* 512 MB 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(void)
+{
+	unsigned long v, s;
+	phys_addr_t p;
+
+	v = KERNELBASE;
+	p = PPC_MEMSTART;
+	s = 0;
+
+	if (__map_without_ltlbs) {
+		return s;
+	}
+
+	while (s <= (total_lowmem - LARGE_PAGE_SIZE_16M)) {
+		pmd_t *pmdp;
+		unsigned long val = p | _PMD_SIZE_16M | _PAGE_HWEXEC | _PAGE_HWWRITE;
+
+		spin_lock(&init_mm.page_table_lock);
+		pmdp = pmd_offset(pgd_offset_k(v), v);
+		pmd_val(*pmdp++) = val;
+		pmd_val(*pmdp++) = val;
+		pmd_val(*pmdp++) = val;
+		pmd_val(*pmdp++) = val;
+		spin_unlock(&init_mm.page_table_lock);
+
+		v += LARGE_PAGE_SIZE_16M;
+		p += LARGE_PAGE_SIZE_16M;
+		s += LARGE_PAGE_SIZE_16M;
+	}
+
+	while (s <= (total_lowmem - LARGE_PAGE_SIZE_4M)) {
+		pmd_t *pmdp;
+		unsigned long val = p | _PMD_SIZE_4M | _PAGE_HWEXEC | _PAGE_HWWRITE;
+
+		spin_lock(&init_mm.page_table_lock);
+		pmdp = pmd_offset(pgd_offset_k(v), v);
+		pmd_val(*pmdp) = val;
+		spin_unlock(&init_mm.page_table_lock);
+
+		v += LARGE_PAGE_SIZE_4M;
+		p += LARGE_PAGE_SIZE_4M;
+		s += LARGE_PAGE_SIZE_4M;
+	}
+
+	return s;
+}