1/*
2 * Modifications by Kumar Gala (galak@kernel.crashing.org) to support
3 * E500 Book E processors.
4 *
5 * Copyright 2004 Freescale Semiconductor, Inc
6 *
7 * This file contains the routines for initializing the MMU
8 * on the 4xx series of chips.
9 *  -- paulus
10 *
11 *  Derived from arch/ppc/mm/init.c:
12 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
13 *
14 *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
15 *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
16 *    Copyright (C) 1996 Paul Mackerras
17 *  Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
18 *
19 *  Derived from "arch/i386/mm/init.c"
20 *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
21 *
22 *  This program is free software; you can redistribute it and/or
23 *  modify it under the terms of the GNU General Public License
24 *  as published by the Free Software Foundation; either version
25 *  2 of the License, or (at your option) any later version.
26 *
27 */
28
29#include <linux/signal.h>
30#include <linux/sched.h>
31#include <linux/kernel.h>
32#include <linux/errno.h>
33#include <linux/string.h>
34#include <linux/types.h>
35#include <linux/ptrace.h>
36#include <linux/mman.h>
37#include <linux/mm.h>
38#include <linux/swap.h>
39#include <linux/stddef.h>
40#include <linux/vmalloc.h>
41#include <linux/init.h>
42#include <linux/delay.h>
43#include <linux/highmem.h>
44
45#include <asm/pgalloc.h>
46#include <asm/prom.h>
47#include <asm/io.h>
48#include <asm/mmu_context.h>
49#include <asm/pgtable.h>
50#include <asm/mmu.h>
51#include <asm/uaccess.h>
52#include <asm/smp.h>
53#include <asm/bootx.h>
54#include <asm/machdep.h>
55#include <asm/setup.h>
56
57extern void loadcam_entry(unsigned int index);
58unsigned int tlbcam_index;
59unsigned int num_tlbcam_entries;
60static unsigned long __cam0, __cam1, __cam2;
61extern unsigned long total_lowmem;
62extern unsigned long __max_low_memory;
63#define MAX_LOW_MEM	CONFIG_LOWMEM_SIZE
64
65#define NUM_TLBCAMS	(16)
66
67struct tlbcam {
68   	u32	MAS0;
69	u32	MAS1;
70	u32	MAS2;
71	u32	MAS3;
72	u32	MAS7;
73} TLBCAM[NUM_TLBCAMS];
74
75struct tlbcamrange {
76   	unsigned long start;
77	unsigned long limit;
78	phys_addr_t phys;
79} tlbcam_addrs[NUM_TLBCAMS];
80
81extern unsigned int tlbcam_index;
82
83/*
84 * Return PA for this VA if it is mapped by a CAM, or 0
85 */
86unsigned long v_mapped_by_tlbcam(unsigned long va)
87{
88	int b;
89	for (b = 0; b < tlbcam_index; ++b)
90		if (va >= tlbcam_addrs[b].start && va < tlbcam_addrs[b].limit)
91			return tlbcam_addrs[b].phys + (va - tlbcam_addrs[b].start);
92	return 0;
93}
94
95/*
96 * Return VA for a given PA or 0 if not mapped
97 */
98unsigned long p_mapped_by_tlbcam(unsigned long pa)
99{
100	int b;
101	for (b = 0; b < tlbcam_index; ++b)
102		if (pa >= tlbcam_addrs[b].phys
103	    	    && pa < (tlbcam_addrs[b].limit-tlbcam_addrs[b].start)
104		              +tlbcam_addrs[b].phys)
105			return tlbcam_addrs[b].start+(pa-tlbcam_addrs[b].phys);
106	return 0;
107}
108
109/*
110 * Set up one of the I/D BAT (block address translation) register pairs.
111 * The parameters are not checked; in particular size must be a power
112 * of 4 between 4k and 256M.
113 */
114void settlbcam(int index, unsigned long virt, phys_addr_t phys,
115		unsigned int size, int flags, unsigned int pid)
116{
117	unsigned int tsize, lz;
118
119	asm ("cntlzw %0,%1" : "=r" (lz) : "r" (size));
120	tsize = (21 - lz) / 2;
121
122#ifdef CONFIG_SMP
123	if ((flags & _PAGE_NO_CACHE) == 0)
124		flags |= _PAGE_COHERENT;
125#endif
126
127	TLBCAM[index].MAS0 = MAS0_TLBSEL(1) | MAS0_ESEL(index) | MAS0_NV(index+1);
128	TLBCAM[index].MAS1 = MAS1_VALID | MAS1_IPROT | MAS1_TSIZE(tsize) | MAS1_TID(pid);
129	TLBCAM[index].MAS2 = virt & PAGE_MASK;
130
131	TLBCAM[index].MAS2 |= (flags & _PAGE_WRITETHRU) ? MAS2_W : 0;
132	TLBCAM[index].MAS2 |= (flags & _PAGE_NO_CACHE) ? MAS2_I : 0;
133	TLBCAM[index].MAS2 |= (flags & _PAGE_COHERENT) ? MAS2_M : 0;
134	TLBCAM[index].MAS2 |= (flags & _PAGE_GUARDED) ? MAS2_G : 0;
135	TLBCAM[index].MAS2 |= (flags & _PAGE_ENDIAN) ? MAS2_E : 0;
136
137	TLBCAM[index].MAS3 = (phys & PAGE_MASK) | MAS3_SX | MAS3_SR;
138	TLBCAM[index].MAS3 |= ((flags & _PAGE_RW) ? MAS3_SW : 0);
139
140#ifndef CONFIG_KGDB     /* want user access for breakpoints */
141	if (flags & _PAGE_USER) {
142	   TLBCAM[index].MAS3 |= MAS3_UX | MAS3_UR;
143	   TLBCAM[index].MAS3 |= ((flags & _PAGE_RW) ? MAS3_UW : 0);
144	}
145#else
146	TLBCAM[index].MAS3 |= MAS3_UX | MAS3_UR;
147	TLBCAM[index].MAS3 |= ((flags & _PAGE_RW) ? MAS3_UW : 0);
148#endif
149
150	tlbcam_addrs[index].start = virt;
151	tlbcam_addrs[index].limit = virt + size - 1;
152	tlbcam_addrs[index].phys = phys;
153
154	loadcam_entry(index);
155}
156
157void invalidate_tlbcam_entry(int index)
158{
159	TLBCAM[index].MAS0 = MAS0_TLBSEL(1) | MAS0_ESEL(index);
160	TLBCAM[index].MAS1 = ~MAS1_VALID;
161
162	loadcam_entry(index);
163}
164
165void __init cam_mapin_ram(unsigned long cam0, unsigned long cam1,
166		unsigned long cam2)
167{
168	settlbcam(0, KERNELBASE, PPC_MEMSTART, cam0, _PAGE_KERNEL, 0);
169	tlbcam_index++;
170	if (cam1) {
171		tlbcam_index++;
172		settlbcam(1, KERNELBASE+cam0, PPC_MEMSTART+cam0, cam1, _PAGE_KERNEL, 0);
173	}
174	if (cam2) {
175		tlbcam_index++;
176		settlbcam(2, KERNELBASE+cam0+cam1, PPC_MEMSTART+cam0+cam1, cam2, _PAGE_KERNEL, 0);
177	}
178}
179
180/*
181 * MMU_init_hw does the chip-specific initialization of the MMU hardware.
182 */
183void __init MMU_init_hw(void)
184{
185	flush_instruction_cache();
186}
187
188unsigned long __init mmu_mapin_ram(void)
189{
190	cam_mapin_ram(__cam0, __cam1, __cam2);
191
192	return __cam0 + __cam1 + __cam2;
193}
194
195
196void __init
197adjust_total_lowmem(void)
198{
199	unsigned long max_low_mem = MAX_LOW_MEM;
200	unsigned long cam_max = 0x10000000;
201	unsigned long ram;
202
203	/* adjust CAM size to max_low_mem */
204	if (max_low_mem < cam_max)
205		cam_max = max_low_mem;
206
207	/* adjust lowmem size to max_low_mem */
208	if (max_low_mem < total_lowmem)
209		ram = max_low_mem;
210	else
211		ram = total_lowmem;
212
213	/* Calculate CAM values */
214	__cam0 = 1UL << 2 * (__ilog2(ram) / 2);
215	if (__cam0 > cam_max)
216		__cam0 = cam_max;
217	ram -= __cam0;
218	if (ram) {
219		__cam1 = 1UL << 2 * (__ilog2(ram) / 2);
220		if (__cam1 > cam_max)
221			__cam1 = cam_max;
222		ram -= __cam1;
223	}
224	if (ram) {
225		__cam2 = 1UL << 2 * (__ilog2(ram) / 2);
226		if (__cam2 > cam_max)
227			__cam2 = cam_max;
228		ram -= __cam2;
229	}
230
231	printk(KERN_INFO "Memory CAM mapping: CAM0=%ldMb, CAM1=%ldMb,"
232			" CAM2=%ldMb residual: %ldMb\n",
233			__cam0 >> 20, __cam1 >> 20, __cam2 >> 20,
234			(total_lowmem - __cam0 - __cam1 - __cam2) >> 20);
235	__max_low_memory = max_low_mem = __cam0 + __cam1 + __cam2;
236}
237