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