1/*
2 * Modifications by Kumar Gala (galak@kernel.crashing.org) to support
3 * E500 Book E processors.
4 *
5 * Copyright 2004,2010 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#include <linux/memblock.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/machdep.h>
54#include <asm/setup.h>
55#include <asm/paca.h>
56
57#include "mmu_decl.h"
58
59unsigned int tlbcam_index;
60
61#define NUM_TLBCAMS	(64)
62struct tlbcam TLBCAM[NUM_TLBCAMS];
63
64struct tlbcamrange {
65	unsigned long start;
66	unsigned long limit;
67	phys_addr_t phys;
68} tlbcam_addrs[NUM_TLBCAMS];
69
70unsigned long tlbcam_sz(int idx)
71{
72	return tlbcam_addrs[idx].limit - tlbcam_addrs[idx].start + 1;
73}
74
75/*
76 * Return PA for this VA if it is mapped by a CAM, or 0
77 */
78phys_addr_t v_mapped_by_tlbcam(unsigned long va)
79{
80	int b;
81	for (b = 0; b < tlbcam_index; ++b)
82		if (va >= tlbcam_addrs[b].start && va < tlbcam_addrs[b].limit)
83			return tlbcam_addrs[b].phys + (va - tlbcam_addrs[b].start);
84	return 0;
85}
86
87/*
88 * Return VA for a given PA or 0 if not mapped
89 */
90unsigned long p_mapped_by_tlbcam(phys_addr_t pa)
91{
92	int b;
93	for (b = 0; b < tlbcam_index; ++b)
94		if (pa >= tlbcam_addrs[b].phys
95			&& pa < (tlbcam_addrs[b].limit-tlbcam_addrs[b].start)
96		              +tlbcam_addrs[b].phys)
97			return tlbcam_addrs[b].start+(pa-tlbcam_addrs[b].phys);
98	return 0;
99}
100
101/*
102 * Set up a variable-size TLB entry (tlbcam). The parameters are not checked;
103 * in particular size must be a power of 4 between 4k and the max supported by
104 * an implementation; max may further be limited by what can be represented in
105 * an unsigned long (for example, 32-bit implementations cannot support a 4GB
106 * size).
107 */
108static void settlbcam(int index, unsigned long virt, phys_addr_t phys,
109		unsigned long size, unsigned long flags, unsigned int pid)
110{
111	unsigned int tsize;
112
113	tsize = __ilog2(size) - 10;
114
115#ifdef CONFIG_SMP
116	if ((flags & _PAGE_NO_CACHE) == 0)
117		flags |= _PAGE_COHERENT;
118#endif
119
120	TLBCAM[index].MAS0 = MAS0_TLBSEL(1) | MAS0_ESEL(index) | MAS0_NV(index+1);
121	TLBCAM[index].MAS1 = MAS1_VALID | MAS1_IPROT | MAS1_TSIZE(tsize) | MAS1_TID(pid);
122	TLBCAM[index].MAS2 = virt & PAGE_MASK;
123
124	TLBCAM[index].MAS2 |= (flags & _PAGE_WRITETHRU) ? MAS2_W : 0;
125	TLBCAM[index].MAS2 |= (flags & _PAGE_NO_CACHE) ? MAS2_I : 0;
126	TLBCAM[index].MAS2 |= (flags & _PAGE_COHERENT) ? MAS2_M : 0;
127	TLBCAM[index].MAS2 |= (flags & _PAGE_GUARDED) ? MAS2_G : 0;
128	TLBCAM[index].MAS2 |= (flags & _PAGE_ENDIAN) ? MAS2_E : 0;
129
130	TLBCAM[index].MAS3 = (phys & MAS3_RPN) | MAS3_SX | MAS3_SR;
131	TLBCAM[index].MAS3 |= ((flags & _PAGE_RW) ? MAS3_SW : 0);
132	if (mmu_has_feature(MMU_FTR_BIG_PHYS))
133		TLBCAM[index].MAS7 = (u64)phys >> 32;
134
135	/* Below is unlikely -- only for large user pages or similar */
136	if (pte_user(flags)) {
137	   TLBCAM[index].MAS3 |= MAS3_UX | MAS3_UR;
138	   TLBCAM[index].MAS3 |= ((flags & _PAGE_RW) ? MAS3_UW : 0);
139	}
140
141	tlbcam_addrs[index].start = virt;
142	tlbcam_addrs[index].limit = virt + size - 1;
143	tlbcam_addrs[index].phys = phys;
144
145	loadcam_entry(index);
146}
147
148unsigned long calc_cam_sz(unsigned long ram, unsigned long virt,
149			  phys_addr_t phys)
150{
151	unsigned int camsize = __ilog2(ram);
152	unsigned int align = __ffs(virt | phys);
153	unsigned long max_cam;
154
155	if ((mfspr(SPRN_MMUCFG) & MMUCFG_MAVN) == MMUCFG_MAVN_V1) {
156		/* Convert (4^max) kB to (2^max) bytes */
157		max_cam = ((mfspr(SPRN_TLB1CFG) >> 16) & 0xf) * 2 + 10;
158		camsize &= ~1U;
159		align &= ~1U;
160	} else {
161		/* Convert (2^max) kB to (2^max) bytes */
162		max_cam = __ilog2(mfspr(SPRN_TLB1PS)) + 10;
163	}
164
165	if (camsize > align)
166		camsize = align;
167	if (camsize > max_cam)
168		camsize = max_cam;
169
170	return 1UL << camsize;
171}
172
173static unsigned long map_mem_in_cams_addr(phys_addr_t phys, unsigned long virt,
174					unsigned long ram, int max_cam_idx)
175{
176	int i;
177	unsigned long amount_mapped = 0;
178
179	/* Calculate CAM values */
180	for (i = 0; ram && i < max_cam_idx; i++) {
181		unsigned long cam_sz;
182
183		cam_sz = calc_cam_sz(ram, virt, phys);
184		settlbcam(i, virt, phys, cam_sz, pgprot_val(PAGE_KERNEL_X), 0);
185
186		ram -= cam_sz;
187		amount_mapped += cam_sz;
188		virt += cam_sz;
189		phys += cam_sz;
190	}
191	tlbcam_index = i;
192
193#ifdef CONFIG_PPC64
194	get_paca()->tcd.esel_next = i;
195	get_paca()->tcd.esel_max = mfspr(SPRN_TLB1CFG) & TLBnCFG_N_ENTRY;
196	get_paca()->tcd.esel_first = i;
197#endif
198
199	return amount_mapped;
200}
201
202unsigned long map_mem_in_cams(unsigned long ram, int max_cam_idx)
203{
204	unsigned long virt = PAGE_OFFSET;
205	phys_addr_t phys = memstart_addr;
206
207	return map_mem_in_cams_addr(phys, virt, ram, max_cam_idx);
208}
209
210#ifdef CONFIG_PPC32
211
212#if defined(CONFIG_LOWMEM_CAM_NUM_BOOL) && (CONFIG_LOWMEM_CAM_NUM >= NUM_TLBCAMS)
213#error "LOWMEM_CAM_NUM must be less than NUM_TLBCAMS"
214#endif
215
216unsigned long __init mmu_mapin_ram(unsigned long top)
217{
218	return tlbcam_addrs[tlbcam_index - 1].limit - PAGE_OFFSET + 1;
219}
220
221/*
222 * MMU_init_hw does the chip-specific initialization of the MMU hardware.
223 */
224void __init MMU_init_hw(void)
225{
226	flush_instruction_cache();
227}
228
229void __init adjust_total_lowmem(void)
230{
231	unsigned long ram;
232	int i;
233
234	/* adjust lowmem size to __max_low_memory */
235	ram = min((phys_addr_t)__max_low_memory, (phys_addr_t)total_lowmem);
236
237	i = switch_to_as1();
238	__max_low_memory = map_mem_in_cams(ram, CONFIG_LOWMEM_CAM_NUM);
239	restore_to_as0(i, 0, 0, 1);
240
241	pr_info("Memory CAM mapping: ");
242	for (i = 0; i < tlbcam_index - 1; i++)
243		pr_cont("%lu/", tlbcam_sz(i) >> 20);
244	pr_cont("%lu Mb, residual: %dMb\n", tlbcam_sz(tlbcam_index - 1) >> 20,
245	        (unsigned int)((total_lowmem - __max_low_memory) >> 20));
246
247	memblock_set_current_limit(memstart_addr + __max_low_memory);
248}
249
250void setup_initial_memory_limit(phys_addr_t first_memblock_base,
251				phys_addr_t first_memblock_size)
252{
253	phys_addr_t limit = first_memblock_base + first_memblock_size;
254
255	/* 64M mapped initially according to head_fsl_booke.S */
256	memblock_set_current_limit(min_t(u64, limit, 0x04000000));
257}
258
259#ifdef CONFIG_RELOCATABLE
260int __initdata is_second_reloc;
261notrace void __init relocate_init(u64 dt_ptr, phys_addr_t start)
262{
263	unsigned long base = KERNELBASE;
264
265	kernstart_addr = start;
266	if (is_second_reloc) {
267		virt_phys_offset = PAGE_OFFSET - memstart_addr;
268		return;
269	}
270
271	/*
272	 * Relocatable kernel support based on processing of dynamic
273	 * relocation entries. Before we get the real memstart_addr,
274	 * We will compute the virt_phys_offset like this:
275	 * virt_phys_offset = stext.run - kernstart_addr
276	 *
277	 * stext.run = (KERNELBASE & ~0x3ffffff) +
278	 *				(kernstart_addr & 0x3ffffff)
279	 * When we relocate, we have :
280	 *
281	 *	(kernstart_addr & 0x3ffffff) = (stext.run & 0x3ffffff)
282	 *
283	 * hence:
284	 *  virt_phys_offset = (KERNELBASE & ~0x3ffffff) -
285	 *                              (kernstart_addr & ~0x3ffffff)
286	 *
287	 */
288	start &= ~0x3ffffff;
289	base &= ~0x3ffffff;
290	virt_phys_offset = base - start;
291	early_get_first_memblock_info(__va(dt_ptr), NULL);
292	/*
293	 * We now get the memstart_addr, then we should check if this
294	 * address is the same as what the PAGE_OFFSET map to now. If
295	 * not we have to change the map of PAGE_OFFSET to memstart_addr
296	 * and do a second relocation.
297	 */
298	if (start != memstart_addr) {
299		int n;
300		long offset = start - memstart_addr;
301
302		is_second_reloc = 1;
303		n = switch_to_as1();
304		/* map a 64M area for the second relocation */
305		if (memstart_addr > start)
306			map_mem_in_cams(0x4000000, CONFIG_LOWMEM_CAM_NUM);
307		else
308			map_mem_in_cams_addr(start, PAGE_OFFSET + offset,
309					0x4000000, CONFIG_LOWMEM_CAM_NUM);
310		restore_to_as0(n, offset, __va(dt_ptr), 1);
311		/* We should never reach here */
312		panic("Relocation error");
313	}
314}
315#endif
316#endif
317