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 <linux/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#ifdef CONFIG_FSL_BOOKE
 76/*
 77 * Return PA for this VA if it is mapped by a CAM, or 0
 78 */
 79phys_addr_t v_block_mapped(unsigned long va)
 80{
 81	int b;
 82	for (b = 0; b < tlbcam_index; ++b)
 83		if (va >= tlbcam_addrs[b].start && va < tlbcam_addrs[b].limit)
 84			return tlbcam_addrs[b].phys + (va - tlbcam_addrs[b].start);
 85	return 0;
 86}
 87
 88/*
 89 * Return VA for a given PA or 0 if not mapped
 90 */
 91unsigned long p_block_mapped(phys_addr_t pa)
 92{
 93	int b;
 94	for (b = 0; b < tlbcam_index; ++b)
 95		if (pa >= tlbcam_addrs[b].phys
 96			&& pa < (tlbcam_addrs[b].limit-tlbcam_addrs[b].start)
 97		              +tlbcam_addrs[b].phys)
 98			return tlbcam_addrs[b].start+(pa-tlbcam_addrs[b].phys);
 99	return 0;
100}
101#endif
102
103/*
104 * Set up a variable-size TLB entry (tlbcam). The parameters are not checked;
105 * in particular size must be a power of 4 between 4k and the max supported by
106 * an implementation; max may further be limited by what can be represented in
107 * an unsigned long (for example, 32-bit implementations cannot support a 4GB
108 * size).
109 */
110static void settlbcam(int index, unsigned long virt, phys_addr_t phys,
111		unsigned long size, unsigned long flags, unsigned int pid)
112{
113	unsigned int tsize;
114
115	tsize = __ilog2(size) - 10;
116
117#if defined(CONFIG_SMP) || defined(CONFIG_PPC_E500MC)
118	if ((flags & _PAGE_NO_CACHE) == 0)
119		flags |= _PAGE_COHERENT;
120#endif
121
122	TLBCAM[index].MAS0 = MAS0_TLBSEL(1) | MAS0_ESEL(index) | MAS0_NV(index+1);
123	TLBCAM[index].MAS1 = MAS1_VALID | MAS1_IPROT | MAS1_TSIZE(tsize) | MAS1_TID(pid);
124	TLBCAM[index].MAS2 = virt & PAGE_MASK;
125
126	TLBCAM[index].MAS2 |= (flags & _PAGE_WRITETHRU) ? MAS2_W : 0;
127	TLBCAM[index].MAS2 |= (flags & _PAGE_NO_CACHE) ? MAS2_I : 0;
128	TLBCAM[index].MAS2 |= (flags & _PAGE_COHERENT) ? MAS2_M : 0;
129	TLBCAM[index].MAS2 |= (flags & _PAGE_GUARDED) ? MAS2_G : 0;
130	TLBCAM[index].MAS2 |= (flags & _PAGE_ENDIAN) ? MAS2_E : 0;
131
132	TLBCAM[index].MAS3 = (phys & MAS3_RPN) | MAS3_SX | MAS3_SR;
133	TLBCAM[index].MAS3 |= ((flags & _PAGE_RW) ? MAS3_SW : 0);
134	if (mmu_has_feature(MMU_FTR_BIG_PHYS))
135		TLBCAM[index].MAS7 = (u64)phys >> 32;
136
137	/* Below is unlikely -- only for large user pages or similar */
138	if (pte_user(__pte(flags))) {
139	   TLBCAM[index].MAS3 |= MAS3_UX | MAS3_UR;
140	   TLBCAM[index].MAS3 |= ((flags & _PAGE_RW) ? MAS3_UW : 0);
141	}
142
143	tlbcam_addrs[index].start = virt;
144	tlbcam_addrs[index].limit = virt + size - 1;
145	tlbcam_addrs[index].phys = phys;
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					bool dryrun)
176{
177	int i;
178	unsigned long amount_mapped = 0;
179
180	/* Calculate CAM values */
181	for (i = 0; ram && i < max_cam_idx; i++) {
182		unsigned long cam_sz;
183
184		cam_sz = calc_cam_sz(ram, virt, phys);
185		if (!dryrun)
186			settlbcam(i, virt, phys, cam_sz,
187				  pgprot_val(PAGE_KERNEL_X), 0);
188
189		ram -= cam_sz;
190		amount_mapped += cam_sz;
191		virt += cam_sz;
192		phys += cam_sz;
193	}
194
195	if (dryrun)
196		return amount_mapped;
197
198	loadcam_multi(0, i, max_cam_idx);
199	tlbcam_index = i;
200
201#ifdef CONFIG_PPC64
202	get_paca()->tcd.esel_next = i;
203	get_paca()->tcd.esel_max = mfspr(SPRN_TLB1CFG) & TLBnCFG_N_ENTRY;
204	get_paca()->tcd.esel_first = i;
205#endif
206
207	return amount_mapped;
208}
209
210unsigned long map_mem_in_cams(unsigned long ram, int max_cam_idx, bool dryrun)
211{
212	unsigned long virt = PAGE_OFFSET;
213	phys_addr_t phys = memstart_addr;
214
215	return map_mem_in_cams_addr(phys, virt, ram, max_cam_idx, dryrun);
216}
217
218#ifdef CONFIG_PPC32
219
220#if defined(CONFIG_LOWMEM_CAM_NUM_BOOL) && (CONFIG_LOWMEM_CAM_NUM >= NUM_TLBCAMS)
221#error "LOWMEM_CAM_NUM must be less than NUM_TLBCAMS"
222#endif
223
224unsigned long __init mmu_mapin_ram(unsigned long top)
225{
226	return tlbcam_addrs[tlbcam_index - 1].limit - PAGE_OFFSET + 1;
227}
228
229/*
230 * MMU_init_hw does the chip-specific initialization of the MMU hardware.
231 */
232void __init MMU_init_hw(void)
233{
234	flush_instruction_cache();
235}
236
237void __init adjust_total_lowmem(void)
238{
239	unsigned long ram;
240	int i;
241
242	/* adjust lowmem size to __max_low_memory */
243	ram = min((phys_addr_t)__max_low_memory, (phys_addr_t)total_lowmem);
244
245	i = switch_to_as1();
246	__max_low_memory = map_mem_in_cams(ram, CONFIG_LOWMEM_CAM_NUM, false);
247	restore_to_as0(i, 0, 0, 1);
248
249	pr_info("Memory CAM mapping: ");
250	for (i = 0; i < tlbcam_index - 1; i++)
251		pr_cont("%lu/", tlbcam_sz(i) >> 20);
252	pr_cont("%lu Mb, residual: %dMb\n", tlbcam_sz(tlbcam_index - 1) >> 20,
253	        (unsigned int)((total_lowmem - __max_low_memory) >> 20));
254
255	memblock_set_current_limit(memstart_addr + __max_low_memory);
256}
257
258void setup_initial_memory_limit(phys_addr_t first_memblock_base,
259				phys_addr_t first_memblock_size)
260{
261	phys_addr_t limit = first_memblock_base + first_memblock_size;
262
263	/* 64M mapped initially according to head_fsl_booke.S */
264	memblock_set_current_limit(min_t(u64, limit, 0x04000000));
265}
266
267#ifdef CONFIG_RELOCATABLE
268int __initdata is_second_reloc;
269notrace void __init relocate_init(u64 dt_ptr, phys_addr_t start)
270{
271	unsigned long base = KERNELBASE;
272
273	kernstart_addr = start;
274	if (is_second_reloc) {
275		virt_phys_offset = PAGE_OFFSET - memstart_addr;
276		return;
277	}
278
279	/*
280	 * Relocatable kernel support based on processing of dynamic
281	 * relocation entries. Before we get the real memstart_addr,
282	 * We will compute the virt_phys_offset like this:
283	 * virt_phys_offset = stext.run - kernstart_addr
284	 *
285	 * stext.run = (KERNELBASE & ~0x3ffffff) +
286	 *				(kernstart_addr & 0x3ffffff)
287	 * When we relocate, we have :
288	 *
289	 *	(kernstart_addr & 0x3ffffff) = (stext.run & 0x3ffffff)
290	 *
291	 * hence:
292	 *  virt_phys_offset = (KERNELBASE & ~0x3ffffff) -
293	 *                              (kernstart_addr & ~0x3ffffff)
294	 *
295	 */
296	start &= ~0x3ffffff;
297	base &= ~0x3ffffff;
298	virt_phys_offset = base - start;
299	early_get_first_memblock_info(__va(dt_ptr), NULL);
300	/*
301	 * We now get the memstart_addr, then we should check if this
302	 * address is the same as what the PAGE_OFFSET map to now. If
303	 * not we have to change the map of PAGE_OFFSET to memstart_addr
304	 * and do a second relocation.
305	 */
306	if (start != memstart_addr) {
307		int n;
308		long offset = start - memstart_addr;
309
310		is_second_reloc = 1;
311		n = switch_to_as1();
312		/* map a 64M area for the second relocation */
313		if (memstart_addr > start)
314			map_mem_in_cams(0x4000000, CONFIG_LOWMEM_CAM_NUM,
315					false);
316		else
317			map_mem_in_cams_addr(start, PAGE_OFFSET + offset,
318					0x4000000, CONFIG_LOWMEM_CAM_NUM,
319					false);
320		restore_to_as0(n, offset, __va(dt_ptr), 1);
321		/* We should never reach here */
322		panic("Relocation error");
323	}
324}
325#endif
326#endif