1/*
2 *  This file contains the routines setting up the linux page tables.
3 *
4 * Copyright (C) 2008 Michal Simek
5 * Copyright (C) 2008 PetaLogix
6 *
7 *    Copyright (C) 2007 Xilinx, Inc.  All rights reserved.
8 *
9 *  Derived from arch/ppc/mm/pgtable.c:
10 *    -- paulus
11 *
12 *  Derived from arch/ppc/mm/init.c:
13 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
14 *
15 *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
16 *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
17 *    Copyright (C) 1996 Paul Mackerras
18 *  Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
19 *
20 *  Derived from "arch/i386/mm/init.c"
21 *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
22 *
23 *  This file is subject to the terms and conditions of the GNU General
24 *  Public License.  See the file COPYING in the main directory of this
25 *  archive for more details.
26 *
27 */
28
29#include <linux/export.h>
30#include <linux/kernel.h>
31#include <linux/types.h>
32#include <linux/vmalloc.h>
33#include <linux/init.h>
34
35#include <asm/pgtable.h>
36#include <asm/pgalloc.h>
37#include <linux/io.h>
38#include <asm/mmu.h>
39#include <asm/sections.h>
40#include <asm/fixmap.h>
41
42unsigned long ioremap_base;
43unsigned long ioremap_bot;
44EXPORT_SYMBOL(ioremap_bot);
45
46#ifndef CONFIG_SMP
47struct pgtable_cache_struct quicklists;
48#endif
49
50static void __iomem *__ioremap(phys_addr_t addr, unsigned long size,
51		unsigned long flags)
52{
53	unsigned long v, i;
54	phys_addr_t p;
55	int err;
56
57	/*
58	 * Choose an address to map it to.
59	 * Once the vmalloc system is running, we use it.
60	 * Before then, we use space going down from ioremap_base
61	 * (ioremap_bot records where we're up to).
62	 */
63	p = addr & PAGE_MASK;
64	size = PAGE_ALIGN(addr + size) - p;
65
66	/*
67	 * Don't allow anybody to remap normal RAM that we're using.
68	 * mem_init() sets high_memory so only do the check after that.
69	 *
70	 * However, allow remap of rootfs: TBD
71	 */
72
73	if (mem_init_done &&
74		p >= memory_start && p < virt_to_phys(high_memory) &&
75		!(p >= __virt_to_phys((phys_addr_t)__bss_stop) &&
76		p < __virt_to_phys((phys_addr_t)__bss_stop))) {
77		pr_warn("__ioremap(): phys addr "PTE_FMT" is RAM lr %pf\n",
78			(unsigned long)p, __builtin_return_address(0));
79		return NULL;
80	}
81
82	if (size == 0)
83		return NULL;
84
85	/*
86	 * Is it already mapped? If the whole area is mapped then we're
87	 * done, otherwise remap it since we want to keep the virt addrs for
88	 * each request contiguous.
89	 *
90	 * We make the assumption here that if the bottom and top
91	 * of the range we want are mapped then it's mapped to the
92	 * same virt address (and this is contiguous).
93	 *  -- Cort
94	 */
95
96	if (mem_init_done) {
97		struct vm_struct *area;
98		area = get_vm_area(size, VM_IOREMAP);
99		if (area == NULL)
100			return NULL;
101		v = (unsigned long) area->addr;
102	} else {
103		v = (ioremap_bot -= size);
104	}
105
106	if ((flags & _PAGE_PRESENT) == 0)
107		flags |= _PAGE_KERNEL;
108	if (flags & _PAGE_NO_CACHE)
109		flags |= _PAGE_GUARDED;
110
111	err = 0;
112	for (i = 0; i < size && err == 0; i += PAGE_SIZE)
113		err = map_page(v + i, p + i, flags);
114	if (err) {
115		if (mem_init_done)
116			vfree((void *)v);
117		return NULL;
118	}
119
120	return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK));
121}
122
123void __iomem *ioremap(phys_addr_t addr, unsigned long size)
124{
125	return __ioremap(addr, size, _PAGE_NO_CACHE);
126}
127EXPORT_SYMBOL(ioremap);
128
129void iounmap(void __iomem *addr)
130{
131	if ((__force void *)addr > high_memory &&
132					(unsigned long) addr < ioremap_bot)
133		vfree((void *) (PAGE_MASK & (unsigned long) addr));
134}
135EXPORT_SYMBOL(iounmap);
136
137
138int map_page(unsigned long va, phys_addr_t pa, int flags)
139{
140	pmd_t *pd;
141	pte_t *pg;
142	int err = -ENOMEM;
143	/* Use upper 10 bits of VA to index the first level map */
144	pd = pmd_offset(pgd_offset_k(va), va);
145	/* Use middle 10 bits of VA to index the second-level map */
146	pg = pte_alloc_kernel(pd, va); /* from powerpc - pgtable.c */
147	/* pg = pte_alloc_kernel(&init_mm, pd, va); */
148
149	if (pg != NULL) {
150		err = 0;
151		set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT,
152				__pgprot(flags)));
153		if (unlikely(mem_init_done))
154			_tlbie(va);
155	}
156	return err;
157}
158
159/*
160 * Map in all of physical memory starting at CONFIG_KERNEL_START.
161 */
162void __init mapin_ram(void)
163{
164	unsigned long v, p, s, f;
165
166	v = CONFIG_KERNEL_START;
167	p = memory_start;
168	for (s = 0; s < lowmem_size; s += PAGE_SIZE) {
169		f = _PAGE_PRESENT | _PAGE_ACCESSED |
170				_PAGE_SHARED | _PAGE_HWEXEC;
171		if ((char *) v < _stext || (char *) v >= _etext)
172			f |= _PAGE_WRENABLE;
173		else
174			/* On the MicroBlaze, no user access
175			   forces R/W kernel access */
176			f |= _PAGE_USER;
177		map_page(v, p, f);
178		v += PAGE_SIZE;
179		p += PAGE_SIZE;
180	}
181}
182
183/* is x a power of 2? */
184#define is_power_of_2(x)	((x) != 0 && (((x) & ((x) - 1)) == 0))
185
186/* Scan the real Linux page tables and return a PTE pointer for
187 * a virtual address in a context.
188 * Returns true (1) if PTE was found, zero otherwise.  The pointer to
189 * the PTE pointer is unmodified if PTE is not found.
190 */
191static int get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep)
192{
193	pgd_t	*pgd;
194	pmd_t	*pmd;
195	pte_t	*pte;
196	int     retval = 0;
197
198	pgd = pgd_offset(mm, addr & PAGE_MASK);
199	if (pgd) {
200		pmd = pmd_offset(pgd, addr & PAGE_MASK);
201		if (pmd_present(*pmd)) {
202			pte = pte_offset_kernel(pmd, addr & PAGE_MASK);
203			if (pte) {
204				retval = 1;
205				*ptep = pte;
206			}
207		}
208	}
209	return retval;
210}
211
212/* Find physical address for this virtual address.  Normally used by
213 * I/O functions, but anyone can call it.
214 */
215unsigned long iopa(unsigned long addr)
216{
217	unsigned long pa;
218
219	pte_t *pte;
220	struct mm_struct *mm;
221
222	/* Allow mapping of user addresses (within the thread)
223	 * for DMA if necessary.
224	 */
225	if (addr < TASK_SIZE)
226		mm = current->mm;
227	else
228		mm = &init_mm;
229
230	pa = 0;
231	if (get_pteptr(mm, addr, &pte))
232		pa = (pte_val(*pte) & PAGE_MASK) | (addr & ~PAGE_MASK);
233
234	return pa;
235}
236
237__init_refok pte_t *pte_alloc_one_kernel(struct mm_struct *mm,
238		unsigned long address)
239{
240	pte_t *pte;
241	if (mem_init_done) {
242		pte = (pte_t *)__get_free_page(GFP_KERNEL |
243					__GFP_REPEAT | __GFP_ZERO);
244	} else {
245		pte = (pte_t *)early_get_page();
246		if (pte)
247			clear_page(pte);
248	}
249	return pte;
250}
251
252void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t flags)
253{
254	unsigned long address = __fix_to_virt(idx);
255
256	if (idx >= __end_of_fixed_addresses)
257		BUG();
258
259	map_page(address, phys, pgprot_val(flags));
260}
261