1/*
2 * Provide common bits of early_ioremap() support for architectures needing
3 * temporary mappings during boot before ioremap() is available.
4 *
5 * This is mostly a direct copy of the x86 early_ioremap implementation.
6 *
7 * (C) Copyright 1995 1996, 2014 Linus Torvalds
8 *
9 */
10#include <linux/kernel.h>
11#include <linux/init.h>
12#include <linux/io.h>
13#include <linux/module.h>
14#include <linux/slab.h>
15#include <linux/mm.h>
16#include <linux/vmalloc.h>
17#include <asm/fixmap.h>
18#include <asm/early_ioremap.h>
19
20#ifdef CONFIG_MMU
21static int early_ioremap_debug __initdata;
22
23static int __init early_ioremap_debug_setup(char *str)
24{
25	early_ioremap_debug = 1;
26
27	return 0;
28}
29early_param("early_ioremap_debug", early_ioremap_debug_setup);
30
31static int after_paging_init __initdata;
32
33void __init __weak early_ioremap_shutdown(void)
34{
35}
36
37void __init early_ioremap_reset(void)
38{
39	early_ioremap_shutdown();
40	after_paging_init = 1;
41}
42
43/*
44 * Generally, ioremap() is available after paging_init() has been called.
45 * Architectures wanting to allow early_ioremap after paging_init() can
46 * define __late_set_fixmap and __late_clear_fixmap to do the right thing.
47 */
48#ifndef __late_set_fixmap
49static inline void __init __late_set_fixmap(enum fixed_addresses idx,
50					    phys_addr_t phys, pgprot_t prot)
51{
52	BUG();
53}
54#endif
55
56#ifndef __late_clear_fixmap
57static inline void __init __late_clear_fixmap(enum fixed_addresses idx)
58{
59	BUG();
60}
61#endif
62
63static void __iomem *prev_map[FIX_BTMAPS_SLOTS] __initdata;
64static unsigned long prev_size[FIX_BTMAPS_SLOTS] __initdata;
65static unsigned long slot_virt[FIX_BTMAPS_SLOTS] __initdata;
66
67void __init early_ioremap_setup(void)
68{
69	int i;
70
71	for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
72		if (WARN_ON(prev_map[i]))
73			break;
74
75	for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
76		slot_virt[i] = __fix_to_virt(FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*i);
77}
78
79static int __init check_early_ioremap_leak(void)
80{
81	int count = 0;
82	int i;
83
84	for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
85		if (prev_map[i])
86			count++;
87
88	if (WARN(count, KERN_WARNING
89		 "Debug warning: early ioremap leak of %d areas detected.\n"
90		 "please boot with early_ioremap_debug and report the dmesg.\n",
91		 count))
92		return 1;
93	return 0;
94}
95late_initcall(check_early_ioremap_leak);
96
97static void __init __iomem *
98__early_ioremap(resource_size_t phys_addr, unsigned long size, pgprot_t prot)
99{
100	unsigned long offset;
101	resource_size_t last_addr;
102	unsigned int nrpages;
103	enum fixed_addresses idx;
104	int i, slot;
105
106	WARN_ON(system_state != SYSTEM_BOOTING);
107
108	slot = -1;
109	for (i = 0; i < FIX_BTMAPS_SLOTS; i++) {
110		if (!prev_map[i]) {
111			slot = i;
112			break;
113		}
114	}
115
116	if (WARN(slot < 0, "%s(%08llx, %08lx) not found slot\n",
117		 __func__, (u64)phys_addr, size))
118		return NULL;
119
120	/* Don't allow wraparound or zero size */
121	last_addr = phys_addr + size - 1;
122	if (WARN_ON(!size || last_addr < phys_addr))
123		return NULL;
124
125	prev_size[slot] = size;
126	/*
127	 * Mappings have to be page-aligned
128	 */
129	offset = offset_in_page(phys_addr);
130	phys_addr &= PAGE_MASK;
131	size = PAGE_ALIGN(last_addr + 1) - phys_addr;
132
133	/*
134	 * Mappings have to fit in the FIX_BTMAP area.
135	 */
136	nrpages = size >> PAGE_SHIFT;
137	if (WARN_ON(nrpages > NR_FIX_BTMAPS))
138		return NULL;
139
140	/*
141	 * Ok, go for it..
142	 */
143	idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*slot;
144	while (nrpages > 0) {
145		if (after_paging_init)
146			__late_set_fixmap(idx, phys_addr, prot);
147		else
148			__early_set_fixmap(idx, phys_addr, prot);
149		phys_addr += PAGE_SIZE;
150		--idx;
151		--nrpages;
152	}
153	WARN(early_ioremap_debug, "%s(%08llx, %08lx) [%d] => %08lx + %08lx\n",
154	     __func__, (u64)phys_addr, size, slot, offset, slot_virt[slot]);
155
156	prev_map[slot] = (void __iomem *)(offset + slot_virt[slot]);
157	return prev_map[slot];
158}
159
160void __init early_iounmap(void __iomem *addr, unsigned long size)
161{
162	unsigned long virt_addr;
163	unsigned long offset;
164	unsigned int nrpages;
165	enum fixed_addresses idx;
166	int i, slot;
167
168	slot = -1;
169	for (i = 0; i < FIX_BTMAPS_SLOTS; i++) {
170		if (prev_map[i] == addr) {
171			slot = i;
172			break;
173		}
174	}
175
176	if (WARN(slot < 0, "early_iounmap(%p, %08lx) not found slot\n",
177		 addr, size))
178		return;
179
180	if (WARN(prev_size[slot] != size,
181		 "early_iounmap(%p, %08lx) [%d] size not consistent %08lx\n",
182		 addr, size, slot, prev_size[slot]))
183		return;
184
185	WARN(early_ioremap_debug, "early_iounmap(%p, %08lx) [%d]\n",
186	     addr, size, slot);
187
188	virt_addr = (unsigned long)addr;
189	if (WARN_ON(virt_addr < fix_to_virt(FIX_BTMAP_BEGIN)))
190		return;
191
192	offset = offset_in_page(virt_addr);
193	nrpages = PAGE_ALIGN(offset + size) >> PAGE_SHIFT;
194
195	idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*slot;
196	while (nrpages > 0) {
197		if (after_paging_init)
198			__late_clear_fixmap(idx);
199		else
200			__early_set_fixmap(idx, 0, FIXMAP_PAGE_CLEAR);
201		--idx;
202		--nrpages;
203	}
204	prev_map[slot] = NULL;
205}
206
207/* Remap an IO device */
208void __init __iomem *
209early_ioremap(resource_size_t phys_addr, unsigned long size)
210{
211	return __early_ioremap(phys_addr, size, FIXMAP_PAGE_IO);
212}
213
214/* Remap memory */
215void __init *
216early_memremap(resource_size_t phys_addr, unsigned long size)
217{
218	return (__force void *)__early_ioremap(phys_addr, size,
219					       FIXMAP_PAGE_NORMAL);
220}
221#ifdef FIXMAP_PAGE_RO
222void __init *
223early_memremap_ro(resource_size_t phys_addr, unsigned long size)
224{
225	return (__force void *)__early_ioremap(phys_addr, size, FIXMAP_PAGE_RO);
226}
227#endif
228
229#define MAX_MAP_CHUNK	(NR_FIX_BTMAPS << PAGE_SHIFT)
230
231void __init copy_from_early_mem(void *dest, phys_addr_t src, unsigned long size)
232{
233	unsigned long slop, clen;
234	char *p;
235
236	while (size) {
237		slop = offset_in_page(src);
238		clen = size;
239		if (clen > MAX_MAP_CHUNK - slop)
240			clen = MAX_MAP_CHUNK - slop;
241		p = early_memremap(src & PAGE_MASK, clen + slop);
242		memcpy(dest, p + slop, clen);
243		early_memunmap(p, clen + slop);
244		dest += clen;
245		src += clen;
246		size -= clen;
247	}
248}
249
250#else /* CONFIG_MMU */
251
252void __init __iomem *
253early_ioremap(resource_size_t phys_addr, unsigned long size)
254{
255	return (__force void __iomem *)phys_addr;
256}
257
258/* Remap memory */
259void __init *
260early_memremap(resource_size_t phys_addr, unsigned long size)
261{
262	return (void *)phys_addr;
263}
264void __init *
265early_memremap_ro(resource_size_t phys_addr, unsigned long size)
266{
267	return (void *)phys_addr;
268}
269
270void __init early_iounmap(void __iomem *addr, unsigned long size)
271{
272}
273
274#endif /* CONFIG_MMU */
275
276
277void __init early_memunmap(void *addr, unsigned long size)
278{
279	early_iounmap((__force void __iomem *)addr, size);
280}
281