1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Provide common bits of early_ioremap() support for architectures needing
4 * temporary mappings during boot before ioremap() is available.
5 *
6 * This is mostly a direct copy of the x86 early_ioremap implementation.
7 *
8 * (C) Copyright 1995 1996, 2014 Linus Torvalds
9 *
10 */
11#include <linux/kernel.h>
12#include <linux/init.h>
13#include <linux/io.h>
14#include <linux/module.h>
15#include <linux/slab.h>
16#include <linux/mm.h>
17#include <linux/vmalloc.h>
18#include <asm/fixmap.h>
19#include <asm/early_ioremap.h>
20#include "internal.h"
21
22#ifdef CONFIG_MMU
23static int early_ioremap_debug __initdata;
24
25static int __init early_ioremap_debug_setup(char *str)
26{
27	early_ioremap_debug = 1;
28
29	return 0;
30}
31early_param("early_ioremap_debug", early_ioremap_debug_setup);
32
33static int after_paging_init __initdata;
34
35pgprot_t __init __weak early_memremap_pgprot_adjust(resource_size_t phys_addr,
36						    unsigned long size,
37						    pgprot_t prot)
38{
39	return prot;
40}
41
42void __init early_ioremap_reset(void)
43{
44	after_paging_init = 1;
45}
46
47/*
48 * Generally, ioremap() is available after paging_init() has been called.
49 * Architectures wanting to allow early_ioremap after paging_init() can
50 * define __late_set_fixmap and __late_clear_fixmap to do the right thing.
51 */
52#ifndef __late_set_fixmap
53static inline void __init __late_set_fixmap(enum fixed_addresses idx,
54					    phys_addr_t phys, pgprot_t prot)
55{
56	BUG();
57}
58#endif
59
60#ifndef __late_clear_fixmap
61static inline void __init __late_clear_fixmap(enum fixed_addresses idx)
62{
63	BUG();
64}
65#endif
66
67static void __iomem *prev_map[FIX_BTMAPS_SLOTS] __initdata;
68static unsigned long prev_size[FIX_BTMAPS_SLOTS] __initdata;
69static unsigned long slot_virt[FIX_BTMAPS_SLOTS] __initdata;
70
71void __init early_ioremap_setup(void)
72{
73	int i;
74
75	for (i = 0; i < FIX_BTMAPS_SLOTS; i++) {
76		WARN_ON_ONCE(prev_map[i]);
77		slot_virt[i] = __fix_to_virt(FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*i);
78	}
79}
80
81static int __init check_early_ioremap_leak(void)
82{
83	int count = 0;
84	int i;
85
86	for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
87		if (prev_map[i])
88			count++;
89
90	if (WARN(count, KERN_WARNING
91		 "Debug warning: early ioremap leak of %d areas detected.\n"
92		 "please boot with early_ioremap_debug and report the dmesg.\n",
93		 count))
94		return 1;
95	return 0;
96}
97late_initcall(check_early_ioremap_leak);
98
99static void __init __iomem *
100__early_ioremap(resource_size_t phys_addr, unsigned long size, pgprot_t prot)
101{
102	unsigned long offset;
103	resource_size_t last_addr;
104	unsigned int nrpages;
105	enum fixed_addresses idx;
106	int i, slot;
107
108	WARN_ON(system_state >= SYSTEM_RUNNING);
109
110	slot = -1;
111	for (i = 0; i < FIX_BTMAPS_SLOTS; i++) {
112		if (!prev_map[i]) {
113			slot = i;
114			break;
115		}
116	}
117
118	if (WARN(slot < 0, "%s(%pa, %08lx) not found slot\n",
119		 __func__, &phys_addr, size))
120		return NULL;
121
122	/* Don't allow wraparound or zero size */
123	last_addr = phys_addr + size - 1;
124	if (WARN_ON(!size || last_addr < phys_addr))
125		return NULL;
126
127	prev_size[slot] = size;
128	/*
129	 * Mappings have to be page-aligned
130	 */
131	offset = offset_in_page(phys_addr);
132	phys_addr &= PAGE_MASK;
133	size = PAGE_ALIGN(last_addr + 1) - phys_addr;
134
135	/*
136	 * Mappings have to fit in the FIX_BTMAP area.
137	 */
138	nrpages = size >> PAGE_SHIFT;
139	if (WARN_ON(nrpages > NR_FIX_BTMAPS))
140		return NULL;
141
142	/*
143	 * Ok, go for it..
144	 */
145	idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*slot;
146	while (nrpages > 0) {
147		if (after_paging_init)
148			__late_set_fixmap(idx, phys_addr, prot);
149		else
150			__early_set_fixmap(idx, phys_addr, prot);
151		phys_addr += PAGE_SIZE;
152		--idx;
153		--nrpages;
154	}
155	WARN(early_ioremap_debug, "%s(%pa, %08lx) [%d] => %08lx + %08lx\n",
156	     __func__, &phys_addr, size, slot, offset, slot_virt[slot]);
157
158	prev_map[slot] = (void __iomem *)(offset + slot_virt[slot]);
159	return prev_map[slot];
160}
161
162void __init early_iounmap(void __iomem *addr, unsigned long size)
163{
164	unsigned long virt_addr;
165	unsigned long offset;
166	unsigned int nrpages;
167	enum fixed_addresses idx;
168	int i, slot;
169
170	slot = -1;
171	for (i = 0; i < FIX_BTMAPS_SLOTS; i++) {
172		if (prev_map[i] == addr) {
173			slot = i;
174			break;
175		}
176	}
177
178	if (WARN(slot < 0, "%s(%p, %08lx) not found slot\n",
179		  __func__, addr, size))
180		return;
181
182	if (WARN(prev_size[slot] != size,
183		 "%s(%p, %08lx) [%d] size not consistent %08lx\n",
184		  __func__, addr, size, slot, prev_size[slot]))
185		return;
186
187	WARN(early_ioremap_debug, "%s(%p, %08lx) [%d]\n",
188	      __func__, addr, size, slot);
189
190	virt_addr = (unsigned long)addr;
191	if (WARN_ON(virt_addr < fix_to_virt(FIX_BTMAP_BEGIN)))
192		return;
193
194	offset = offset_in_page(virt_addr);
195	nrpages = PAGE_ALIGN(offset + size) >> PAGE_SHIFT;
196
197	idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*slot;
198	while (nrpages > 0) {
199		if (after_paging_init)
200			__late_clear_fixmap(idx);
201		else
202			__early_set_fixmap(idx, 0, FIXMAP_PAGE_CLEAR);
203		--idx;
204		--nrpages;
205	}
206	prev_map[slot] = NULL;
207}
208
209/* Remap an IO device */
210void __init __iomem *
211early_ioremap(resource_size_t phys_addr, unsigned long size)
212{
213	return __early_ioremap(phys_addr, size, FIXMAP_PAGE_IO);
214}
215
216/* Remap memory */
217void __init *
218early_memremap(resource_size_t phys_addr, unsigned long size)
219{
220	pgprot_t prot = early_memremap_pgprot_adjust(phys_addr, size,
221						     FIXMAP_PAGE_NORMAL);
222
223	return (__force void *)__early_ioremap(phys_addr, size, prot);
224}
225#ifdef FIXMAP_PAGE_RO
226void __init *
227early_memremap_ro(resource_size_t phys_addr, unsigned long size)
228{
229	pgprot_t prot = early_memremap_pgprot_adjust(phys_addr, size,
230						     FIXMAP_PAGE_RO);
231
232	return (__force void *)__early_ioremap(phys_addr, size, prot);
233}
234#endif
235
236#ifdef CONFIG_ARCH_USE_MEMREMAP_PROT
237void __init *
238early_memremap_prot(resource_size_t phys_addr, unsigned long size,
239		    unsigned long prot_val)
240{
241	return (__force void *)__early_ioremap(phys_addr, size,
242					       __pgprot(prot_val));
243}
244#endif
245
246#define MAX_MAP_CHUNK	(NR_FIX_BTMAPS << PAGE_SHIFT)
247
248void __init copy_from_early_mem(void *dest, phys_addr_t src, unsigned long size)
249{
250	unsigned long slop, clen;
251	char *p;
252
253	while (size) {
254		slop = offset_in_page(src);
255		clen = size;
256		if (clen > MAX_MAP_CHUNK - slop)
257			clen = MAX_MAP_CHUNK - slop;
258		p = early_memremap(src & PAGE_MASK, clen + slop);
259		memcpy(dest, p + slop, clen);
260		early_memunmap(p, clen + slop);
261		dest += clen;
262		src += clen;
263		size -= clen;
264	}
265}
266
267#else /* CONFIG_MMU */
268
269void __init __iomem *
270early_ioremap(resource_size_t phys_addr, unsigned long size)
271{
272	return (__force void __iomem *)phys_addr;
273}
274
275/* Remap memory */
276void __init *
277early_memremap(resource_size_t phys_addr, unsigned long size)
278{
279	return (void *)phys_addr;
280}
281void __init *
282early_memremap_ro(resource_size_t phys_addr, unsigned long size)
283{
284	return (void *)phys_addr;
285}
286
287void __init early_iounmap(void __iomem *addr, unsigned long size)
288{
289}
290
291#endif /* CONFIG_MMU */
292
293
294void __init early_memunmap(void *addr, unsigned long size)
295{
296	early_iounmap((__force void __iomem *)addr, size);
297}
298