1 // SPDX-License-Identifier: GPL-2.0-or-later
2 
3 #include <linux/io.h>
4 #include <linux/slab.h>
5 #include <linux/vmalloc.h>
6 
7 /**
8  * Low level function to establish the page tables for an IO mapping
9  */
__ioremap_at(phys_addr_t pa,void * ea,unsigned long size,pgprot_t prot)10 void __iomem *__ioremap_at(phys_addr_t pa, void *ea, unsigned long size, pgprot_t prot)
11 {
12 	int ret;
13 	unsigned long va = (unsigned long)ea;
14 
15 	/* We don't support the 4K PFN hack with ioremap */
16 	if (pgprot_val(prot) & H_PAGE_4K_PFN)
17 		return NULL;
18 
19 	if ((ea + size) >= (void *)IOREMAP_END) {
20 		pr_warn("Outside the supported range\n");
21 		return NULL;
22 	}
23 
24 	WARN_ON(pa & ~PAGE_MASK);
25 	WARN_ON(((unsigned long)ea) & ~PAGE_MASK);
26 	WARN_ON(size & ~PAGE_MASK);
27 
28 	if (slab_is_available()) {
29 		ret = ioremap_page_range(va, va + size, pa, prot);
30 		if (ret)
31 			unmap_kernel_range(va, size);
32 	} else {
33 		ret = early_ioremap_range(va, pa, size, prot);
34 	}
35 
36 	if (ret)
37 		return NULL;
38 
39 	return (void __iomem *)ea;
40 }
41 EXPORT_SYMBOL(__ioremap_at);
42 
43 /**
44  * Low level function to tear down the page tables for an IO mapping. This is
45  * used for mappings that are manipulated manually, like partial unmapping of
46  * PCI IOs or ISA space.
47  */
__iounmap_at(void * ea,unsigned long size)48 void __iounmap_at(void *ea, unsigned long size)
49 {
50 	WARN_ON(((unsigned long)ea) & ~PAGE_MASK);
51 	WARN_ON(size & ~PAGE_MASK);
52 
53 	unmap_kernel_range((unsigned long)ea, size);
54 }
55 EXPORT_SYMBOL(__iounmap_at);
56 
__ioremap_caller(phys_addr_t addr,unsigned long size,pgprot_t prot,void * caller)57 void __iomem *__ioremap_caller(phys_addr_t addr, unsigned long size,
58 			       pgprot_t prot, void *caller)
59 {
60 	phys_addr_t paligned, offset;
61 	void __iomem *ret;
62 	int err;
63 
64 	/* We don't support the 4K PFN hack with ioremap */
65 	if (pgprot_val(prot) & H_PAGE_4K_PFN)
66 		return NULL;
67 
68 	/*
69 	 * Choose an address to map it to. Once the vmalloc system is running,
70 	 * we use it. Before that, we map using addresses going up from
71 	 * ioremap_bot.  vmalloc will use the addresses from IOREMAP_BASE
72 	 * through ioremap_bot.
73 	 */
74 	paligned = addr & PAGE_MASK;
75 	offset = addr & ~PAGE_MASK;
76 	size = PAGE_ALIGN(addr + size) - paligned;
77 
78 	if (size == 0 || paligned == 0)
79 		return NULL;
80 
81 	if (slab_is_available())
82 		return do_ioremap(paligned, offset, size, prot, caller);
83 
84 	err = early_ioremap_range(ioremap_bot, paligned, size, prot);
85 	if (err)
86 		return NULL;
87 
88 	ret = (void __iomem *)ioremap_bot + offset;
89 	ioremap_bot += size;
90 
91 	return ret;
92 }
93 
94 /*
95  * Unmap an IO region and remove it from vmalloc'd list.
96  * Access to IO memory should be serialized by driver.
97  */
iounmap(volatile void __iomem * token)98 void iounmap(volatile void __iomem *token)
99 {
100 	void *addr;
101 
102 	if (!slab_is_available())
103 		return;
104 
105 	addr = (void *)((unsigned long __force)PCI_FIX_ADDR(token) & PAGE_MASK);
106 
107 	if ((unsigned long)addr < ioremap_bot) {
108 		pr_warn("Attempt to iounmap early bolted mapping at 0x%p\n", addr);
109 		return;
110 	}
111 	vunmap(addr);
112 }
113 EXPORT_SYMBOL(iounmap);
114