xref: /openbmc/linux/lib/pci_iomap.c (revision b5d40f02)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Implement the default iomap interfaces
4  *
5  * (C) Copyright 2004 Linus Torvalds
6  */
7 #include <linux/pci.h>
8 #include <linux/io.h>
9 
10 #include <linux/export.h>
11 
12 #ifdef CONFIG_PCI
13 /**
14  * pci_iomap_range - create a virtual mapping cookie for a PCI BAR
15  * @dev: PCI device that owns the BAR
16  * @bar: BAR number
17  * @offset: map memory at the given offset in BAR
18  * @maxlen: max length of the memory to map
19  *
20  * Using this function you will get a __iomem address to your device BAR.
21  * You can access it using ioread*() and iowrite*(). These functions hide
22  * the details if this is a MMIO or PIO address space and will just do what
23  * you expect from them in the correct way.
24  *
25  * @maxlen specifies the maximum length to map. If you want to get access to
26  * the complete BAR from offset to the end, pass %0 here.
27  * */
pci_iomap_range(struct pci_dev * dev,int bar,unsigned long offset,unsigned long maxlen)28 void __iomem *pci_iomap_range(struct pci_dev *dev,
29 			      int bar,
30 			      unsigned long offset,
31 			      unsigned long maxlen)
32 {
33 	resource_size_t start = pci_resource_start(dev, bar);
34 	resource_size_t len = pci_resource_len(dev, bar);
35 	unsigned long flags = pci_resource_flags(dev, bar);
36 
37 	if (len <= offset || !start)
38 		return NULL;
39 	len -= offset;
40 	start += offset;
41 	if (maxlen && len > maxlen)
42 		len = maxlen;
43 	if (flags & IORESOURCE_IO)
44 		return __pci_ioport_map(dev, start, len);
45 	if (flags & IORESOURCE_MEM)
46 		return ioremap(start, len);
47 	/* What? */
48 	return NULL;
49 }
50 EXPORT_SYMBOL(pci_iomap_range);
51 
52 /**
53  * pci_iomap_wc_range - create a virtual WC mapping cookie for a PCI BAR
54  * @dev: PCI device that owns the BAR
55  * @bar: BAR number
56  * @offset: map memory at the given offset in BAR
57  * @maxlen: max length of the memory to map
58  *
59  * Using this function you will get a __iomem address to your device BAR.
60  * You can access it using ioread*() and iowrite*(). These functions hide
61  * the details if this is a MMIO or PIO address space and will just do what
62  * you expect from them in the correct way. When possible write combining
63  * is used.
64  *
65  * @maxlen specifies the maximum length to map. If you want to get access to
66  * the complete BAR from offset to the end, pass %0 here.
67  * */
pci_iomap_wc_range(struct pci_dev * dev,int bar,unsigned long offset,unsigned long maxlen)68 void __iomem *pci_iomap_wc_range(struct pci_dev *dev,
69 				 int bar,
70 				 unsigned long offset,
71 				 unsigned long maxlen)
72 {
73 	resource_size_t start = pci_resource_start(dev, bar);
74 	resource_size_t len = pci_resource_len(dev, bar);
75 	unsigned long flags = pci_resource_flags(dev, bar);
76 
77 
78 	if (flags & IORESOURCE_IO)
79 		return NULL;
80 
81 	if (len <= offset || !start)
82 		return NULL;
83 
84 	len -= offset;
85 	start += offset;
86 	if (maxlen && len > maxlen)
87 		len = maxlen;
88 
89 	if (flags & IORESOURCE_MEM)
90 		return ioremap_wc(start, len);
91 
92 	/* What? */
93 	return NULL;
94 }
95 EXPORT_SYMBOL_GPL(pci_iomap_wc_range);
96 
97 /**
98  * pci_iomap - create a virtual mapping cookie for a PCI BAR
99  * @dev: PCI device that owns the BAR
100  * @bar: BAR number
101  * @maxlen: length of the memory to map
102  *
103  * Using this function you will get a __iomem address to your device BAR.
104  * You can access it using ioread*() and iowrite*(). These functions hide
105  * the details if this is a MMIO or PIO address space and will just do what
106  * you expect from them in the correct way.
107  *
108  * @maxlen specifies the maximum length to map. If you want to get access to
109  * the complete BAR without checking for its length first, pass %0 here.
110  * */
pci_iomap(struct pci_dev * dev,int bar,unsigned long maxlen)111 void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long maxlen)
112 {
113 	return pci_iomap_range(dev, bar, 0, maxlen);
114 }
115 EXPORT_SYMBOL(pci_iomap);
116 
117 /**
118  * pci_iomap_wc - create a virtual WC mapping cookie for a PCI BAR
119  * @dev: PCI device that owns the BAR
120  * @bar: BAR number
121  * @maxlen: length of the memory to map
122  *
123  * Using this function you will get a __iomem address to your device BAR.
124  * You can access it using ioread*() and iowrite*(). These functions hide
125  * the details if this is a MMIO or PIO address space and will just do what
126  * you expect from them in the correct way. When possible write combining
127  * is used.
128  *
129  * @maxlen specifies the maximum length to map. If you want to get access to
130  * the complete BAR without checking for its length first, pass %0 here.
131  * */
pci_iomap_wc(struct pci_dev * dev,int bar,unsigned long maxlen)132 void __iomem *pci_iomap_wc(struct pci_dev *dev, int bar, unsigned long maxlen)
133 {
134 	return pci_iomap_wc_range(dev, bar, 0, maxlen);
135 }
136 EXPORT_SYMBOL_GPL(pci_iomap_wc);
137 
138 /*
139  * pci_iounmap() somewhat illogically comes from lib/iomap.c for the
140  * CONFIG_GENERIC_IOMAP case, because that's the code that knows about
141  * the different IOMAP ranges.
142  *
143  * But if the architecture does not use the generic iomap code, and if
144  * it has _not_ defined it's own private pci_iounmap function, we define
145  * it here.
146  *
147  * NOTE! This default implementation assumes that if the architecture
148  * support ioport mapping (HAS_IOPORT_MAP), the ioport mapping will
149  * be fixed to the range [ PCI_IOBASE, PCI_IOBASE+IO_SPACE_LIMIT [,
150  * and does not need unmapping with 'ioport_unmap()'.
151  *
152  * If you have different rules for your architecture, you need to
153  * implement your own pci_iounmap() that knows the rules for where
154  * and how IO vs MEM get mapped.
155  *
156  * This code is odd, and the ARCH_HAS/ARCH_WANTS #define logic comes
157  * from legacy <asm-generic/io.h> header file behavior. In particular,
158  * it would seem to make sense to do the iounmap(p) for the non-IO-space
159  * case here regardless, but that's not what the old header file code
160  * did. Probably incorrectly, but this is meant to be bug-for-bug
161  * compatible.
162  */
163 #if defined(ARCH_WANTS_GENERIC_PCI_IOUNMAP)
164 
pci_iounmap(struct pci_dev * dev,void __iomem * p)165 void pci_iounmap(struct pci_dev *dev, void __iomem *p)
166 {
167 #ifdef ARCH_HAS_GENERIC_IOPORT_MAP
168 	uintptr_t start = (uintptr_t) PCI_IOBASE;
169 	uintptr_t addr = (uintptr_t) p;
170 
171 	if (addr >= start && addr < start + IO_SPACE_LIMIT)
172 		return;
173 #endif
174 	iounmap(p);
175 }
176 EXPORT_SYMBOL(pci_iounmap);
177 
178 #endif /* ARCH_WANTS_GENERIC_PCI_IOUNMAP */
179 
180 #endif /* CONFIG_PCI */
181