iomap.c

  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#include "pci.h" /* for pci_bar_index_is_valid() */
 13
 14/**
 15 * pci_iomap_range - create a virtual mapping cookie for a PCI BAR
 16 * @dev: PCI device that owns the BAR
 17 * @bar: BAR number
 18 * @offset: map memory at the given offset in BAR
 19 * @maxlen: max length of the memory to map
 20 *
 21 * Using this function you will get a __iomem address to your device BAR.
 22 * You can access it using ioread*() and iowrite*(). These functions hide
 23 * the details if this is a MMIO or PIO address space and will just do what
 24 * you expect from them in the correct way.
 25 *
 26 * @maxlen specifies the maximum length to map. If you want to get access to
 27 * the complete BAR from offset to the end, pass %0 here.
 28 * */
 29void __iomem *pci_iomap_range(struct pci_dev *dev,
 30			      int bar,
 31			      unsigned long offset,
 32			      unsigned long maxlen)
 33{
 34	resource_size_t start, len;
 35	unsigned long flags;
 36
 37	if (!pci_bar_index_is_valid(bar))
 38		return NULL;
 39
 40	start = pci_resource_start(dev, bar);
 41	len = pci_resource_len(dev, bar);
 42	flags = pci_resource_flags(dev, bar);
 43
 44	if (len <= offset || !start)
 45		return NULL;
 46
 47	len -= offset;
 48	start += offset;
 49	if (maxlen && len > maxlen)
 50		len = maxlen;
 51	if (flags & IORESOURCE_IO)
 52		return __pci_ioport_map(dev, start, len);
 53	if (flags & IORESOURCE_MEM)
 54		return ioremap(start, len);
 55	/* What? */
 56	return NULL;
 57}
 58EXPORT_SYMBOL(pci_iomap_range);
 59
 60/**
 61 * pci_iomap_wc_range - create a virtual WC mapping cookie for a PCI BAR
 62 * @dev: PCI device that owns the BAR
 63 * @bar: BAR number
 64 * @offset: map memory at the given offset in BAR
 65 * @maxlen: max length of the memory to map
 66 *
 67 * Using this function you will get a __iomem address to your device BAR.
 68 * You can access it using ioread*() and iowrite*(). These functions hide
 69 * the details if this is a MMIO or PIO address space and will just do what
 70 * you expect from them in the correct way. When possible write combining
 71 * is used.
 72 *
 73 * @maxlen specifies the maximum length to map. If you want to get access to
 74 * the complete BAR from offset to the end, pass %0 here.
 75 * */
 76void __iomem *pci_iomap_wc_range(struct pci_dev *dev,
 77				 int bar,
 78				 unsigned long offset,
 79				 unsigned long maxlen)
 80{
 81	resource_size_t start, len;
 82	unsigned long flags;
 83
 84	if (!pci_bar_index_is_valid(bar))
 85		return NULL;
 86
 87	start = pci_resource_start(dev, bar);
 88	len = pci_resource_len(dev, bar);
 89	flags = pci_resource_flags(dev, bar);
 90
 91	if (len <= offset || !start)
 92		return NULL;
 93	if (flags & IORESOURCE_IO)
 94		return NULL;
 95
 96	len -= offset;
 97	start += offset;
 98	if (maxlen && len > maxlen)
 99		len = maxlen;
100
101	if (flags & IORESOURCE_MEM)
102		return ioremap_wc(start, len);
103
104	/* What? */
105	return NULL;
106}
107EXPORT_SYMBOL_GPL(pci_iomap_wc_range);
108
109/**
110 * pci_iomap - create a virtual mapping cookie for a PCI BAR
111 * @dev: PCI device that owns the BAR
112 * @bar: BAR number
113 * @maxlen: length of the memory to map
114 *
115 * Using this function you will get a __iomem address to your device BAR.
116 * You can access it using ioread*() and iowrite*(). These functions hide
117 * the details if this is a MMIO or PIO address space and will just do what
118 * you expect from them in the correct way.
119 *
120 * @maxlen specifies the maximum length to map. If you want to get access to
121 * the complete BAR without checking for its length first, pass %0 here.
122 * */
123void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long maxlen)
124{
125	return pci_iomap_range(dev, bar, 0, maxlen);
126}
127EXPORT_SYMBOL(pci_iomap);
128
129/**
130 * pci_iomap_wc - create a virtual WC mapping cookie for a PCI BAR
131 * @dev: PCI device that owns the BAR
132 * @bar: BAR number
133 * @maxlen: length of the memory to map
134 *
135 * Using this function you will get a __iomem address to your device BAR.
136 * You can access it using ioread*() and iowrite*(). These functions hide
137 * the details if this is a MMIO or PIO address space and will just do what
138 * you expect from them in the correct way. When possible write combining
139 * is used.
140 *
141 * @maxlen specifies the maximum length to map. If you want to get access to
142 * the complete BAR without checking for its length first, pass %0 here.
143 * */
144void __iomem *pci_iomap_wc(struct pci_dev *dev, int bar, unsigned long maxlen)
145{
146	return pci_iomap_wc_range(dev, bar, 0, maxlen);
147}
148EXPORT_SYMBOL_GPL(pci_iomap_wc);
149
150/*
151 * pci_iounmap() somewhat illogically comes from lib/iomap.c for the
152 * CONFIG_GENERIC_IOMAP case, because that's the code that knows about
153 * the different IOMAP ranges.
154 *
155 * But if the architecture does not use the generic iomap code, and if
156 * it has _not_ defined its own private pci_iounmap function, we define
157 * it here.
158 *
159 * NOTE! This default implementation assumes that if the architecture
160 * support ioport mapping (HAS_IOPORT_MAP), the ioport mapping will
161 * be fixed to the range [ PCI_IOBASE, PCI_IOBASE+IO_SPACE_LIMIT [,
162 * and does not need unmapping with 'ioport_unmap()'.
163 *
164 * If you have different rules for your architecture, you need to
165 * implement your own pci_iounmap() that knows the rules for where
166 * and how IO vs MEM get mapped.
167 *
168 * This code is odd, and the ARCH_HAS/ARCH_WANTS #define logic comes
169 * from legacy <asm-generic/io.h> header file behavior. In particular,
170 * it would seem to make sense to do the iounmap(p) for the non-IO-space
171 * case here regardless, but that's not what the old header file code
172 * did. Probably incorrectly, but this is meant to be bug-for-bug
173 * compatible.
174 */
175#if defined(ARCH_WANTS_GENERIC_PCI_IOUNMAP)
176
177void pci_iounmap(struct pci_dev *dev, void __iomem *p)
178{
179#ifdef ARCH_HAS_GENERIC_IOPORT_MAP
180	uintptr_t start = (uintptr_t) PCI_IOBASE;
181	uintptr_t addr = (uintptr_t) p;
182
183	if (addr >= start && addr < start + IO_SPACE_LIMIT)
184		return;
185#endif
186	iounmap(p);
187}
188EXPORT_SYMBOL(pci_iounmap);
189
190#endif /* ARCH_WANTS_GENERIC_PCI_IOUNMAP */