1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * arch/xtensa/kernel/pci.c
4 *
5 * PCI bios-type initialisation for PCI machines
6 *
7 * Copyright (C) 2001-2005 Tensilica Inc.
8 *
9 * Based largely on work from Cort (ppc/kernel/pci.c)
10 * IO functions copied from sparc.
11 *
12 * Chris Zankel <chris@zankel.net>
13 */
14
15 #include <linux/kernel.h>
16 #include <linux/pci.h>
17 #include <linux/delay.h>
18 #include <linux/string.h>
19 #include <linux/init.h>
20 #include <linux/sched.h>
21 #include <linux/errno.h>
22 #include <linux/memblock.h>
23
24 #include <asm/pci-bridge.h>
25 #include <asm/platform.h>
26
27 /*
28 * We need to avoid collisions with `mirrored' VGA ports
29 * and other strange ISA hardware, so we always want the
30 * addresses to be allocated in the 0x000-0x0ff region
31 * modulo 0x400.
32 *
33 * Why? Because some silly external IO cards only decode
34 * the low 10 bits of the IO address. The 0x00-0xff region
35 * is reserved for motherboard devices that decode all 16
36 * bits, so it's ok to allocate at, say, 0x2800-0x28ff,
37 * but we want to try to avoid allocating at 0x2900-0x2bff
38 * which might have be mirrored at 0x0100-0x03ff..
39 */
40 resource_size_t
pcibios_align_resource(void * data,const struct resource * res,resource_size_t size,resource_size_t align)41 pcibios_align_resource(void *data, const struct resource *res,
42 resource_size_t size, resource_size_t align)
43 {
44 struct pci_dev *dev = data;
45 resource_size_t start = res->start;
46
47 if (res->flags & IORESOURCE_IO) {
48 if (size > 0x100) {
49 pr_err("PCI: I/O Region %s/%d too large (%u bytes)\n",
50 pci_name(dev), dev->resource - res,
51 size);
52 }
53
54 if (start & 0x300)
55 start = (start + 0x3ff) & ~0x3ff;
56 }
57
58 return start;
59 }
60
pcibios_fixup_bus(struct pci_bus * bus)61 void pcibios_fixup_bus(struct pci_bus *bus)
62 {
63 if (bus->parent) {
64 /* This is a subordinate bridge */
65 pci_read_bridge_bases(bus);
66 }
67 }
68
69 /*
70 * Platform support for /proc/bus/pci/X/Y mmap()s.
71 * -- paulus.
72 */
73
pci_iobar_pfn(struct pci_dev * pdev,int bar,struct vm_area_struct * vma)74 int pci_iobar_pfn(struct pci_dev *pdev, int bar, struct vm_area_struct *vma)
75 {
76 struct pci_controller *pci_ctrl = (struct pci_controller*) pdev->sysdata;
77 resource_size_t ioaddr = pci_resource_start(pdev, bar);
78
79 if (!pci_ctrl)
80 return -EINVAL; /* should never happen */
81
82 /* Convert to an offset within this PCI controller */
83 ioaddr -= (unsigned long)pci_ctrl->io_space.base;
84
85 vma->vm_pgoff += (ioaddr + pci_ctrl->io_space.start) >> PAGE_SHIFT;
86 return 0;
87 }
88