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