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 41 pcibios_align_resource(void *data, const struct resource *res, 42 const struct resource *empty_res, 43 resource_size_t size, resource_size_t align) 44 { 45 struct pci_dev *dev = data; 46 resource_size_t start = res->start; 47 48 if (res->flags & IORESOURCE_IO) { 49 if (size > 0x100) { 50 pr_err("PCI: I/O Region %s/%d too large (%u bytes)\n", 51 pci_name(dev), dev->resource - res, 52 size); 53 } 54 55 if (start & 0x300) 56 start = (start + 0x3ff) & ~0x3ff; 57 } else if (res->flags & IORESOURCE_MEM) { 58 start = pci_align_resource(dev, res, empty_res, size, align); 59 } 60 61 return start; 62 } 63 64 void pcibios_fixup_bus(struct pci_bus *bus) 65 { 66 if (bus->parent) { 67 /* This is a subordinate bridge */ 68 pci_read_bridge_bases(bus); 69 } 70 } 71 72 /* 73 * Platform support for /proc/bus/pci/X/Y mmap()s. 74 * -- paulus. 75 */ 76 77 int pci_iobar_pfn(struct pci_dev *pdev, int bar, struct vm_area_struct *vma) 78 { 79 struct pci_controller *pci_ctrl = (struct pci_controller*) pdev->sysdata; 80 resource_size_t ioaddr = pci_resource_start(pdev, bar); 81 82 if (!pci_ctrl) 83 return -EINVAL; /* should never happen */ 84 85 /* Convert to an offset within this PCI controller */ 86 ioaddr -= (unsigned long)pci_ctrl->io_space.base; 87 88 vma->vm_pgoff += (ioaddr + pci_ctrl->io_space.start) >> PAGE_SHIFT; 89 return 0; 90 } 91