1 /* 2 * pci.c -- basic PCI support code 3 * 4 * This program is free software; you can redistribute it and/or modify it 5 * under the terms of the GNU General Public License as published by the 6 * Free Software Foundation; either version 2 of the License, or (at your 7 * option) any later version. 8 * 9 * (C) Copyright 2011, Greg Ungerer <gerg@uclinux.org> 10 */ 11 12 #include <linux/kernel.h> 13 #include <linux/types.h> 14 #include <linux/mm.h> 15 #include <linux/init.h> 16 #include <linux/pci.h> 17 18 /* 19 * From arch/i386/kernel/pci-i386.c: 20 * 21 * We need to avoid collisions with `mirrored' VGA ports 22 * and other strange ISA hardware, so we always want the 23 * addresses to be allocated in the 0x000-0x0ff region 24 * modulo 0x400. 25 * 26 * Why? Because some silly external IO cards only decode 27 * the low 10 bits of the IO address. The 0x00-0xff region 28 * is reserved for motherboard devices that decode all 16 29 * bits, so it's ok to allocate at, say, 0x2800-0x28ff, 30 * but we want to try to avoid allocating at 0x2900-0x2bff 31 * which might be mirrored at 0x0100-0x03ff.. 32 */ 33 resource_size_t pcibios_align_resource(void *data, const struct resource *res, 34 resource_size_t size, resource_size_t align) 35 { 36 resource_size_t start = res->start; 37 38 if ((res->flags & IORESOURCE_IO) && (start & 0x300)) 39 start = (start + 0x3ff) & ~0x3ff; 40 41 start = (start + align - 1) & ~(align - 1); 42 43 return start; 44 } 45 46 /* 47 * This is taken from the ARM code for this. 48 */ 49 int pcibios_enable_device(struct pci_dev *dev, int mask) 50 { 51 struct resource *r; 52 u16 cmd, newcmd; 53 int idx; 54 55 pci_read_config_word(dev, PCI_COMMAND, &cmd); 56 newcmd = cmd; 57 58 for (idx = 0; idx < 6; idx++) { 59 /* Only set up the requested stuff */ 60 if (!(mask & (1 << idx))) 61 continue; 62 63 r = dev->resource + idx; 64 if (!r->start && r->end) { 65 pr_err("PCI: Device %s not available because of resource collisions\n", 66 pci_name(dev)); 67 return -EINVAL; 68 } 69 if (r->flags & IORESOURCE_IO) 70 newcmd |= PCI_COMMAND_IO; 71 if (r->flags & IORESOURCE_MEM) 72 newcmd |= PCI_COMMAND_MEMORY; 73 } 74 75 /* 76 * Bridges (eg, cardbus bridges) need to be fully enabled 77 */ 78 if ((dev->class >> 16) == PCI_BASE_CLASS_BRIDGE) 79 newcmd |= PCI_COMMAND_IO | PCI_COMMAND_MEMORY; 80 81 82 if (newcmd != cmd) { 83 pr_info("PCI: enabling device %s (0x%04x -> 0x%04x)\n", 84 pci_name(dev), cmd, newcmd); 85 pci_write_config_word(dev, PCI_COMMAND, newcmd); 86 } 87 return 0; 88 } 89 90 void pcibios_fixup_bus(struct pci_bus *bus) 91 { 92 struct pci_dev *dev; 93 94 list_for_each_entry(dev, &bus->devices, bus_list) { 95 pci_write_config_byte(dev, PCI_CACHE_LINE_SIZE, 8); 96 pci_write_config_byte(dev, PCI_LATENCY_TIMER, 32); 97 } 98 } 99 100 char *pcibios_setup(char *str) 101 { 102 return str; 103 } 104 105