arch/m68k/kernel/pcibios.c

   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