arch/arm/mach-integrator/pci.c

   1 /*
   2  *  linux/arch/arm/mach-integrator/pci-integrator.c
   3  *
   4  *  Copyright (C) 1999 ARM Limited
   5  *  Copyright (C) 2000 Deep Blue Solutions Ltd
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  *
  21  *
  22  *  PCI functions for Integrator
  23  */
  24 #include <linux/kernel.h>
  25 #include <linux/pci.h>
  26 #include <linux/interrupt.h>
  27 #include <linux/init.h>
  28
  29 #include <asm/irq.h>
  30 #include <asm/system.h>
  31 #include <asm/mach/pci.h>
  32 #include <asm/mach-types.h>
  33
  34 /*
  35  * A small note about bridges and interrupts.  The DECchip 21050 (and
  36  * later) adheres to the PCI-PCI bridge specification.  This says that
  37  * the interrupts on the other side of a bridge are swizzled in the
  38  * following manner:
  39  *
  40  * Dev    Interrupt   Interrupt
  41  *        Pin on      Pin on
  42  *        Device      Connector
  43  *
  44  *   4    A           A
  45  *        B           B
  46  *        C           C
  47  *        D           D
  48  *
  49  *   5    A           B
  50  *        B           C
  51  *        C           D
  52  *        D           A
  53  *
  54  *   6    A           C
  55  *        B           D
  56  *        C           A
  57  *        D           B
  58  *
  59  *   7    A           D
  60  *        B           A
  61  *        C           B
  62  *        D           C
  63  *
  64  * Where A = pin 1, B = pin 2 and so on and pin=0 = default = A.
  65  * Thus, each swizzle is ((pin-1) + (device#-4)) % 4
  66  *
  67  * The following code swizzles for exactly one bridge.
  68  */
  69 static inline int bridge_swizzle(int pin, unsigned int slot)
  70 {
  71         return (pin + slot) & 3;
  72 }
  73
  74 /*
  75  * This routine handles multiple bridges.
  76  */
  77 static u8 __init integrator_swizzle(struct pci_dev *dev, u8 *pinp)
  78 {
  79         int pin = *pinp;
  80
  81         if (pin == 0)
  82                 pin = 1;
  83
  84         pin -= 1;
  85         while (dev->bus->self) {
  86                 pin = bridge_swizzle(pin, PCI_SLOT(dev->devfn));
  87                 /*
  88                  * move up the chain of bridges, swizzling as we go.
  89                  */
  90                 dev = dev->bus->self;
  91         }
  92         *pinp = pin + 1;
  93
  94         return PCI_SLOT(dev->devfn);
  95 }
  96
  97 static int irq_tab[4] __initdata = {
  98         IRQ_AP_PCIINT0, IRQ_AP_PCIINT1, IRQ_AP_PCIINT2, IRQ_AP_PCIINT3
  99 };
 100
 101 /*
 102  * map the specified device/slot/pin to an IRQ.  This works out such
 103  * that slot 9 pin 1 is INT0, pin 2 is INT1, and slot 10 pin 1 is INT1.
 104  */
 105 static int __init integrator_map_irq(struct pci_dev *dev, u8 slot, u8 pin)
 106 {
 107         int intnr = ((slot - 9) + (pin - 1)) & 3;
 108
 109         return irq_tab[intnr];
 110 }
 111
 112 extern void pci_v3_init(void *);
 113
 114 static struct hw_pci integrator_pci __initdata = {
 115         .swizzle                = integrator_swizzle,
 116         .map_irq                = integrator_map_irq,
 117         .setup                  = pci_v3_setup,
 118         .nr_controllers         = 1,
 119         .scan                   = pci_v3_scan_bus,
 120         .preinit                = pci_v3_preinit,
 121         .postinit               = pci_v3_postinit,
 122 };
 123
 124 static int __init integrator_pci_init(void)
 125 {
 126         if (machine_is_integrator())
 127                 pci_common_init(&integrator_pci);
 128         return 0;
 129 }
 130
 131 subsys_initcall(integrator_pci_init);