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/ptrace.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/init.h>
  29
  30 #include <asm/irq.h>
  31 #include <asm/system.h>
  32 #include <asm/mach/pci.h>
  33 #include <asm/mach-types.h>
  34
  35 /*
  36  * A small note about bridges and interrupts.  The DECchip 21050 (and
  37  * later) adheres to the PCI-PCI bridge specification.  This says that
  38  * the interrupts on the other side of a bridge are swizzled in the
  39  * following manner:
  40  *
  41  * Dev    Interrupt   Interrupt
  42  *        Pin on      Pin on
  43  *        Device      Connector
  44  *
  45  *   4    A           A
  46  *        B           B
  47  *        C           C
  48  *        D           D
  49  *
  50  *   5    A           B
  51  *        B           C
  52  *        C           D
  53  *        D           A
  54  *
  55  *   6    A           C
  56  *        B           D
  57  *        C           A
  58  *        D           B
  59  *
  60  *   7    A           D
  61  *        B           A
  62  *        C           B
  63  *        D           C
  64  *
  65  * Where A = pin 1, B = pin 2 and so on and pin=0 = default = A.
  66  * Thus, each swizzle is ((pin-1) + (device#-4)) % 4
  67  *
  68  * The following code swizzles for exactly one bridge.
  69  */
  70 static inline int bridge_swizzle(int pin, unsigned int slot)
  71 {
  72         return (pin + slot) & 3;
  73 }
  74
  75 /*
  76  * This routine handles multiple bridges.
  77  */
  78 static u8 __init integrator_swizzle(struct pci_dev *dev, u8 *pinp)
  79 {
  80         int pin = *pinp;
  81
  82         if (pin == 0)
  83                 pin = 1;
  84
  85         pin -= 1;
  86         while (dev->bus->self) {
  87                 pin = bridge_swizzle(pin, PCI_SLOT(dev->devfn));
  88                 /*
  89                  * move up the chain of bridges, swizzling as we go.
  90                  */
  91                 dev = dev->bus->self;
  92         }
  93         *pinp = pin + 1;
  94
  95         return PCI_SLOT(dev->devfn);
  96 }
  97
  98 static int irq_tab[4] __initdata = {
  99         IRQ_AP_PCIINT0, IRQ_AP_PCIINT1, IRQ_AP_PCIINT2, IRQ_AP_PCIINT3
 100 };
 101
 102 /*
 103  * map the specified device/slot/pin to an IRQ.  This works out such
 104  * that slot 9 pin 1 is INT0, pin 2 is INT1, and slot 10 pin 1 is INT1.
 105  */
 106 static int __init integrator_map_irq(struct pci_dev *dev, u8 slot, u8 pin)
 107 {
 108         int intnr = ((slot - 9) + (pin - 1)) & 3;
 109
 110         return irq_tab[intnr];
 111 }
 112
 113 extern void pci_v3_init(void *);
 114
 115 static struct hw_pci integrator_pci __initdata = {
 116         .swizzle                = integrator_swizzle,
 117         .map_irq                = integrator_map_irq,
 118         .setup                  = pci_v3_setup,
 119         .nr_controllers         = 1,
 120         .scan                   = pci_v3_scan_bus,
 121         .preinit                = pci_v3_preinit,
 122         .postinit               = pci_v3_postinit,
 123 };
 124
 125 static int __init integrator_pci_init(void)
 126 {
 127         if (machine_is_integrator())
 128                 pci_common_init(&integrator_pci);
 129         return 0;
 130 }
 131
 132 subsys_initcall(integrator_pci_init);