release/src-rt-6.x/linux/linux-2.6/arch/i386/pci/visws.c

   1 /*
   2  *      Low-Level PCI Support for SGI Visual Workstation
   3  *
   4  *      (c) 1999--2000 Martin Mares <mj@ucw.cz>
   5  */
   6
   7 #include <linux/kernel.h>
   8 #include <linux/pci.h>
   9 #include <linux/init.h>
  10
  11 #include "cobalt.h"
  12 #include "lithium.h"
  13
  14 #include "pci.h"
  15
  16
  17 extern struct pci_raw_ops pci_direct_conf1;
  18
  19 static int pci_visws_enable_irq(struct pci_dev *dev) { return 0; }
  20 static void pci_visws_disable_irq(struct pci_dev *dev) { }
  21
  22 int (*pcibios_enable_irq)(struct pci_dev *dev) = &pci_visws_enable_irq;
  23 void (*pcibios_disable_irq)(struct pci_dev *dev) = &pci_visws_disable_irq;
  24
  25 void __init pcibios_penalize_isa_irq(int irq, int active) {}
  26
  27
  28 unsigned int pci_bus0, pci_bus1;
  29
  30 static inline u8 bridge_swizzle(u8 pin, u8 slot)
  31 {
  32         return (((pin - 1) + slot) % 4) + 1;
  33 }
  34
  35 static u8 __init visws_swizzle(struct pci_dev *dev, u8 *pinp)
  36 {
  37         u8 pin = *pinp;
  38
  39         while (dev->bus->self) {        /* Move up the chain of bridges. */
  40                 pin = bridge_swizzle(pin, PCI_SLOT(dev->devfn));
  41                 dev = dev->bus->self;
  42         }
  43         *pinp = pin;
  44
  45         return PCI_SLOT(dev->devfn);
  46 }
  47
  48 static int __init visws_map_irq(struct pci_dev *dev, u8 slot, u8 pin)
  49 {
  50         int irq, bus = dev->bus->number;
  51
  52         pin--;
  53
  54         /* Nothing useful at PIIX4 pin 1 */
  55         if (bus == pci_bus0 && slot == 4 && pin == 0)
  56                 return -1;
  57
  58         /* PIIX4 USB is on Bus 0, Slot 4, Line 3 */
  59         if (bus == pci_bus0 && slot == 4 && pin == 3) {
  60                 irq = CO_IRQ(CO_APIC_PIIX4_USB);
  61                 goto out;
  62         }
  63
  64         /* First pin spread down 1 APIC entry per slot */
  65         if (pin == 0) {
  66                 irq = CO_IRQ((bus == pci_bus0 ? CO_APIC_PCIB_BASE0 :
  67                                                 CO_APIC_PCIA_BASE0) + slot);
  68                 goto out;
  69         }
  70
  71         /* lines 1,2,3 from any slot is shared in this twirly pattern */
  72         if (bus == pci_bus1) {
  73                 /* lines 1-3 from devices 0 1 rotate over 2 apic entries */
  74                 irq = CO_IRQ(CO_APIC_PCIA_BASE123 + ((slot + (pin - 1)) % 2));
  75         } else { /* bus == pci_bus0 */
  76                 /* lines 1-3 from devices 0-3 rotate over 3 apic entries */
  77                 if (slot == 0)
  78                         slot = 3; /* same pattern */
  79                 irq = CO_IRQ(CO_APIC_PCIA_BASE123 + ((3 - slot) + (pin - 1) % 3));
  80         }
  81 out:
  82         printk(KERN_DEBUG "PCI: Bus %d Slot %d Line %d -> IRQ %d\n", bus, slot, pin, irq);
  83         return irq;
  84 }
  85
  86 void __init pcibios_update_irq(struct pci_dev *dev, int irq)
  87 {
  88         pci_write_config_byte(dev, PCI_INTERRUPT_LINE, irq);
  89 }
  90
  91 static int __init pcibios_init(void)
  92 {
  93         /* The VISWS supports configuration access type 1 only */
  94         pci_probe = (pci_probe | PCI_PROBE_CONF1) &
  95                     ~(PCI_PROBE_BIOS | PCI_PROBE_CONF2);
  96
  97         pci_bus0 = li_pcib_read16(LI_PCI_BUSNUM) & 0xff;
  98         pci_bus1 = li_pcia_read16(LI_PCI_BUSNUM) & 0xff;
  99
 100         printk(KERN_INFO "PCI: Lithium bridge A bus: %u, "
 101                 "bridge B (PIIX4) bus: %u\n", pci_bus1, pci_bus0);
 102
 103         raw_pci_ops = &pci_direct_conf1;
 104         pci_scan_bus(pci_bus0, &pci_root_ops, NULL);
 105         pci_scan_bus(pci_bus1, &pci_root_ops, NULL);
 106         pci_fixup_irqs(visws_swizzle, visws_map_irq);
 107         pcibios_resource_survey();
 108         return 0;
 109 }
 110
 111 subsys_initcall(pcibios_init);