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/sched.h>
25 #include <linux/kernel.h>
26 #include <linux/pci.h>
27 #include <linux/ptrace.h>
28 #include <linux/interrupt.h>
29 #include <linux/init.h>
30
31 #include <asm/irq.h>
32 #include <asm/system.h>
33 #include <asm/mach/pci.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 */
bridge_swizzle(int pin,unsigned int slot)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 */
integrator_swizzle(struct pci_dev * dev,u8 * pinp)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_PCIINT0, IRQ_PCIINT1, IRQ_PCIINT2, IRQ_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 */
integrator_map_irq(struct pci_dev * dev,u8 slot,u8 pin)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_setup_resources(struct resource **res);
114 extern void pci_v3_init(void *);
115
116 struct hw_pci integrator_pci __initdata = {
117 .setup_resources = pci_v3_setup_resources,
118 .init = pci_v3_init,
119 .mem_offset = 0x40000000,
120 .swizzle = integrator_swizzle,
121 .map_irq = integrator_map_irq,
122 };
123