1 /*
2 * PCI operations for the Sega Dreamcast
3 *
4 * Copyright (C) 2001, 2002 M. R. Brown
5 * Copyright (C) 2002, 2003 Paul Mundt
6 *
7 * This file is subject to the terms and conditions of the GNU General Public
8 * License. See the file "COPYING" in the main directory of this archive
9 * for more details.
10 */
11
12 #include <linux/sched.h>
13 #include <linux/kernel.h>
14 #include <linux/param.h>
15 #include <linux/interrupt.h>
16 #include <linux/init.h>
17 #include <linux/irq.h>
18 #include <linux/pci.h>
19 #include <linux/module.h>
20 #include <linux/io.h>
21 #include <mach/pci.h>
22
23 /*
24 * The !gapspci_config_access case really shouldn't happen, ever, unless
25 * someone implicitly messes around with the last devfn value.. otherwise we
26 * only support a single device anyways, and if we didn't have a BBA, we
27 * wouldn't make it terribly far through the PCI setup anyways.
28 *
29 * Also, we could very easily support both Type 0 and Type 1 configurations
30 * here, but since it doesn't seem that there is any such implementation in
31 * existence, we don't bother.
32 *
33 * I suppose if someone actually gets around to ripping the chip out of
34 * the BBA and hanging some more devices off of it, then this might be
35 * something to take into consideration. However, due to the cost of the BBA,
36 * and the general lack of activity by DC hardware hackers, this doesn't seem
37 * likely to happen anytime soon.
38 */
gapspci_config_access(unsigned char bus,unsigned int devfn)39 static int gapspci_config_access(unsigned char bus, unsigned int devfn)
40 {
41 return (bus == 0) && (devfn == 0);
42 }
43
44 /*
45 * We can also actually read and write in b/w/l sizes! Thankfully this part
46 * was at least done right, and we don't have to do the stupid masking and
47 * shifting that we do on the 7751! Small wonders never cease to amaze.
48 */
gapspci_read(struct pci_bus * bus,unsigned int devfn,int where,int size,u32 * val)49 static int gapspci_read(struct pci_bus *bus, unsigned int devfn, int where, int size, u32 *val)
50 {
51 *val = 0xffffffff;
52
53 if (!gapspci_config_access(bus->number, devfn))
54 return PCIBIOS_DEVICE_NOT_FOUND;
55
56 switch (size) {
57 case 1: *val = inb(GAPSPCI_BBA_CONFIG+where); break;
58 case 2: *val = inw(GAPSPCI_BBA_CONFIG+where); break;
59 case 4: *val = inl(GAPSPCI_BBA_CONFIG+where); break;
60 }
61
62 return PCIBIOS_SUCCESSFUL;
63 }
64
gapspci_write(struct pci_bus * bus,unsigned int devfn,int where,int size,u32 val)65 static int gapspci_write(struct pci_bus *bus, unsigned int devfn, int where, int size, u32 val)
66 {
67 if (!gapspci_config_access(bus->number, devfn))
68 return PCIBIOS_DEVICE_NOT_FOUND;
69
70 switch (size) {
71 case 1: outb(( u8)val, GAPSPCI_BBA_CONFIG+where); break;
72 case 2: outw((u16)val, GAPSPCI_BBA_CONFIG+where); break;
73 case 4: outl((u32)val, GAPSPCI_BBA_CONFIG+where); break;
74 }
75
76 return PCIBIOS_SUCCESSFUL;
77 }
78
79 struct pci_ops gapspci_pci_ops = {
80 .read = gapspci_read,
81 .write = gapspci_write,
82 };
83