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  */
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  */
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 
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