1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 1999, 2000, 2004 MIPS Technologies, Inc.
4 * All rights reserved.
5 * Authors: Carsten Langgaard <carstenl@mips.com>
6 * Maciej W. Rozycki <macro@mips.com>
7 */
8 #include <linux/types.h>
9 #include <linux/pci.h>
10 #include <linux/kernel.h>
11
12 #include <asm/gt64120.h>
13
14 #define PCI_ACCESS_READ 0
15 #define PCI_ACCESS_WRITE 1
16
17 /*
18 * PCI configuration cycle AD bus definition
19 */
20 /* Type 0 */
21 #define PCI_CFG_TYPE0_REG_SHF 0
22 #define PCI_CFG_TYPE0_FUNC_SHF 8
23
24 /* Type 1 */
25 #define PCI_CFG_TYPE1_REG_SHF 0
26 #define PCI_CFG_TYPE1_FUNC_SHF 8
27 #define PCI_CFG_TYPE1_DEV_SHF 11
28 #define PCI_CFG_TYPE1_BUS_SHF 16
29
30 static int gt64xxx_pci0_pcibios_config_access(unsigned char access_type,
31 struct pci_bus *bus, unsigned int devfn, int where, u32 * data)
32 {
33 unsigned char busnum = bus->number;
34 u32 intr;
35
36 if ((busnum == 0) && (devfn >= PCI_DEVFN(31, 0)))
37 return -1; /* Because of a bug in the galileo (for slot 31). */
38
39 /* Clear cause register bits */
40 GT_WRITE(GT_INTRCAUSE_OFS, ~(GT_INTRCAUSE_MASABORT0_BIT |
41 GT_INTRCAUSE_TARABORT0_BIT));
42
43 /* Setup address */
44 GT_WRITE(GT_PCI0_CFGADDR_OFS,
45 (busnum << GT_PCI0_CFGADDR_BUSNUM_SHF) |
46 (devfn << GT_PCI0_CFGADDR_FUNCTNUM_SHF) |
47 ((where / 4) << GT_PCI0_CFGADDR_REGNUM_SHF) |
48 GT_PCI0_CFGADDR_CONFIGEN_BIT);
49
50 if (access_type == PCI_ACCESS_WRITE) {
51 if (busnum == 0 && PCI_SLOT(devfn) == 0) {
52 /*
53 * The Galileo system controller is acting
54 * differently than other devices.
55 */
56 GT_WRITE(GT_PCI0_CFGDATA_OFS, *data);
57 } else
58 __GT_WRITE(GT_PCI0_CFGDATA_OFS, *data);
59 } else {
60 if (busnum == 0 && PCI_SLOT(devfn) == 0) {
61 /*
62 * The Galileo system controller is acting
63 * differently than other devices.
64 */
65 *data = GT_READ(GT_PCI0_CFGDATA_OFS);
66 } else
67 *data = __GT_READ(GT_PCI0_CFGDATA_OFS);
68 }
69
70 /* Check for master or target abort */
71 intr = GT_READ(GT_INTRCAUSE_OFS);
72
73 if (intr & (GT_INTRCAUSE_MASABORT0_BIT | GT_INTRCAUSE_TARABORT0_BIT)) {
74 /* Error occurred */
75
76 /* Clear bits */
77 GT_WRITE(GT_INTRCAUSE_OFS, ~(GT_INTRCAUSE_MASABORT0_BIT |
78 GT_INTRCAUSE_TARABORT0_BIT));
79
80 return -1;
81 }
82
83 return 0;
84 }
85
86
87 /*
88 * We can't address 8 and 16 bit words directly. Instead we have to
89 * read/write a 32bit word and mask/modify the data we actually want.
90 */
91 static int gt64xxx_pci0_pcibios_read(struct pci_bus *bus, unsigned int devfn,
92 int where, int size, u32 * val)
93 {
94 u32 data = 0;
95
96 if (gt64xxx_pci0_pcibios_config_access(PCI_ACCESS_READ, bus, devfn,
97 where, &data))
98 return PCIBIOS_DEVICE_NOT_FOUND;
99
100 if (size == 1)
101 *val = (data >> ((where & 3) << 3)) & 0xff;
102 else if (size == 2)
103 *val = (data >> ((where & 3) << 3)) & 0xffff;
104 else
105 *val = data;
106
107 return PCIBIOS_SUCCESSFUL;
108 }
109
110 static int gt64xxx_pci0_pcibios_write(struct pci_bus *bus, unsigned int devfn,
111 int where, int size, u32 val)
112 {
113 u32 data = 0;
114
115 if (size == 4)
116 data = val;
117 else {
118 if (gt64xxx_pci0_pcibios_config_access(PCI_ACCESS_READ, bus,
119 devfn, where, &data))
120 return PCIBIOS_DEVICE_NOT_FOUND;
121
122 if (size == 1)
123 data = (data & ~(0xff << ((where & 3) << 3))) |
124 (val << ((where & 3) << 3));
125 else if (size == 2)
126 data = (data & ~(0xffff << ((where & 3) << 3))) |
127 (val << ((where & 3) << 3));
128 }
129
130 if (gt64xxx_pci0_pcibios_config_access(PCI_ACCESS_WRITE, bus, devfn,
131 where, &data))
132 return PCIBIOS_DEVICE_NOT_FOUND;
133
134 return PCIBIOS_SUCCESSFUL;
135 }
136
137 struct pci_ops gt64xxx_pci0_ops = {
138 .read = gt64xxx_pci0_pcibios_read,
139 .write = gt64xxx_pci0_pcibios_write
140 };
141
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