1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 1999, 2000, 2004, 2005 MIPS Technologies, Inc.
4 * All rights reserved.
5 * Authors: Carsten Langgaard <carstenl@mips.com>
6 * Maciej W. Rozycki <macro@mips.com>
7 * Copyright (C) 2005 Ralf Baechle (ralf@linux-mips.org)
8 *
9 * MIPS boards specific PCI support.
10 */
11 #include <linux/types.h>
12 #include <linux/pci.h>
13 #include <linux/kernel.h>
14
15 #include <asm/mips-boards/msc01_pci.h>
16
17 #define PCI_ACCESS_READ 0
18 #define PCI_ACCESS_WRITE 1
19
20 /*
21 * PCI configuration cycle AD bus definition
22 */
23 /* Type 0 */
24 #define PCI_CFG_TYPE0_REG_SHF 0
25 #define PCI_CFG_TYPE0_FUNC_SHF 8
26
27 /* Type 1 */
28 #define PCI_CFG_TYPE1_REG_SHF 0
29 #define PCI_CFG_TYPE1_FUNC_SHF 8
30 #define PCI_CFG_TYPE1_DEV_SHF 11
31 #define PCI_CFG_TYPE1_BUS_SHF 16
32
msc_pcibios_config_access(unsigned char access_type,struct pci_bus * bus,unsigned int devfn,int where,u32 * data)33 static int msc_pcibios_config_access(unsigned char access_type,
34 struct pci_bus *bus, unsigned int devfn, int where, u32 * data)
35 {
36 unsigned char busnum = bus->number;
37 u32 intr;
38
39 /* Clear status register bits. */
40 MSC_WRITE(MSC01_PCI_INTSTAT,
41 (MSC01_PCI_INTCFG_MA_BIT | MSC01_PCI_INTCFG_TA_BIT));
42
43 MSC_WRITE(MSC01_PCI_CFGADDR,
44 ((busnum << MSC01_PCI_CFGADDR_BNUM_SHF) |
45 (PCI_SLOT(devfn) << MSC01_PCI_CFGADDR_DNUM_SHF) |
46 (PCI_FUNC(devfn) << MSC01_PCI_CFGADDR_FNUM_SHF) |
47 ((where / 4) << MSC01_PCI_CFGADDR_RNUM_SHF)));
48
49 /* Perform access */
50 if (access_type == PCI_ACCESS_WRITE)
51 MSC_WRITE(MSC01_PCI_CFGDATA, *data);
52 else
53 MSC_READ(MSC01_PCI_CFGDATA, *data);
54
55 /* Detect Master/Target abort */
56 MSC_READ(MSC01_PCI_INTSTAT, intr);
57 if (intr & (MSC01_PCI_INTCFG_MA_BIT | MSC01_PCI_INTCFG_TA_BIT)) {
58 /* Error occurred */
59
60 /* Clear bits */
61 MSC_WRITE(MSC01_PCI_INTSTAT,
62 (MSC01_PCI_INTCFG_MA_BIT | MSC01_PCI_INTCFG_TA_BIT));
63
64 return -1;
65 }
66
67 return 0;
68 }
69
70
71 /*
72 * We can't address 8 and 16 bit words directly. Instead we have to
73 * read/write a 32bit word and mask/modify the data we actually want.
74 */
msc_pcibios_read(struct pci_bus * bus,unsigned int devfn,int where,int size,u32 * val)75 static int msc_pcibios_read(struct pci_bus *bus, unsigned int devfn,
76 int where, int size, u32 * val)
77 {
78 u32 data = 0;
79
80 if ((size == 2) && (where & 1))
81 return PCIBIOS_BAD_REGISTER_NUMBER;
82 else if ((size == 4) && (where & 3))
83 return PCIBIOS_BAD_REGISTER_NUMBER;
84
85 if (msc_pcibios_config_access(PCI_ACCESS_READ, bus, devfn, where,
86 &data))
87 return -1;
88
89 if (size == 1)
90 *val = (data >> ((where & 3) << 3)) & 0xff;
91 else if (size == 2)
92 *val = (data >> ((where & 3) << 3)) & 0xffff;
93 else
94 *val = data;
95
96 return PCIBIOS_SUCCESSFUL;
97 }
98
msc_pcibios_write(struct pci_bus * bus,unsigned int devfn,int where,int size,u32 val)99 static int msc_pcibios_write(struct pci_bus *bus, unsigned int devfn,
100 int where, int size, u32 val)
101 {
102 u32 data = 0;
103
104 if ((size == 2) && (where & 1))
105 return PCIBIOS_BAD_REGISTER_NUMBER;
106 else if ((size == 4) && (where & 3))
107 return PCIBIOS_BAD_REGISTER_NUMBER;
108
109 if (size == 4)
110 data = val;
111 else {
112 if (msc_pcibios_config_access(PCI_ACCESS_READ, bus, devfn,
113 where, &data))
114 return -1;
115
116 if (size == 1)
117 data = (data & ~(0xff << ((where & 3) << 3))) |
118 (val << ((where & 3) << 3));
119 else if (size == 2)
120 data = (data & ~(0xffff << ((where & 3) << 3))) |
121 (val << ((where & 3) << 3));
122 }
123
124 if (msc_pcibios_config_access(PCI_ACCESS_WRITE, bus, devfn, where,
125 &data))
126 return -1;
127
128 return PCIBIOS_SUCCESSFUL;
129 }
130
131 struct pci_ops msc_pci_ops = {
132 .read = msc_pcibios_read,
133 .write = msc_pcibios_write
134 };
135