1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Generic SH7786 PCI-Express operations.
4 *
5 * Copyright (C) 2009 - 2010 Paul Mundt
6 */
7 #include <linux/kernel.h>
8 #include <linux/init.h>
9 #include <linux/pci.h>
10 #include <linux/io.h>
11 #include <linux/spinlock.h>
12 #include "pcie-sh7786.h"
13
14 enum {
15 PCI_ACCESS_READ,
16 PCI_ACCESS_WRITE,
17 };
18
sh7786_pcie_config_access(unsigned char access_type,struct pci_bus * bus,unsigned int devfn,int where,u32 * data)19 static int sh7786_pcie_config_access(unsigned char access_type,
20 struct pci_bus *bus, unsigned int devfn, int where, u32 *data)
21 {
22 struct pci_channel *chan = bus->sysdata;
23 int dev, func, type, reg;
24
25 dev = PCI_SLOT(devfn);
26 func = PCI_FUNC(devfn);
27 type = !!bus->parent;
28 reg = where & ~3;
29
30 if (bus->number > 255 || dev > 31 || func > 7)
31 return PCIBIOS_FUNC_NOT_SUPPORTED;
32
33 /*
34 * While each channel has its own memory-mapped extended config
35 * space, it's generally only accessible when in endpoint mode.
36 * When in root complex mode, the controller is unable to target
37 * itself with either type 0 or type 1 accesses, and indeed, any
38 * controller initiated target transfer to its own config space
39 * result in a completer abort.
40 *
41 * Each channel effectively only supports a single device, but as
42 * the same channel <-> device access works for any PCI_SLOT()
43 * value, we cheat a bit here and bind the controller's config
44 * space to devfn 0 in order to enable self-enumeration. In this
45 * case the regular PAR/PDR path is sidelined and the mangled
46 * config access itself is initiated as a SuperHyway transaction.
47 */
48 if (pci_is_root_bus(bus)) {
49 if (dev == 0) {
50 if (access_type == PCI_ACCESS_READ)
51 *data = pci_read_reg(chan, PCI_REG(reg));
52 else
53 pci_write_reg(chan, *data, PCI_REG(reg));
54
55 return PCIBIOS_SUCCESSFUL;
56 } else if (dev > 1)
57 return PCIBIOS_DEVICE_NOT_FOUND;
58 }
59
60 /* Clear errors */
61 pci_write_reg(chan, pci_read_reg(chan, SH4A_PCIEERRFR), SH4A_PCIEERRFR);
62
63 /* Set the PIO address */
64 pci_write_reg(chan, (bus->number << 24) | (dev << 19) |
65 (func << 16) | reg, SH4A_PCIEPAR);
66
67 /* Enable the configuration access */
68 pci_write_reg(chan, (1 << 31) | (type << 8), SH4A_PCIEPCTLR);
69
70 /* Check for errors */
71 if (pci_read_reg(chan, SH4A_PCIEERRFR) & 0x10)
72 return PCIBIOS_DEVICE_NOT_FOUND;
73
74 /* Check for master and target aborts */
75 if (pci_read_reg(chan, SH4A_PCIEPCICONF1) & ((1 << 29) | (1 << 28)))
76 return PCIBIOS_DEVICE_NOT_FOUND;
77
78 if (access_type == PCI_ACCESS_READ)
79 *data = pci_read_reg(chan, SH4A_PCIEPDR);
80 else
81 pci_write_reg(chan, *data, SH4A_PCIEPDR);
82
83 /* Disable the configuration access */
84 pci_write_reg(chan, 0, SH4A_PCIEPCTLR);
85
86 return PCIBIOS_SUCCESSFUL;
87 }
88
sh7786_pcie_read(struct pci_bus * bus,unsigned int devfn,int where,int size,u32 * val)89 static int sh7786_pcie_read(struct pci_bus *bus, unsigned int devfn,
90 int where, int size, u32 *val)
91 {
92 unsigned long flags;
93 int ret;
94 u32 data;
95
96 if ((size == 2) && (where & 1))
97 return PCIBIOS_BAD_REGISTER_NUMBER;
98 else if ((size == 4) && (where & 3))
99 return PCIBIOS_BAD_REGISTER_NUMBER;
100
101 raw_spin_lock_irqsave(&pci_config_lock, flags);
102 ret = sh7786_pcie_config_access(PCI_ACCESS_READ, bus,
103 devfn, where, &data);
104 if (ret != PCIBIOS_SUCCESSFUL) {
105 *val = 0xffffffff;
106 goto out;
107 }
108
109 if (size == 1)
110 *val = (data >> ((where & 3) << 3)) & 0xff;
111 else if (size == 2)
112 *val = (data >> ((where & 2) << 3)) & 0xffff;
113 else
114 *val = data;
115
116 dev_dbg(&bus->dev, "pcie-config-read: bus=%3d devfn=0x%04x "
117 "where=0x%04x size=%d val=0x%08lx\n", bus->number,
118 devfn, where, size, (unsigned long)*val);
119
120 out:
121 raw_spin_unlock_irqrestore(&pci_config_lock, flags);
122 return ret;
123 }
124
sh7786_pcie_write(struct pci_bus * bus,unsigned int devfn,int where,int size,u32 val)125 static int sh7786_pcie_write(struct pci_bus *bus, unsigned int devfn,
126 int where, int size, u32 val)
127 {
128 unsigned long flags;
129 int shift, ret;
130 u32 data;
131
132 if ((size == 2) && (where & 1))
133 return PCIBIOS_BAD_REGISTER_NUMBER;
134 else if ((size == 4) && (where & 3))
135 return PCIBIOS_BAD_REGISTER_NUMBER;
136
137 raw_spin_lock_irqsave(&pci_config_lock, flags);
138 ret = sh7786_pcie_config_access(PCI_ACCESS_READ, bus,
139 devfn, where, &data);
140 if (ret != PCIBIOS_SUCCESSFUL)
141 goto out;
142
143 dev_dbg(&bus->dev, "pcie-config-write: bus=%3d devfn=0x%04x "
144 "where=0x%04x size=%d val=%08lx\n", bus->number,
145 devfn, where, size, (unsigned long)val);
146
147 if (size == 1) {
148 shift = (where & 3) << 3;
149 data &= ~(0xff << shift);
150 data |= ((val & 0xff) << shift);
151 } else if (size == 2) {
152 shift = (where & 2) << 3;
153 data &= ~(0xffff << shift);
154 data |= ((val & 0xffff) << shift);
155 } else
156 data = val;
157
158 ret = sh7786_pcie_config_access(PCI_ACCESS_WRITE, bus,
159 devfn, where, &data);
160 out:
161 raw_spin_unlock_irqrestore(&pci_config_lock, flags);
162 return ret;
163 }
164
165 struct pci_ops sh7786_pci_ops = {
166 .read = sh7786_pcie_read,
167 .write = sh7786_pcie_write,
168 };
169