1 // SPDX-License-Identifier: GPL-2.0
3 * Generic SH7786 PCI-Express operations.
5 * Copyright (C) 2009 - 2010 Paul Mundt
7 #include <linux/kernel.h>
8 #include <linux/init.h>
11 #include <linux/spinlock.h>
12 #include "pcie-sh7786.h"
19 static int sh7786_pcie_config_access(unsigned char access_type,
20 struct pci_bus *bus, unsigned int devfn, int where, u32 *data)
22 struct pci_channel *chan = bus->sysdata;
23 int dev, func, type, reg;
25 dev = PCI_SLOT(devfn);
26 func = PCI_FUNC(devfn);
30 if (bus->number > 255 || dev > 31 || func > 7)
31 return PCIBIOS_FUNC_NOT_SUPPORTED;
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.
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.
48 if (pci_is_root_bus(bus)) {
50 if (access_type == PCI_ACCESS_READ)
51 *data = pci_read_reg(chan, PCI_REG(reg));
53 pci_write_reg(chan, *data, PCI_REG(reg));
55 return PCIBIOS_SUCCESSFUL;
57 return PCIBIOS_DEVICE_NOT_FOUND;
61 pci_write_reg(chan, pci_read_reg(chan, SH4A_PCIEERRFR), SH4A_PCIEERRFR);
63 /* Set the PIO address */
64 pci_write_reg(chan, (bus->number << 24) | (dev << 19) |
65 (func << 16) | reg, SH4A_PCIEPAR);
67 /* Enable the configuration access */
68 pci_write_reg(chan, (1 << 31) | (type << 8), SH4A_PCIEPCTLR);
70 /* Check for errors */
71 if (pci_read_reg(chan, SH4A_PCIEERRFR) & 0x10)
72 return PCIBIOS_DEVICE_NOT_FOUND;
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;
78 if (access_type == PCI_ACCESS_READ)
79 *data = pci_read_reg(chan, SH4A_PCIEPDR);
81 pci_write_reg(chan, *data, SH4A_PCIEPDR);
83 /* Disable the configuration access */
84 pci_write_reg(chan, 0, SH4A_PCIEPCTLR);
86 return PCIBIOS_SUCCESSFUL;
89 static int sh7786_pcie_read(struct pci_bus *bus, unsigned int devfn,
90 int where, int size, u32 *val)
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;
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) {
110 *val = (data >> ((where & 3) << 3)) & 0xff;
112 *val = (data >> ((where & 2) << 3)) & 0xffff;
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);
121 raw_spin_unlock_irqrestore(&pci_config_lock, flags);
125 static int sh7786_pcie_write(struct pci_bus *bus, unsigned int devfn,
126 int where, int size, u32 val)
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;
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)
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);
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);
158 ret = sh7786_pcie_config_access(PCI_ACCESS_WRITE, bus,
159 devfn, where, &data);
161 raw_spin_unlock_irqrestore(&pci_config_lock, flags);
165 struct pci_ops sh7786_pci_ops = {
166 .read = sh7786_pcie_read,
167 .write = sh7786_pcie_write,