1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (C) 2001,2002,2003 Broadcom Corporation
4 * Copyright (C) 2004 by Ralf Baechle (ralf@linux-mips.org)
5 */
6
7/*
8 * BCM1250-specific PCI support
9 *
10 * This module provides the glue between Linux's PCI subsystem
11 * and the hardware. We basically provide glue for accessing
12 * configuration space, and set up the translation for I/O
13 * space accesses.
14 *
15 * To access configuration space, we use ioremap. In the 32-bit
16 * kernel, this consumes either 4 or 8 page table pages, and 16MB of
17 * kernel mapped memory. Hopefully neither of these should be a huge
18 * problem.
19 */
20#include <linux/types.h>
21#include <linux/pci.h>
22#include <linux/kernel.h>
23#include <linux/init.h>
24#include <linux/mm.h>
25#include <linux/console.h>
26#include <linux/tty.h>
27#include <linux/vt.h>
28
29#include <asm/io.h>
30
31#include <asm/sibyte/sb1250_defs.h>
32#include <asm/sibyte/sb1250_regs.h>
33#include <asm/sibyte/sb1250_scd.h>
34#include <asm/sibyte/board.h>
35
36/*
37 * Macros for calculating offsets into config space given a device
38 * structure or dev/fun/reg
39 */
40#define CFGOFFSET(bus, devfn, where) (((bus)<<16) + ((devfn)<<8) + (where))
41#define CFGADDR(bus, devfn, where) CFGOFFSET((bus)->number, (devfn), where)
42
43static void *cfg_space;
44
45#define PCI_BUS_ENABLED 1
46#define LDT_BUS_ENABLED 2
47#define PCI_DEVICE_MODE 4
48
49static int sb1250_bus_status;
50
51#define PCI_BRIDGE_DEVICE 0
52#define LDT_BRIDGE_DEVICE 1
53
54#ifdef CONFIG_SIBYTE_HAS_LDT
55/*
56 * HT's level-sensitive interrupts require EOI, which is generated
57 * through a 4MB memory-mapped region
58 */
59unsigned long ldt_eoi_space;
60#endif
61
62/*
63 * Read/write 32-bit values in config space.
64 */
65static inline u32 READCFG32(u32 addr)
66{
67 return *(u32 *) (cfg_space + (addr & ~3));
68}
69
70static inline void WRITECFG32(u32 addr, u32 data)
71{
72 *(u32 *) (cfg_space + (addr & ~3)) = data;
73}
74
75int pcibios_map_irq(const struct pci_dev *dev, u8 slot, u8 pin)
76{
77 return dev->irq;
78}
79
80/* Do platform specific device initialization at pci_enable_device() time */
81int pcibios_plat_dev_init(struct pci_dev *dev)
82{
83 return 0;
84}
85
86/*
87 * Some checks before doing config cycles:
88 * In PCI Device Mode, hide everything on bus 0 except the LDT host
89 * bridge. Otherwise, access is controlled by bridge MasterEn bits.
90 */
91static int sb1250_pci_can_access(struct pci_bus *bus, int devfn)
92{
93 u32 devno;
94
95 if (!(sb1250_bus_status & (PCI_BUS_ENABLED | PCI_DEVICE_MODE)))
96 return 0;
97
98 if (bus->number == 0) {
99 devno = PCI_SLOT(devfn);
100 if (devno == LDT_BRIDGE_DEVICE)
101 return (sb1250_bus_status & LDT_BUS_ENABLED) != 0;
102 else if (sb1250_bus_status & PCI_DEVICE_MODE)
103 return 0;
104 else
105 return 1;
106 } else
107 return 1;
108}
109
110/*
111 * Read/write access functions for various sizes of values
112 * in config space. Return all 1's for disallowed accesses
113 * for a kludgy but adequate simulation of master aborts.
114 */
115
116static int sb1250_pcibios_read(struct pci_bus *bus, unsigned int devfn,
117 int where, int size, u32 * val)
118{
119 u32 data = 0;
120
121 if ((size == 2) && (where & 1))
122 return PCIBIOS_BAD_REGISTER_NUMBER;
123 else if ((size == 4) && (where & 3))
124 return PCIBIOS_BAD_REGISTER_NUMBER;
125
126 if (sb1250_pci_can_access(bus, devfn))
127 data = READCFG32(CFGADDR(bus, devfn, where));
128 else
129 data = 0xFFFFFFFF;
130
131 if (size == 1)
132 *val = (data >> ((where & 3) << 3)) & 0xff;
133 else if (size == 2)
134 *val = (data >> ((where & 3) << 3)) & 0xffff;
135 else
136 *val = data;
137
138 return PCIBIOS_SUCCESSFUL;
139}
140
141static int sb1250_pcibios_write(struct pci_bus *bus, unsigned int devfn,
142 int where, int size, u32 val)
143{
144 u32 cfgaddr = CFGADDR(bus, devfn, where);
145 u32 data = 0;
146
147 if ((size == 2) && (where & 1))
148 return PCIBIOS_BAD_REGISTER_NUMBER;
149 else if ((size == 4) && (where & 3))
150 return PCIBIOS_BAD_REGISTER_NUMBER;
151
152 if (!sb1250_pci_can_access(bus, devfn))
153 return PCIBIOS_BAD_REGISTER_NUMBER;
154
155 data = READCFG32(addr: cfgaddr);
156
157 if (size == 1)
158 data = (data & ~(0xff << ((where & 3) << 3))) |
159 (val << ((where & 3) << 3));
160 else if (size == 2)
161 data = (data & ~(0xffff << ((where & 3) << 3))) |
162 (val << ((where & 3) << 3));
163 else
164 data = val;
165
166 WRITECFG32(addr: cfgaddr, data);
167
168 return PCIBIOS_SUCCESSFUL;
169}
170
171struct pci_ops sb1250_pci_ops = {
172 .read = sb1250_pcibios_read,
173 .write = sb1250_pcibios_write,
174};
175
176static struct resource sb1250_mem_resource = {
177 .name = "SB1250 PCI MEM",
178 .start = 0x40000000UL,
179 .end = 0x5fffffffUL,
180 .flags = IORESOURCE_MEM,
181};
182
183static struct resource sb1250_io_resource = {
184 .name = "SB1250 PCI I/O",
185 .start = 0x00000000UL,
186 .end = 0x01ffffffUL,
187 .flags = IORESOURCE_IO,
188};
189
190struct pci_controller sb1250_controller = {
191 .pci_ops = &sb1250_pci_ops,
192 .mem_resource = &sb1250_mem_resource,
193 .io_resource = &sb1250_io_resource,
194};
195
196static int __init sb1250_pcibios_init(void)
197{
198 void __iomem *io_map_base;
199 uint32_t cmdreg;
200 uint64_t reg;
201
202 /* CFE will assign PCI resources */
203 pci_set_flags(flags: PCI_PROBE_ONLY);
204
205 /* Avoid ISA compat ranges. */
206 PCIBIOS_MIN_IO = 0x00008000UL;
207 PCIBIOS_MIN_MEM = 0x01000000UL;
208
209 /* Set I/O resource limits. */
210 ioport_resource.end = 0x01ffffffUL; /* 32MB accessible by sb1250 */
211 iomem_resource.end = 0xffffffffUL; /* no HT support yet */
212
213 cfg_space =
214 ioremap(offset: A_PHYS_LDTPCI_CFG_MATCH_BITS, size: 16 * 1024 * 1024);
215
216 /*
217 * See if the PCI bus has been configured by the firmware.
218 */
219 reg = __raw_readq(addr: IOADDR(A_SCD_SYSTEM_CFG));
220 if (!(reg & M_SYS_PCI_HOST)) {
221 sb1250_bus_status |= PCI_DEVICE_MODE;
222 } else {
223 cmdreg =
224 READCFG32(CFGOFFSET
225 (0, PCI_DEVFN(PCI_BRIDGE_DEVICE, 0),
226 PCI_COMMAND));
227 if (!(cmdreg & PCI_COMMAND_MASTER)) {
228 printk
229 ("PCI: Skipping PCI probe. Bus is not initialized.\n");
230 iounmap(addr: cfg_space);
231 return 0;
232 }
233 sb1250_bus_status |= PCI_BUS_ENABLED;
234 }
235
236 /*
237 * Establish mappings in KSEG2 (kernel virtual) to PCI I/O
238 * space. Use "match bytes" policy to make everything look
239 * little-endian. So, you need to also set
240 * CONFIG_SWAP_IO_SPACE, but this is the combination that
241 * works correctly with most of Linux's drivers.
242 * XXX ehs: Should this happen in PCI Device mode?
243 */
244 io_map_base = ioremap(offset: A_PHYS_LDTPCI_IO_MATCH_BYTES, size: 1024 * 1024);
245 sb1250_controller.io_map_base = (unsigned long)io_map_base;
246 set_io_port_base((unsigned long)io_map_base);
247
248#ifdef CONFIG_SIBYTE_HAS_LDT
249 /*
250 * Also check the LDT bridge's enable, just in case we didn't
251 * initialize that one.
252 */
253
254 cmdreg = READCFG32(CFGOFFSET(0, PCI_DEVFN(LDT_BRIDGE_DEVICE, 0),
255 PCI_COMMAND));
256 if (cmdreg & PCI_COMMAND_MASTER) {
257 sb1250_bus_status |= LDT_BUS_ENABLED;
258
259 /*
260 * Need bits 23:16 to convey vector number. Note that
261 * this consumes 4MB of kernel-mapped memory
262 * (Kseg2/Kseg3) for 32-bit kernel.
263 */
264 ldt_eoi_space = (unsigned long)
265 ioremap(A_PHYS_LDT_SPECIAL_MATCH_BYTES,
266 4 * 1024 * 1024);
267 }
268#endif
269
270 register_pci_controller(&sb1250_controller);
271
272#ifdef CONFIG_VGA_CONSOLE
273 console_lock();
274 do_take_over_console(sw: &vga_con, first: 0, MAX_NR_CONSOLES - 1, deflt: 1);
275 console_unlock();
276#endif
277 return 0;
278}
279arch_initcall(sb1250_pcibios_init);
280

source code of linux/arch/mips/pci/pci-sb1250.c