1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (C) 2001,2002,2005 Broadcom Corporation
4 * Copyright (C) 2004 by Ralf Baechle (ralf@linux-mips.org)
5 */
6
7 /*
8 * BCM1480/1455-specific HT support (looking like PCI)
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 */
21 #include <linux/types.h>
22 #include <linux/pci.h>
23 #include <linux/kernel.h>
24 #include <linux/init.h>
25 #include <linux/mm.h>
26 #include <linux/console.h>
27 #include <linux/tty.h>
28
29 #include <asm/sibyte/bcm1480_regs.h>
30 #include <asm/sibyte/bcm1480_scd.h>
31 #include <asm/sibyte/board.h>
32 #include <asm/io.h>
33
34 /*
35 * Macros for calculating offsets into config space given a device
36 * structure or dev/fun/reg
37 */
38 #define CFGOFFSET(bus, devfn, where) (((bus)<<16)+((devfn)<<8)+(where))
39 #define CFGADDR(bus, devfn, where) CFGOFFSET((bus)->number, (devfn), where)
40
41 static void *ht_cfg_space;
42
43 #define PCI_BUS_ENABLED 1
44 #define PCI_DEVICE_MODE 2
45
46 static int bcm1480ht_bus_status;
47
48 #define PCI_BRIDGE_DEVICE 0
49 #define HT_BRIDGE_DEVICE 1
50
51 /*
52 * HT's level-sensitive interrupts require EOI, which is generated
53 * through a 4MB memory-mapped region
54 */
55 unsigned long ht_eoi_space;
56
57 /*
58 * Read/write 32-bit values in config space.
59 */
READCFG32(u32 addr)60 static inline u32 READCFG32(u32 addr)
61 {
62 return *(u32 *)(ht_cfg_space + (addr&~3));
63 }
64
WRITECFG32(u32 addr,u32 data)65 static inline void WRITECFG32(u32 addr, u32 data)
66 {
67 *(u32 *)(ht_cfg_space + (addr & ~3)) = data;
68 }
69
70 /*
71 * Some checks before doing config cycles:
72 * In PCI Device Mode, hide everything on bus 0 except the LDT host
73 * bridge. Otherwise, access is controlled by bridge MasterEn bits.
74 */
bcm1480ht_can_access(struct pci_bus * bus,int devfn)75 static int bcm1480ht_can_access(struct pci_bus *bus, int devfn)
76 {
77 u32 devno;
78
79 if (!(bcm1480ht_bus_status & (PCI_BUS_ENABLED | PCI_DEVICE_MODE)))
80 return 0;
81
82 if (bus->number == 0) {
83 devno = PCI_SLOT(devfn);
84 if (bcm1480ht_bus_status & PCI_DEVICE_MODE)
85 return 0;
86 }
87 return 1;
88 }
89
90 /*
91 * Read/write access functions for various sizes of values
92 * in config space. Return all 1's for disallowed accesses
93 * for a kludgy but adequate simulation of master aborts.
94 */
95
bcm1480ht_pcibios_read(struct pci_bus * bus,unsigned int devfn,int where,int size,u32 * val)96 static int bcm1480ht_pcibios_read(struct pci_bus *bus, unsigned int devfn,
97 int where, int size, u32 * val)
98 {
99 u32 data = 0;
100
101 if ((size == 2) && (where & 1))
102 return PCIBIOS_BAD_REGISTER_NUMBER;
103 else if ((size == 4) && (where & 3))
104 return PCIBIOS_BAD_REGISTER_NUMBER;
105
106 if (bcm1480ht_can_access(bus, devfn))
107 data = READCFG32(CFGADDR(bus, devfn, where));
108 else
109 data = 0xFFFFFFFF;
110
111 if (size == 1)
112 *val = (data >> ((where & 3) << 3)) & 0xff;
113 else if (size == 2)
114 *val = (data >> ((where & 3) << 3)) & 0xffff;
115 else
116 *val = data;
117
118 return PCIBIOS_SUCCESSFUL;
119 }
120
bcm1480ht_pcibios_write(struct pci_bus * bus,unsigned int devfn,int where,int size,u32 val)121 static int bcm1480ht_pcibios_write(struct pci_bus *bus, unsigned int devfn,
122 int where, int size, u32 val)
123 {
124 u32 cfgaddr = CFGADDR(bus, devfn, where);
125 u32 data = 0;
126
127 if ((size == 2) && (where & 1))
128 return PCIBIOS_BAD_REGISTER_NUMBER;
129 else if ((size == 4) && (where & 3))
130 return PCIBIOS_BAD_REGISTER_NUMBER;
131
132 if (!bcm1480ht_can_access(bus, devfn))
133 return PCIBIOS_BAD_REGISTER_NUMBER;
134
135 data = READCFG32(cfgaddr);
136
137 if (size == 1)
138 data = (data & ~(0xff << ((where & 3) << 3))) |
139 (val << ((where & 3) << 3));
140 else if (size == 2)
141 data = (data & ~(0xffff << ((where & 3) << 3))) |
142 (val << ((where & 3) << 3));
143 else
144 data = val;
145
146 WRITECFG32(cfgaddr, data);
147
148 return PCIBIOS_SUCCESSFUL;
149 }
150
bcm1480ht_pcibios_get_busno(void)151 static int bcm1480ht_pcibios_get_busno(void)
152 {
153 return 0;
154 }
155
156 struct pci_ops bcm1480ht_pci_ops = {
157 .read = bcm1480ht_pcibios_read,
158 .write = bcm1480ht_pcibios_write,
159 };
160
161 static struct resource bcm1480ht_mem_resource = {
162 .name = "BCM1480 HT MEM",
163 .start = A_BCM1480_PHYS_HT_MEM_MATCH_BYTES,
164 .end = A_BCM1480_PHYS_HT_MEM_MATCH_BYTES + 0x1fffffffUL,
165 .flags = IORESOURCE_MEM,
166 };
167
168 static struct resource bcm1480ht_io_resource = {
169 .name = "BCM1480 HT I/O",
170 .start = A_BCM1480_PHYS_HT_IO_MATCH_BYTES,
171 .end = A_BCM1480_PHYS_HT_IO_MATCH_BYTES + 0x01ffffffUL,
172 .flags = IORESOURCE_IO,
173 };
174
175 struct pci_controller bcm1480ht_controller = {
176 .pci_ops = &bcm1480ht_pci_ops,
177 .mem_resource = &bcm1480ht_mem_resource,
178 .io_resource = &bcm1480ht_io_resource,
179 .index = 1,
180 .get_busno = bcm1480ht_pcibios_get_busno,
181 .io_offset = A_BCM1480_PHYS_HT_IO_MATCH_BYTES,
182 };
183
bcm1480ht_pcibios_init(void)184 static int __init bcm1480ht_pcibios_init(void)
185 {
186 ht_cfg_space = ioremap(A_BCM1480_PHYS_HT_CFG_MATCH_BITS, 16*1024*1024);
187
188 /* CFE doesn't always init all HT paths, so we always scan */
189 bcm1480ht_bus_status |= PCI_BUS_ENABLED;
190
191 ht_eoi_space = (unsigned long)
192 ioremap(A_BCM1480_PHYS_HT_SPECIAL_MATCH_BYTES,
193 4 * 1024 * 1024);
194 bcm1480ht_controller.io_map_base = (unsigned long)
195 ioremap(A_BCM1480_PHYS_HT_IO_MATCH_BYTES, 65536);
196 bcm1480ht_controller.io_map_base -= bcm1480ht_controller.io_offset;
197
198 register_pci_controller(&bcm1480ht_controller);
199
200 return 0;
201 }
202
203 arch_initcall(bcm1480ht_pcibios_init);
204