1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (C) 2001 Dave Engebretsen, IBM Corporation
4 * Copyright (C) 2003 Anton Blanchard <anton@au.ibm.com>, IBM
5 *
6 * RTAS specific routines for PCI.
7 *
8 * Based on code from pci.c, chrp_pci.c and pSeries_pci.c
9 */
10
11#include <linux/kernel.h>
12#include <linux/threads.h>
13#include <linux/pci.h>
14#include <linux/string.h>
15#include <linux/init.h>
16#include <linux/pgtable.h>
17#include <linux/of_address.h>
18#include <linux/of_fdt.h>
19
20#include <asm/io.h>
21#include <asm/irq.h>
22#include <asm/machdep.h>
23#include <asm/pci-bridge.h>
24#include <asm/iommu.h>
25#include <asm/rtas.h>
26#include <asm/mpic.h>
27#include <asm/ppc-pci.h>
28#include <asm/eeh.h>
29
30/* RTAS tokens */
31static int read_pci_config;
32static int write_pci_config;
33static int ibm_read_pci_config;
34static int ibm_write_pci_config;
35
36static inline int config_access_valid(struct pci_dn *dn, int where)
37{
38 if (where < 256)
39 return 1;
40 if (where < 4096 && dn->pci_ext_config_space)
41 return 1;
42
43 return 0;
44}
45
46int rtas_pci_dn_read_config(struct pci_dn *pdn, int where, int size, u32 *val)
47{
48 int returnval = -1;
49 unsigned long buid, addr;
50 int ret;
51
52 if (!pdn)
53 return PCIBIOS_DEVICE_NOT_FOUND;
54 if (!config_access_valid(dn: pdn, where))
55 return PCIBIOS_BAD_REGISTER_NUMBER;
56#ifdef CONFIG_EEH
57 if (pdn->edev && pdn->edev->pe &&
58 (pdn->edev->pe->state & EEH_PE_CFG_BLOCKED))
59 return PCIBIOS_SET_FAILED;
60#endif
61
62 addr = rtas_config_addr(pdn->busno, pdn->devfn, where);
63 buid = pdn->phb->buid;
64 if (buid) {
65 ret = rtas_call(ibm_read_pci_config, 4, 2, &returnval,
66 addr, BUID_HI(buid), BUID_LO(buid), size);
67 } else {
68 ret = rtas_call(read_pci_config, 2, 2, &returnval, addr, size);
69 }
70 *val = returnval;
71
72 if (ret)
73 return PCIBIOS_DEVICE_NOT_FOUND;
74
75 return PCIBIOS_SUCCESSFUL;
76}
77
78static int rtas_pci_read_config(struct pci_bus *bus,
79 unsigned int devfn,
80 int where, int size, u32 *val)
81{
82 struct pci_dn *pdn;
83 int ret;
84
85 *val = 0xFFFFFFFF;
86
87 pdn = pci_get_pdn_by_devfn(bus, devfn);
88
89 /* Validity of pdn is checked in here */
90 ret = rtas_pci_dn_read_config(pdn, where, size, val);
91 if (*val == EEH_IO_ERROR_VALUE(size) &&
92 eeh_dev_check_failure(pdn_to_eeh_dev(pdn)))
93 return PCIBIOS_DEVICE_NOT_FOUND;
94
95 return ret;
96}
97
98int rtas_pci_dn_write_config(struct pci_dn *pdn, int where, int size, u32 val)
99{
100 unsigned long buid, addr;
101 int ret;
102
103 if (!pdn)
104 return PCIBIOS_DEVICE_NOT_FOUND;
105 if (!config_access_valid(dn: pdn, where))
106 return PCIBIOS_BAD_REGISTER_NUMBER;
107#ifdef CONFIG_EEH
108 if (pdn->edev && pdn->edev->pe &&
109 (pdn->edev->pe->state & EEH_PE_CFG_BLOCKED))
110 return PCIBIOS_SET_FAILED;
111#endif
112
113 addr = rtas_config_addr(pdn->busno, pdn->devfn, where);
114 buid = pdn->phb->buid;
115 if (buid) {
116 ret = rtas_call(ibm_write_pci_config, 5, 1, NULL, addr,
117 BUID_HI(buid), BUID_LO(buid), size, (ulong) val);
118 } else {
119 ret = rtas_call(write_pci_config, 3, 1, NULL, addr, size, (ulong)val);
120 }
121
122 if (ret)
123 return PCIBIOS_DEVICE_NOT_FOUND;
124
125 return PCIBIOS_SUCCESSFUL;
126}
127
128static int rtas_pci_write_config(struct pci_bus *bus,
129 unsigned int devfn,
130 int where, int size, u32 val)
131{
132 struct pci_dn *pdn;
133
134 pdn = pci_get_pdn_by_devfn(bus, devfn);
135
136 /* Validity of pdn is checked in here. */
137 return rtas_pci_dn_write_config(pdn, where, size, val);
138}
139
140static struct pci_ops rtas_pci_ops = {
141 .read = rtas_pci_read_config,
142 .write = rtas_pci_write_config,
143};
144
145static int is_python(struct device_node *dev)
146{
147 const char *model = of_get_property(node: dev, name: "model", NULL);
148
149 if (model && strstr(model, "Python"))
150 return 1;
151
152 return 0;
153}
154
155static void python_countermeasures(struct device_node *dev)
156{
157 struct resource registers;
158 void __iomem *chip_regs;
159 volatile u32 val;
160
161 if (of_address_to_resource(dev, index: 0, r: &registers)) {
162 printk(KERN_ERR "Can't get address for Python workarounds !\n");
163 return;
164 }
165
166 /* Python's register file is 1 MB in size. */
167 chip_regs = ioremap(offset: registers.start & ~(0xfffffUL), size: 0x100000);
168
169 /*
170 * Firmware doesn't always clear this bit which is critical
171 * for good performance - Anton
172 */
173
174#define PRG_CL_RESET_VALID 0x00010000
175
176 val = in_be32(chip_regs + 0xf6030);
177 if (val & PRG_CL_RESET_VALID) {
178 printk(KERN_INFO "Python workaround: ");
179 val &= ~PRG_CL_RESET_VALID;
180 out_be32(chip_regs + 0xf6030, val);
181 /*
182 * We must read it back for changes to
183 * take effect
184 */
185 val = in_be32(chip_regs + 0xf6030);
186 printk("reg0: %x\n", val);
187 }
188
189 iounmap(addr: chip_regs);
190}
191
192void __init init_pci_config_tokens(void)
193{
194 read_pci_config = rtas_function_token(RTAS_FN_READ_PCI_CONFIG);
195 write_pci_config = rtas_function_token(RTAS_FN_WRITE_PCI_CONFIG);
196 ibm_read_pci_config = rtas_function_token(RTAS_FN_IBM_READ_PCI_CONFIG);
197 ibm_write_pci_config = rtas_function_token(RTAS_FN_IBM_WRITE_PCI_CONFIG);
198}
199
200unsigned long get_phb_buid(struct device_node *phb)
201{
202 struct resource r;
203
204 if (ibm_read_pci_config == -1)
205 return 0;
206 if (of_address_to_resource(dev: phb, index: 0, r: &r))
207 return 0;
208 return r.start;
209}
210
211static int phb_set_bus_ranges(struct device_node *dev,
212 struct pci_controller *phb)
213{
214 const __be32 *bus_range;
215 unsigned int len;
216
217 bus_range = of_get_property(node: dev, name: "bus-range", lenp: &len);
218 if (bus_range == NULL || len < 2 * sizeof(int)) {
219 return 1;
220 }
221
222 phb->first_busno = be32_to_cpu(bus_range[0]);
223 phb->last_busno = be32_to_cpu(bus_range[1]);
224
225 return 0;
226}
227
228int rtas_setup_phb(struct pci_controller *phb)
229{
230 struct device_node *dev = phb->dn;
231
232 if (is_python(dev))
233 python_countermeasures(dev);
234
235 if (phb_set_bus_ranges(dev, phb))
236 return 1;
237
238 phb->ops = &rtas_pci_ops;
239 phb->buid = get_phb_buid(phb: dev);
240
241 return 0;
242}
243

source code of linux/arch/powerpc/kernel/rtas_pci.c