1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Support PCI IO workaround
4  *
5  *  Copyright (C) 2006 Benjamin Herrenschmidt <benh@kernel.crashing.org>
6  *		       IBM, Corp.
7  *  (C) Copyright 2007-2008 TOSHIBA CORPORATION
8  */
9 #undef DEBUG
10 
11 #include <linux/kernel.h>
12 #include <linux/sched/mm.h>	/* for init_mm */
13 
14 #include <asm/io.h>
15 #include <asm/machdep.h>
16 #include <asm/pgtable.h>
17 #include <asm/ppc-pci.h>
18 #include <asm/io-workarounds.h>
19 #include <asm/pte-walk.h>
20 
21 
22 #define IOWA_MAX_BUS	8
23 
24 static struct iowa_bus iowa_busses[IOWA_MAX_BUS];
25 static unsigned int iowa_bus_count;
26 
27 static struct iowa_bus *iowa_pci_find(unsigned long vaddr, unsigned long paddr)
28 {
29 	int i, j;
30 	struct resource *res;
31 	unsigned long vstart, vend;
32 
33 	for (i = 0; i < iowa_bus_count; i++) {
34 		struct iowa_bus *bus = &iowa_busses[i];
35 		struct pci_controller *phb = bus->phb;
36 
37 		if (vaddr) {
38 			vstart = (unsigned long)phb->io_base_virt;
39 			vend = vstart + phb->pci_io_size - 1;
40 			if ((vaddr >= vstart) && (vaddr <= vend))
41 				return bus;
42 		}
43 
44 		if (paddr)
45 			for (j = 0; j < 3; j++) {
46 				res = &phb->mem_resources[j];
47 				if (paddr >= res->start && paddr <= res->end)
48 					return bus;
49 			}
50 	}
51 
52 	return NULL;
53 }
54 
55 #ifdef CONFIG_PPC_INDIRECT_MMIO
56 struct iowa_bus *iowa_mem_find_bus(const PCI_IO_ADDR addr)
57 {
58 	unsigned hugepage_shift;
59 	struct iowa_bus *bus;
60 	int token;
61 
62 	token = PCI_GET_ADDR_TOKEN(addr);
63 
64 	if (token && token <= iowa_bus_count)
65 		bus = &iowa_busses[token - 1];
66 	else {
67 		unsigned long vaddr, paddr;
68 		pte_t *ptep;
69 
70 		vaddr = (unsigned long)PCI_FIX_ADDR(addr);
71 		if (vaddr < PHB_IO_BASE || vaddr >= PHB_IO_END)
72 			return NULL;
73 		/*
74 		 * We won't find huge pages here (iomem). Also can't hit
75 		 * a page table free due to init_mm
76 		 */
77 		ptep = find_init_mm_pte(vaddr, &hugepage_shift);
78 		if (ptep == NULL)
79 			paddr = 0;
80 		else {
81 			WARN_ON(hugepage_shift);
82 			paddr = pte_pfn(*ptep) << PAGE_SHIFT;
83 		}
84 		bus = iowa_pci_find(vaddr, paddr);
85 
86 		if (bus == NULL)
87 			return NULL;
88 	}
89 
90 	return bus;
91 }
92 #else /* CONFIG_PPC_INDIRECT_MMIO */
93 struct iowa_bus *iowa_mem_find_bus(const PCI_IO_ADDR addr)
94 {
95 	return NULL;
96 }
97 #endif /* !CONFIG_PPC_INDIRECT_MMIO */
98 
99 #ifdef CONFIG_PPC_INDIRECT_PIO
100 struct iowa_bus *iowa_pio_find_bus(unsigned long port)
101 {
102 	unsigned long vaddr = (unsigned long)pci_io_base + port;
103 	return iowa_pci_find(vaddr, 0);
104 }
105 #else
106 struct iowa_bus *iowa_pio_find_bus(unsigned long port)
107 {
108 	return NULL;
109 }
110 #endif
111 
112 #define DEF_PCI_AC_RET(name, ret, at, al, space, aa)		\
113 static ret iowa_##name at					\
114 {								\
115 	struct iowa_bus *bus;					\
116 	bus = iowa_##space##_find_bus(aa);			\
117 	if (bus && bus->ops && bus->ops->name)			\
118 		return bus->ops->name al;			\
119 	return __do_##name al;					\
120 }
121 
122 #define DEF_PCI_AC_NORET(name, at, al, space, aa)		\
123 static void iowa_##name at					\
124 {								\
125 	struct iowa_bus *bus;					\
126 	bus = iowa_##space##_find_bus(aa);			\
127 	if (bus && bus->ops && bus->ops->name) {		\
128 		bus->ops->name al;				\
129 		return;						\
130 	}							\
131 	__do_##name al;						\
132 }
133 
134 #include <asm/io-defs.h>
135 
136 #undef DEF_PCI_AC_RET
137 #undef DEF_PCI_AC_NORET
138 
139 static const struct ppc_pci_io iowa_pci_io = {
140 
141 #define DEF_PCI_AC_RET(name, ret, at, al, space, aa)	.name = iowa_##name,
142 #define DEF_PCI_AC_NORET(name, at, al, space, aa)	.name = iowa_##name,
143 
144 #include <asm/io-defs.h>
145 
146 #undef DEF_PCI_AC_RET
147 #undef DEF_PCI_AC_NORET
148 
149 };
150 
151 #ifdef CONFIG_PPC_INDIRECT_MMIO
152 void __iomem *iowa_ioremap(phys_addr_t addr, unsigned long size,
153 			   pgprot_t prot, void *caller)
154 {
155 	struct iowa_bus *bus;
156 	void __iomem *res = __ioremap_caller(addr, size, prot, caller);
157 	int busno;
158 
159 	bus = iowa_pci_find(0, (unsigned long)addr);
160 	if (bus != NULL) {
161 		busno = bus - iowa_busses;
162 		PCI_SET_ADDR_TOKEN(res, busno + 1);
163 	}
164 	return res;
165 }
166 #endif /* !CONFIG_PPC_INDIRECT_MMIO */
167 
168 bool io_workaround_inited;
169 
170 /* Enable IO workaround */
171 static void io_workaround_init(void)
172 {
173 	if (io_workaround_inited)
174 		return;
175 	ppc_pci_io = iowa_pci_io;
176 	io_workaround_inited = true;
177 }
178 
179 /* Register new bus to support workaround */
180 void iowa_register_bus(struct pci_controller *phb, struct ppc_pci_io *ops,
181 		       int (*initfunc)(struct iowa_bus *, void *), void *data)
182 {
183 	struct iowa_bus *bus;
184 	struct device_node *np = phb->dn;
185 
186 	io_workaround_init();
187 
188 	if (iowa_bus_count >= IOWA_MAX_BUS) {
189 		pr_err("IOWA:Too many pci bridges, "
190 		       "workarounds disabled for %pOF\n", np);
191 		return;
192 	}
193 
194 	bus = &iowa_busses[iowa_bus_count];
195 	bus->phb = phb;
196 	bus->ops = ops;
197 	bus->private = data;
198 
199 	if (initfunc)
200 		if ((*initfunc)(bus, data))
201 			return;
202 
203 	iowa_bus_count++;
204 
205 	pr_debug("IOWA:[%d]Add bus, %pOF.\n", iowa_bus_count-1, np);
206 }
207 
208