1 /*
2  * Support PCI IO workaround
3  *
4  *  Copyright (C) 2006 Benjamin Herrenschmidt <benh@kernel.crashing.org>
5  *		       IBM, Corp.
6  *  (C) Copyright 2007-2008 TOSHIBA CORPORATION
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License version 2 as
10  * published by the Free Software Foundation.
11  */
12 #undef DEBUG
13 
14 #include <linux/kernel.h>
15 #include <linux/sched.h>	/* for init_mm */
16 
17 #include <asm/io.h>
18 #include <asm/machdep.h>
19 #include <asm/pgtable.h>
20 #include <asm/ppc-pci.h>
21 #include <asm/io-workarounds.h>
22 
23 #define IOWA_MAX_BUS	8
24 
25 static struct iowa_bus iowa_busses[IOWA_MAX_BUS];
26 static unsigned int iowa_bus_count;
27 
28 static struct iowa_bus *iowa_pci_find(unsigned long vaddr, unsigned long paddr)
29 {
30 	int i, j;
31 	struct resource *res;
32 	unsigned long vstart, vend;
33 
34 	for (i = 0; i < iowa_bus_count; i++) {
35 		struct iowa_bus *bus = &iowa_busses[i];
36 		struct pci_controller *phb = bus->phb;
37 
38 		if (vaddr) {
39 			vstart = (unsigned long)phb->io_base_virt;
40 			vend = vstart + phb->pci_io_size - 1;
41 			if ((vaddr >= vstart) && (vaddr <= vend))
42 				return bus;
43 		}
44 
45 		if (paddr)
46 			for (j = 0; j < 3; j++) {
47 				res = &phb->mem_resources[j];
48 				if (paddr >= res->start && paddr <= res->end)
49 					return bus;
50 			}
51 	}
52 
53 	return NULL;
54 }
55 
56 #ifdef CONFIG_PPC_INDIRECT_MMIO
57 struct iowa_bus *iowa_mem_find_bus(const PCI_IO_ADDR addr)
58 {
59 	unsigned hugepage_shift;
60 	struct iowa_bus *bus;
61 	int token;
62 
63 	token = PCI_GET_ADDR_TOKEN(addr);
64 
65 	if (token && token <= iowa_bus_count)
66 		bus = &iowa_busses[token - 1];
67 	else {
68 		unsigned long vaddr, paddr;
69 		pte_t *ptep;
70 
71 		vaddr = (unsigned long)PCI_FIX_ADDR(addr);
72 		if (vaddr < PHB_IO_BASE || vaddr >= PHB_IO_END)
73 			return NULL;
74 
75 		ptep = find_linux_pte_or_hugepte(init_mm.pgd, vaddr,
76 						 &hugepage_shift);
77 		if (ptep == NULL)
78 			paddr = 0;
79 		else {
80 			/*
81 			 * we don't have hugepages backing iomem
82 			 */
83 			WARN_ON(hugepage_shift);
84 			paddr = pte_pfn(*ptep) << PAGE_SHIFT;
85 		}
86 		bus = iowa_pci_find(vaddr, paddr);
87 
88 		if (bus == NULL)
89 			return NULL;
90 	}
91 
92 	return bus;
93 }
94 #else /* CONFIG_PPC_INDIRECT_MMIO */
95 struct iowa_bus *iowa_mem_find_bus(const PCI_IO_ADDR addr)
96 {
97 	return NULL;
98 }
99 #endif /* !CONFIG_PPC_INDIRECT_MMIO */
100 
101 #ifdef CONFIG_PPC_INDIRECT_PIO
102 struct iowa_bus *iowa_pio_find_bus(unsigned long port)
103 {
104 	unsigned long vaddr = (unsigned long)pci_io_base + port;
105 	return iowa_pci_find(vaddr, 0);
106 }
107 #else
108 struct iowa_bus *iowa_pio_find_bus(unsigned long port)
109 {
110 	return NULL;
111 }
112 #endif
113 
114 #define DEF_PCI_AC_RET(name, ret, at, al, space, aa)		\
115 static ret iowa_##name at					\
116 {								\
117 	struct iowa_bus *bus;					\
118 	bus = iowa_##space##_find_bus(aa);			\
119 	if (bus && bus->ops && bus->ops->name)			\
120 		return bus->ops->name al;			\
121 	return __do_##name al;					\
122 }
123 
124 #define DEF_PCI_AC_NORET(name, at, al, space, aa)		\
125 static void iowa_##name at					\
126 {								\
127 	struct iowa_bus *bus;					\
128 	bus = iowa_##space##_find_bus(aa);			\
129 	if (bus && bus->ops && bus->ops->name) {		\
130 		bus->ops->name al;				\
131 		return;						\
132 	}							\
133 	__do_##name al;						\
134 }
135 
136 #include <asm/io-defs.h>
137 
138 #undef DEF_PCI_AC_RET
139 #undef DEF_PCI_AC_NORET
140 
141 static const struct ppc_pci_io iowa_pci_io = {
142 
143 #define DEF_PCI_AC_RET(name, ret, at, al, space, aa)	.name = iowa_##name,
144 #define DEF_PCI_AC_NORET(name, at, al, space, aa)	.name = iowa_##name,
145 
146 #include <asm/io-defs.h>
147 
148 #undef DEF_PCI_AC_RET
149 #undef DEF_PCI_AC_NORET
150 
151 };
152 
153 #ifdef CONFIG_PPC_INDIRECT_MMIO
154 static void __iomem *iowa_ioremap(phys_addr_t addr, unsigned long size,
155 				  unsigned long flags, void *caller)
156 {
157 	struct iowa_bus *bus;
158 	void __iomem *res = __ioremap_caller(addr, size, flags, caller);
159 	int busno;
160 
161 	bus = iowa_pci_find(0, (unsigned long)addr);
162 	if (bus != NULL) {
163 		busno = bus - iowa_busses;
164 		PCI_SET_ADDR_TOKEN(res, busno + 1);
165 	}
166 	return res;
167 }
168 #else /* CONFIG_PPC_INDIRECT_MMIO */
169 #define iowa_ioremap NULL
170 #endif /* !CONFIG_PPC_INDIRECT_MMIO */
171 
172 /* Enable IO workaround */
173 static void io_workaround_init(void)
174 {
175 	static int io_workaround_inited;
176 
177 	if (io_workaround_inited)
178 		return;
179 	ppc_pci_io = iowa_pci_io;
180 	ppc_md.ioremap = iowa_ioremap;
181 	io_workaround_inited = 1;
182 }
183 
184 /* Register new bus to support workaround */
185 void iowa_register_bus(struct pci_controller *phb, struct ppc_pci_io *ops,
186 		       int (*initfunc)(struct iowa_bus *, void *), void *data)
187 {
188 	struct iowa_bus *bus;
189 	struct device_node *np = phb->dn;
190 
191 	io_workaround_init();
192 
193 	if (iowa_bus_count >= IOWA_MAX_BUS) {
194 		pr_err("IOWA:Too many pci bridges, "
195 		       "workarounds disabled for %s\n", np->full_name);
196 		return;
197 	}
198 
199 	bus = &iowa_busses[iowa_bus_count];
200 	bus->phb = phb;
201 	bus->ops = ops;
202 	bus->private = data;
203 
204 	if (initfunc)
205 		if ((*initfunc)(bus, data))
206 			return;
207 
208 	iowa_bus_count++;
209 
210 	pr_debug("IOWA:[%d]Add bus, %s.\n", iowa_bus_count-1, np->full_name);
211 }
212 
213