1 /*
2  * PowerNV LPC bus handling.
3  *
4  * Copyright 2013 IBM Corp.
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License
8  * as published by the Free Software Foundation; either version
9  * 2 of the License, or (at your option) any later version.
10  */
11 
12 #include <linux/kernel.h>
13 #include <linux/of.h>
14 #include <linux/bug.h>
15 
16 #include <asm/machdep.h>
17 #include <asm/firmware.h>
18 #include <asm/xics.h>
19 #include <asm/opal.h>
20 #include <asm/prom.h>
21 
22 static int opal_lpc_chip_id = -1;
23 
24 static u8 opal_lpc_inb(unsigned long port)
25 {
26 	int64_t rc;
27 	__be32 data;
28 
29 	if (opal_lpc_chip_id < 0 || port > 0xffff)
30 		return 0xff;
31 	rc = opal_lpc_read(opal_lpc_chip_id, OPAL_LPC_IO, port, &data, 1);
32 	return rc ? 0xff : be32_to_cpu(data);
33 }
34 
35 static __le16 __opal_lpc_inw(unsigned long port)
36 {
37 	int64_t rc;
38 	__be32 data;
39 
40 	if (opal_lpc_chip_id < 0 || port > 0xfffe)
41 		return 0xffff;
42 	if (port & 1)
43 		return (__le16)opal_lpc_inb(port) << 8 | opal_lpc_inb(port + 1);
44 	rc = opal_lpc_read(opal_lpc_chip_id, OPAL_LPC_IO, port, &data, 2);
45 	return rc ? 0xffff : be32_to_cpu(data);
46 }
47 static u16 opal_lpc_inw(unsigned long port)
48 {
49 	return le16_to_cpu(__opal_lpc_inw(port));
50 }
51 
52 static __le32 __opal_lpc_inl(unsigned long port)
53 {
54 	int64_t rc;
55 	__be32 data;
56 
57 	if (opal_lpc_chip_id < 0 || port > 0xfffc)
58 		return 0xffffffff;
59 	if (port & 3)
60 		return (__le32)opal_lpc_inb(port    ) << 24 |
61 		       (__le32)opal_lpc_inb(port + 1) << 16 |
62 		       (__le32)opal_lpc_inb(port + 2) <<  8 |
63 			       opal_lpc_inb(port + 3);
64 	rc = opal_lpc_read(opal_lpc_chip_id, OPAL_LPC_IO, port, &data, 4);
65 	return rc ? 0xffffffff : be32_to_cpu(data);
66 }
67 
68 static u32 opal_lpc_inl(unsigned long port)
69 {
70 	return le32_to_cpu(__opal_lpc_inl(port));
71 }
72 
73 static void opal_lpc_outb(u8 val, unsigned long port)
74 {
75 	if (opal_lpc_chip_id < 0 || port > 0xffff)
76 		return;
77 	opal_lpc_write(opal_lpc_chip_id, OPAL_LPC_IO, port, val, 1);
78 }
79 
80 static void __opal_lpc_outw(__le16 val, unsigned long port)
81 {
82 	if (opal_lpc_chip_id < 0 || port > 0xfffe)
83 		return;
84 	if (port & 1) {
85 		opal_lpc_outb(val >> 8, port);
86 		opal_lpc_outb(val     , port + 1);
87 		return;
88 	}
89 	opal_lpc_write(opal_lpc_chip_id, OPAL_LPC_IO, port, val, 2);
90 }
91 
92 static void opal_lpc_outw(u16 val, unsigned long port)
93 {
94 	__opal_lpc_outw(cpu_to_le16(val), port);
95 }
96 
97 static void __opal_lpc_outl(__le32 val, unsigned long port)
98 {
99 	if (opal_lpc_chip_id < 0 || port > 0xfffc)
100 		return;
101 	if (port & 3) {
102 		opal_lpc_outb(val >> 24, port);
103 		opal_lpc_outb(val >> 16, port + 1);
104 		opal_lpc_outb(val >>  8, port + 2);
105 		opal_lpc_outb(val      , port + 3);
106 		return;
107 	}
108 	opal_lpc_write(opal_lpc_chip_id, OPAL_LPC_IO, port, val, 4);
109 }
110 
111 static void opal_lpc_outl(u32 val, unsigned long port)
112 {
113 	__opal_lpc_outl(cpu_to_le32(val), port);
114 }
115 
116 static void opal_lpc_insb(unsigned long p, void *b, unsigned long c)
117 {
118 	u8 *ptr = b;
119 
120 	while(c--)
121 		*(ptr++) = opal_lpc_inb(p);
122 }
123 
124 static void opal_lpc_insw(unsigned long p, void *b, unsigned long c)
125 {
126 	__le16 *ptr = b;
127 
128 	while(c--)
129 		*(ptr++) = __opal_lpc_inw(p);
130 }
131 
132 static void opal_lpc_insl(unsigned long p, void *b, unsigned long c)
133 {
134 	__le32 *ptr = b;
135 
136 	while(c--)
137 		*(ptr++) = __opal_lpc_inl(p);
138 }
139 
140 static void opal_lpc_outsb(unsigned long p, const void *b, unsigned long c)
141 {
142 	const u8 *ptr = b;
143 
144 	while(c--)
145 		opal_lpc_outb(*(ptr++), p);
146 }
147 
148 static void opal_lpc_outsw(unsigned long p, const void *b, unsigned long c)
149 {
150 	const __le16 *ptr = b;
151 
152 	while(c--)
153 		__opal_lpc_outw(*(ptr++), p);
154 }
155 
156 static void opal_lpc_outsl(unsigned long p, const void *b, unsigned long c)
157 {
158 	const __le32 *ptr = b;
159 
160 	while(c--)
161 		__opal_lpc_outl(*(ptr++), p);
162 }
163 
164 static const struct ppc_pci_io opal_lpc_io = {
165 	.inb	= opal_lpc_inb,
166 	.inw	= opal_lpc_inw,
167 	.inl	= opal_lpc_inl,
168 	.outb	= opal_lpc_outb,
169 	.outw	= opal_lpc_outw,
170 	.outl	= opal_lpc_outl,
171 	.insb	= opal_lpc_insb,
172 	.insw	= opal_lpc_insw,
173 	.insl	= opal_lpc_insl,
174 	.outsb	= opal_lpc_outsb,
175 	.outsw	= opal_lpc_outsw,
176 	.outsl	= opal_lpc_outsl,
177 };
178 
179 void opal_lpc_init(void)
180 {
181 	struct device_node *np;
182 
183 	/*
184 	 * Look for a Power8 LPC bus tagged as "primary",
185 	 * we currently support only one though the OPAL APIs
186 	 * support any number.
187 	 */
188 	for_each_compatible_node(np, NULL, "ibm,power8-lpc") {
189 		if (!of_device_is_available(np))
190 			continue;
191 		if (!of_get_property(np, "primary", NULL))
192 			continue;
193 		opal_lpc_chip_id = of_get_ibm_chip_id(np);
194 		break;
195 	}
196 	if (opal_lpc_chip_id < 0)
197 		return;
198 
199 	/* Setup special IO ops */
200 	ppc_pci_io = opal_lpc_io;
201 	isa_io_special = true;
202 
203 	pr_info("OPAL: Power8 LPC bus found, chip ID %d\n", opal_lpc_chip_id);
204 }
205