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 #include <linux/debugfs.h>
16 #include <linux/io.h>
17 #include <linux/slab.h>
18 
19 #include <asm/machdep.h>
20 #include <asm/firmware.h>
21 #include <asm/xics.h>
22 #include <asm/opal.h>
23 #include <asm/prom.h>
24 #include <asm/uaccess.h>
25 
26 static int opal_lpc_chip_id = -1;
27 
28 static u8 opal_lpc_inb(unsigned long port)
29 {
30 	int64_t rc;
31 	__be32 data;
32 
33 	if (opal_lpc_chip_id < 0 || port > 0xffff)
34 		return 0xff;
35 	rc = opal_lpc_read(opal_lpc_chip_id, OPAL_LPC_IO, port, &data, 1);
36 	return rc ? 0xff : be32_to_cpu(data);
37 }
38 
39 static __le16 __opal_lpc_inw(unsigned long port)
40 {
41 	int64_t rc;
42 	__be32 data;
43 
44 	if (opal_lpc_chip_id < 0 || port > 0xfffe)
45 		return 0xffff;
46 	if (port & 1)
47 		return (__le16)opal_lpc_inb(port) << 8 | opal_lpc_inb(port + 1);
48 	rc = opal_lpc_read(opal_lpc_chip_id, OPAL_LPC_IO, port, &data, 2);
49 	return rc ? 0xffff : be32_to_cpu(data);
50 }
51 static u16 opal_lpc_inw(unsigned long port)
52 {
53 	return le16_to_cpu(__opal_lpc_inw(port));
54 }
55 
56 static __le32 __opal_lpc_inl(unsigned long port)
57 {
58 	int64_t rc;
59 	__be32 data;
60 
61 	if (opal_lpc_chip_id < 0 || port > 0xfffc)
62 		return 0xffffffff;
63 	if (port & 3)
64 		return (__le32)opal_lpc_inb(port    ) << 24 |
65 		       (__le32)opal_lpc_inb(port + 1) << 16 |
66 		       (__le32)opal_lpc_inb(port + 2) <<  8 |
67 			       opal_lpc_inb(port + 3);
68 	rc = opal_lpc_read(opal_lpc_chip_id, OPAL_LPC_IO, port, &data, 4);
69 	return rc ? 0xffffffff : be32_to_cpu(data);
70 }
71 
72 static u32 opal_lpc_inl(unsigned long port)
73 {
74 	return le32_to_cpu(__opal_lpc_inl(port));
75 }
76 
77 static void opal_lpc_outb(u8 val, unsigned long port)
78 {
79 	if (opal_lpc_chip_id < 0 || port > 0xffff)
80 		return;
81 	opal_lpc_write(opal_lpc_chip_id, OPAL_LPC_IO, port, val, 1);
82 }
83 
84 static void __opal_lpc_outw(__le16 val, unsigned long port)
85 {
86 	if (opal_lpc_chip_id < 0 || port > 0xfffe)
87 		return;
88 	if (port & 1) {
89 		opal_lpc_outb(val >> 8, port);
90 		opal_lpc_outb(val     , port + 1);
91 		return;
92 	}
93 	opal_lpc_write(opal_lpc_chip_id, OPAL_LPC_IO, port, val, 2);
94 }
95 
96 static void opal_lpc_outw(u16 val, unsigned long port)
97 {
98 	__opal_lpc_outw(cpu_to_le16(val), port);
99 }
100 
101 static void __opal_lpc_outl(__le32 val, unsigned long port)
102 {
103 	if (opal_lpc_chip_id < 0 || port > 0xfffc)
104 		return;
105 	if (port & 3) {
106 		opal_lpc_outb(val >> 24, port);
107 		opal_lpc_outb(val >> 16, port + 1);
108 		opal_lpc_outb(val >>  8, port + 2);
109 		opal_lpc_outb(val      , port + 3);
110 		return;
111 	}
112 	opal_lpc_write(opal_lpc_chip_id, OPAL_LPC_IO, port, val, 4);
113 }
114 
115 static void opal_lpc_outl(u32 val, unsigned long port)
116 {
117 	__opal_lpc_outl(cpu_to_le32(val), port);
118 }
119 
120 static void opal_lpc_insb(unsigned long p, void *b, unsigned long c)
121 {
122 	u8 *ptr = b;
123 
124 	while(c--)
125 		*(ptr++) = opal_lpc_inb(p);
126 }
127 
128 static void opal_lpc_insw(unsigned long p, void *b, unsigned long c)
129 {
130 	__le16 *ptr = b;
131 
132 	while(c--)
133 		*(ptr++) = __opal_lpc_inw(p);
134 }
135 
136 static void opal_lpc_insl(unsigned long p, void *b, unsigned long c)
137 {
138 	__le32 *ptr = b;
139 
140 	while(c--)
141 		*(ptr++) = __opal_lpc_inl(p);
142 }
143 
144 static void opal_lpc_outsb(unsigned long p, const void *b, unsigned long c)
145 {
146 	const u8 *ptr = b;
147 
148 	while(c--)
149 		opal_lpc_outb(*(ptr++), p);
150 }
151 
152 static void opal_lpc_outsw(unsigned long p, const void *b, unsigned long c)
153 {
154 	const __le16 *ptr = b;
155 
156 	while(c--)
157 		__opal_lpc_outw(*(ptr++), p);
158 }
159 
160 static void opal_lpc_outsl(unsigned long p, const void *b, unsigned long c)
161 {
162 	const __le32 *ptr = b;
163 
164 	while(c--)
165 		__opal_lpc_outl(*(ptr++), p);
166 }
167 
168 static const struct ppc_pci_io opal_lpc_io = {
169 	.inb	= opal_lpc_inb,
170 	.inw	= opal_lpc_inw,
171 	.inl	= opal_lpc_inl,
172 	.outb	= opal_lpc_outb,
173 	.outw	= opal_lpc_outw,
174 	.outl	= opal_lpc_outl,
175 	.insb	= opal_lpc_insb,
176 	.insw	= opal_lpc_insw,
177 	.insl	= opal_lpc_insl,
178 	.outsb	= opal_lpc_outsb,
179 	.outsw	= opal_lpc_outsw,
180 	.outsl	= opal_lpc_outsl,
181 };
182 
183 #ifdef CONFIG_DEBUG_FS
184 struct lpc_debugfs_entry {
185 	enum OpalLPCAddressType lpc_type;
186 };
187 
188 static ssize_t lpc_debug_read(struct file *filp, char __user *ubuf,
189 			      size_t count, loff_t *ppos)
190 {
191 	struct lpc_debugfs_entry *lpc = filp->private_data;
192 	u32 data, pos, len, todo;
193 	int rc;
194 
195 	if (!access_ok(VERIFY_WRITE, ubuf, count))
196 		return -EFAULT;
197 
198 	todo = count;
199 	while (todo) {
200 		pos = *ppos;
201 
202 		/*
203 		 * Select access size based on count and alignment and
204 		 * access type. IO and MEM only support byte acceses,
205 		 * FW supports all 3.
206 		 */
207 		len = 1;
208 		if (lpc->lpc_type == OPAL_LPC_FW) {
209 			if (todo > 3 && (pos & 3) == 0)
210 				len = 4;
211 			else if (todo > 1 && (pos & 1) == 0)
212 				len = 2;
213 		}
214 		rc = opal_lpc_read(opal_lpc_chip_id, lpc->lpc_type, pos,
215 				   &data, len);
216 		if (rc)
217 			return -ENXIO;
218 		switch(len) {
219 		case 4:
220 			rc = __put_user((u32)data, (u32 __user *)ubuf);
221 			break;
222 		case 2:
223 			rc = __put_user((u16)data, (u16 __user *)ubuf);
224 			break;
225 		default:
226 			rc = __put_user((u8)data, (u8 __user *)ubuf);
227 			break;
228 		}
229 		if (rc)
230 			return -EFAULT;
231 		*ppos += len;
232 		ubuf += len;
233 		todo -= len;
234 	}
235 
236 	return count;
237 }
238 
239 static ssize_t lpc_debug_write(struct file *filp, const char __user *ubuf,
240 			       size_t count, loff_t *ppos)
241 {
242 	struct lpc_debugfs_entry *lpc = filp->private_data;
243 	u32 data, pos, len, todo;
244 	int rc;
245 
246 	if (!access_ok(VERIFY_READ, ubuf, count))
247 		return -EFAULT;
248 
249 	todo = count;
250 	while (todo) {
251 		pos = *ppos;
252 
253 		/*
254 		 * Select access size based on count and alignment and
255 		 * access type. IO and MEM only support byte acceses,
256 		 * FW supports all 3.
257 		 */
258 		len = 1;
259 		if (lpc->lpc_type == OPAL_LPC_FW) {
260 			if (todo > 3 && (pos & 3) == 0)
261 				len = 4;
262 			else if (todo > 1 && (pos & 1) == 0)
263 				len = 2;
264 		}
265 		switch(len) {
266 		case 4:
267 			rc = __get_user(data, (u32 __user *)ubuf);
268 			break;
269 		case 2:
270 			rc = __get_user(data, (u16 __user *)ubuf);
271 			break;
272 		default:
273 			rc = __get_user(data, (u8 __user *)ubuf);
274 			break;
275 		}
276 		if (rc)
277 			return -EFAULT;
278 
279 		rc = opal_lpc_write(opal_lpc_chip_id, lpc->lpc_type, pos,
280 				    data, len);
281 		if (rc)
282 			return -ENXIO;
283 		*ppos += len;
284 		ubuf += len;
285 		todo -= len;
286 	}
287 
288 	return count;
289 }
290 
291 static const struct file_operations lpc_fops = {
292 	.read =		lpc_debug_read,
293 	.write =	lpc_debug_write,
294 	.open =		simple_open,
295 	.llseek =	default_llseek,
296 };
297 
298 static int opal_lpc_debugfs_create_type(struct dentry *folder,
299 					const char *fname,
300 					enum OpalLPCAddressType type)
301 {
302 	struct lpc_debugfs_entry *entry;
303 	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
304 	if (!entry)
305 		return -ENOMEM;
306 	entry->lpc_type = type;
307 	debugfs_create_file(fname, 0600, folder, entry, &lpc_fops);
308 	return 0;
309 }
310 
311 static int opal_lpc_init_debugfs(void)
312 {
313 	struct dentry *root;
314 	int rc = 0;
315 
316 	if (opal_lpc_chip_id < 0)
317 		return -ENODEV;
318 
319 	root = debugfs_create_dir("lpc", powerpc_debugfs_root);
320 
321 	rc |= opal_lpc_debugfs_create_type(root, "io", OPAL_LPC_IO);
322 	rc |= opal_lpc_debugfs_create_type(root, "mem", OPAL_LPC_MEM);
323 	rc |= opal_lpc_debugfs_create_type(root, "fw", OPAL_LPC_FW);
324 	return rc;
325 }
326 device_initcall(opal_lpc_init_debugfs);
327 #endif  /* CONFIG_DEBUG_FS */
328 
329 void opal_lpc_init(void)
330 {
331 	struct device_node *np;
332 
333 	/*
334 	 * Look for a Power8 LPC bus tagged as "primary",
335 	 * we currently support only one though the OPAL APIs
336 	 * support any number.
337 	 */
338 	for_each_compatible_node(np, NULL, "ibm,power8-lpc") {
339 		if (!of_device_is_available(np))
340 			continue;
341 		if (!of_get_property(np, "primary", NULL))
342 			continue;
343 		opal_lpc_chip_id = of_get_ibm_chip_id(np);
344 		break;
345 	}
346 	if (opal_lpc_chip_id < 0)
347 		return;
348 
349 	/* Setup special IO ops */
350 	ppc_pci_io = opal_lpc_io;
351 	isa_io_special = true;
352 
353 	pr_info("OPAL: Power8 LPC bus found, chip ID %d\n", opal_lpc_chip_id);
354 }
355