xref: /openbmc/linux/drivers/ssb/sprom.c (revision ecba1060)
1 /*
2  * Sonics Silicon Backplane
3  * Common SPROM support routines
4  *
5  * Copyright (C) 2005-2008 Michael Buesch <mb@bu3sch.de>
6  * Copyright (C) 2005 Martin Langer <martin-langer@gmx.de>
7  * Copyright (C) 2005 Stefano Brivio <st3@riseup.net>
8  * Copyright (C) 2005 Danny van Dyk <kugelfang@gentoo.org>
9  * Copyright (C) 2005 Andreas Jaggi <andreas.jaggi@waterwave.ch>
10  *
11  * Licensed under the GNU/GPL. See COPYING for details.
12  */
13 
14 #include "ssb_private.h"
15 
16 
17 static const struct ssb_sprom *fallback_sprom;
18 
19 
20 static int sprom2hex(const u16 *sprom, char *buf, size_t buf_len,
21 		     size_t sprom_size_words)
22 {
23 	int i, pos = 0;
24 
25 	for (i = 0; i < sprom_size_words; i++)
26 		pos += snprintf(buf + pos, buf_len - pos - 1,
27 				"%04X", swab16(sprom[i]) & 0xFFFF);
28 	pos += snprintf(buf + pos, buf_len - pos - 1, "\n");
29 
30 	return pos + 1;
31 }
32 
33 static int hex2sprom(u16 *sprom, const char *dump, size_t len,
34 		     size_t sprom_size_words)
35 {
36 	char tmp[5] = { 0 };
37 	int cnt = 0;
38 	unsigned long parsed;
39 
40 	if (len < sprom_size_words * 2)
41 		return -EINVAL;
42 
43 	while (cnt < sprom_size_words) {
44 		memcpy(tmp, dump, 4);
45 		dump += 4;
46 		parsed = simple_strtoul(tmp, NULL, 16);
47 		sprom[cnt++] = swab16((u16)parsed);
48 	}
49 
50 	return 0;
51 }
52 
53 /* Common sprom device-attribute show-handler */
54 ssize_t ssb_attr_sprom_show(struct ssb_bus *bus, char *buf,
55 			    int (*sprom_read)(struct ssb_bus *bus, u16 *sprom))
56 {
57 	u16 *sprom;
58 	int err = -ENOMEM;
59 	ssize_t count = 0;
60 	size_t sprom_size_words = bus->sprom_size;
61 
62 	sprom = kcalloc(sprom_size_words, sizeof(u16), GFP_KERNEL);
63 	if (!sprom)
64 		goto out;
65 
66 	/* Use interruptible locking, as the SPROM write might
67 	 * be holding the lock for several seconds. So allow userspace
68 	 * to cancel operation. */
69 	err = -ERESTARTSYS;
70 	if (mutex_lock_interruptible(&bus->sprom_mutex))
71 		goto out_kfree;
72 	err = sprom_read(bus, sprom);
73 	mutex_unlock(&bus->sprom_mutex);
74 
75 	if (!err)
76 		count = sprom2hex(sprom, buf, PAGE_SIZE, sprom_size_words);
77 
78 out_kfree:
79 	kfree(sprom);
80 out:
81 	return err ? err : count;
82 }
83 
84 /* Common sprom device-attribute store-handler */
85 ssize_t ssb_attr_sprom_store(struct ssb_bus *bus,
86 			     const char *buf, size_t count,
87 			     int (*sprom_check_crc)(const u16 *sprom, size_t size),
88 			     int (*sprom_write)(struct ssb_bus *bus, const u16 *sprom))
89 {
90 	u16 *sprom;
91 	int res = 0, err = -ENOMEM;
92 	size_t sprom_size_words = bus->sprom_size;
93 
94 	sprom = kcalloc(bus->sprom_size, sizeof(u16), GFP_KERNEL);
95 	if (!sprom)
96 		goto out;
97 	err = hex2sprom(sprom, buf, count, sprom_size_words);
98 	if (err) {
99 		err = -EINVAL;
100 		goto out_kfree;
101 	}
102 	err = sprom_check_crc(sprom, sprom_size_words);
103 	if (err) {
104 		err = -EINVAL;
105 		goto out_kfree;
106 	}
107 
108 	/* Use interruptible locking, as the SPROM write might
109 	 * be holding the lock for several seconds. So allow userspace
110 	 * to cancel operation. */
111 	err = -ERESTARTSYS;
112 	if (mutex_lock_interruptible(&bus->sprom_mutex))
113 		goto out_kfree;
114 	err = ssb_devices_freeze(bus);
115 	if (err == -EOPNOTSUPP) {
116 		ssb_printk(KERN_ERR PFX "SPROM write: Could not freeze devices. "
117 			   "No suspend support. Is CONFIG_PM enabled?\n");
118 		goto out_unlock;
119 	}
120 	if (err) {
121 		ssb_printk(KERN_ERR PFX "SPROM write: Could not freeze all devices\n");
122 		goto out_unlock;
123 	}
124 	res = sprom_write(bus, sprom);
125 	err = ssb_devices_thaw(bus);
126 	if (err)
127 		ssb_printk(KERN_ERR PFX "SPROM write: Could not thaw all devices\n");
128 out_unlock:
129 	mutex_unlock(&bus->sprom_mutex);
130 out_kfree:
131 	kfree(sprom);
132 out:
133 	if (res)
134 		return res;
135 	return err ? err : count;
136 }
137 
138 /**
139  * ssb_arch_set_fallback_sprom - Set a fallback SPROM for use if no SPROM is found.
140  *
141  * @sprom: The SPROM data structure to register.
142  *
143  * With this function the architecture implementation may register a fallback
144  * SPROM data structure. The fallback is only used for PCI based SSB devices,
145  * where no valid SPROM can be found in the shadow registers.
146  *
147  * This function is useful for weird architectures that have a half-assed SSB device
148  * hardwired to their PCI bus.
149  *
150  * Note that it does only work with PCI attached SSB devices. PCMCIA devices currently
151  * don't use this fallback.
152  * Architectures must provide the SPROM for native SSB devices anyway,
153  * so the fallback also isn't used for native devices.
154  *
155  * This function is available for architecture code, only. So it is not exported.
156  */
157 int ssb_arch_set_fallback_sprom(const struct ssb_sprom *sprom)
158 {
159 	if (fallback_sprom)
160 		return -EEXIST;
161 	fallback_sprom = sprom;
162 
163 	return 0;
164 }
165 
166 const struct ssb_sprom *ssb_get_fallback_sprom(void)
167 {
168 	return fallback_sprom;
169 }
170