1 /*
2 * This program is free software; you can redistribute it and/or modify it
3 * under the terms of the GNU General Public License version 2 as published
4 * by the Free Software Foundation.
5 *
6 * Copyright (C) 2004 Liu Peng Infineon IFAP DC COM CPE
7 * Copyright (C) 2010 John Crispin <john@phrozen.org>
8 */
9
10 #include <linux/err.h>
11 #include <linux/module.h>
12 #include <linux/types.h>
13 #include <linux/kernel.h>
14 #include <linux/io.h>
15 #include <linux/slab.h>
16 #include <linux/mtd/mtd.h>
17 #include <linux/mtd/map.h>
18 #include <linux/mtd/partitions.h>
19 #include <linux/mtd/cfi.h>
20 #include <linux/platform_device.h>
21 #include <linux/mtd/physmap.h>
22 #include <linux/of.h>
23
24 #include <lantiq_soc.h>
25
26 /*
27 * The NOR flash is connected to the same external bus unit (EBU) as PCI.
28 * To make PCI work we need to enable the endianness swapping for the address
29 * written to the EBU. This endianness swapping works for PCI correctly but
30 * fails for attached NOR devices. To workaround this we need to use a complex
31 * map. The workaround involves swapping all addresses whilst probing the chip.
32 * Once probing is complete we stop swapping the addresses but swizzle the
33 * unlock addresses to ensure that access to the NOR device works correctly.
34 */
35
36 enum {
37 LTQ_NOR_PROBING,
38 LTQ_NOR_NORMAL
39 };
40
41 struct ltq_mtd {
42 struct resource *res;
43 struct mtd_info *mtd;
44 struct map_info *map;
45 };
46
47 static const char ltq_map_name[] = "ltq_nor";
48
49 static map_word
ltq_read16(struct map_info * map,unsigned long adr)50 ltq_read16(struct map_info *map, unsigned long adr)
51 {
52 unsigned long flags;
53 map_word temp;
54
55 if (map->map_priv_1 == LTQ_NOR_PROBING)
56 adr ^= 2;
57 spin_lock_irqsave(&ebu_lock, flags);
58 temp.x[0] = *(u16 *)(map->virt + adr);
59 spin_unlock_irqrestore(&ebu_lock, flags);
60 return temp;
61 }
62
63 static void
ltq_write16(struct map_info * map,map_word d,unsigned long adr)64 ltq_write16(struct map_info *map, map_word d, unsigned long adr)
65 {
66 unsigned long flags;
67
68 if (map->map_priv_1 == LTQ_NOR_PROBING)
69 adr ^= 2;
70 spin_lock_irqsave(&ebu_lock, flags);
71 *(u16 *)(map->virt + adr) = d.x[0];
72 spin_unlock_irqrestore(&ebu_lock, flags);
73 }
74
75 /*
76 * The following 2 functions copy data between iomem and a cached memory
77 * section. As memcpy() makes use of pre-fetching we cannot use it here.
78 * The normal alternative of using memcpy_{to,from}io also makes use of
79 * memcpy() on MIPS so it is not applicable either. We are therefore stuck
80 * with having to use our own loop.
81 */
82 static void
ltq_copy_from(struct map_info * map,void * to,unsigned long from,ssize_t len)83 ltq_copy_from(struct map_info *map, void *to,
84 unsigned long from, ssize_t len)
85 {
86 unsigned char *f = (unsigned char *)map->virt + from;
87 unsigned char *t = (unsigned char *)to;
88 unsigned long flags;
89
90 spin_lock_irqsave(&ebu_lock, flags);
91 while (len--)
92 *t++ = *f++;
93 spin_unlock_irqrestore(&ebu_lock, flags);
94 }
95
96 static void
ltq_copy_to(struct map_info * map,unsigned long to,const void * from,ssize_t len)97 ltq_copy_to(struct map_info *map, unsigned long to,
98 const void *from, ssize_t len)
99 {
100 unsigned char *f = (unsigned char *)from;
101 unsigned char *t = (unsigned char *)map->virt + to;
102 unsigned long flags;
103
104 spin_lock_irqsave(&ebu_lock, flags);
105 while (len--)
106 *t++ = *f++;
107 spin_unlock_irqrestore(&ebu_lock, flags);
108 }
109
110 static int
ltq_mtd_probe(struct platform_device * pdev)111 ltq_mtd_probe(struct platform_device *pdev)
112 {
113 struct ltq_mtd *ltq_mtd;
114 struct cfi_private *cfi;
115 int err;
116
117 ltq_mtd = devm_kzalloc(&pdev->dev, sizeof(struct ltq_mtd), GFP_KERNEL);
118 if (!ltq_mtd)
119 return -ENOMEM;
120
121 platform_set_drvdata(pdev, ltq_mtd);
122
123 ltq_mtd->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
124 if (!ltq_mtd->res) {
125 dev_err(&pdev->dev, "failed to get memory resource\n");
126 return -ENOENT;
127 }
128
129 ltq_mtd->map = devm_kzalloc(&pdev->dev, sizeof(struct map_info),
130 GFP_KERNEL);
131 if (!ltq_mtd->map)
132 return -ENOMEM;
133
134 ltq_mtd->map->phys = ltq_mtd->res->start;
135 ltq_mtd->map->size = resource_size(ltq_mtd->res);
136 ltq_mtd->map->virt = devm_ioremap_resource(&pdev->dev, ltq_mtd->res);
137 if (IS_ERR(ltq_mtd->map->virt))
138 return PTR_ERR(ltq_mtd->map->virt);
139
140 ltq_mtd->map->name = ltq_map_name;
141 ltq_mtd->map->bankwidth = 2;
142 ltq_mtd->map->read = ltq_read16;
143 ltq_mtd->map->write = ltq_write16;
144 ltq_mtd->map->copy_from = ltq_copy_from;
145 ltq_mtd->map->copy_to = ltq_copy_to;
146
147 ltq_mtd->map->map_priv_1 = LTQ_NOR_PROBING;
148 ltq_mtd->mtd = do_map_probe("cfi_probe", ltq_mtd->map);
149 ltq_mtd->map->map_priv_1 = LTQ_NOR_NORMAL;
150
151 if (!ltq_mtd->mtd) {
152 dev_err(&pdev->dev, "probing failed\n");
153 return -ENXIO;
154 }
155
156 ltq_mtd->mtd->dev.parent = &pdev->dev;
157 mtd_set_of_node(ltq_mtd->mtd, pdev->dev.of_node);
158
159 cfi = ltq_mtd->map->fldrv_priv;
160 cfi->addr_unlock1 ^= 1;
161 cfi->addr_unlock2 ^= 1;
162
163 err = mtd_device_register(ltq_mtd->mtd, NULL, 0);
164 if (err) {
165 dev_err(&pdev->dev, "failed to add partitions\n");
166 goto err_destroy;
167 }
168
169 return 0;
170
171 err_destroy:
172 map_destroy(ltq_mtd->mtd);
173 return err;
174 }
175
176 static int
ltq_mtd_remove(struct platform_device * pdev)177 ltq_mtd_remove(struct platform_device *pdev)
178 {
179 struct ltq_mtd *ltq_mtd = platform_get_drvdata(pdev);
180
181 if (ltq_mtd && ltq_mtd->mtd) {
182 mtd_device_unregister(ltq_mtd->mtd);
183 map_destroy(ltq_mtd->mtd);
184 }
185 return 0;
186 }
187
188 static const struct of_device_id ltq_mtd_match[] = {
189 { .compatible = "lantiq,nor" },
190 {},
191 };
192 MODULE_DEVICE_TABLE(of, ltq_mtd_match);
193
194 static struct platform_driver ltq_mtd_driver = {
195 .probe = ltq_mtd_probe,
196 .remove = ltq_mtd_remove,
197 .driver = {
198 .name = "ltq-nor",
199 .of_match_table = ltq_mtd_match,
200 },
201 };
202
203 module_platform_driver(ltq_mtd_driver);
204
205 MODULE_LICENSE("GPL");
206 MODULE_AUTHOR("John Crispin <john@phrozen.org>");
207 MODULE_DESCRIPTION("Lantiq SoC NOR");
208
