1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 *
4 * Copyright (C) 2004 Liu Peng Infineon IFAP DC COM CPE
5 * Copyright (C) 2010 John Crispin <john@phrozen.org>
6 */
7
8 #include <linux/err.h>
9 #include <linux/module.h>
10 #include <linux/types.h>
11 #include <linux/kernel.h>
12 #include <linux/io.h>
13 #include <linux/slab.h>
14 #include <linux/mtd/mtd.h>
15 #include <linux/mtd/map.h>
16 #include <linux/mtd/partitions.h>
17 #include <linux/mtd/cfi.h>
18 #include <linux/platform_device.h>
19 #include <linux/mtd/physmap.h>
20 #include <linux/of.h>
21
22 #include <lantiq_soc.h>
23
24 /*
25 * The NOR flash is connected to the same external bus unit (EBU) as PCI.
26 * To make PCI work we need to enable the endianness swapping for the address
27 * written to the EBU. This endianness swapping works for PCI correctly but
28 * fails for attached NOR devices. To workaround this we need to use a complex
29 * map. The workaround involves swapping all addresses whilst probing the chip.
30 * Once probing is complete we stop swapping the addresses but swizzle the
31 * unlock addresses to ensure that access to the NOR device works correctly.
32 */
33
34 enum {
35 LTQ_NOR_PROBING,
36 LTQ_NOR_NORMAL
37 };
38
39 struct ltq_mtd {
40 struct resource *res;
41 struct mtd_info *mtd;
42 struct map_info *map;
43 };
44
45 static const char ltq_map_name[] = "ltq_nor";
46
47 static map_word
ltq_read16(struct map_info * map,unsigned long adr)48 ltq_read16(struct map_info *map, unsigned long adr)
49 {
50 unsigned long flags;
51 map_word temp;
52
53 if (map->map_priv_1 == LTQ_NOR_PROBING)
54 adr ^= 2;
55 spin_lock_irqsave(&ebu_lock, flags);
56 temp.x[0] = *(u16 *)(map->virt + adr);
57 spin_unlock_irqrestore(&ebu_lock, flags);
58 return temp;
59 }
60
61 static void
ltq_write16(struct map_info * map,map_word d,unsigned long adr)62 ltq_write16(struct map_info *map, map_word d, unsigned long adr)
63 {
64 unsigned long flags;
65
66 if (map->map_priv_1 == LTQ_NOR_PROBING)
67 adr ^= 2;
68 spin_lock_irqsave(&ebu_lock, flags);
69 *(u16 *)(map->virt + adr) = d.x[0];
70 spin_unlock_irqrestore(&ebu_lock, flags);
71 }
72
73 /*
74 * The following 2 functions copy data between iomem and a cached memory
75 * section. As memcpy() makes use of pre-fetching we cannot use it here.
76 * The normal alternative of using memcpy_{to,from}io also makes use of
77 * memcpy() on MIPS so it is not applicable either. We are therefore stuck
78 * with having to use our own loop.
79 */
80 static void
ltq_copy_from(struct map_info * map,void * to,unsigned long from,ssize_t len)81 ltq_copy_from(struct map_info *map, void *to,
82 unsigned long from, ssize_t len)
83 {
84 unsigned char *f = (unsigned char *)map->virt + from;
85 unsigned char *t = (unsigned char *)to;
86 unsigned long flags;
87
88 spin_lock_irqsave(&ebu_lock, flags);
89 while (len--)
90 *t++ = *f++;
91 spin_unlock_irqrestore(&ebu_lock, flags);
92 }
93
94 static void
ltq_copy_to(struct map_info * map,unsigned long to,const void * from,ssize_t len)95 ltq_copy_to(struct map_info *map, unsigned long to,
96 const void *from, ssize_t len)
97 {
98 unsigned char *f = (unsigned char *)from;
99 unsigned char *t = (unsigned char *)map->virt + to;
100 unsigned long flags;
101
102 spin_lock_irqsave(&ebu_lock, flags);
103 while (len--)
104 *t++ = *f++;
105 spin_unlock_irqrestore(&ebu_lock, flags);
106 }
107
108 static int
ltq_mtd_probe(struct platform_device * pdev)109 ltq_mtd_probe(struct platform_device *pdev)
110 {
111 struct ltq_mtd *ltq_mtd;
112 struct cfi_private *cfi;
113 int err;
114
115 ltq_mtd = devm_kzalloc(&pdev->dev, sizeof(struct ltq_mtd), GFP_KERNEL);
116 if (!ltq_mtd)
117 return -ENOMEM;
118
119 platform_set_drvdata(pdev, ltq_mtd);
120
121 ltq_mtd->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
122 if (!ltq_mtd->res) {
123 dev_err(&pdev->dev, "failed to get memory resource\n");
124 return -ENOENT;
125 }
126
127 ltq_mtd->map = devm_kzalloc(&pdev->dev, sizeof(struct map_info),
128 GFP_KERNEL);
129 if (!ltq_mtd->map)
130 return -ENOMEM;
131
132 ltq_mtd->map->phys = ltq_mtd->res->start;
133 ltq_mtd->map->size = resource_size(ltq_mtd->res);
134 ltq_mtd->map->virt = devm_ioremap_resource(&pdev->dev, ltq_mtd->res);
135 if (IS_ERR(ltq_mtd->map->virt))
136 return PTR_ERR(ltq_mtd->map->virt);
137
138 ltq_mtd->map->name = ltq_map_name;
139 ltq_mtd->map->bankwidth = 2;
140 ltq_mtd->map->read = ltq_read16;
141 ltq_mtd->map->write = ltq_write16;
142 ltq_mtd->map->copy_from = ltq_copy_from;
143 ltq_mtd->map->copy_to = ltq_copy_to;
144
145 ltq_mtd->map->map_priv_1 = LTQ_NOR_PROBING;
146 ltq_mtd->mtd = do_map_probe("cfi_probe", ltq_mtd->map);
147 ltq_mtd->map->map_priv_1 = LTQ_NOR_NORMAL;
148
149 if (!ltq_mtd->mtd) {
150 dev_err(&pdev->dev, "probing failed\n");
151 return -ENXIO;
152 }
153
154 ltq_mtd->mtd->dev.parent = &pdev->dev;
155 mtd_set_of_node(ltq_mtd->mtd, pdev->dev.of_node);
156
157 cfi = ltq_mtd->map->fldrv_priv;
158 cfi->addr_unlock1 ^= 1;
159 cfi->addr_unlock2 ^= 1;
160
161 err = mtd_device_register(ltq_mtd->mtd, NULL, 0);
162 if (err) {
163 dev_err(&pdev->dev, "failed to add partitions\n");
164 goto err_destroy;
165 }
166
167 return 0;
168
169 err_destroy:
170 map_destroy(ltq_mtd->mtd);
171 return err;
172 }
173
174 static int
ltq_mtd_remove(struct platform_device * pdev)175 ltq_mtd_remove(struct platform_device *pdev)
176 {
177 struct ltq_mtd *ltq_mtd = platform_get_drvdata(pdev);
178
179 if (ltq_mtd && ltq_mtd->mtd) {
180 mtd_device_unregister(ltq_mtd->mtd);
181 map_destroy(ltq_mtd->mtd);
182 }
183 return 0;
184 }
185
186 static const struct of_device_id ltq_mtd_match[] = {
187 { .compatible = "lantiq,nor" },
188 {},
189 };
190 MODULE_DEVICE_TABLE(of, ltq_mtd_match);
191
192 static struct platform_driver ltq_mtd_driver = {
193 .probe = ltq_mtd_probe,
194 .remove = ltq_mtd_remove,
195 .driver = {
196 .name = "ltq-nor",
197 .of_match_table = ltq_mtd_match,
198 },
199 };
200
201 module_platform_driver(ltq_mtd_driver);
202
203 MODULE_LICENSE("GPL");
204 MODULE_AUTHOR("John Crispin <john@phrozen.org>");
205 MODULE_DESCRIPTION("Lantiq SoC NOR");
206