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 <blogic@openwrt.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
36enum {
37	LTQ_NOR_PROBING,
38	LTQ_NOR_NORMAL
39};
40
41struct ltq_mtd {
42	struct resource *res;
43	struct mtd_info *mtd;
44	struct map_info *map;
45};
46
47static const char ltq_map_name[] = "ltq_nor";
48static const char * const ltq_probe_types[] = { "cmdlinepart", "ofpart", NULL };
49
50static map_word
51ltq_read16(struct map_info *map, unsigned long adr)
52{
53	unsigned long flags;
54	map_word temp;
55
56	if (map->map_priv_1 == LTQ_NOR_PROBING)
57		adr ^= 2;
58	spin_lock_irqsave(&ebu_lock, flags);
59	temp.x[0] = *(u16 *)(map->virt + adr);
60	spin_unlock_irqrestore(&ebu_lock, flags);
61	return temp;
62}
63
64static void
65ltq_write16(struct map_info *map, map_word d, unsigned long adr)
66{
67	unsigned long flags;
68
69	if (map->map_priv_1 == LTQ_NOR_PROBING)
70		adr ^= 2;
71	spin_lock_irqsave(&ebu_lock, flags);
72	*(u16 *)(map->virt + adr) = d.x[0];
73	spin_unlock_irqrestore(&ebu_lock, flags);
74}
75
76/*
77 * The following 2 functions copy data between iomem and a cached memory
78 * section. As memcpy() makes use of pre-fetching we cannot use it here.
79 * The normal alternative of using memcpy_{to,from}io also makes use of
80 * memcpy() on MIPS so it is not applicable either. We are therefore stuck
81 * with having to use our own loop.
82 */
83static void
84ltq_copy_from(struct map_info *map, void *to,
85	unsigned long from, ssize_t len)
86{
87	unsigned char *f = (unsigned char *)map->virt + from;
88	unsigned char *t = (unsigned char *)to;
89	unsigned long flags;
90
91	spin_lock_irqsave(&ebu_lock, flags);
92	while (len--)
93		*t++ = *f++;
94	spin_unlock_irqrestore(&ebu_lock, flags);
95}
96
97static void
98ltq_copy_to(struct map_info *map, unsigned long to,
99	const void *from, ssize_t len)
100{
101	unsigned char *f = (unsigned char *)from;
102	unsigned char *t = (unsigned char *)map->virt + to;
103	unsigned long flags;
104
105	spin_lock_irqsave(&ebu_lock, flags);
106	while (len--)
107		*t++ = *f++;
108	spin_unlock_irqrestore(&ebu_lock, flags);
109}
110
111static int
112ltq_mtd_probe(struct platform_device *pdev)
113{
114	struct mtd_part_parser_data ppdata;
115	struct ltq_mtd *ltq_mtd;
116	struct cfi_private *cfi;
117	int err;
118
119	if (of_machine_is_compatible("lantiq,falcon") &&
120			(ltq_boot_select() != BS_FLASH)) {
121		dev_err(&pdev->dev, "invalid bootstrap options\n");
122		return -ENODEV;
123	}
124
125	ltq_mtd = devm_kzalloc(&pdev->dev, sizeof(struct ltq_mtd), GFP_KERNEL);
126	if (!ltq_mtd)
127		return -ENOMEM;
128
129	platform_set_drvdata(pdev, ltq_mtd);
130
131	ltq_mtd->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
132	if (!ltq_mtd->res) {
133		dev_err(&pdev->dev, "failed to get memory resource\n");
134		return -ENOENT;
135	}
136
137	ltq_mtd->map = devm_kzalloc(&pdev->dev, sizeof(struct map_info),
138				    GFP_KERNEL);
139	if (!ltq_mtd->map)
140		return -ENOMEM;
141
142	ltq_mtd->map->phys = ltq_mtd->res->start;
143	ltq_mtd->map->size = resource_size(ltq_mtd->res);
144	ltq_mtd->map->virt = devm_ioremap_resource(&pdev->dev, ltq_mtd->res);
145	if (IS_ERR(ltq_mtd->map->virt))
146		return PTR_ERR(ltq_mtd->map->virt);
147
148	ltq_mtd->map->name = ltq_map_name;
149	ltq_mtd->map->bankwidth = 2;
150	ltq_mtd->map->read = ltq_read16;
151	ltq_mtd->map->write = ltq_write16;
152	ltq_mtd->map->copy_from = ltq_copy_from;
153	ltq_mtd->map->copy_to = ltq_copy_to;
154
155	ltq_mtd->map->map_priv_1 = LTQ_NOR_PROBING;
156	ltq_mtd->mtd = do_map_probe("cfi_probe", ltq_mtd->map);
157	ltq_mtd->map->map_priv_1 = LTQ_NOR_NORMAL;
158
159	if (!ltq_mtd->mtd) {
160		dev_err(&pdev->dev, "probing failed\n");
161		return -ENXIO;
162	}
163
164	ltq_mtd->mtd->owner = THIS_MODULE;
165
166	cfi = ltq_mtd->map->fldrv_priv;
167	cfi->addr_unlock1 ^= 1;
168	cfi->addr_unlock2 ^= 1;
169
170	ppdata.of_node = pdev->dev.of_node;
171	err = mtd_device_parse_register(ltq_mtd->mtd, ltq_probe_types,
172					&ppdata, NULL, 0);
173	if (err) {
174		dev_err(&pdev->dev, "failed to add partitions\n");
175		goto err_destroy;
176	}
177
178	return 0;
179
180err_destroy:
181	map_destroy(ltq_mtd->mtd);
182	return err;
183}
184
185static int
186ltq_mtd_remove(struct platform_device *pdev)
187{
188	struct ltq_mtd *ltq_mtd = platform_get_drvdata(pdev);
189
190	if (ltq_mtd && ltq_mtd->mtd) {
191		mtd_device_unregister(ltq_mtd->mtd);
192		map_destroy(ltq_mtd->mtd);
193	}
194	return 0;
195}
196
197static const struct of_device_id ltq_mtd_match[] = {
198	{ .compatible = "lantiq,nor" },
199	{},
200};
201MODULE_DEVICE_TABLE(of, ltq_mtd_match);
202
203static struct platform_driver ltq_mtd_driver = {
204	.probe = ltq_mtd_probe,
205	.remove = ltq_mtd_remove,
206	.driver = {
207		.name = "ltq-nor",
208		.of_match_table = ltq_mtd_match,
209	},
210};
211
212module_platform_driver(ltq_mtd_driver);
213
214MODULE_LICENSE("GPL");
215MODULE_AUTHOR("John Crispin <blogic@openwrt.org>");
216MODULE_DESCRIPTION("Lantiq SoC NOR");
217