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";
48
49static map_word
50ltq_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
63static void
64ltq_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 */
82static void
83ltq_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
96static void
97ltq_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
110static int
111ltq_mtd_probe(struct platform_device *pdev)
112{
113	struct mtd_part_parser_data ppdata;
114	struct ltq_mtd *ltq_mtd;
115	struct cfi_private *cfi;
116	int err;
117
118	if (of_machine_is_compatible("lantiq,falcon") &&
119			(ltq_boot_select() != BS_FLASH)) {
120		dev_err(&pdev->dev, "invalid bootstrap options\n");
121		return -ENODEV;
122	}
123
124	ltq_mtd = devm_kzalloc(&pdev->dev, sizeof(struct ltq_mtd), GFP_KERNEL);
125	if (!ltq_mtd)
126		return -ENOMEM;
127
128	platform_set_drvdata(pdev, ltq_mtd);
129
130	ltq_mtd->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
131	if (!ltq_mtd->res) {
132		dev_err(&pdev->dev, "failed to get memory resource\n");
133		return -ENOENT;
134	}
135
136	ltq_mtd->map = devm_kzalloc(&pdev->dev, sizeof(struct map_info),
137				    GFP_KERNEL);
138	if (!ltq_mtd->map)
139		return -ENOMEM;
140
141	ltq_mtd->map->phys = ltq_mtd->res->start;
142	ltq_mtd->map->size = resource_size(ltq_mtd->res);
143	ltq_mtd->map->virt = devm_ioremap_resource(&pdev->dev, ltq_mtd->res);
144	if (IS_ERR(ltq_mtd->map->virt))
145		return PTR_ERR(ltq_mtd->map->virt);
146
147	ltq_mtd->map->name = ltq_map_name;
148	ltq_mtd->map->bankwidth = 2;
149	ltq_mtd->map->read = ltq_read16;
150	ltq_mtd->map->write = ltq_write16;
151	ltq_mtd->map->copy_from = ltq_copy_from;
152	ltq_mtd->map->copy_to = ltq_copy_to;
153
154	ltq_mtd->map->map_priv_1 = LTQ_NOR_PROBING;
155	ltq_mtd->mtd = do_map_probe("cfi_probe", ltq_mtd->map);
156	ltq_mtd->map->map_priv_1 = LTQ_NOR_NORMAL;
157
158	if (!ltq_mtd->mtd) {
159		dev_err(&pdev->dev, "probing failed\n");
160		return -ENXIO;
161	}
162
163	ltq_mtd->mtd->dev.parent = &pdev->dev;
164
165	cfi = ltq_mtd->map->fldrv_priv;
166	cfi->addr_unlock1 ^= 1;
167	cfi->addr_unlock2 ^= 1;
168
169	ppdata.of_node = pdev->dev.of_node;
170	err = mtd_device_parse_register(ltq_mtd->mtd, NULL, &ppdata, NULL, 0);
171	if (err) {
172		dev_err(&pdev->dev, "failed to add partitions\n");
173		goto err_destroy;
174	}
175
176	return 0;
177
178err_destroy:
179	map_destroy(ltq_mtd->mtd);
180	return err;
181}
182
183static int
184ltq_mtd_remove(struct platform_device *pdev)
185{
186	struct ltq_mtd *ltq_mtd = platform_get_drvdata(pdev);
187
188	if (ltq_mtd && ltq_mtd->mtd) {
189		mtd_device_unregister(ltq_mtd->mtd);
190		map_destroy(ltq_mtd->mtd);
191	}
192	return 0;
193}
194
195static const struct of_device_id ltq_mtd_match[] = {
196	{ .compatible = "lantiq,nor" },
197	{},
198};
199MODULE_DEVICE_TABLE(of, ltq_mtd_match);
200
201static struct platform_driver ltq_mtd_driver = {
202	.probe = ltq_mtd_probe,
203	.remove = ltq_mtd_remove,
204	.driver = {
205		.name = "ltq-nor",
206		.of_match_table = ltq_mtd_match,
207	},
208};
209
210module_platform_driver(ltq_mtd_driver);
211
212MODULE_LICENSE("GPL");
213MODULE_AUTHOR("John Crispin <blogic@openwrt.org>");
214MODULE_DESCRIPTION("Lantiq SoC NOR");
215