lantiq-flash.c

  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
 34enum {
 35	LTQ_NOR_PROBING,
 36	LTQ_NOR_NORMAL
 37};
 38
 39struct ltq_mtd {
 40	struct resource *res;
 41	struct mtd_info *mtd;
 42	struct map_info *map;
 43};
 44
 45static const char ltq_map_name[] = "ltq_nor";
 46
 47static map_word
 48ltq_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
 61static void
 62ltq_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 */
 80static void
 81ltq_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
 94static void
 95ltq_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
108static int
109ltq_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->map->virt = devm_platform_get_and_ioremap_resource(pdev, 0, &ltq_mtd->res);
122	if (IS_ERR(ltq_mtd->map->virt))
123		return PTR_ERR(ltq_mtd->map->virt);
124
125	ltq_mtd->map = devm_kzalloc(&pdev->dev, sizeof(struct map_info),
126				    GFP_KERNEL);
127	if (!ltq_mtd->map)
128		return -ENOMEM;
129
130	ltq_mtd->map->phys = ltq_mtd->res->start;
131	ltq_mtd->map->size = resource_size(ltq_mtd->res);
132
133	ltq_mtd->map->name = ltq_map_name;
134	ltq_mtd->map->bankwidth = 2;
135	ltq_mtd->map->read = ltq_read16;
136	ltq_mtd->map->write = ltq_write16;
137	ltq_mtd->map->copy_from = ltq_copy_from;
138	ltq_mtd->map->copy_to = ltq_copy_to;
139
140	ltq_mtd->map->map_priv_1 = LTQ_NOR_PROBING;
141	ltq_mtd->mtd = do_map_probe("cfi_probe", ltq_mtd->map);
142	ltq_mtd->map->map_priv_1 = LTQ_NOR_NORMAL;
143
144	if (!ltq_mtd->mtd) {
145		dev_err(&pdev->dev, "probing failed\n");
146		return -ENXIO;
147	}
148
149	ltq_mtd->mtd->dev.parent = &pdev->dev;
150	mtd_set_of_node(ltq_mtd->mtd, pdev->dev.of_node);
151
152	cfi = ltq_mtd->map->fldrv_priv;
153	cfi->addr_unlock1 ^= 1;
154	cfi->addr_unlock2 ^= 1;
155
156	err = mtd_device_register(ltq_mtd->mtd, NULL, 0);
157	if (err) {
158		dev_err(&pdev->dev, "failed to add partitions\n");
159		goto err_destroy;
160	}
161
162	return 0;
163
164err_destroy:
165	map_destroy(ltq_mtd->mtd);
166	return err;
167}
168
169static void ltq_mtd_remove(struct platform_device *pdev)
170{
171	struct ltq_mtd *ltq_mtd = platform_get_drvdata(pdev);
172
173	if (ltq_mtd && ltq_mtd->mtd) {
174		mtd_device_unregister(ltq_mtd->mtd);
175		map_destroy(ltq_mtd->mtd);
176	}
177}
178
179static const struct of_device_id ltq_mtd_match[] = {
180	{ .compatible = "lantiq,nor" },
181	{},
182};
183MODULE_DEVICE_TABLE(of, ltq_mtd_match);
184
185static struct platform_driver ltq_mtd_driver = {
186	.probe = ltq_mtd_probe,
187	.remove = ltq_mtd_remove,
188	.driver = {
189		.name = "ltq-nor",
190		.of_match_table = ltq_mtd_match,
191	},
192};
193
194module_platform_driver(ltq_mtd_driver);
195
196MODULE_LICENSE("GPL");
197MODULE_AUTHOR("John Crispin <john@phrozen.org>");
198MODULE_DESCRIPTION("Lantiq SoC NOR");