1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * drivers/mtd/maps/ixp4xx.c
4 *
5 * MTD Map file for IXP4XX based systems. Please do not make per-board
6 * changes in here. If your board needs special setup, do it in your
7 * platform level code in arch/arm/mach-ixp4xx/board-setup.c
8 *
9 * Original Author: Intel Corporation
10 * Maintainer: Deepak Saxena <dsaxena@mvista.com>
11 *
12 * Copyright (C) 2002 Intel Corporation
13 * Copyright (C) 2003-2004 MontaVista Software, Inc.
14 *
15 */
16
17#include <linux/err.h>
18#include <linux/module.h>
19#include <linux/types.h>
20#include <linux/kernel.h>
21#include <linux/string.h>
22#include <linux/slab.h>
23#include <linux/ioport.h>
24#include <linux/device.h>
25#include <linux/platform_device.h>
26
27#include <linux/mtd/mtd.h>
28#include <linux/mtd/map.h>
29#include <linux/mtd/partitions.h>
30
31#include <asm/io.h>
32#include <asm/mach/flash.h>
33
34#include <linux/reboot.h>
35
36/*
37 * Read/write a 16 bit word from flash address 'addr'.
38 *
39 * When the cpu is in little-endian mode it swizzles the address lines
40 * ('address coherency') so we need to undo the swizzling to ensure commands
41 * and the like end up on the correct flash address.
42 *
43 * To further complicate matters, due to the way the expansion bus controller
44 * handles 32 bit reads, the byte stream ABCD is stored on the flash as:
45 *     D15    D0
46 *     +---+---+
47 *     | A | B | 0
48 *     +---+---+
49 *     | C | D | 2
50 *     +---+---+
51 * This means that on LE systems each 16 bit word must be swapped. Note that
52 * this requires CONFIG_MTD_CFI_BE_BYTE_SWAP to be enabled to 'unswap' the CFI
53 * data and other flash commands which are always in D7-D0.
54 */
55#ifndef __ARMEB__
56#ifndef CONFIG_MTD_CFI_BE_BYTE_SWAP
57#  error CONFIG_MTD_CFI_BE_BYTE_SWAP required
58#endif
59
60static inline u16 flash_read16(void __iomem *addr)
61{
62	return be16_to_cpu(__raw_readw((void __iomem *)((unsigned long)addr ^ 0x2)));
63}
64
65static inline void flash_write16(u16 d, void __iomem *addr)
66{
67	__raw_writew(cpu_to_be16(d), (void __iomem *)((unsigned long)addr ^ 0x2));
68}
69
70#define	BYTE0(h)	((h) & 0xFF)
71#define	BYTE1(h)	(((h) >> 8) & 0xFF)
72
73#else
74
75static inline u16 flash_read16(const void __iomem *addr)
76{
77	return __raw_readw(addr);
78}
79
80static inline void flash_write16(u16 d, void __iomem *addr)
81{
82	__raw_writew(d, addr);
83}
84
85#define	BYTE0(h)	(((h) >> 8) & 0xFF)
86#define	BYTE1(h)	((h) & 0xFF)
87#endif
88
89static map_word ixp4xx_read16(struct map_info *map, unsigned long ofs)
90{
91	map_word val;
92	val.x[0] = flash_read16(map->virt + ofs);
93	return val;
94}
95
96/*
97 * The IXP4xx expansion bus only allows 16-bit wide acceses
98 * when attached to a 16-bit wide device (such as the 28F128J3A),
99 * so we can't just memcpy_fromio().
100 */
101static void ixp4xx_copy_from(struct map_info *map, void *to,
102			     unsigned long from, ssize_t len)
103{
104	u8 *dest = (u8 *) to;
105	void __iomem *src = map->virt + from;
106
107	if (len <= 0)
108		return;
109
110	if (from & 1) {
111		*dest++ = BYTE1(flash_read16(src-1));
112		src++;
113		--len;
114	}
115
116	while (len >= 2) {
117		u16 data = flash_read16(src);
118		*dest++ = BYTE0(data);
119		*dest++ = BYTE1(data);
120		src += 2;
121		len -= 2;
122	}
123
124	if (len > 0)
125		*dest++ = BYTE0(flash_read16(src));
126}
127
128/*
129 * Unaligned writes are ignored, causing the 8-bit
130 * probe to fail and proceed to the 16-bit probe (which succeeds).
131 */
132static void ixp4xx_probe_write16(struct map_info *map, map_word d, unsigned long adr)
133{
134	if (!(adr & 1))
135		flash_write16(d.x[0], map->virt + adr);
136}
137
138/*
139 * Fast write16 function without the probing check above
140 */
141static void ixp4xx_write16(struct map_info *map, map_word d, unsigned long adr)
142{
143	flash_write16(d.x[0], map->virt + adr);
144}
145
146struct ixp4xx_flash_info {
147	struct mtd_info *mtd;
148	struct map_info map;
149	struct resource *res;
150};
151
152static const char * const probes[] = { "RedBoot", "cmdlinepart", NULL };
153
154static int ixp4xx_flash_remove(struct platform_device *dev)
155{
156	struct flash_platform_data *plat = dev_get_platdata(&dev->dev);
157	struct ixp4xx_flash_info *info = platform_get_drvdata(dev);
158
159	if(!info)
160		return 0;
161
162	if (info->mtd) {
163		mtd_device_unregister(info->mtd);
164		map_destroy(info->mtd);
165	}
166
167	if (plat->exit)
168		plat->exit();
169
170	return 0;
171}
172
173static int ixp4xx_flash_probe(struct platform_device *dev)
174{
175	struct flash_platform_data *plat = dev_get_platdata(&dev->dev);
176	struct ixp4xx_flash_info *info;
177	struct mtd_part_parser_data ppdata = {
178		.origin = dev->resource->start,
179	};
180	int err = -1;
181
182	if (!plat)
183		return -ENODEV;
184
185	if (plat->init) {
186		err = plat->init();
187		if (err)
188			return err;
189	}
190
191	info = devm_kzalloc(&dev->dev, sizeof(struct ixp4xx_flash_info),
192			    GFP_KERNEL);
193	if(!info) {
194		err = -ENOMEM;
195		goto Error;
196	}
197
198	platform_set_drvdata(dev, info);
199
200	/*
201	 * Tell the MTD layer we're not 1:1 mapped so that it does
202	 * not attempt to do a direct access on us.
203	 */
204	info->map.phys = NO_XIP;
205	info->map.size = resource_size(dev->resource);
206
207	/*
208	 * We only support 16-bit accesses for now. If and when
209	 * any board use 8-bit access, we'll fixup the driver to
210	 * handle that.
211	 */
212	info->map.bankwidth = 2;
213	info->map.name = dev_name(&dev->dev);
214	info->map.read = ixp4xx_read16;
215	info->map.write = ixp4xx_probe_write16;
216	info->map.copy_from = ixp4xx_copy_from;
217
218	info->map.virt = devm_ioremap_resource(&dev->dev, dev->resource);
219	if (IS_ERR(info->map.virt)) {
220		err = PTR_ERR(info->map.virt);
221		goto Error;
222	}
223
224	info->mtd = do_map_probe(plat->map_name, &info->map);
225	if (!info->mtd) {
226		printk(KERN_ERR "IXP4XXFlash: map_probe failed\n");
227		err = -ENXIO;
228		goto Error;
229	}
230	info->mtd->dev.parent = &dev->dev;
231
232	/* Use the fast version */
233	info->map.write = ixp4xx_write16;
234
235	err = mtd_device_parse_register(info->mtd, probes, &ppdata,
236			plat->parts, plat->nr_parts);
237	if (err) {
238		printk(KERN_ERR "Could not parse partitions\n");
239		goto Error;
240	}
241
242	return 0;
243
244Error:
245	ixp4xx_flash_remove(dev);
246	return err;
247}
248
249static struct platform_driver ixp4xx_flash_driver = {
250	.probe		= ixp4xx_flash_probe,
251	.remove		= ixp4xx_flash_remove,
252	.driver		= {
253		.name	= "IXP4XX-Flash",
254	},
255};
256
257module_platform_driver(ixp4xx_flash_driver);
258
259MODULE_LICENSE("GPL");
260MODULE_DESCRIPTION("MTD map driver for Intel IXP4xx systems");
261MODULE_AUTHOR("Deepak Saxena");
262MODULE_ALIAS("platform:IXP4XX-Flash");
263