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