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ixp4xx.c
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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 <[email protected]>
10  *
11  * Copyright (C) 2002 Intel Corporation
12  * Copyright (C) 2003-2004 MontaVista Software, Inc.
13  *
14  */
15 
16 #include <linux/module.h>
17 #include <linux/types.h>
18 #include <linux/init.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 
59 static inline u16 flash_read16(void __iomem *addr)
60 {
61  return be16_to_cpu(__raw_readw((void __iomem *)((unsigned long)addr ^ 0x2)));
62 }
63 
64 static 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 
74 static inline u16 flash_read16(const void __iomem *addr)
75 {
76  return __raw_readw(addr);
77 }
78 
79 static 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 
88 static 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  */
100 static 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  */
131 static 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  */
140 static 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 
146  struct mtd_info *mtd;
147  struct map_info map;
148  struct resource *res;
149 };
150 
151 static const char *probes[] = { "RedBoot", "cmdlinepart", NULL };
152 
153 static int ixp4xx_flash_remove(struct platform_device *dev)
154 {
155  struct flash_platform_data *plat = dev->dev.platform_data;
156  struct ixp4xx_flash_info *info = platform_get_drvdata(dev);
157 
158  platform_set_drvdata(dev, NULL);
159 
160  if(!info)
161  return 0;
162 
163  if (info->mtd) {
164  mtd_device_unregister(info->mtd);
165  map_destroy(info->mtd);
166  }
167  if (info->map.virt)
168  iounmap(info->map.virt);
169 
170  if (info->res) {
171  release_resource(info->res);
172  kfree(info->res);
173  }
174 
175  if (plat->exit)
176  plat->exit();
177 
178  return 0;
179 }
180 
181 static int ixp4xx_flash_probe(struct platform_device *dev)
182 {
183  struct flash_platform_data *plat = dev->dev.platform_data;
184  struct ixp4xx_flash_info *info;
185  struct mtd_part_parser_data ppdata = {
186  .origin = dev->resource->start,
187  };
188  int err = -1;
189 
190  if (!plat)
191  return -ENODEV;
192 
193  if (plat->init) {
194  err = plat->init();
195  if (err)
196  return err;
197  }
198 
199  info = kzalloc(sizeof(struct ixp4xx_flash_info), GFP_KERNEL);
200  if(!info) {
201  err = -ENOMEM;
202  goto Error;
203  }
204 
205  platform_set_drvdata(dev, info);
206 
207  /*
208  * Tell the MTD layer we're not 1:1 mapped so that it does
209  * not attempt to do a direct access on us.
210  */
211  info->map.phys = NO_XIP;
212  info->map.size = resource_size(dev->resource);
213 
214  /*
215  * We only support 16-bit accesses for now. If and when
216  * any board use 8-bit access, we'll fixup the driver to
217  * handle that.
218  */
219  info->map.bankwidth = 2;
220  info->map.name = dev_name(&dev->dev);
221  info->map.read = ixp4xx_read16;
222  info->map.write = ixp4xx_probe_write16;
223  info->map.copy_from = ixp4xx_copy_from;
224 
225  info->res = request_mem_region(dev->resource->start,
226  resource_size(dev->resource),
227  "IXP4XXFlash");
228  if (!info->res) {
229  printk(KERN_ERR "IXP4XXFlash: Could not reserve memory region\n");
230  err = -ENOMEM;
231  goto Error;
232  }
233 
234  info->map.virt = ioremap(dev->resource->start,
235  resource_size(dev->resource));
236  if (!info->map.virt) {
237  printk(KERN_ERR "IXP4XXFlash: Failed to ioremap region\n");
238  err = -EIO;
239  goto Error;
240  }
241 
242  info->mtd = do_map_probe(plat->map_name, &info->map);
243  if (!info->mtd) {
244  printk(KERN_ERR "IXP4XXFlash: map_probe failed\n");
245  err = -ENXIO;
246  goto Error;
247  }
248  info->mtd->owner = THIS_MODULE;
249 
250  /* Use the fast version */
251  info->map.write = ixp4xx_write16;
252 
253  err = mtd_device_parse_register(info->mtd, probes, &ppdata,
254  plat->parts, plat->nr_parts);
255  if (err) {
256  printk(KERN_ERR "Could not parse partitions\n");
257  goto Error;
258  }
259 
260  return 0;
261 
262 Error:
263  ixp4xx_flash_remove(dev);
264  return err;
265 }
266 
267 static struct platform_driver ixp4xx_flash_driver = {
268  .probe = ixp4xx_flash_probe,
269  .remove = ixp4xx_flash_remove,
270  .driver = {
271  .name = "IXP4XX-Flash",
272  .owner = THIS_MODULE,
273  },
274 };
275 
276 module_platform_driver(ixp4xx_flash_driver);
277 
278 MODULE_LICENSE("GPL");
279 MODULE_DESCRIPTION("MTD map driver for Intel IXP4xx systems");
280 MODULE_AUTHOR("Deepak Saxena");
281 MODULE_ALIAS("platform:IXP4XX-Flash");