drivers/mtd/maps/ixp4xx.c

   1 /*
   2  * $Id: ixp4xx.c,v 1.9 2006/11/30 02:03:18 gerg Exp $
   3  *
   4  * drivers/mtd/maps/ixp4xx.c
   5  *
   6  * MTD Map file for IXP4XX based systems. Please do not make per-board
   7  * changes in here. If your board needs special setup, do it in your
   8  * platform level code in arch/arm/mach-ixp4xx/board-setup.c
   9  *
  10  * Original Author: Intel Corporation
  11  * Maintainer: Deepak Saxena <dsaxena@mvista.com>
  12  *
  13  * Copyright (C) 2002 Intel Corporation
  14  * Copyright (C) 2003-2004 MontaVista Software, Inc.
  15  *
  16  */
  17
  18 #include <linux/module.h>
  19 #include <linux/types.h>
  20 #include <linux/init.h>
  21 #include <linux/kernel.h>
  22 #include <linux/string.h>
  23 #include <linux/slab.h>
  24 #include <linux/ioport.h>
  25 #include <linux/device.h>
  26 #include <linux/platform_device.h>
  27
  28 #include <linux/mtd/mtd.h>
  29 #include <linux/mtd/map.h>
  30 #include <linux/mtd/partitions.h>
  31
  32 #include <asm/io.h>
  33 #include <asm/mach/flash.h>
  34
  35 #include <linux/reboot.h>
  36
  37 /*
  38  * Read/write a 16 bit word from flash address 'addr'.
  39  *
  40  * When the cpu is in little-endian mode it swizzles the address lines
  41  * ('address coherency') so we need to undo the swizzling to ensure commands
  42  * and the like end up on the correct flash address.
  43  *
  44  * To further complicate matters, due to the way the expansion bus controller
  45  * handles 32 bit reads, the byte stream ABCD is stored on the flash as:
  46  *     D15    D0
  47  *     +---+---+
  48  *     | A | B | 0
  49  *     +---+---+
  50  *     | C | D | 2
  51  *     +---+---+
  52  * This means that on LE systems each 16 bit word must be swapped. Note that
  53  * this requires CONFIG_MTD_CFI_BE_BYTE_SWAP to be enabled to 'unswap' the CFI
  54  * data and other flash commands which are always in D7-D0.
  55  */
  56 #ifndef __ARMEB__
  57 #ifndef CONFIG_MTD_CFI_BE_BYTE_SWAP
  58 #  error CONFIG_MTD_CFI_BE_BYTE_SWAP required
  59 #endif
  60
  61 static inline u16 flash_read16(void __iomem *addr)
  62 {
  63         return be16_to_cpu(__raw_readw((void __iomem *)((unsigned long)addr ^ 0x2)));
  64 }
  65
  66 static inline void flash_write16(u16 d, void __iomem *addr)
  67 {
  68         __raw_writew(cpu_to_be16(d), (void __iomem *)((unsigned long)addr ^ 0x2));
  69 }
  70
  71 #define BYTE0(h)        ((h) & 0xFF)
  72 #define BYTE1(h)        (((h) >> 8) & 0xFF)
  73
  74 #else
  75
  76 static inline u16 flash_read16(const void __iomem *addr)
  77 {
  78         return __raw_readw(addr);
  79 }
  80
  81 static inline void flash_write16(u16 d, void __iomem *addr)
  82 {
  83         __raw_writew(d, addr);
  84 }
  85
  86 #define BYTE0(h)        (((h) >> 8) & 0xFF)
  87 #define BYTE1(h)        ((h) & 0xFF)
  88 #endif
  89
  90 static map_word ixp4xx_read16(struct map_info *map, unsigned long ofs)
  91 {
  92         map_word val;
  93         val.x[0] = flash_read16(map->virt + ofs);
  94         return val;
  95 }
  96
  97 /*
  98  * The IXP4xx expansion bus only allows 16-bit wide acceses
  99  * when attached to a 16-bit wide device (such as the 28F128J3A),
 100  * so we can't just memcpy_fromio().
 101  */
 102 static void ixp4xx_copy_from(struct map_info *map, void *to,
 103                              unsigned long from, ssize_t len)
 104 {
 105         u8 *dest = (u8 *) to;
 106         void __iomem *src = map->virt + from;
 107
 108         if (len <= 0)
 109                 return;
 110
 111         if (from & 1) {
 112                 *dest++ = BYTE1(flash_read16(src));
 113                 src++;
 114                 --len;
 115         }
 116
 117         while (len >= 2) {
 118                 u16 data = flash_read16(src);
 119                 *dest++ = BYTE0(data);
 120                 *dest++ = BYTE1(data);
 121                 src += 2;
 122                 len -= 2;
 123         }
 124
 125         if (len > 0)
 126                 *dest++ = BYTE0(flash_read16(src));
 127 }
 128
 129 /*
 130  * Unaligned writes are ignored, causing the 8-bit
 131  * probe to fail and proceed to the 16-bit probe (which succeeds).
 132  */
 133 static void ixp4xx_probe_write16(struct map_info *map, map_word d, unsigned long adr)
 134 {
 135         if (!(adr & 1))
 136                 flash_write16(d.x[0], map->virt + adr);
 137 }
 138
 139 /*
 140  * Fast write16 function without the probing check above
 141  */
 142 static void ixp4xx_write16(struct map_info *map, map_word d, unsigned long adr)
 143 {
 144         flash_write16(d.x[0], map->virt + adr);
 145 }
 146
 147 struct ixp4xx_flash_info {
 148         struct mtd_info *mtd;
 149         struct map_info map;
 150         struct mtd_partition *partitions;
 151         struct resource *res;
 152 };
 153
 154 static const char *probes[] = { "RedBoot", "cmdlinepart", NULL };
 155
 156 static int ixp4xx_flash_remove(struct platform_device *dev)
 157 {
 158         struct flash_platform_data *plat = dev->dev.platform_data;
 159         struct ixp4xx_flash_info *info = platform_get_drvdata(dev);
 160
 161         platform_set_drvdata(dev, NULL);
 162
 163         if(!info)
 164                 return 0;
 165
 166         if (info->mtd) {
 167                 del_mtd_partitions(info->mtd);
 168                 map_destroy(info->mtd);
 169         }
 170         if (info->map.virt)
 171                 iounmap(info->map.virt);
 172
 173         kfree(info->partitions);
 174
 175         if (info->res) {
 176                 release_resource(info->res);
 177                 kfree(info->res);
 178         }
 179
 180         if (plat->exit)
 181                 plat->exit();
 182
 183         return 0;
 184 }
 185
 186 static int ixp4xx_flash_probe(struct platform_device *dev)
 187 {
 188         struct flash_platform_data *plat = dev->dev.platform_data;
 189         struct ixp4xx_flash_info *info;
 190         int err = -1;
 191
 192         if (!plat)
 193                 return -ENODEV;
 194
 195         if (plat->init) {
 196                 err = plat->init();
 197                 if (err)
 198                         return err;
 199         }
 200
 201         info = kmalloc(sizeof(struct ixp4xx_flash_info), GFP_KERNEL);
 202         if(!info) {
 203                 err = -ENOMEM;
 204                 goto Error;
 205         }
 206         memzero(info, sizeof(struct ixp4xx_flash_info));
 207
 208         platform_set_drvdata(dev, info);
 209
 210         /*
 211          * Tell the MTD layer we're not 1:1 mapped so that it does
 212          * not attempt to do a direct access on us.
 213          */
 214         info->map.phys = NO_XIP;
 215         info->map.size = dev->resource->end - dev->resource->start + 1;
 216
 217         /*
 218          * We only support 16-bit accesses for now. If and when
 219          * any board use 8-bit access, we'll fixup the driver to
 220          * handle that.
 221          */
 222         info->map.bankwidth = 2;
 223         info->map.name = dev->dev.bus_id;
 224         info->map.read = ixp4xx_read16,
 225         info->map.write = ixp4xx_probe_write16,
 226         info->map.copy_from = ixp4xx_copy_from,
 227
 228         info->res = request_mem_region(dev->resource->start,
 229                         dev->resource->end - dev->resource->start + 1,
 230                         "IXP4XXFlash");
 231         if (!info->res) {
 232                 printk(KERN_ERR "IXP4XXFlash: Could not reserve memory region\n");
 233                 err = -ENOMEM;
 234                 goto Error;
 235         }
 236
 237         info->map.virt = ioremap(dev->resource->start,
 238                                  dev->resource->end - dev->resource->start + 1);
 239         if (!info->map.virt) {
 240                 printk(KERN_ERR "IXP4XXFlash: Failed to ioremap region\n");
 241                 err = -EIO;
 242                 goto Error;
 243         }
 244
 245         info->mtd = do_map_probe(plat->map_name, &info->map);
 246         if (!info->mtd) {
 247                 printk(KERN_ERR "IXP4XXFlash: map_probe failed\n");
 248                 err = -ENXIO;
 249                 goto Error;
 250         }
 251         info->mtd->owner = THIS_MODULE;
 252
 253         /* Use the fast version */
 254         info->map.write = ixp4xx_write16,
 255
 256         err = parse_mtd_partitions(info->mtd, probes, &info->partitions, dev->resource->start);
 257         if (err > 0) {
 258                 err = add_mtd_partitions(info->mtd, info->partitions, err);
 259                 if(err)
 260                         printk(KERN_ERR "Could not parse partitions\n");
 261         }
 262
 263         if (err)
 264                 goto Error;
 265
 266         return 0;
 267
 268 Error:
 269         ixp4xx_flash_remove(dev);
 270         return err;
 271 }
 272
 273 static struct platform_driver ixp4xx_flash_driver = {
 274         .probe          = ixp4xx_flash_probe,
 275         .remove         = ixp4xx_flash_remove,
 276         .driver         = {
 277                 .name   = "IXP4XX-Flash",
 278         },
 279 };
 280
 281 static int __init ixp4xx_flash_init(void)
 282 {
 283         return platform_driver_register(&ixp4xx_flash_driver);
 284 }
 285
 286 static void __exit ixp4xx_flash_exit(void)
 287 {
 288         platform_driver_unregister(&ixp4xx_flash_driver);
 289 }
 290
 291
 292 module_init(ixp4xx_flash_init);
 293 module_exit(ixp4xx_flash_exit);
 294
 295 MODULE_LICENSE("GPL");
 296 MODULE_DESCRIPTION("MTD map driver for Intel IXP4xx systems");
 297 MODULE_AUTHOR("Deepak Saxena");