drivers/mtd/maps/ixp4xx.c

   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
  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
 145 struct ixp4xx_flash_info {
 146         struct mtd_info *mtd;
 147         struct map_info map;
 148         struct resource *res;
 149 };
 150
 151 static const char * const probes[] = { "RedBoot", "cmdlinepart", NULL };
 152
 153 static 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
 172 static 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->owner = THIS_MODULE;
 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
 243 Error:
 244         ixp4xx_flash_remove(dev);
 245         return err;
 246 }
 247
 248 static 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
 256 module_platform_driver(ixp4xx_flash_driver);
 257
 258 MODULE_LICENSE("GPL");
 259 MODULE_DESCRIPTION("MTD map driver for Intel IXP4xx systems");
 260 MODULE_AUTHOR("Deepak Saxena");
 261 MODULE_ALIAS("platform:IXP4XX-Flash");