linux/drivers/mtd/maps/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 <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/init.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->owner = THIS_MODULE;
 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                .owner  = THIS_MODULE,
 255        },
 256};
 257
 258module_platform_driver(ixp4xx_flash_driver);
 259
 260MODULE_LICENSE("GPL");
 261MODULE_DESCRIPTION("MTD map driver for Intel IXP4xx systems");
 262MODULE_AUTHOR("Deepak Saxena");
 263MODULE_ALIAS("platform:IXP4XX-Flash");
 264