mini2440 Norflash驱动移植过程

我不知道友善linux2.6.32的内核是否支持了mini2440的norflash，我在这里还是亲自的把mini2440的norflash支持上。移植过程分享如下：
           
一.添加配置项
1、修改 drivers/mtd/maps/Kconfig文件,在config_EDB7312配置项下添加如下内容:
config MTD_MINI2440
tristate 'CFI Flash device mapped onMINI2440'
depends on ARM && MTD_CFI
help
This enables access to the CFI Flash on the CogentMINI2440 board.
If you have such a board, say 'Y' here.
2、修改 drivers/mtd/maps/Makefile文件,在obj-$(CONFIG_MTD_EDB7312)+= edb7312.o下添加如下内容:
obj-$(CONFIG_MTD_MINI2440)+= mini2440.o
3、复制驱动文件mini2440.c到drivers/mtd/maps目录下
二.配置编译内核
# make menuconfig
以下内容必选:
Memory Technology Devices(MTD)-->
<*>Memory Technology Device (MTD) support
[*]MTD partitioning support
  <*>Direct char device access to MTD devices
  <*>Caching block device access to MTD devices
RAM/ROM/Flash chip drivers-->
  <*>Detect flash chips by Common Flash Interface (CFI) probe
  <*>Support for Inter/Sharp flash chips
  <*>Supportfor AMD/Fujitsu/Spansion flash chips

  <*>CFI flash device mapped on mini2440
下列内容(在flash上架fat16/fat32/ntfs/ext2等文件系统时才需要选上)不要选，否则会出现加载驱动模块时会出现ftl_cs:FTL header not found.
DeviceDrivers ->
  Memory Technology Devices (MTD) ->
      <>FTL (Flash Translation Layer) support
      <> NFTL(NAND Flash Translation Layer) support
      <>INFTL(Inverse NAND Flash Translation Layer) support

三.根据edb7312单板的norflash驱动(linux/mtd/maps/edb7312.c)来写mini2440的norflash驱动
代码在mini2440.c中(带详细注释)

/*支持单板:mini2440
*支持内核:3.1.2版本
*模仿驱动:/linux/drivers/mtd/maps/edb7312.c
*/

#include
#include
#include
#include
#include
#include
#include
#include

#define WINDOW_ADDR 0x00000000 /* NOR FLASH物理地址 */
#define WINDOW_SIZE 0x00200000 /* NOR FLASH大小 */
#define BUSWIDTH 2 /*估计是2Byte*/
/* 探测的接口类型，可以是'cfi_probe', 'jedec_probe', 'map_rom', NULL }; */
#define PROBETYPES { 'cfi_probe', NULL }

#define MSG_PREFIX 'MINI2440-NOR:' /*printk的前缀 */
#define MTDID 'mini2440-nor' /*MTD驱动*/

static struct mtd_info *mymtd;

/*定义一个map_info，代表一块norflash*/
struct map_info mini2440nor_map =
{
.name = 'NOR flash on MINI2440',
.size = WINDOW_SIZE,
.bankwidth = BUSWIDTH,
.phys = WINDOW_ADDR,
};

/* 默认分区信息*/
static struct mtd_partition static_partitions[3] =
{
{
.name = 'bootloader',
.size = 0x40000,//256K
.offset = 0
},
{
.name = 'Kernel',
.size = 0x100000,//1M
.offset = 0x40000
},
{
.name = 'RootFS',
.size = 0xC0000,//768K
.offset = 0x140000
},
};

static const char *probes[] = {NULL};
static int mtd_parts_nb = 0;
static struct mtd_partition *mtd_parts = 0;

/*Norflash模型初始化函数
*<1>物理地址映射为虚拟地址: mini2440nor_map.virt = ioremap(WINDOW_ADDR, WINDOW_SIZE);
*<2>探测norflash芯片,得到map_info:do_map_probe(); //应该是mtd_info,而不是map_info，转载者注释
*<3>探测分区信息,得到mtd_partition：parse_mtd_partitions();
*<4>利用map_info和mtd_partition注册设备:mtd_device_register();//应该是mtd_info,而不是map_info，转载者注释
*/
int __init init_mini2440nor(void)
{
static const char *rom_probe_types[] = PROBETYPES;
const char **type;
const char *part_type = 0;

printk(KERN_NOTICE MSG_PREFIX '0x%08x at 0x%08xn', WINDOW_SIZE, WINDOW_ADDR);

/*物理地址映射为虚拟地址*/
mini2440nor_map.virt = ioremap(WINDOW_ADDR, WINDOW_SIZE);
if (!mini2440nor_map.virt)
{
printk(MSG_PREFIX 'failed to ioremapn');
return -EIO;
}
simple_map_init(&mini2440nor_map);

mymtd = 0;
type = rom_probe_types;
for (; !mymtd && *type; type++)
{
/*根据map_info探测norflash芯片，若成功则返回mtd_info*/
mymtd = do_map_probe(*type, &mini2440nor_map);
}
if (mymtd)
{
mymtd->owner = THIS_MODULE;

/*探测分区信息，若探测成功，则mtd_parts中保存了分区信息；若探测失败，使用数组定义的默认分区信息*/
mtd_parts_nb = parse_mtd_partitions(mymtd, probes, &mtd_parts, MTDID);
if (mtd_parts_nb > 0)
part_type = 'detected';
if (mtd_parts_nb == 0)
{
mtd_parts = static_partitions;
mtd_parts_nb = ARRAY_SIZE(static_partitions);
part_type = 'static';
}

if (mtd_parts_nb == 0)
printk(KERN_NOTICE MSG_PREFIX 'no partition info availablen');
else
printk(KERN_NOTICE MSG_PREFIX 'using %s partition definitionn',
part_type);

/*注册设备*/
mtd_device_register(mymtd, NULL, 0);
mtd_device_register(mymtd, mtd_parts, mtd_parts_nb);
return 0;
}
iounmap((void *)mini2440nor_map.virt);
return -ENXIO;
}

/*Norflash模块卸载函数
*<1>注销设备:mtd_device_unregister();
*<2>销毁map_info:map_destroy();
*<3>取消映射:iounmap();
*/
static void __exit cleanup_mini2440nor(void)
{
if (mymtd)
{
/*注销设备*/
mtd_device_unregister(mymtd);
/*销毁map_info*/
map_destroy(mymtd);

}
if (mini2440nor_map.virt)
{
iounmap((void*)mini2440nor_map.virt);
mini2440nor_map.virt = 0;
}
}

module_init(init_mini2440nor);
module_exit(cleanup_mini2440nor);

MODULE_LICENSE('GPL');
MODULE_AUTHOR('WeiDong Wu <625769020@qq.com>');
MODULE_DESCRIPTION('Generic configurable MTD map driver');