移植较新（Linux3.19）内核至mini2440开发板（一）

下面开始正题

注：内核启动时可能会出现乱码，可以在u-boot下设置如下环境变量：setenv bootargs noinitrd root=/dev/mtdblock3 init=/linuxrc console=ttySAC0,115200

saveenv 

1.1下载Linux3.19的源代码

从Linux kernel的官方网站可以下载最新的内核代码，我们选择linux-3.19.4.tar.gz这个文件下载。下载后解压至工作目录。进入内核目录，打开Makefile文件，修改如下两行：

-ARCH ?= $(SUBARCH)

-CROSS_COMPILE ?= $(CONFIG_CROSS_COMPILE:"%"=%)

+ARCH ?= $(SUBARCH)

+CROSS_COMPILE ?= $(CONFIG_CROSS_COMPILE:"%"=%)

保存退出后执行

root@ginger-virtual-machine:/home/ginger/mini2440/linux-3.19.3# make menuconfig

打开内核配置界面，不做任何操作直接退出，然后在终端执行

root@ginger-virtual-machine:/home/ginger/mini2440/linux-3.19.3# make mini2440_defconfig
显示
## configuration written to .config
#

说明已经对采用了内核自带的mini2440的配置，这样可以减少我们手动配置内核的工作量。此时我们执行

root@ginger-virtual-machine:/home/ginger/mini2440/linux-3.19.3# make zImage
发现已经可以编译内核并生成内核镜像，这是因为新版本的Linux内核已经添加了对mini2440的支持.

1.2添加对平台的支持

在/linux-3.19.3/arch/arm/mach-s3c24xx目录下有一个名为mach-mini2440.c的源文件， 但是我们不使用它，将其删除后将该目录下的mach-smdk2440.c文件复制一份并改名为mach-mini2440.c.打开mach-mini2440.c文件，将其中关于LCD的定义均删除，后续我们将自己添加LCD驱动相关代码。

/* LCD driver info */
 
static struct s3c2410fb_display smdk2440_lcd_cfg __initdata = {
 
	.lcdcon5	= S3C2410_LCDCON5_FRM565 |
			  S3C2410_LCDCON5_INVVLINE |
			  S3C2410_LCDCON5_INVVFRAME |
			  S3C2410_LCDCON5_PWREN |
			  S3C2410_LCDCON5_HWSWP,
 
	.type		= S3C2410_LCDCON1_TFT,
 
	.width		= 240,
	.height		= 320,
 
	.pixclock	= 166667, /* HCLK 60 MHz, divisor 10 */
	.xres		= 240,
	.yres		= 320,
	.bpp		= 16,
	.left_margin	= 20,
	.right_margin	= 8,
	.hsync_len	= 4,
	.upper_margin	= 8,
	.lower_margin	= 7,
	.vsync_len	= 4,
};
 
static struct s3c2410fb_mach_info smdk2440_fb_info __initdata = {
	.displays	= &smdk2440_lcd_cfg,
	.num_displays	= 1,
	.default_display = 0,
 
#if 0
	/* currently setup by downloader */
	.gpccon		= 0xaa940659,
	.gpccon_mask	= 0xffffffff,
	.gpcup		= 0x0000ffff,
	.gpcup_mask	= 0xffffffff,
	.gpdcon		= 0xaa84aaa0,
	.gpdcon_mask	= 0xffffffff,
	.gpdup		= 0x0000faff,
	.gpdup_mask	= 0xffffffff,
#endif
 
	.lpcsel		= ((0xCE6) & ~7) | 1<<4,
};
同时将static struct platform_device *mini2440_devices[] __initdata 函数中的&s3c_device_lcd,注释，将static void __init mini2440_machine_init(void)函数中的s3c24xx_fb_set_platdata(&mini2440_fb_info)和smdk_machine_init();注释。然后使用替换功能将代码中的所有smdk2440均替换为mini2440.
1.3修改晶振频率

将static void __init mini2440_init_time(void)函数中的s3c2440_init_clocks(16934400);更改为s3c2440_init_clocks(12000000)

1.4找到MACHINE_START(S3C2440, "SMDK2440")函数，将其修改为MACHINE_START(MINI2440, "Ginger's board")，如果不修改，将导致内核启动时直接卡在Starting kernel .......................处。此时保存后编译，内核已可以正常编译，但此时还有大部分驱动未编写，内核还无法正常启动。下一步我们将在源码中增加关于nand flash分区表的相关内容

1.5添加nand flash的支持

在mach-mini2440.c中增加以下内容

/* NAND Flash on MINI2440 board */
 
static struct mtd_partition mini2440_default_nand_part[]  = {
 	[0] = {
 		.name	= "supervivi",
 		.size	= 0x00040000,
 		.offset	= 0,
 	},
 	[1] = {
 		.name	= "param",
 		.offset = 0x00040000,
 		.size	= 0x00020000,
 	},
 	[2] = {
 		.name	= "Kernel",
 		.offset = 0x00060000,
 		.size	= 0x00500000,
 	},
 	[3] = {
 		.name	= "root",
 		.offset = 0x00560000,
		.size	= 1024 * 1024 * 1024, //
	},
	[4] = {
		.name	= "nand",
		.offset = 0x00000000,
		.size	= 1024 * 1024 * 1024, //
	},
};
 
static struct s3c2410_nand_set mini2440_nand_sets[]  = {
	[0] = {
		.name		= "nand",
		.nr_chips	= 1,
		.nr_partitions	= ARRAY_SIZE(mini2440_default_nand_part),
		.partitions	= mini2440_default_nand_part,
		.flash_bbt 	= 1, /* we use u-boot to create a BBT */
	},
};
 
static struct s3c2410_platform_nand mini2440_nand_info = {
	.tacls		= 0,
	.twrph0		= 25,
	.twrph1		= 15,
	.nr_sets	= ARRAY_SIZE(mini2440_nand_sets),
	.sets		= mini2440_nand_sets,
	.ignore_unset_ecc = 1,
};
添加如下头文件
#include 
#include 
#include 
#include 
#include 
在static struct platform_device *mini2440_devices[] __initdata函数中增加&s3c_device_nand,在static void __init mini2440_machine_init(void)函数中增加s3c_nand_set_platdata(&mini2440_nand_info);
保存后编译，下载到开发板上，可看到如下启动信息：
s3c24xx-nand s3c2440-nand: Tacls=1, 9ns Twrph0=3 29ns, Twrph1=2 19ns
s3c24xx-nand s3c2440-nand: NAND soft ECC
nand: device found, Manufacturer ID: 0xec, Chip ID: 0xda
nand: Samsung NAND 256MiB 3,3V 8-bit
nand: 256 MiB, SLC, erase size: 128 KiB, page size: 2048, OOB size: 64
Creating 5 MTD partitions on "nand":
0x000000000000-0x000000040000 : "supervivi"
__nand_correct_data: uncorrectable ECC error
0x000000040000-0x000000060000 : "param"
ftl_cs: FTL header not found.
0x000000060000-0x000000560000 : "Kernel"
ftl_cs: FTL header not found.
0x000000560000-0x000040560000 : "root"
mtd: partition "root" extends beyond the end of device "nand" -- size truncated to 0xfaa0000
ftl_cs: FTL header not found.
0x000000000000-0x000040000000 : "nand"
mtd: partition "nand" extends beyond the end of device "nand" -- size truncated to 0x10000000
__nand_correct_data: uncorrectable ECC error

发现开发板已经可以识别nand flash的信息，但是打印出如下信息：
ftl_cs: FTL header not found.
解决方法如下：在内核根目录下执行make menuconfig,进入
Device Drivers ->
Memory Technology Devices (MTD) ->
去掉如下选项
<>FTL (Flash Translation Layer) support
<> NFTL (NAND Flash Translation Layer) support
<>INFTL (Inverse NAND Flash Translation Layer) support
保存后重新编译即可。
1.6到目前为止已经完成了对nand flash的支持，但是因为缺少根文件系统，内核依旧无法正常启动。接下去我们将为内核添加对yaffs2的支持。

在终端下执行#git clone git://www.aleph1.co.uk/yaffs2 获取最新的yaffs2源码。同步完后，进入yaffs2目录，执行# ./patch-ker.sh c m 内核源码路径，既可对内核打上yaffs2的补丁。进入内核目录，执行make menuconfig

选择File systems  --->  

 [*] Miscellaneous filesystems  --->       
 │    <*>   yaffs2 file system support
保存后退出，重新编译，此时会遇到几个错误，因为新版的Linux内核有一些对文件操作的函数进行了修改，我们需要按照错误逐一进行修改。按照错误：
fs/yaffs2/yaffs_vfs.c: In function 'yaffs_readpage_nolock':
fs/yaffs2/yaffs_vfs.c:286: error: 'struct file' has no member named 'f_dentry'
fs/yaffs2/yaffs_vfs.c: In function 'yaffs_hold_space':
fs/yaffs2/yaffs_vfs.c:484: error: 'struct file' has no member named 'f_dentry'
fs/yaffs2/yaffs_vfs.c: In function 'yaffs_release_space':
fs/yaffs2/yaffs_vfs.c:502: error: 'struct file' has no member named 'f_dentry'
fs/yaffs2/yaffs_vfs.c: In function 'yaffs_file_write':
fs/yaffs2/yaffs_vfs.c:594: error: 'struct file' has no member named 'f_dentry'
fs/yaffs2/yaffs_vfs.c:606: error: 'struct file' has no member named 'f_dentry'
fs/yaffs2/yaffs_vfs.c: In function 'yaffs_file_flush':
fs/yaffs2/yaffs_vfs.c:730: error: 'struct file' has no member named 'f_dentry'
fs/yaffs2/yaffs_vfs.c:741: error: too few arguments to function 'yaffs_flush_file'
fs/yaffs2/yaffs_vfs.c: In function 'yaffs_sync_object':
fs/yaffs2/yaffs_vfs.c:771: error: too few arguments to function 'yaffs_flush_file'
fs/yaffs2/yaffs_vfs.c: At top level:
fs/yaffs2/yaffs_vfs.c:781: error: 'generic_file_aio_read' undeclared here (not in a function)
fs/yaffs2/yaffs_vfs.c:782: error: 'generic_file_aio_write' undeclared here (not in a function)
fs/yaffs2/yaffs_vfs.c:787: error: 'generic_file_splice_write' undeclared here (not in a function)
fs/yaffs2/yaffs_vfs.c: In function 'yaffs_iterate':
fs/yaffs2/yaffs_vfs.c:1719: error: 'struct file' has no member named 'f_dentry'
fs/yaffs2/yaffs_vfs.c: In function 'yaffs_flush_inodes':
fs/yaffs2/yaffs_vfs.c:2190: error: too few arguments to function 'yaffs_flush_file'
fs/yaffs2/yaffs_vfs.c: In function 'yaffs_flush_super':
fs/yaffs2/yaffs_vfs.c:2203: error: too few arguments to function 'yaffs_flush_whole_cache'

打开/fs/yaffs2/yaffs_vfs.c,使用替换功能，将代码中的所有f_dentry均替换为f_path.dentry，将所有的yaffs_flush_file(obj, 1, 0);替换为yaffs_flush_file(obj, 1, 0,1);将yaffs_flush_file(obj, 1, datasync);替换为yaffs_flush_file(obj, 1, datasync,1);将yaffs_flush_file(obj, 1, 0);替换为yaffs_flush_file(obj, 1, 0,1);yaffs_flush_whole_cache(dev);替换为yaffs_flush_whole_cache(dev,1);
718行附近
-	.read = do_sync_read,
-	.write = do_sync_write,
+	.read = new_sync_read,
+	.write = new_sync_write,
-	.aio_read = generic_file_aio_read,
-	.aio_write = generic_file_aio_write,
+       .read_iter =	generic_file_read_iter,
+       .write_iter =	generic_file_write_iter,
-	.splice_write = generic_file_splice_write,
+	.splice_write = iter_file_splice_write,

保存后重新编译，下载内核至开发板，同时烧录文件系统（为了测试方便，这次我先使用友善提供的制作好的文件系统root_qtopia.img在以后的教程中我们也会制作自己的文件系统），重启开发板，看到如下引导信息
Starting kernel ...
 
Booting Linux on physical CPU 0x0
Linux version 3.19.3 (root@ginger-virtual-machine) (gcc version 4.4.3 (ctng-1.6.1) ) #6 Sat Apr 25 13:37:14 CST 2015