上位机：ubuntu14.04 64bit
下位机:qq2440
交叉编译器:arm-linux-gcc 3.4.1
下位机使用的linux内核版本:kernel2.6.13
1.插入u盘时错误信息如下:
[root@FriendlyARM /home]# usb 1-1: new full speed USB device using s3c2410-ohci and address 6
usb 1-1: device descriptor read/64, error -110
usb 1-1: device descriptor read/64, error -110
usb 1-1: new full speed USB device using s3c2410-ohci and address 7
usb 1-1: device descriptor read/64, error -110
usb 1-1: device descriptor read/64, error -110
usb 1-1: new full speed USB device using s3c2410-ohci and address 8
usb 1-1: device not accepting address 8, error -110
usb 1-1: new full speed USB device using s3c2410-ohci and address 9
usb 1-1: device not accepting address 9, error -110
2.解决方案如下:
2.1修改drivers/usb/host/ohci-s3c2410.c文件，添加以下内容：
a.先添加头文件#include <mach/regs-clock.h>
b.在s3c2410_start_hc函数中添加以下内容：
bash/shell Code复制内容到剪贴板 unsigned long upllvalue = (0x78 << 12) | (0x02 << 4) | (0x03);while (upllvalue != __raw_readl(S3C2410_UPLLCON)) {
__raw_writel(upllvalue, S3C2410_UPLLCON);mdelay(1);
}添加后的s3c2410_start_hc函数如下:
bash/shell Code复制内容到剪贴板 static void s3c2410_start_hc(struct platform_device *dev, struct usb_hcd *hcd){
struct s3c2410_hcd_info *info = dev->dev.platform_data;dev_dbg(&dev->dev, "s3c2410_start_hc:\n");
clk_enable(clk);if (info != NULL) {
info->hcd = hcd;info->report_oc = s3c2410_hcd_oc;
if (info->enable_oc != NULL) {(info->enable_oc)(info, 1);
}}
unsigned long upllvalue = (0x78 << 12) | (0x02 << 4) | (0x03);while (upllvalue != __raw_readl(S3C2410_UPLLCON)) {
__raw_writel(upllvalue, S3C2410_UPLLCON);mdelay(1);
}}
2.2总结：以上修改的函数功能是启动主机控制器,因为usb时钟设置有问题，因而在开启主机控制器时修改时钟,修改后的S3C2410_UPLLCON的值为0xF4100008;
3.注意：本版本内核没有头文件regs-clock.h，因而我从其他内核中复制过来的，命令如下:
jello@jello-Inspiron-N4050:~/Downloads/qq2440/linux/kernel-2.6.13$ cp /tftpboot/kernel-2.6.35.7/arch/arm/mach-s3c2410/include/mach/regs-clock.h ./