我目前正在尝试编译 Linux USB UART 驱动程序，此处提供： http://www.exar.com/connectivity/uart-and-bridging-solutions/usb-uarts/xr21v1410
该驱动程序由 2 个头文件和 1 个大型 C 文件组成。这些是 Makefile 的内容：
obj-m := vizzini.o
KERNELDIR ?= /lib/modules/$(shell uname -r)/build
PWD := $(shell pwd)
EXTRA_CFLAGS := -DDEBUG=0
all:
$(MAKE) -C $(KERNELDIR) M=$(PWD)
modules_install:
$(MAKE) -C $(KERNELDIR) M=$(PWD) modules_install
clean:
rm -rf *.o *~ core .depend .*.cmd *.ko *.mod.c .tmp_versions vtty
这是我运行 make 时编译器抛出的错误：
[sj755@localhost xr21v141x-lnx-2.6.35-pak]$ make
make -C /lib/modules/3.4.9-2.fc16.x86_64/build M=/home/sj755/Downloads/xr21v141x-lnx-2.6.35-pak
make[1]: Entering directory `/usr/src/kernels/3.4.9-2.fc16.x86_64'
LD /home/sj755/Downloads/xr21v141x-lnx-2.6.35-pak/built-in.o
CC [M] /home/sj755/Downloads/xr21v141x-lnx-2.6.35-pak/vizzini.o
/home/sj755/Downloads/xr21v141x-lnx-2.6.35-pak/vizzini.c:1643:9: warning: initialization from incompatible pointer type [enabled by default]
/home/sj755/Downloads/xr21v141x-lnx-2.6.35-pak/vizzini.c:1643:9: warning: (near initialization for ‘vizzini_device.ioctl’) [enabled by default]
/home/sj755/Downloads/xr21v141x-lnx-2.6.35-pak/vizzini.c:1646:9: warning: initialization from incompatible pointer type [enabled by default]
/home/sj755/Downloads/xr21v141x-lnx-2.6.35-pak/vizzini.c:1646:9: warning: (near initialization for ‘vizzini_device.tiocmget’) [enabled by default]
/home/sj755/Downloads/xr21v141x-lnx-2.6.35-pak/vizzini.c:1647:9: warning: initialization from incompatible pointer type [enabled by default]
/home/sj755/Downloads/xr21v141x-lnx-2.6.35-pak/vizzini.c:1647:9: warning: (near initialization for ‘vizzini_device.tiocmset’) [enabled by default]
/home/sj755/Downloads/xr21v141x-lnx-2.6.35-pak/vizzini.c: In function ‘vizzini_init’:
/home/sj755/Downloads/xr21v141x-lnx-2.6.35-pak/vizzini.c:1663:9: error: implicit declaration of function ‘usb_serial_register’ [-Werror=implicit-function-declaration]
/home/sj755/Downloads/xr21v141x-lnx-2.6.35-pak/vizzini.c:1677:9: error: implicit declaration of function ‘usb_serial_deregister’ [-Werror=implicit-function-declaration]
/home/sj755/Downloads/xr21v141x-lnx-2.6.35-pak/vizzini.c: In function ‘__check_debug’:
/home/sj755/Downloads/xr21v141x-lnx-2.6.35-pak/vizzini.c:1698:83: warning: return from incompatible pointer type [enabled by default]
cc1: some warnings being treated as errors
make[2]: *** [/home/sj755/Downloads/xr21v141x-lnx-2.6.35-pak/vizzini.o] Error 1
make[1]: *** [_module_/home/sj755/Downloads/xr21v141x-lnx-2.6.35-pak] Error 2
make[1]: Leaving directory `/usr/src/kernels/3.4.9-2.fc16.x86_64'
make: *** [all] Error 2
这些是主 c 源文件中包含的标头：
#include <linux/kernel.h>
#include <linux/jiffies.h>
#include <linux/errno.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/module.h>
#include <linux/usb.h>
#include <linux/usb/serial.h>
#include <linux/serial.h>
#include <linux/slab.h>
#include <asm/unaligned.h>
#include <asm/uaccess.h>
#include <linux/usb/cdc.h>
#ifndef CDC_DATA_INTERFACE_TYPE
#define CDC_DATA_INTERFACE_TYPE 0x0a
#endif
#ifndef USB_RT_ACM
#define USB_RT_ACM (USB_TYPE_CLASS | USB_RECIP_INTERFACE)
#define ACM_CTRL_DTR 0x01
#define ACM_CTRL_RTS 0x02
#define ACM_CTRL_DCD 0x01
#define ACM_CTRL_DSR 0x02
#define ACM_CTRL_BRK 0x04
#define ACM_CTRL_RI 0x08
#define ACM_CTRL_FRAMING 0x10
#define ACM_CTRL_PARITY 0x20
#define ACM_CTRL_OVERRUN 0x40
#endif
#include "linux/version.h"
#include "vizzini.h"
运行Linux内核3.4.9-2.fc16.x86_64
我将非常感谢任何解决错误的帮助。
答案1
在最新版本的 Linux 内核中，usb_serial_register和usb_serial_deregister函数被设为静态。因此，这些函数仅以文本形式存在于内核对象文件中。可以使用and代替usb_serial_register_drivers。usb_serial_deregister_drivers
下面是两组函数的定义：
int usb_serial_register(struct usb_serial_driver *driver);
void usb_serial_deregister(struct usb_serial_driver *device);
int usb_serial_register_drivers(struct usb_driver *udriver,
struct usb_serial_driver * const serial_drivers[]);
void usb_serial_deregister_drivers(struct usb_driver *udriver,
struct usb_serial_driver * const serial_drivers[]);
usb_serial_register_drivers采用 NULL 终止的指向要注册的 USB 串行驱动程序的指针数组以及用于匹配设备/接口的 usb_driver。两组函数的详细信息可以在这里阅读：
http://lxr.free-electrons.com/source/drivers/usb/serial/usb-serial.c?v=3.4#L1379
http://www.cs.fsu.edu/~baker/devices/lxr/http/source/linux/drivers/usb/serial/usb-serial.c#L1337
在驱动程序的源代码中，诸如此类的行：
retval = usb_serial_register(&vizzini_device);
被替换为：
struct usb_serial_driver *serial_drivers[2] = {&vizzini_device,NULL};
retval = usb_serial_register_drivers(&vizzini_driver,serial_drivers);
vizzini_driver 和 vizzini_device 在代码中的其他位置定义如下：
static struct usb_driver vizzini_driver = {
.name = "vizzini",
.probe = usb_serial_probe,
.disconnect = vizzini_disconnect,
.id_table = id_table,
.no_dynamic_id = 1,
};
static struct usb_serial_driver vizzini_device = {
.driver = {
.owner = THIS_MODULE,
.name = "vizzini",
},
.usb_driver = &vizzini_driver,
.description = "Vizzini USB serial port",
.id_table = id_table,
.calc_num_ports = vizzini_calc_num_ports,
.probe = vizzini_probe,
.open = vizzini_open,
.close = vizzini_close,
.write = vizzini_write,
.write_room = vizzini_write_room,
.ioctl = vizzini_ioctl,
.set_termios = vizzini_set_termios,
.break_ctl = vizzini_break_ctl,
.tiocmget = vizzini_tiocmget,
.tiocmset = vizzini_tiocmset,
.attach = vizzini_attach,
.disconnect = vizzini_serial_disconnect,
.release = vizzini_serial_release,
.read_int_callback = vizzini_int_callback,
};
答案2
内核内部的 API 远非稳定，因此除非驱动程序与内核源代码大致相同，否则它将无法工作（并且您给出的警告/错误消息指向该确切方向）。大多数树外驱动程序都是可怕的代码，所以对它持保留态度。查看当前内核是否支持这一点，无论是官方的还是在临时驱动程序中。查看Linux-USB，您可能会在那里找到一些指示。