11.1.1 示例驱动程序源代码(mypci.c)

/*
 * 与PCI函数进行交互的简单KLD
 *
 * Murray Stokely
 */

#include <sys/param.h>		/* kernel.h中使用的定义 */
#include <sys/module.h>
#include <sys/systm.h>
#include <sys/errno.h>
#include <sys/kernel.h>		/* 模块初始化中使用的类型 */
#include <sys/conf.h>		/* cdevsw结构 */
#include <sys/uio.h>		/* uio结构 */
#include <sys/malloc.h>
#include <sys/bus.h>		/* pci总线用到的结构、原型 */

#include <machine/bus.h>
#include <sys/rman.h>
#include <machine/resource.h>

#include <dev/pci/pcivar.h>	/* 为了使用get_pci宏! */
#include <dev/pci/pcireg.h>

/* softc保存我们每个实例的数据。 */
struct mypci_softc {
	device_t	my_dev;
	struct cdev	*my_cdev;
};

/* 函数原型 */
static d_open_t		mypci_open;
static d_close_t	mypci_close;
static d_read_t		mypci_read;
static d_write_t	mypci_write;

/* 字符设备入口点 */

static struct cdevsw mypci_cdevsw = {
	.d_version =	D_VERSION,
	.d_open =	mypci_open,
	.d_close =	mypci_close,
	.d_read =	mypci_read,
	.d_write =	mypci_write,
	.d_name =	"mypci",
};

/*
 * 在cdevsw例程中，我们通过结构体cdev中的成员si_drv1找出我们的softc。
 * 当我们建立/dev项时，在我们的已附着的例程中，
 * 我们设置这个变量指向我们的softc。
 */

int
mypci_open(struct cdev *dev, int oflags, int devtype, d_thread_t *td)
{
	struct mypci_softc *sc;

	/* Look up our softc. */
	sc = dev->si_drv1;
	device_printf(sc->my_dev, "Opened successfully.\n");
	return (0);
}

int
mypci_close(struct cdev *dev, int fflag, int devtype, d_thread_t *td)
{
	struct mypci_softc *sc;

	/* Look up our softc. */
	sc = dev->si_drv1;
	device_printf(sc->my_dev, "Closed.\n");
	return (0);
}

int
mypci_read(struct cdev *dev, struct uio *uio, int ioflag)
{
	struct mypci_softc *sc;

	/* Look up our softc. */
	sc = dev->si_drv1;
	device_printf(sc->my_dev, "Asked to read %d bytes.\n", uio->uio_resid);
	return (0);
}

int
mypci_write(struct cdev *dev, struct uio *uio, int ioflag)
{
	struct mypci_softc *sc;

	/* Look up our softc. */
	sc = dev->si_drv1;
	device_printf(sc->my_dev, "Asked to write %d bytes.\n", uio->uio_resid);
	return (0);
}

/* PCI支持函数 */

/*
 * 将某个设置的标识与这个驱动程序支持的标识相比较。
 * 如果相符，设置描述字符并返回成功。
 */
static int
mypci_probe(device_t dev)
{

	device_printf(dev, "MyPCI Probe\nVendor ID : 0x%x\nDevice ID : 0x%x\n",
	    pci_get_vendor(dev), pci_get_device(dev));

	if (pci_get_vendor(dev) == 0x11c1) {
		printf("We've got the Winmodem, probe successful!\n");
		device_set_desc(dev, "WinModem");
		return (BUS_PROBE_DEFAULT);
	}
	return (ENXIO);
}

/* 只有当探测成功时才调用连接函数 */

static int
mypci_attach(device_t dev)
{
	struct mypci_softc *sc;

	printf("MyPCI Attach for : deviceID : 0x%x\n", pci_get_devid(dev));

	/* Look up our softc and initialize its fields. */
	sc = device_get_softc(dev);
	sc->my_dev = dev;

	/*
	 * Create a /dev entry for this device.  The kernel will assign us
	 * a major number automatically.  We use the unit number of this
	 * device as the minor number and name the character device
	 * "mypci<unit>".
	 */
	sc->my_cdev = make_dev(&mypci_cdevsw, device_get_unit(dev),
	    UID_ROOT, GID_WHEEL, 0600, "mypci%u", device_get_unit(dev));
	sc->my_cdev->si_drv1 = sc;
	printf("Mypci device loaded.\n");
	return (0);
}

/* 分离设备。 */

static int
mypci_detach(device_t dev)
{
	struct mypci_softc *sc;

	/* Teardown the state in our softc created in our attach routine. */
	sc = device_get_softc(dev);
	destroy_dev(sc->my_cdev);
	printf("Mypci detach!\n");
	return (0);
}

/* 系统关闭期间在sync之后调用。 */

static int
mypci_shutdown(device_t dev)
{

	printf("Mypci shutdown!\n");
	return (0);
}

/*
 * 设备挂起例程。
 */
static int
mypci_suspend(device_t dev)
{

	printf("Mypci suspend!\n");
	return (0);
}

/*
 * 设备恢复（重新开始）例程。
 */
static int
mypci_resume(device_t dev)
{

	printf("Mypci resume!\n");
	return (0);
}

static device_method_t mypci_methods[] = {
	/* 设备接口 */
	DEVMETHOD(device_probe,		mypci_probe),
	DEVMETHOD(device_attach,	mypci_attach),
	DEVMETHOD(device_detach,	mypci_detach),
	DEVMETHOD(device_shutdown,	mypci_shutdown),
	DEVMETHOD(device_suspend,	mypci_suspend),
	DEVMETHOD(device_resume,	mypci_resume),

	{ 0, 0 }
};

static devclass_t mypci_devclass;

DEFINE_CLASS_0(mypci, mypci_driver, mypci_methods, sizeof(struct mypci_softc));
DRIVER_MODULE(mypci, pci, mypci_driver, mypci_devclass, 0, 0);

11.1.2 示例驱动程序的Makefile

# 驱动程序mypci的Makefile

KMOD=	mypci
SRCS=	mypci.c
SRCS+=	device_if.h bus_if.h pci_if.h

.include <bsd.kmod.mk>

　　如果你将上面的源文件和 Makefile放入一个目录，你可以运行 make编译示例驱动程序。 还有，你可以运行make load 将驱动程序装载到当前正在运行的内核中，而make unload可在装载后卸载驱动程序。

11.1.3 更多资源

• PCI Special Interest Group

• PCI System Architecture, Fourth Edition by Tom Shanley, et al.