在模块中读写pcie slot的寄存器状态

写了一个模块想模拟一下pcie slot的外部按钮事件，想法是通过改pcie插槽的寄存器的状态，然后有pciehp的中断/轮询机制来触发 对应的处理流程，可是实验过程中没有出现预期的结果...，功力尚浅～～

#include <linux/module.h>
#include <linux/init.h>
#include <linux/pci.h>
#include <linux/kernel.h>
#define PCI_EXP_SLTSTA_PDS 0x0040 /* Presence Detect State */
#define PCI_EXP_SLTSTA_PDC 0x0008 /* Presence Detect Changed */
#define PCI_EXP_SLTSTA 26 /* Slot Status */
#define PCI_EXP_SLTCTL_PCC 0x0400 /* Power Controller Control */
#define POWER_OFF PCI_EXP_SLTCTL_PCC
#define PCI_EXP_SLTCTL 24 /* Slot Control */
static struct pci_dev *dev;
static struct pci_bus *bus;
static int domain = 0x0000;
static int busnr = 0;
module_param(domain, int, 0644);
module_param(busnr, int, 0644);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("GuZheng [e-mail]");
static int __init pcie_conf_init(void)
{
int retval = 0;
u16 slot_ctrl;
u16 slot_cmd;
u16 cmd_mask;
bus = pci_find_bus(domain, busnr);
if (!bus) {
printk("==can not get pci_bus==\\n");
return -1;
}
printk("Succeed get pci bus:%s\\n", bus->name);
dev = bus->self;
if (!dev) {
printk("==can not get dev==\\n");
return -1;
}
retval = pcie_capability_read_word(dev, PCI_EXP_SLTCTL, &slot_ctrl);
if (retval) {
printk("%s can not read pcie register!\\n", __func__);
return retval;
}
printk("Succeed read pcie slot register!\\n");
cmd_mask = PCI_EXP_SLTCTL_PCC;
slot_cmd = POWER_OFF;
slot_ctrl &= ~cmd_mask;
slot_ctrl |= (cmd_mask & slot_cmd);
retval = pcie_capability_write_word(dev, PCI_EXP_SLTCTL, slot_ctrl);
if (retval) {
printk("%s can not read pcie register!\\n", __func__);
return retval;
}
printk("Succeed write pcie slot register!\\n");
return retval;
}
static void __exit pcie_conf_exit(void)
{
printk("exit module!\\n");
return;
}
module_init(pcie_conf_init);
module_exit(pcie_conf_exit);