Xilinx FPGA PCIE Linux驱动程序(4)

goto exit; } exit:

return ret; }

ssize_t XPCIe_WriteMem(constchar *buf, size_t count) {

int ret = 0;

dma_addr_t dma_addr;

if ( (count % 4) != 0 ) {

printk(\,gDrvrName); ret = -1; return ret; //goto exit; }

// Now it is safe to copy the data from user space. if ( copy_from_user(gWriteBuffer, buf, count) ) {

ret = -1;

printk(\,gDrvrName); return ret; //goto exit; }

//set DMA semaphore if in loopback down(&gSem[SEM_DMA]);

// pci_map_single return the physical address corresponding to // the virtual address passed to it as the 2nd parameter

dma_addr = pci_map_single(gDev, gWriteBuffer, BUF_SIZE, PCI_DMA_FROMDEVICE); if ( 0 == dma_addr ) {

printk(\,gDrvrName); ret = -1;

up(&gSem[SEM_DMA]); return ret;

//goto exit; // return 之前要释放互斥量，不能直接return }

// Now pass the physical address to the device hardware. This is now // the source physical address for the DMA and hence the to be // put on Memory Transactions

// Do DMA transfer here....

// 直接调用read write 函数进行传输? // 宋宝华第页流程图

printk(\, gDrvrName, (unsignedint)gReadBuffer, (unsignedint)dma_addr);

// Unmap the DMA buffer so it is safe for normal access again.

pci_unmap_single(gDev, dma_addr, BUF_SIZE, PCI_DMA_FROMDEVICE);

up(&gSem[SEM_DMA]);

exit:

return (ret); }

u32 XPCIe_ReadCfgReg (u32 byte) {

u32 pciReg;

if (pci_read_config_dword(gDev, byte, &pciReg) < 0) {

printk(\,gDrvrName); return (-1); }

return (pciReg); }

u32 XPCIe_WriteCfgReg (u32 byte, u32 val) {

if (pci_write_config_dword(gDev, byte, val) < 0) {

printk(\,gDrvrName); return (-1); } return 1; }