Linux/AM5728: PCIe EP configuration

Part Number:AM5728

Tool/software: Linux

Hi,TI

I use am5728-evm board and ti-processor-sdk-linux-am57xx-evm-04.01.00.06.

I try to let the am5728-evm board as a Ep device.but something is strange.

at pci-dra7xx.c file,I can see the code.

899 static int dra7xx_pcie_resume(struct device *dev)
900 {
901         struct dra7xx_pcie *dra7xx = dev_get_drvdata(dev);
902         struct dw_pcie *pci = dra7xx->pci;
903         u32 val;
904
905         if (dra7xx->mode != DW_PCIE_RC_TYPE)
906                 return 0;
907
908         printk("pcie: dra7xx_pcie_resume\n");
909         /* set MSE */
910         val = dw_pcie_readl_dbi(pci, PCI_COMMAND);
911         //val = dw_pcie_readl_dbi(pci, base, PCI_COMMAND);
912         val |= PCI_COMMAND_MEMORY;
913         //dw_pcie_writel_dbi(pci, base, PCI_COMMAND, val)
914         dw_pcie_writel_dbi(pci, PCI_COMMAND, val);
915
916         return 0;
917 }

the RC will set the MEM_SPACE_EN bit,but I copy this to EP mode.when the CFG_MSE_EVT is active.and I will enable the MEM_SPACE_EN bit.

it is failed. I can't set this bit at kernel,but I can use devmem2 to set it.

Here is my question:

(1) why I can't set this bit at kernel? If it is possible,please tell me how.