+/**\r
+ PCI read-modify-write operation.\r
+\r
+ @param PeiServices An indirect pointer to the PEI Services Table\r
+ published by the PEI Foundation.\r
+\r
+ @param This Pointer to local data for the interface.\r
+\r
+ @param Width The width of the access. Enumerated in bytes. Type\r
+ EFI_PEI_PCI_CFG_PPI_WIDTH is defined in Read().\r
+\r
+ @param Address The physical address of the access.\r
+\r
+ @param SetBits Points to value to bitwise-OR with the read configuration value.\r
+ The size of the value is determined by Width.\r
+\r
+ @param ClearBits Points to the value to negate and bitwise-AND with the read configuration value.\r
+ The size of the value is determined by Width.\r
+\r
+\r
+ @retval EFI_SUCCESS The function completed successfully.\r
+\r
+ @retval EFI_DEVICE_ERROR There was a problem with the transaction.\r
+\r
+ @retval EFI_DEVICE_NOT_READY The device is not capable of supporting\r
+ the operation at this time.\r
+\r
+**/\r