China Factory Visit, waht should I prepare and how long it iwll take to get the visa?

Hi, I am an INDIAN working in Oman and we have factory in PRC ( Wuxi ) and wanted to visit factory. I am intending to be in PRC for a week. Kindly suggest what type of documents do i need to arrange to get my Chinese entry permit and how much is the fee and how much time will it take?.