On Thursday 22 October 2015 15:27:05 Loc Ho wrote: > > > > phy-xgene.c > > ----------- > > > > Looking at other drivers under drivers/phy, I could find phy-xgene.c which > > is close Keystone SerDes driver (. This is called APM X-Gene Multi-Purpose > > PHY driver. It defines following mode per the driver code > > > > MODE_SATA = 0, /* List them for simple reference */ > > MODE_SGMII = 1, > > MODE_PCIE = 2, > > MODE_USB = 3, > > MODE_XFI = 4, > > > > But seems to support only MODE_SATA. From the code, it appears, this driver > > is expected to be enhanced in the future to support additional modes. I have > > copied the author to this email to participate in this discussion. > > Let me comment on this APM X-Gene driver. This driver is dead and > won't be supported in near or foreseeable future. And someday, it will > be ripped out. Based on experience, this solution (having PHY driver > in Linux) can't be supported across boards and etc as it is just too > much maintenance. And therefore, we followed Arnd B guidance and move > all this into the boot loader. From Linux or OS perspective, it only > cares about the interface in which its interface with. This is just > your reference and may be this will help you as well. This depends a lot on the use case. If the chip is only used on server parts that have a real firmware and you can deliver bug fixes for the firmware if necessary, it's always best to do as much of the setup as possible there, and let Linux see a simplified view of the hardware. However, for embedded systems that tend to ship with a minimal binary bootloader and no way to update that as an end-user, we rely on Linux to know about all the hardware that requires some form of setup, which is why we have all sorts of drivers and frameworks in the kernel that a server can easily ignore. While keystone can show up in servers that won't use this driver, my impression is that its main market is actually in embedded space. Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
