Messages in this thread | | | Date | Tue, 2 Jun 2015 20:09:56 -0700 | From | Bin Gao <> | Subject | Re: [PATCH v5 2/2] arch/x86: remove pci uart early console from early_prink.c |
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On Wed, Jun 03, 2015 at 12:16:36AM +0000, Anderson, Stuart R wrote: > Bin, et al, > > What we are losing here is the ability to specify a UART by its bus address > instead of just supplying the memory or io address. There are some cases > where this is useful, though I admit it is probably not going to be widely > used. I have seen a platform where the location of the UART moves depending > on the firmware version, but the bus address (B:D.F) did not change. There > are also some platforms where you do not know the address until you boot the > OS and can use the UART to login and find the address of the UART (oops. > Chicken and egg problem). > > Also, I was going to soon send a patch to allow "pciserial32" for the case where the UART registers are 32-bit aligned instead of 8-bit aligned. > > Stuart >
Theare are several reasons that we want to move it to serial_core. First, pci is arch independent, so putting these codes in serial_core (which is arch independent) makes more sense. Second, B:D.F may change across SoCs, then to support new SoC we only need change command line but don't need to change the code. Lastly, there could be other non-x86 platforms using it in the future.
-Bin
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