On Mon, Oct 19, 2015 at 1:14 PM, Rob Herring <robherri...@gmail.com> wrote: > On Wed, Oct 14, 2015 at 11:55 AM, Sergey Temerkhanov > <s.temerkha...@gmail.com> wrote: >> On some systems, UART initialization is performed before running U-Boot. >> This commit allows to skip UART re-initializaion on those systems >> >> Signed-off-by: Sergey Temerkhanov <s.temerkha...@gmail.com> >> Signed-off-by: Radha Mohan Chintakuntla <rchintakun...@cavium.com> >> >> Reviewed-by: Simon Glass <s...@chromium.org> > > I'll comment on this now that I'm here, but as the rest of the thread > said, please send to DT list. > >> diff --git a/doc/device-tree-bindings/serial/pl01x.txt >> b/doc/device-tree-bindings/serial/pl01x.txt >> index 61c27d1..0591497 100644 >> --- a/doc/device-tree-bindings/serial/pl01x.txt >> +++ b/doc/device-tree-bindings/serial/pl01x.txt >> @@ -5,3 +5,6 @@ Required properties: >> - reg: exactly one register range with length 0x1000 >> - clock: input clock frequency for the UART (used to calculate the baud >> rate divisor) >> + >> +Optional properties: >> +- u-boot,skip-init: skip UART initialization at start. > > What are you trying to accomplish by skipping? > > stdout-path can take options now, so what about making it an option there: > > stdout-path = &serial0:no-init
It's not about a single UART but all UARTs present in the platform. Some of them might have different reference clocks/PLL settings/whatever which can be tricky to support with FDT editing/rebuilding/etc. Especially if those reference clocks can be reprogrammed between runs. > > I have similar concerns with this as I did with the early init flag. > This requires the dtb and u-boot to be in sync. For example, you have > this option in the dtb, but then you add clock initialization to your > platform which changes the default clock frequency of the UART. Now if > you boot with an older dtb and new u-boot, then it will break because > the UART is at the wrong baudrate. It's not a problem at all since the U-Boot image with an attached DTB is being used. And that DTB comes from the U-Boot source tree. > > Rob _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
