On Tue, Jan 3, 2017 at 3:38 AM, jonsm...@gmail.com <jonsm...@gmail.com> wrote: > I recently ran into a probably with the UARTs on the A64. Many > Bluetooth modules (like Ampak) use the UART. The data rate of EDR BT > is 3Mb/s with about 2.1Mb/s though put. To handle this most systems > set the speed of the BT UART to 3Mb/s. > > By default the Allwinner UART clock input is OSC24. When using OSC24 > the maximum speed the UART can be set to is 1.5Mb/s. The clock input > (apb2) can be changed over to PERIPH0x2 (1.2ghz) via the device tree > and 3Mb/s is then supported. > > But... there's a problem, UART0 (the console) is using the same master > clock source. So when you change the clock input over to PERIPH0x2 the > console stops working. There is no mechanism in Linux to handle this > clock source change and adjust the dividers on active uarts. So it > would be best if this master clock was set very early in u-boot and > then the console is adjusted to use it. > > Are there any downsides to making this change in u-boot?
I don't understand, did you find this behaviour with these SPL changes or general sunxi u-boot? thanks! -- Jagan Teki Free Software Engineer | www.openedev.com U-Boot, Linux | Upstream Maintainer Hyderabad, India. _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
