On Thu, Feb 4, 2021 at 12:58 PM David Gibson <[email protected]> wrote: > > On Wed, Feb 03, 2021 at 10:24:48PM +0800, Bin Meng wrote: > > From: Bin Meng <[email protected]> > > > > At present the <clock-frequency> property of the serial node is > > populated with value zero. U-Boot's ns16550 driver is not happy > > about this, so let's fill in a meaningful value. > > Are you sure this is correct - that is that the serial clock is really > the same as the overall system clock? Quite often there's some kind > of divider in between. >
Yes, see the U-Boot codes include/configs/qemu-ppce500.h #define CONFIG_SYS_NS16550_CLK (get_bus_freq(0)) get_bus_freq(0) eventually returns the platform clock frequency which is 400MHz. But the value doesn't matter anyway for QEMU. We don't emulate any baud rate specific thing for a serial port. We only need a sane value that is non-zero. Regards, Bin
