On Thu, Jun 23, 2022 at 02:13:56PM +0200, Pali Rohár wrote:
Commit d293759d55cc ("serial: ns16550: Add support for SPL_DEBUG_UART_BASE") fixed support for setting correct early debug UART base address in SPL.
But after this commit, output from Marvell A385 BootROM is truncated or lost and not fully present on serial console.
Debugging this issue showed that BootROM just put bytes into UART HW output buffer and does not wait until UART HW transmit all characters. U-Boot ns16550 early debug is initialized very early and during its initialization is resetting UART HW and flushing remaining transmit buffer (which still contains BootROM output).
Fix this issue by waiting in init function prior resetting UART HW until TxEmpty bit in UART Line Status Register is set. TxEmpty is set when all remaining bytes from HW buffer are transmitted.
Signed-off-by: Pali Rohár pali@kernel.org Reviewed-by: Stefan Roese sr@denx.de
Applied to u-boot/next, thanks!