[U-Boot] [PATCH] riscv: serial: fix to load binary file over y-modem

[Sagar Shrikant Kadam]

This patch fixes the failure where loady a y-modem serial loader
fails to load a binary over the serial port.

#loady <load-addr> <baudrate>

With loady after the serial port on board is put in receive mode, the
tera-term sends a file using y-modem mode, but the tstc/getc never comes
to know that a character has been received in RX buffer, and so cannot
identify the header which results in serial transfer failure.

RX watermark bit is set when ever a character is received on serial port.
Using RX watermark bit in the IP register solves this problem.

Patch is based on commit 884512f7dbf9 ("Merge tag 'uniphier-v2019.07'
of https://gitlab.denx.de/u-boot/custodians/u-boot-uniphier").

Booted linux kernel uImage loaded over y-modem on the HiFive Unleashed A00
board.


Sagar Shrikant Kadam (1):
  riscv : serial: use rx watermark to indicate rx data is present

 drivers/serial/serial_sifive.c | 23 +++++++----------------
 1 file changed, 7 insertions(+), 16 deletions(-)

-- 
2.7.4