android_kernel_msm-6.1_noth.../drivers/tty
Robert Hodaszi c4465bff4d tty: serial: fsl_lpuart: reduce RX watermark to 0 on LS1028A
[ Upstream commit a82c3df955f8c1c726e4976527aa6ae924a67dd9 ]

LS1028A is using DMA with LPUART. Having RX watermark set to 1, means
DMA transactions are started only after receiving the second character.

On other platforms with newer LPUART IP, Receiver Idle Empty function
initiates the DMA request after the receiver is idling for 4 characters.
But this feature is missing on LS1028A, which is causing a 1-character
delay in the RX direction on this platform.

Set RX watermark to 0 to initiate RX DMA after each character.

Link: https://lore.kernel.org/linux-serial/20230607103459.1222426-1-robert.hodaszi@digi.com/
Fixes: 9ad9df844754 ("tty: serial: fsl_lpuart: Fix the wrong RXWATER setting for rx dma case")
Cc: stable <stable@kernel.org>
Signed-off-by: Robert Hodaszi <robert.hodaszi@digi.com>
Message-ID: <20230609121334.1878626-1-robert.hodaszi@digi.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-06-28 11:12:17 +02:00
..
hvc hvc/xen: prevent concurrent accesses to the shared ring 2023-03-30 12:49:09 +02:00
ipwireless
serdev
serial tty: serial: fsl_lpuart: reduce RX watermark to 0 on LS1028A 2023-06-28 11:12:17 +02:00
vt vc_screen: reload load of struct vc_data pointer in vcs_write() to avoid UAF 2023-05-24 17:32:51 +01:00
amiserial.c
ehv_bytechan.c
goldfish.c
Kconfig
Makefile
mips_ejtag_fdc.c
moxa.c
mxser.c
n_gsm.c
n_hdlc.c
n_null.c
n_tty.c
nozomi.c
pty.c
rpmsg_tty.c
synclink_gt.c
sysrq.c
tty.h tty: Prevent writing chars during tcsetattr TCSADRAIN/FLUSH 2023-05-11 23:03:01 +09:00
tty_audit.c
tty_baudrate.c
tty_buffer.c
tty_io.c tty: Prevent writing chars during tcsetattr TCSADRAIN/FLUSH 2023-05-11 23:03:01 +09:00
tty_ioctl.c tty: Prevent writing chars during tcsetattr TCSADRAIN/FLUSH 2023-05-11 23:03:01 +09:00
tty_jobctrl.c
tty_ldisc.c
tty_ldsem.c
tty_mutex.c
tty_port.c
ttynull.c
vcc.c