This should help to avoid unnecessary gaps in transmission while
adding little overhead due to low default Tx threshold level (2
bytes).
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Link: https://lore.kernel.org/r/1567017475-11919-6-git-send-email-sorganov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
imx_set_termios(): avoid writing baud rate divider registers when the
values to be written are the same as current. Any writing seems to
restart transmission/receiving logic in the hardware, that leads to
data breakage even when rate doesn't in fact change. E.g., user
switches RTS/CTS handshake and suddenly gets broken bytes.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Link: https://lore.kernel.org/r/1567017475-11919-5-git-send-email-sorganov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
imx_set_termios(): disabling individual interrupt requests in UART for
duration of the routine is pointless. Get rid of it.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Link: https://lore.kernel.org/r/1567017475-11919-4-git-send-email-sorganov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
imx_set_termios(): stopping receiver and transmitter does harm when
something that doesn't touch transmission format/rate changes, such as
RTS/CTS handshake.
OTOH, it does no good on baud rate or format change, as
synchronization on upper-level protocols is still required to do it
right.
Therefore, just stop doing it.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Link: https://lore.kernel.org/r/1567017475-11919-3-git-send-email-sorganov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
imx_set_termios(): remove busy-waiting "drain Tx FIFO" loop. Worse
yet, it was potentially unbounded wait due to RTS/CTS (hardware)
handshake.
Let user space ensure draining is done before termios change, if
draining is needed in the first place.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Link: https://lore.kernel.org/r/1567017475-11919-2-git-send-email-sorganov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Called in only one place, for RS232, it only obscures things, as it
doesn't go well with 2 similar named functions,
imx_uart_rts_inactive() and imx_uart_rts_active(), that both are
RS485-specific.
Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de>
Tested-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Link: https://lore.kernel.org/r/1564167161-3972-4-git-send-email-sorganov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
imx_uart_set_mctrl() happened to set UCR2_CTSC bit whenever TIOCM_RTS
was set, no matter if RTS/CTS handshake is enabled or not. Now fixed by
turning handshake on only when CRTSCTS bit for the port is set.
Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de>
Tested-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Link: https://lore.kernel.org/r/1564167161-3972-3-git-send-email-sorganov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Don't let receiver hardware automatically control RTS output if it
was requested to be inactive.
To ensure this, set_termios() shouldn't set UCR2_CTSC bit if UCR2_CTS
(=TIOCM_RTS) is cleared. Added corresponding check in imx_uart_rts_auto()
to fix this.
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de>
Tested-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Link: https://lore.kernel.org/r/1564167161-3972-2-git-send-email-sorganov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Avoid repeating the same code for rs485 twice.
Make it obvious we clear CRTSCTS bit in termios->c_cflag whenever
sport->have_rtscts is false.
Make it obvious we clear UCR2_IRTS whenever CRTSCTS is set.
Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de>
Tested-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Link: https://lore.kernel.org/r/1561558293-7683-4-git-send-email-sorganov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Set common bits in a separate statement to make initialization
explicit and not repeat the common part.
Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de>
Tested-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Reviewed-by: Uwe Kleine-Knig <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/1561558293-7683-3-git-send-email-sorganov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
imx_uart_set_termios() called imx_uart_rts_active(), or
imx_uart_rts_inactive() before taking port->port.lock.
As a consequence, sport->port.mctrl that these functions modify
could have been changed without holding port->port.lock.
Moved locking of port->port.lock above the calls to fix the issue.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
dev_info() is more appropriate for printing messages inside drivers, so
switch to dev_info().
Signed-off-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Each time the DMA engine signals a transaction error the driver prints
a message at error level. Getting transaction errors is pretty much
expected on baudrate mismatches and the correspoding error counters
are increased in this case properly. Remove the error message which
is possibly repeated at a very high rate which can lock up the whole
system.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The ipg clock only needs to be unprepared in case preparing
per clock fails. The ipg clock has already disabled at the point.
Fixes: 1cf93e0d54 ("serial: imx: remove the uart_console() check")
Signed-off-by: Stefan Agner <stefan@agner.ch>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Back in 2015 when irda was dropped from the driver imx1 was broken. This
change reintroduces the support for the third interrupt of the UART.
Fixes: afe9cbb1a6 ("serial: imx: drop support for IRDA")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Leonard Crestez <leonard.crestez@nxp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
On some i.MX SoCs' low power mode, such as i.MX7D's LPSR(low power
state retention), UART iomux settings will be lost, need to add
pinctrl sleep/default mode switch during suspend/resume to make
sure UART iomux settings are correct after resume.
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In noirq suspend/resume stage with no_console_suspend enabled,
imx_uart_console_write() may be called to print out log_buf
message by printk(), so there will be race condition between
imx_uart_console_write() and imx_uart_save/restore_context(),
need to add lock to protect the registers save/restore operations.
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Before the program enters the uart ISR, the local interrupt has been
disabled by the system, so it's not appropriate to use spin_lock_irqsave
interface in the ISR.
Signed-off-by: jun qian <hangdianqj@163.com>
Reviewed-by: Barry Song <21cnbao@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Correct to check the right rx dma cookie status in spit of it
works because only one cookie is running in the current sdma.
But it will not once sdma driver support multi cookies
running based on virt-dma.
Signed-off-by: Robin Gong <yibin.gong@nxp.com>
Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Tested-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Initially when register shadowing was introduced (commit 3a0ab62f43
("serial: imx: implement shadow registers for UCRx and UFCR")) the logic
to handle UCR2_SRST was wrong but documented consistently. Later the
handling was fixed, but the comment was not. This change makes up leeway
for the latter.
Fixes: 0aa821d846 ("serial: imx: fix cached UCR2 read on software reset")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
UCR4_OREN is (depending on the configuration) enabled in startup,
but is never disabled. Fix this by disabling it in shutdown.
Reported-by: Nandor Han <nandor.han@ge.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
According to Documentation/serial/driver the shutdown function should
not disable RTS, so drop it.
Suggested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This properly unmaps DMA SG on device shutdown.
Reported-by: Nandor Han <nandor.han@ge.com>
Suggested-by: Nandor Han <nandor.han@ge.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Remove unrelated CTSC/CTS disabling from imx_uart_disable_dma() and
move it to imx_uart_shutdown(), which is the only user of the DMA
disabling function. This should not change the driver's behaviour,
but improves readability. After this change imx_uart_disable_dma()
does the reverse thing of imx_uart_enable_dma().
Suggested-by: Nandor Han <nandor.han@ge.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To reset the UART the SRST needs be cleared (low active). According
to the documentation the bit will remain active for 4 module clocks
until it is cleared (set to 1).
Hence the real register need to be read in case the cached register
indicates that the SRST bit is zero.
This bug lead to wrong baudrate because the baud rate register got
restored before reset completed in imx_flush_buffer.
Fixes: 3a0ab62f43 ("serial: imx: implement shadow registers for UCRx and UFCR")
Signed-off-by: Stefan Agner <stefan@agner.ch>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When using half-duplex mode (which disables receiver during txing)
the RTS signal cannot be driven low during transmission when using
i.MX UART RTS/CTS control. This seems to be a limitation of the
i.MX UART IP: The RTS (CTS_B) signal is controlled by the receiver.
When the receiver is disabled, the signal stays in UART logic idle
state which is high...
If SER_RS485_RTS_ON_SEND is used, RTS needs to be high active during
transmission. Since this is the default state of the RTS (CTS_B)
signal when the receiver is off, half-duplex mode in this
configuration works fine.
However, a low-active RTS signal (flag SER_RS485_RTS_ON_SEND not set)
cannot be generated when the receiver is turned off.
Print an error if the user selects this unsupported configuration
(both SER_RS485_RTS_ON_SEND and SER_RS485_RX_DURING_TX unset) and
configure the closest working configuration (set the
SER_RS485_RX_DURING_TX flag).
Signed-off-by: Stefan Agner <stefan@agner.ch>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We should get drvdata from struct device directly. Going via
platform_device is an unneeded step back and forth.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Michal Simek <michal.simek@xilinx.com>
Acked-by: Patrice Chotard <patrice.chotard@st.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Having a fixed prefix helps at several places. It ensures that another
driver doesn't use the same function name which confuses the linker and
tools like ctags. It simplifies working with function tracing and
dynamic printk() support which can filter on function names. And last
but not least it helps the human source code reader to understand if a
given function belongs to a driver or a more general part of the kernel.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
serial_core might call the .start_tx callback without any data being
available to send. In this case return early instead of going through
all the setup needed for sending which might include disabling RX in
RS485 half-duplex mode.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When using RS485 half duplex the Transmitter Complete irq is needed to
determine the moment when the transmitter can be disabled. When using
DMA this irq must only be enabled when DMA has completed to transfer all
data. Otherwise the CPU might busily trigger this irq which is not
properly handled and so the also pending irq for the DMA transfer cannot
trigger.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This allows to increase the RX waterlevel which allows to delay the RRDY
irq. The desired effect is that less irqs are needed to handle
characters and so reduce irq count of the system.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Make sure that UCR1.RXDMAEN and UCR1.ATDMAEN (for the DMA case) and
UCR1.RRDYEN (for the PIO case) are off iff UCR1.RXEN is disabled. This
ensures that the fifo isn't read with RX disabled which results in an
exception.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When the UART is used in DMA mode, .stop_rx() does nothing if the port
isn't suspended. This is wrong as .stop_rx() should stop receiving
characters unconditionally. When the port is about to be closed the DMA
channel is stopped in .shutdown(), so this isn't necessary to be in
.stop_rx() here, too.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The aging timer fires if there are characters in the RX fifo but the
water level isn't reached yet. Make sure that the waterlevel is
configured before the aging timer is enabled to trigger a DMA request
(UCR1_ATDMAEN).
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The serial/imx driver is full of inconsistently named and typed
variables that hold different register values.
Consistently use u32 as type (matching what readl and writel use) and
name the variables after the register whose value they are holding.
This makes it easier to notice when UCR2_RTSEN is written to UCR1.
The only difference introduced by this commit in the compiled driver is
that twice the second argument to warn_slowpath_null() changed because the
two WARN_ON in dma_rx_callback() pass __LINE__ to warn_slowpath_null().
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The original code looks as follows:
if (sport->dma_is_enabled) {
... make sure TX DMA is running, i.e. .dma_is_txing = 1
}
if (sport->dma_is_txing)
return;
As .dma_is_txing can only be true if .dma_is_enabled is, the return can
go at the end of the first if body without an additional check.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Neither .dma_is_txing nor .dma_is_rxing can evaluate to true if
.dma_is_enabled evaluates to false:
The only function that sets .dma_is_txing to a non-zero value is
imx_dma_tx() which is only called if .dma_is_enabled is true. Same for
.dma_is_rxing and start_rx_dma(). And before .dma_is_enabled is set to 0
when imx_shutdown calls imx_disable_dma(), .dma_is_rxing and
.dma_is_txing are reset to zero before, too.
For this reason
sport->dma_is_enabled && sport->dma_is_rxing
has the same value as
sport->dma_is_rxing
which allows to simplify three if conditions.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reduces the amount of read accesses to the register space by
shadowing the values for five registers that only change on writing
them. There is a single bit in UCR2 that might change without being
written to it, this is handled accordingly.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This prepares implementing shadow copies for the control registers and
additionally provides a good place to hook in debug code to trace
register usage.
Most of this patch was done using pattern substitution:
perl -p -i -e '
s/\breadl(?:_relaxed)?\((?:sport->port\.|port->)membase \+/imx_uart_readl(sport,/;
s/\bwritel(?:_relaxed)?\(([^,]*), (sport->port\.|port->)membase \+/imx_uart_writel(sport, $1,/;
' drivers/tty/serial/imx.c
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Consistently indicate being called with irqs off and the port lock taken
for all functions that this applies to.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Only the reference manual for the i.MX1 (I have MC9328MX1RM/D Rev 5 from
2004) uses TDMAEN and RDMAEN for these. All reference manuals for the
newer chips use TXDMAEN and RXDMAEN. Update to the newer name with the
assumption that most imx users don't use an imx1 any more.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The imx_ports[] array is indexed using a value derived from the
"serialN" alias in DT, or from platform data, which may lead to an
out-of-bounds access.
Fix this by adding a range check.
Fixes: ff05967a07 ("serial/imx: add of_alias_get_id() reference back")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
imx_shutdown() calls imx_disable_dma if .dma_is_enabled. So after
imx_shudown() completes, .dma_is_enabled is zero. For this reason
.dma_is_enabled is also zero when imx_startup() is called. So the check
for this variable being zero can be dropped.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The .dma_is_inited member is only set to a value != 0 when the port's
startup function calls imx_uart_dma_init(). On shutdown of the port
imx_uart_dma_exit is called which sets the value back to 0. So
.dma_is_inited is always 0 when imx_startup() is called (assuming
.startup() and .shutdown() are correctly balanced) and the check for
!sport->dma_is_inited can go away.
This allows to replace .dma_is_inited by a variable local to
imx_startup.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Handling an irq that isn't enabled can have some undesired side effects.
Some of these are mentioned in the newly introduced code comment. Some
of the irq sources already had their handling right, some don't. Handle
them all in the same consistent way.
The change for USR1_RRDY and USR1_AGTIM drops the check for
dma_is_enabled. This is correct as UCR1_RRDYEN and UCR2_ATEN are always
off if dma is enabled.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Now the variable holding the value of register USR1 is called usr1
instead of sts which is more straight forward. The same is also done for
sts2 which is called usr2 now.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Sergey Organov