98 Commits

Author SHA1 Message Date
Erwan Le Ray
6333a48506 serial: stm32: push DMA RX data before suspending
Data may be stored in DMA RX buffer, when suspending. The data needs
to be pushed to the upper layer. We can't rely on the timeout IRQ (RTOR)
that can't be triggered into low power state. So safely clear DMA request
(DMAR), force the DMA reception routines to push RX buffer content, before
disabling RX DMA. This way, handover to pio mode is safe.
Only call tty_flip_buffer_push() when there is RX data to handle.

Move the locking outside of stm32_usart_receive_chars() to prevent a race
condition, when disabling DMA request upon suspend / pm_runtime_suspend.
Data may be received under IRQ and pushed before
stm32_usart_receive_chars() has pushed older data from DMA rx_buf upon
suspend.
The sequence in suspend routine needs proper locking to avoid this.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20211025134229.8456-4-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-26 19:18:47 +02:00
Erwan Le Ray
6eeb348c84 serial: stm32: terminate / restart DMA transfer at suspend / resume
DMA prevents the system to suspend when an UART RX wake-up source is
using DMA. DMA can't suspend while DMA channels are still active.

Terminate DMA transfer at suspend, and restart a new DMA transfer at
resume. Create stm32_usart_start_rx_dma_cyclic function to factorize
dma RX initialization. Move RX DMA code related to wakeup into
stm32_usart_serial_en_wakeup() routine to ease further improvements
on wakeup from low power modes.

Don't enable/disable wakeup on uninitialized port.

There may be data residue in the RX FIFO while suspending. Flush it at
suspend time. Receiver timeout interrupt won't trigger later in low power
mode, so call stm32_usart_receive_chars() in case there's data to handle.

Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20211025134229.8456-3-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-26 19:18:47 +02:00
Erwan Le Ray
e0abc903de serial: stm32: rework RX dma initialization and release
The RX DMA channel is kept active forever (from the probe). That prevents
going to low power mode when it is used. This change moves the
DMA configuration and enabling procedures to startup routine to allow
transition to low power mode.
The DMA disabling procedure is implemented in stop_rx routine as this
ops has to stop characters reception, and DMA transation in shutdown.
Clean useless dma_async_tx_descriptor initialization to NULL value.

Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20211025134229.8456-2-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-26 19:18:47 +02:00
Erwan Le Ray
d1ec8a2eab serial: stm32: update throttle and unthrottle ops for dma mode
Disable DMA request line (if enabled) to switch in PIO mode in throttle
ops, so the RX data gets queues into the FIFO. The hardware flow control
is triggered when the RX FIFO is full.

Switch back to DMA mode (re-enable DMA request line) in unthrottle ops.
Hardware flow control is stopped when FIFO is not full anymore.

Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20211020150332.10214-4-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-21 10:36:29 +02:00
Erwan Le Ray
33bb2f6ac3 serial: stm32: rework RX over DMA
This patch reworks RX support over DMA to improve reliability:
- change dma buffer cyclic configuration by using 2 periods. DMA buffer
data are handled by a flip-flop between the 2 periods in order to avoid
risk of data loss/corruption
- change the size of dma buffer to 4096 to limit overruns
- add rx errors management (breaks, parity, framing and overrun).
  When an error occurs on the uart line, the dma request line is masked at
  HW level. The SW must 1st clear DMAR (dma request line enable), to
  handle the error, then re-enable DMAR to recover. So, any correct data
  is taken from the DMA buffer, before handling the error itself. Then
  errors are handled from RDR/ISR/FIFO (e.g. in PIO mode). Last, DMA
  reception is resumed.
- add a condition on DMA request line in DMA RX routines in order to
switch to PIO mode when no DMA request line is disabled, even if the DMA
channel is still enabled.
  When the UART is wakeup source and is configured to use DMA for RX, any
  incoming data that wakes up the system isn't correctly received.
  At data reception, the irq_handler handles the WUF irq, and then the
  data reception over DMA.
  As the DMA transfer has been terminated at suspend, and will be restored
  by resume callback (which has no yet been called by system), the data
  can't be received.
  The wake-up data has to be handled in PIO mode while suspend callback
  has not been called.

Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20211020150332.10214-3-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-21 10:36:29 +02:00
Erwan Le Ray
cc58d0a3f0 serial: stm32: re-introduce an irq flag condition in usart_receive_chars
Re-introduce an irq flag condition in usart_receive_chars.
This condition has been deleted by commit 75f4e830fa9c ("serial: do not
restore interrupt state in sysrq helper").
This code was present to handle threaded case, and has been removed
because it is no more needed in this case. Nevertheless an irq safe lock
is still needed in some cases, when DMA should be stopped to receive errors
or breaks in PIO mode.
This patch is a precursor to the complete rework or stm32 serial driver
DMA implementation.

Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20211020150332.10214-2-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-21 10:36:29 +02:00
Tang Bin
3d881e32e2 serial: stm32: use devm_platform_get_and_ioremap_resource()
Use devm_platform_get_and_ioremap_resource() to simplify code.

Signed-off-by: Zhang Shengju <zhangshengju@cmss.chinamobile.com>
Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com>
Link: https://lore.kernel.org/r/20210814131418.13608-1-tangbin@cmss.chinamobile.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-08-16 18:53:15 +02:00
Tang Bin
59bd4eedf1 serial: stm32: use the defined variable to simplify code
Use the defined variable 'dev' to make the code cleaner.

Signed-off-by: Zhang Shengju <zhangshengju@cmss.chinamobile.com>
Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com>
Link: https://lore.kernel.org/r/20210814124951.30084-1-tangbin@cmss.chinamobile.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-08-16 18:52:59 +02:00
Tang Bin
217b04c67b serial: stm32: fix the conditional expression writing
In the function stm32_usart_init_port, intent of the code maybe when
irq returns a value of zero, the return should be '-ENODEV'. But the
conditional expression '? :' maybe clerical error, it should be
'?:' to make '-ENODEV' work.
But in fact, as the example in platform.c is
  * int irq = platform_get_irq(pdev, 0);
  * if (irq < 0)
  * return irq;
So the return value of zero is unnecessary to check, at last remove
the unnecessary '?: -ENODEV'.

Co-developed-by: Zhang Shengju <zhangshengju@cmss.chinamobile.com>
Signed-off-by: Zhang Shengju <zhangshengju@cmss.chinamobile.com>
Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com>
Link: https://lore.kernel.org/r/20210811105136.25392-1-tangbin@cmss.chinamobile.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-08-13 09:11:21 +02:00
Jiri Slaby
3ec2ff3723 tty: make use of tty_get_{char,frame}_size
In the previous patch, we introduced tty_get_char_size() and
tty_get_frame_size() for computing character and frame sizes,
respectively. Here, we make use of them in various tty drivers where
applicable.

The stats look nice: 12 insertions, 169 deletions.

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: David Lin <dtwlin@gmail.com>
Cc: Johan Hovold <johan@kernel.org>
Cc: Alex Elder <elder@kernel.org>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Andy Gross <agross@kernel.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@foss.st.com>
Cc: Oliver Neukum <oneukum@suse.com>
Acked-by: Alex Elder <elder@kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210610090247.2593-4-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-06-15 14:03:27 +02:00
Erwan Le Ray
a7770a4bfc serial: stm32: defer probe for dma devices
Defer device probe operation when a DMA channel request probe deferral.

With this change both DMA channels are acquired before DMA channels are
configured. Once no probe deferral is expected, DMAs are
configured and any failure in their configuration will make the driver
to fallback to interrupt mode as prior this change.

Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Signed-off-by: Etienne Carriere <etienne.carriere@foss.st.com>
Link: https://lore.kernel.org/r/20210610100020.2318-1-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-06-15 14:02:21 +02:00
Johan Hovold
18ee37e138 serial: drop irq-flags initialisations
There's no need to initialise irq-flags variables before saving the
interrupt state.

Drop the redundant initialisations from drivers that got this wrong.

Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210519092541.10137-1-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-20 16:24:05 +02:00
Fabrice Gasnier
2aa1bbb21f serial: stm32: add FIFO threshold configuration
Add the support for two optional DT properties, to configure RX and TX
FIFO thresholds:
- rx-threshold
- tx-threshold
This replaces hard-coded 8 bytes threshold. Keep 8 as the default value if
not specified, for backward compatibility.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>

Changes in v2:
Change added properties naming as proposed by Rob Herring.
Link: https://lore.kernel.org/r/20210413174015.23011-5-erwan.leray@foss.st.com

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-04-22 12:11:25 +02:00
Johan Hovold
cea37afd28 serial: stm32: defer sysrq processing
Use the uart_unlock_and_check_sysrq() helper to defer sysrq processing
until receive processing is done and the port lock has been released.

This allows cleaning up the console_write() implementation by not having
to work around the recursive sysrq case (by dropping locking completely)
and also makes the console code work with PREEMPT_RT by no longer
relying on local_irq_save().

Reviewed-by: Valentin Caron<valentin.caron@foss.st.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210416140557.25177-4-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-04-22 12:04:26 +02:00
Johan Hovold
e359b4411c serial: stm32: fix threaded interrupt handling
When DMA is enabled the receive handler runs in a threaded handler, but
the primary handler up until very recently neither disabled interrupts
in the device or used IRQF_ONESHOT. This would lead to a deadlock if an
interrupt comes in while the threaded receive handler is running under
the port lock.

Commit ad7676812437 ("serial: stm32: fix a deadlock condition with
wakeup event") claimed to fix an unrelated deadlock, but unfortunately
also disabled interrupts in the threaded handler. While this prevents
the deadlock mentioned in the previous paragraph it also defeats the
purpose of using a threaded handler in the first place.

Fix this by making the interrupt one-shot and not disabling interrupts
in the threaded handler.

Note that (receive) DMA must not be used for a console port as the
threaded handler could be interrupted while holding the port lock,
something which could lead to a deadlock in case an interrupt handler
ends up calling printk.

Fixes: ad7676812437 ("serial: stm32: fix a deadlock condition with wakeup event")
Fixes: 3489187204eb ("serial: stm32: adding dma support")
Cc: stable@vger.kernel.org      # 4.9
Cc: Alexandre TORGUE <alexandre.torgue@st.com>
Cc: Gerald Baeza <gerald.baeza@st.com>
Reviewed-by: Valentin Caron<valentin.caron@foss.st.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210416140557.25177-3-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-04-22 12:04:26 +02:00
Martin Devera
3cd6659372 tty/serial: Add rx-tx-swap OF option to stm32-usart
STM32 F7/H7 usarts supports RX & TX pin swapping.
Add option to turn it on.
Tested on STM32MP157.

Acked-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Signed-off-by: Martin Devera <devik@eaxlabs.cz>
Link: https://lore.kernel.org/r/20210328154306.22674-2-devik@eaxlabs.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-04-05 12:06:52 +02:00
Alexandre Torgue
3d530017be serial: stm32: update wakeup IRQ management
The wakeup specific IRQ management is no more needed to wake up the stm32
plaform. A relationship has been established between the EXTI and
the EVENT IRQ, just need to declare the EXTI interrupt instead of the
UART event IRQ.

Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210319184253.5841-5-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-23 10:28:18 +01:00
Erwan Le Ray
c0f3332cb5 serial: stm32: clean wakeup handling in serial_suspend
Remove useless call to stm32_usart_serial_en_wakeup() routine in suspend
callback. When called with "false" argument, this routine is clearing UESM
and WUFIE bits if usart is not wakeup source. Those bits are already
cleared in set_termios(), and then in serial_resume() callback when usart
is wakeup source.

Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210319184253.5841-3-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-23 10:28:18 +01:00
Erwan Le Ray
1631eeeaf0 serial: stm32: rework wakeup management
Rework wakeup management by activating uart as wakeup source when usart
device OR its tty virtual device parent is wakeup source.

This patch aim to avoid potential misalignment between serial and tty
wakeup flags.

Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210319184253.5841-2-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-23 10:28:18 +01:00
Erwan Le Ray
3d82be8be6 serial: stm32: add support for "flush_buffer" ops
Add the support for "flush_buffer" ops in order to flush any write buffers,
reset any DMA state and stop any ongoing DMA transfers when the
port->state->xmit circular buffer is cleared.

Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210304162308.8984-14-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-10 09:34:11 +01:00
Erwan Le Ray
3db1d52466 serial: stm32: fix tx_empty condition
In "tx_empty", we should poll TC bit in both DMA and PIO modes (instead of
TXE) to check transmission data register has been transmitted independently
of the FIFO mode. TC indicates that both transmit register and shift
register are empty. When shift register is empty, tx_empty should return
TIOCSER_TEMT instead of TC value.

Cleans the USART_CR_TC TCCF register define (transmission complete clear
flag) as it is duplicate of USART_ICR_TCCF.

Fixes: 48a6092fb41f ("serial: stm32-usart: Add STM32 USART Driver")
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210304162308.8984-13-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-10 09:34:11 +01:00
Erwan Le Ray
9f77d19207 serial: stm32: add FIFO flush when port is closed
Transmission complete error is sent when ISR_TC is not set. If port closure
is requested despite data in TDR / TX FIFO has not been sent (because of
flow control), ISR_TC is not set and error message is sent on port closure
but also when a new port is opened.

Flush the data when port is closed, so the error isn't printed twice upon
next port opening.

Fixes: 64c32eab6603 ("serial: stm32: Add support of TC bit status check")
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210304162308.8984-12-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-10 09:34:11 +01:00
Erwan Le Ray
315e2d8a12 serial: stm32: fix FIFO flush in startup and set_termios
Fifo flush set USART_RQR register by calling stm32_usart_set_bits
routine (Read/Modify/Write). USART_RQR register is a write only
register. So, read before write isn't correct / relevant to flush
the FIFOs.
Replace stm32_usart_set_bits call by writel_relaxed.

Fixes: 84872dc448fe ("serial: stm32: add RX and TX FIFO flush")
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210304162308.8984-11-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-10 09:34:11 +01:00
Erwan Le Ray
f16b90c2d9 serial: stm32: call stm32_transmit_chars locked
stm32_transmit_chars should be called under lock also in tx DMA callback.

Fixes: 3489187204eb ("serial: stm32: adding dma support")
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Link: https://lore.kernel.org/r/20210304162308.8984-10-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-10 09:34:11 +01:00
Erwan Le Ray
fb4f2e04ac serial: stm32: fix tx dma completion, release channel
This patch add a proper release of dma channels when completing dma tx.

Fixes: 3489187204eb ("serial: stm32: adding dma support")
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210304162308.8984-9-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-10 09:34:10 +01:00
Erwan Le Ray
436c979360 serial: stm32: fix a deadlock in set_termios
CTS/RTS GPIOs support that has been added recently to STM32 UART driver has
introduced scheduled code in a set_termios part protected by a spin lock.
This generates a potential deadlock scenario:

Chain exists of:
&irq_desc_lock_class --> console_owner --> &port_lock_key

Possible unsafe locking scenario:

     CPU0                    CPU1
     ----                    ----
lock(&port_lock_key);
                           lock(console_owner);
                           lock(&port_lock_key);
lock(&irq_desc_lock_class);

*** DEADLOCK ***
4 locks held by stty/766:

Move the scheduled code after the spinlock.

Fixes: 6cf61b9bd7cc ("tty: serial: Add modem control gpio support for STM32 UART")
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210304162308.8984-8-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-10 09:34:10 +01:00
Erwan Le Ray
12761869f0 serial: stm32: fix wake-up flag handling
This patch fixes several issue with wake-up handling:
- the WUF irq is handled several times at wake-up
- the USART is disabled / enabled at suspend to set wake-up flag.
It can cause glitches during RX.

This patch fix those issues:
- clear wake-up flag and disable wake-up irq in WUF irq handling
- enable wake-up from low power on start bit detection at port
configuration
- Unmask the wake-up flag irq at suspend and mask it at resume

In addition, pm_wakeup_event handling is moved from receice_chars to WUF
irq handling.

Fixes: 270e5a74fe4c ("serial: stm32: add wakeup mechanism")
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210304162308.8984-7-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-10 09:34:10 +01:00
Erwan Le Ray
ad76768124 serial: stm32: fix a deadlock condition with wakeup event
Deadlock issue is seen when enabling CONFIG_PROVE_LOCKING=Y, and uart
console as wakeup source. Deadlock occurs when resuming from low power
mode if system is waked up via usart console.
The deadlock is triggered 100% when also disabling console suspend prior
to go to suspend.

Simplified call stack, deadlock condition:
- stm32_console_write <-- spin_lock already held
- print_circular_bug
- pm_wakeup_dev_event <-- triggers lockdep as seen above
- stm32_receive_chars
- stm32_interrupt <-- wakeup via uart console, takes the lock

So, revisit spin_lock in stm32-usart driver:
- there is no need to hold the lock to access ICR (atomic clear of status
  flags)
- only hold the lock inside stm32_receive_chars() routine (no need to
  call pm_wakeup_dev_event with lock held)
- keep stm32_transmit_chars() routine called with lock held

Fixes: 48a6092fb41f ("serial: stm32-usart: Add STM32 USART Driver")
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Link: https://lore.kernel.org/r/20210304162308.8984-6-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-10 09:34:10 +01:00
Erwan Le Ray
25a8e7611d serial: stm32: fix TX and RX FIFO thresholds
TX and RX FIFO thresholds may be cleared after suspend/resume, depending
on the low power mode.

Those configurations (done in startup) are not effective for UART console,
as:
- the reference manual indicates that FIFOEN bit can only be written when
  the USART is disabled (UE=0)
- a set_termios (where UE is set) is requested firstly for console
  enabling, before the startup.

Fixes: 84872dc448fe ("serial: stm32: add RX and TX FIFO flush")
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210304162308.8984-5-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-10 09:34:10 +01:00
Erwan Le Ray
f264c6f6ae serial: stm32: fix incorrect characters on console
Incorrect characters are observed on console during boot. This issue occurs
when init/main.c is modifying termios settings to open /dev/console on the
rootfs.

This patch adds a waiting loop in set_termios to wait for TX shift register
empty (and TX FIFO if any) before stopping serial port.

Fixes: 48a6092fb41f ("serial: stm32-usart: Add STM32 USART Driver")
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210304162308.8984-4-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-10 09:34:10 +01:00
Erwan Le Ray
f4518a8a75 serial: stm32: fix startup by enabling usart for reception
RX is configured, but usart is not enabled in startup function.
Kernel documentation specifies that startup should enable the port for
reception.
Fix the startup by enabling usart for reception.

Fixes: 84872dc448fe ("serial: stm32: add RX and TX FIFO flush")
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210304162308.8984-3-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-10 09:34:10 +01:00
Erwan Le Ray
87fd0741d6 serial: stm32: fix probe and remove order for dma
The probe and remove orders are wrong as the uart_port is registered
before saving device data in the probe, and unregistered after DMA
resource deallocation in the remove. uart_port registering should be
done at the end of probe and unregistering should be done at the begin of
remove to avoid resource allocation issues.

Fix probe and remove orders. This enforce resource allocation occur at
proper time.
Terminate both DMA rx and tx transfers before removing device.

Move pm_runtime after uart_remove_one_port() call in remove() to keep the
probe error path.

Fixes: 3489187204eb ("serial: stm32: adding dma support")
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210304162308.8984-2-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-10 09:34:10 +01:00
Linus Torvalds
a99163e9e7 Devicetree updates for v5.12:
- Sync dtc to upstream version v1.6.0-51-g183df9e9c2b9 and build
   host fdtoverlay
 
 - Add kbuild support to build DT overlays (%.dtbo)
 
 - Drop NULLifying match table in of_match_device(). In preparation for
   this, there are several driver cleanups to use
   (of_)?device_get_match_data().
 
 - Drop pointless wrappers from DT struct device API
 
 - Convert USB binding schemas to use graph schema and remove old plain
   text graph binding doc
 
 - Convert spi-nor and v3d GPU bindings to DT schema
 
 - Tree wide schema fixes for if/then schemas, array size constraints,
   and undocumented compatible strings in examples
 
 - Handle 'no-map' correctly for already reserved memblock regions
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Merge tag 'devicetree-for-5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux

Pull devicetree updates from Rob Herring:

 - Sync dtc to upstream version v1.6.0-51-g183df9e9c2b9 and build host
   fdtoverlay

 - Add kbuild support to build DT overlays (%.dtbo)

 - Drop NULLifying match table in of_match_device().

   In preparation for this, there are several driver cleanups to use
   (of_)?device_get_match_data().

 - Drop pointless wrappers from DT struct device API

 - Convert USB binding schemas to use graph schema and remove old plain
   text graph binding doc

 - Convert spi-nor and v3d GPU bindings to DT schema

 - Tree wide schema fixes for if/then schemas, array size constraints,
   and undocumented compatible strings in examples

 - Handle 'no-map' correctly for already reserved memblock regions

* tag 'devicetree-for-5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux: (35 commits)
  driver core: platform: Drop of_device_node_put() wrapper
  of: Remove of_dev_{get,put}()
  dt-bindings: usb: Change descibe to describe in usbmisc-imx.txt
  dt-bindings: can: rcar_canfd: Group tuples in pin control properties
  dt-bindings: power: renesas,apmu: Group tuples in cpus properties
  dt-bindings: mtd: spi-nor: Convert to DT schema format
  dt-bindings: Use portable sort for version cmp
  dt-bindings: ethernet-controller: fix fixed-link specification
  dt-bindings: irqchip: Add node name to PRUSS INTC
  dt-bindings: interconnect: Fix the expected number of cells
  dt-bindings: Fix errors in 'if' schemas
  dt-bindings: iommu: renesas,ipmmu-vmsa: Make 'power-domains' conditionally required
  dt-bindings: Fix undocumented compatible strings in examples
  kbuild: Add support to build overlays (%.dtbo)
  scripts: dtc: Remove the unused fdtdump.c file
  scripts: dtc: Build fdtoverlay tool
  scripts/dtc: Update to upstream version v1.6.0-51-g183df9e9c2b9
  scripts: dtc: Fetch fdtoverlay.c from external DTC project
  dt-bindings: thermal: sun8i: Fix misplaced schema keyword in compatible strings
  dt-bindings: iio: dac: Fix AD5686 references
  ...
2021-02-22 10:05:12 -08:00
Erwan Le Ray
e0f2a902c9 serial: stm32: improve platform_get_irq condition handling in init_port
Replace "ret" variable by "irq" variable from platform_get_irq condition
handling in stm32_init_port as suggested by Jiri in "STM32 uart cleanup and
improvement" series review.
This change will prevent port->irq to be unexpectly modified by a potential
change of "ret" value introduced by a new patch.

Suggested-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>

Link: https://lore.kernel.org/r/20210121142309.6327-1-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-26 19:21:49 +01:00
Stephen Boyd
d825f0bea2 serial: stm32: Use of_device_get_match_data()
This driver casts away the constness of struct stm32_usart_info that is
pointed to by the of match table. Use of_device_get_match_data() instead
of of_match_device() here and push the const throughout the code so that
we don't cast away const. This nicely avoids referencing the match table
when it is undefined with configurations where CONFIG_OF=n and fixes the
const issues.

Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: <linux-serial@vger.kernel.org>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210123034428.2841052-4-swboyd@chromium.org
2021-01-26 12:17:32 -06:00
Erwan Le Ray
c31c3ea02e serial: stm32: update transmission complete error message in shutdown
The transmission complete error message provides the status of the
ISR_USART_TC bit. This bit, when set, indicates that the transmission
has not been completed.
The bit status indication is not a very understandable information.
The error message sent on console should indicate that the transmission is
not complete, instead of providing USART_TC bit status.
Update the error message and add a comment for better understanding.

Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210106162203.28854-9-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-07 16:19:29 +01:00
Erwan Le Ray
97f3a0850a serial: stm32: clean probe and remove port deinit
Clean probe and remove port deinit by moving clk_disable_unprepare in a
new dedicated deinit_port function.

Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Signed-off-by: Etienne Carriere <etienne.carriere@foss.st.com>
Link: https://lore.kernel.org/r/20210106162203.28854-8-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-07 16:19:29 +01:00
Erwan Le Ray
9359369ada serial: stm32: update conflicting RTS/CTS config comment
The comment for conflicting RTS/CTS config refers to "st, hw-flow-ctrl",
but this property is deprecated since the generic RTS/CTS property has
been introduced by the patch 'serial: stm32: Use generic DT binding for
announcing RTS/CTS lines'.
Update the comment to refer to both generic and deprecated RTS/CTS
properties.

Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210106162203.28854-7-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-07 16:19:29 +01:00
Erwan Le Ray
8ebd966576 serial: stm32: add author
Update email address add new author in authors list.

Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210106162203.28854-5-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-07 16:19:29 +01:00
Erwan Le Ray
56f9a76c27 serial: stm32: add "_usart" prefix in functions name
Adds the prefix "_usart" in the name of stm32 usart functions in order to
ease the usage of kernel trace and tools, such as f-trace.
Allows to trace "stm32_usart_*" functions with f-trace. Without this patch,
all the driver functions needs to be added manually in f-trace filter.

Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
Link: https://lore.kernel.org/r/20210106162203.28854-4-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-07 16:19:29 +01:00
Erwan Le Ray
92fc002386 serial: stm32: fix code cleaning warnings and checks
Fixes checkpatch --strict warnings and checks:
- checkpatch --strict "Unnecessary parentheses"
- checkpatch --strict "Blank lines aren't necessary before a close brace
- checkpatch --strict "Alignment should match open parenthesis"
- checkpatch --strict "Please don't use multiple blank lines"
- checkpatch --strict "Comparison to NULL could be written ..."
- visual check code ordering warning

Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210106162203.28854-3-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-07 16:19:29 +01:00
Erwan Le Ray
e7997f7ff7 serial: stm32: fix DMA initialization error handling
DMA initialization error handling is not properly implemented in the
driver.
Fix DMA initialization error handling by:
- moving TX DMA descriptor request error handling in a new dedicated
fallback_err label
- adding error handling to TX DMA descriptor submission
- adding error handling to RX DMA descriptor submission

This patch depends on '24832ca3ee85 ("tty: serial: stm32-usart: Remove set
but unused 'cookie' variables")' which unfortunately doesn't include a
"Fixes" tag.

Fixes: 3489187204eb ("serial: stm32: adding dma support")
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210106162203.28854-2-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-07 16:19:28 +01:00
Lee Jones
24832ca3ee tty: serial: stm32-usart: Remove set but unused 'cookie' variables
Fixes the following W=1 kernel build warning(s):

 drivers/tty/serial/stm32-usart.c: In function ‘stm32_transmit_chars_dma’:
 drivers/tty/serial/stm32-usart.c:353:15: warning: variable ‘cookie’ set but not used [-Wunused-but-set-variable]
 drivers/tty/serial/stm32-usart.c: In function ‘stm32_of_dma_rx_probe’:
 drivers/tty/serial/stm32-usart.c:1090:15: warning: variable ‘cookie’ set but not used [-Wunused-but-set-variable]

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Gerald Baeza <gerald.baeza@st.com>
Cc: linux-serial@vger.kernel.org
Cc: linux-stm32@st-md-mailman.stormreply.com
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20201104193549.4026187-29-lee.jones@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-11-06 10:54:05 +01:00
Marek Vasut
ad0c274805 serial: stm32: Add RS485 RTS GPIO control again
While the STM32 does support RS485 drive-enable control within the
UART IP itself, some systems have the drive-enable line connected
to a pin which cannot be pinmuxed as RTS. Add support for toggling
the RTS GPIO line using the modem control GPIOs to provide at least
some sort of emulation.

Fixes: 7df5081cbf5e ("serial: stm32: Add RS485 RTS GPIO control")
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Manivannan Sadhasivam <mani@kernel.org>
Cc: Fabrice Gasnier <fabrice.gasnier@st.com>
Cc: linux-stm32@st-md-mailman.stormreply.com
Link: https://lore.kernel.org/r/20200831171045.205691-1-marex@denx.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-09-04 17:16:40 +02:00
Holger Assmann
fdf16d7894 serial: stm32: avoid kernel warning on absence of optional IRQ
stm32_init_port() of the stm32-usart may trigger a warning in
platform_get_irq() when the device tree specifies no wakeup interrupt.

The wakeup interrupt is usually a board-specific GPIO and the driver
functions correctly in its absence. The mainline stm32mp151.dtsi does
not specify it, so all mainline device trees trigger an unnecessary
kernel warning. Use of platform_get_irq_optional() avoids this.

Fixes: 2c58e56096dd ("serial: stm32: fix the get_irq error case")
Signed-off-by: Holger Assmann <h.assmann@pengutronix.de>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200813152757.32751-1-h.assmann@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-08-18 13:32:28 +02:00
Marek Vasut
7df5081cbf serial: stm32: Add RS485 RTS GPIO control
While the STM32 does support RS485 drive-enable control within the
UART IP itself, some systems have the drive-enable line connected
to a pin which cannot be pinmuxed as RTS. Add support for toggling
the RTS GPIO line using the modem control GPIOs to provide at least
some sort of emulation.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Manivannan Sadhasivam <mani@kernel.org>
Cc: Fabrice Gasnier <fabrice.gasnier@st.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-stm32@st-md-mailman.stormreply.com
Link: https://lore.kernel.org/r/20200725144947.537007-1-marex@denx.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-30 08:46:22 +02:00
Erwan Le Ray
6fd9fffb6f serial: stm32: Use generic DT binding for announcing RTS/CTS lines
Add support of generic DT binding for annoucing RTS/CTS lines. The initial
binding 'st,hw-flow-control' is not needed anymore since generic binding
is available, but is kept for backward compatibility.

Signed-off-by: Erwan Le Ray <erwan.leray@st.com>
Link: https://lore.kernel.org/r/20200520133932.30441-3-erwan.leray@st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-01 15:19:39 +02:00
Erwan Le Ray
55484fcc50 serial: stm32: add no_console_suspend support
In order to display console messages in low power mode, console pins
must be kept active after suspend call.

Initial patch "serial: stm32: add support for no_console_suspend" was part
of "STM32 usart power improvement" series, but as dependancy to
console_suspend pinctl state has been removed to fit with Rob comment [1],
this patch has no more dependancy with any other patch of this series.

[1] https://lkml.org/lkml/2019/7/9/451

Signed-off-by: Erwan Le Ray <erwan.leray@st.com>

Link: https://lore.kernel.org/r/20200519094104.27082-1-erwan.leray@st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-19 15:53:36 +02:00
Lukas Wunner
c150c0f362 serial: Allow uart_get_rs485_mode() to return errno
We're about to amend uart_get_rs485_mode() to support a GPIO pin for
rs485 bus termination.  Retrieving the GPIO descriptor may fail, so
allow uart_get_rs485_mode() to return an errno and change all callers
to check for failure.

The GPIO descriptor is going to be stored in struct uart_port.  Pass
that struct to uart_get_rs485_mode() in lieu of a struct device and
struct serial_rs485, both of which are directly accessible from struct
uart_port.

A few drivers call uart_get_rs485_mode() before setting the struct
device pointer in struct uart_port.  Shuffle those calls around where
necessary.

[Heiko Stuebner did the ar933x_uart.c portion, hence his Signed-off-by.]

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/271e814af4b0db3bffbbb74abf2b46b75add4516.1589285873.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-15 14:47:05 +02:00
Manivannan Sadhasivam
6cf61b9bd7 tty: serial: Add modem control gpio support for STM32 UART
STM32 UART controllers have the built in modem control support using
dedicated gpios which can be enabled using 'st,hw-flow-ctrl' flag in DT.
But there might be cases where the board design need to use different
gpios for modem control.

For supporting such cases, this commit adds modem control gpio support
to STM32 UART controller using mctrl_gpio driver.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Acked-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Link: https://lore.kernel.org/r/20200420170204.24541-3-mani@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-15 12:24:15 +02:00