The LPUART can't distinguish between a break signal and a framing error,
so need to count the break characters if there is a framing error and
received data is zero instead of the parity error.
Fixes: 5541a9bacf ("serial: fsl_lpuart: handle break and make sysrq work")
Reviewed-by: Michael Walle <michael@walle.cc>
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20220725050115.12396-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The info structs are local only to the stm32-usart.c driver and are
triggering sparse warnings about being undecalred. Move these into
the main driver code and make them static to avoid the following
warnings:
drivers/tty/serial/stm32-usart.h:42:25: warning: symbol 'stm32f4_info' was not declared. Should it be static?
drivers/tty/serial/stm32-usart.h:63:25: warning: symbol 'stm32f7_info' was not declared. Should it be static?
drivers/tty/serial/stm32-usart.h:85:25: warning: symbol 'stm32h7_info' was not declared. Should it be static?
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Link: https://lore.kernel.org/r/20220721212430.453192-1-ben-linux@fluff.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The LPUART hardware doesn't zero out the parity bit on the received
characters. This behavior won't impact the use cases of CS8 because
the parity bit is the 9th bit which is not currently used by software.
But the parity bit for CS7 must be zeroed out by software in order to
get the correct raw data.
Signed-off-by: Shenwei Wang <shenwei.wang@nxp.com>
Link: https://lore.kernel.org/r/20220714185858.615373-1-shenwei.wang@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In the logic around call to clk_round_rate(), for some corner conditions,
get_clk_div_rate() could return an sub-optimal clock rate. Also, if an
exact clock rate was not found lowest clock was being returned.
Search for suitable clock rate in 2 steps
a) exact match or within 2% tolerance
b) within 5% tolerance
This also takes care of corner conditions.
Fixes: c2194bc999 ("tty: serial: qcom-geni-serial: Remove uart frequency table. Instead, find suitable frequency with call to clk_round_rate")
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Vijaya Krishna Nivarthi <quic_vnivarth@quicinc.com>
Link: https://lore.kernel.org/r/1657911343-1909-1-git-send-email-quic_vnivarth@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The error path when get clock frequency fails in bcm2835aux_serial
driver does not correctly disable the clock.
This flaw was found using a static analysis tool "Hulk Robot", which
reported the following warning when analyzing linux-next/master:
drivers/tty/serial/8250/8250_bcm2835aux.c:
warning: clk_disable_unprepare_missing.cocci
The cocci script checks for the existence of clk_disable_unprepare()
paired with clk_prepare_enable().
Add the missing clk_disable_unprepare() to the error path.
Fixes: fcc446c8aa ("serial: 8250_bcm2835aux: Add ACPI support")
Reported-by: Hulk Robot <hulkci@huawei.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Guo Mengqi <guomengqi3@huawei.com>
Link: https://lore.kernel.org/r/20220715023312.37808-1-guomengqi3@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit d3164e2f3b ("MIPS: Remove VR41xx support") removed support
for MIPS VR41xx platform, so remove exclusive drivers for this
platform, too.
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Link: https://lore.kernel.org/r/20220715140322.135825-1-tsbogend@alpha.franken.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Before the drivers rs485_config() function is called the serial core
already ensures that only one of both options RTS on send or RTS after send
is set. So remove the concerning sanity check in the driver function to
avoid redundancy.
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Lino Sanfilippo <l.sanfilippo@kunbus.com>
Link: https://lore.kernel.org/r/20220710164442.2958979-9-LinoSanfilippo@gmx.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Before the drivers rs485_config() function is called the serial core
already ensures that only one of both options RTS on send or RTS after send
is set. So remove the concerning sanity check in the driver function to
avoid redundancy.
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Lino Sanfilippo <l.sanfilippo@kunbus.com>
Link: https://lore.kernel.org/r/20220710164442.2958979-8-LinoSanfilippo@gmx.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently the RTS delays set via device tree are not clamped to a maximum
value although the device tree bindings documentation for RS485 claims that
only a maximum of 1000 msecs is allowed.
So clamp the values to avoid arbitrary high delay settings. However clamp
the values to 100 instead of 1000 msecs to be consistent which the maximum
that is allowed when setting the delays from userspace via the UART ioctl
TIOCSRS485.
Signed-off-by: Lino Sanfilippo <l.sanfilippo@kunbus.com>
Link: https://lore.kernel.org/r/20220710164442.2958979-6-LinoSanfilippo@gmx.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Move the sanitizing of RS485 delays out of uart_sanitize_serial_rs485()
into the new function uart_sanitize_serial_rs485_delays().
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Lino Sanfilippo <l.sanfilippo@kunbus.com>
Link: https://lore.kernel.org/r/20220710164442.2958979-5-LinoSanfilippo@gmx.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In serial8250_em485_config() the termination GPIO is set with the uart_port
spinlock held. This is an issue if setting the GPIO line can sleep (e.g.
since the concerning GPIO expander is connected via SPI or I2C).
Fix this by setting the termination line outside of the uart_port spinlock
in the serial core and using gpiod_set_value_cansleep() which instead of
gpiod_set_value() allows it to sleep.
Beside fixing the termination GPIO line setting for the 8250 driver this
change also makes setting the termination GPIO generic for all UART
drivers.
Signed-off-by: Lino Sanfilippo <l.sanfilippo@kunbus.com>
Link: https://lore.kernel.org/r/20220710164442.2958979-4-LinoSanfilippo@gmx.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In ar933x_config_rs485() the check for the RTS GPIO is not needed since in
case the GPIO is not available at driver init ar933x_no_rs485 is assigned
to port->rs485_supported and this function is never called. So remove the
check.
Also in uart_set_rs485_config() the serial core already assigns the passed
serial_rs485 struct to the uart port. So remove the assignment in the
drivers rs485_config() function to avoid redundancy.
Signed-off-by: Lino Sanfilippo <l.sanfilippo@kunbus.com>
Link: https://lore.kernel.org/r/20220710164442.2958979-3-LinoSanfilippo@gmx.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
RS485 is not possible without an RTS GPIO regardless of whether RS485 is
enabled at boot time or not. So correct the concerning check in the probe()
function.
Fixes: e849145e1f ("serial: ar933x: Fill in rs485_supported")
Signed-off-by: Lino Sanfilippo <l.sanfilippo@kunbus.com>
Link: https://lore.kernel.org/r/20220710164442.2958979-2-LinoSanfilippo@gmx.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 9cabe26e65 ("serial: 8250_bcm7271: UART errors after resuming
from S2") prevented an early enabling of RTS during resume, but it did
not actively restore the RTS state after resume.
Fixes: 9cabe26e65 ("serial: 8250_bcm7271: UART errors after resuming from S2")
Signed-off-by: Doug Berger <opendmb@gmail.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20220714031316.404918-1-f.fainelli@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
With PSLVERR_RESP_EN parameter set to 1, the device generates an error
response when an attempt to read an empty RBR with FIFO enabled.
This happens when LCR writes are ignored when UART is busy.
dw8250_check_lcr() in retries to update LCR, invokes dw8250_force_idle()
to clear and reset FIFO and eventually reads UART_RX causing the error.
Avoid this by not reading RBR/UART_RX when no data is available.
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: VAMSHI GAJJELA <vamshigajjela@google.com>
Link: https://lore.kernel.org/r/20220713131722.2316829-1-vamshigajjela@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
S3C2410_UCON is a 32bit register, so it must be read with rd_regl()
instead of rd_reg(), otherwise the upper bits will be zeroed. Fix this.
Fixes: 72a43046b6 ("tty: serial: samsung_tty: loopback mode support")
Tested-by: Chanho Park <chanho61.park@samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Chanho Park <chanho61.park@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20220712140745.30362-1-m.szyprowski@samsung.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The Aspeed Virtual UART is only present on Aspeed BMC platforms. Hence
add a dependency on ARCH_ASPEED, to prevent asking the user about this
driver when configuring a kernel without Aspeed BMC support.
Reviewed-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/259138c372d433005b4871789ef9ee8d15320307.1657528861.git.geert+renesas@glider.be
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add support for some of the Brainboxes PCIe (PX) range of
serial cards, including the PX-101, PX-235/PX-246,
PX-203/PX-257, PX-260/PX-701, PX-310, PX-313,
PX-320/PX-324/PX-376/PX-387, PX-335/PX-346, PX-368, PX-420,
PX-803 and PX-846.
Signed-off-by: Cameron Williams <cang1@live.co.uk>
Cc: stable <stable@kernel.org>
Link: https://lore.kernel.org/r/AM5PR0202MB2564669252BDC59BF55A6E87C4879@AM5PR0202MB2564.eurprd02.prod.outlook.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
gsmld_poll() currently fails to handle the following corner cases correctly:
- remote party closed the associated tty
Add the missing checks and map those to EPOLLHUP.
Reorder the checks to group them by their reaction.
Fixes: e1eaea46bb ("tty: n_gsm line discipline")
Signed-off-by: Daniel Starke <daniel.starke@siemens.com>
Link: https://lore.kernel.org/r/20220707113223.3685-4-daniel.starke@siemens.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The current implementation constipates all transmission paths during flow
control except for flow control frames. However, these may not be located
at the beginning of the transmission queue of the control channel.
Ensure that flow control frames in the transmission queue for the control
channel are always handled even if constipated by skipping through other
messages.
Fixes: 0af021678d ("tty: n_gsm: fix deadlock and link starvation in outgoing data path")
Signed-off-by: Daniel Starke <daniel.starke@siemens.com>
Link: https://lore.kernel.org/r/20220707113223.3685-3-daniel.starke@siemens.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
n_gsm is based on the 3GPP 07.010 and its newer version is the 3GPP 27.010.
See https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=1516
The changes from 07.010 to 27.010 are non-functional. Therefore, I refer to
the newer 27.010 here. Chapter 5.3.3 defines the DM response. There exists
no DM command. However, the current implementation incorrectly sends DM as
command in case of unexpected UIH frames in gsm_queue().
Correct this behavior by always sending DM as response.
Fixes: e1eaea46bb ("tty: n_gsm line discipline")
Signed-off-by: Daniel Starke <daniel.starke@siemens.com>
Link: https://lore.kernel.org/r/20220707113223.3685-2-daniel.starke@siemens.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
n_gsm is based on the 3GPP 07.010 and its newer version is the 3GPP 27.010.
See https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=1516
The changes from 07.010 to 27.010 are non-functional. Therefore, I refer to
the newer 27.010 here. Chapter 5.7.3 states that the valid range for the
maximum number of retransmissions (N2) is from 0 to 255 (both including).
gsm_dlci_t1() handles this number incorrectly by performing N2 - 1
retransmission attempts. Setting N2 to zero results in more than 255
retransmission attempts.
Fix gsm_dlci_t1() to comply with 3GPP 27.010.
Fixes: e1eaea46bb ("tty: n_gsm line discipline")
Signed-off-by: Daniel Starke <daniel.starke@siemens.com>
Link: https://lore.kernel.org/r/20220707113223.3685-1-daniel.starke@siemens.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When DT provides rs485-term, set termination flag as supported.
Reviewed-by: Lino Sanfilippo <l.sanfilippo@kunbus.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220704094515.6831-3-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Embed rs485_supported to uart_port to allow serial core to tweak it as
needed.
Reviewed-by: Lino Sanfilippo <l.sanfilippo@kunbus.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220704094515.6831-2-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Some Freescale 8250 implementations have the problem that a single long
break results in one irq per character frame time. The code in
fsl8250_handle_irq() that is supposed to handle that uses the BI bit in
lsr_saved_flags to detect such a situation and then skip the second
received character. However it also stores other error bits and so after
a single frame error the character received in the next irq handling is
passed to the upper layer with a frame error, too.
So after a spike on the data line (which is correctly recognized as a
frame error) the following valid character is thrown away, because the
driver reports a frame error for that one, too.
To weaken this problem restrict saving LSR to only the BI bit.
Note however that the handling is still broken:
- lsr_saved_flags is updated using orig_lsr which is the LSR content
for the first received char, but there might be more in the FIFO, so
a character is thrown away that is received later and not necessarily
the one following the break.
- The doubled break might be the 2nd and 3rd char in the FIFO, so the
workaround doesn't catch these, because serial8250_rx_chars() doesn't
handle the workaround.
- lsr_saved_flags might have set UART_LSR_BI at the entry of
fsl8250_handle_irq() which doesn't originate from
fsl8250_handle_irq()'s "up->lsr_saved_flags |= orig_lsr &
UART_LSR_BI;" but from e.g. from serial8250_tx_empty().
- For a long or a short break this isn't about two characters, but more
or only a single one.
Fixes: 9deaa53ac7 ("serial: add irq handler for Freescale 16550 errata.")
Acked-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20220704085119.55900-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Within gsm_activate_mux() all timers and locks are initiated before the
actual resource for the control channel is allocated. This can lead to race
conditions.
Allocate the control channel DLCI object first to avoid race conditions.
Fixes: e1eaea46bb ("tty: n_gsm line discipline")
Signed-off-by: Daniel Starke <daniel.starke@siemens.com>
Link: https://lore.kernel.org/r/20220701122332.2039-2-daniel.starke@siemens.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The current implementation queues up new control and user packets as needed
and processes this queue down to the ldisc in the same code path.
That means that the upper and the lower layer are hard coupled in the code.
Due to this deadlocks can happen as seen below while transmitting data,
especially during ldisc congestion. Furthermore, the data channels starve
the control channel on high transmission load on the ldisc.
Introduce an additional control channel data queue to prevent timeouts and
link hangups during ldisc congestion. This is being processed before the
user channel data queue in gsm_data_kick(), i.e. with the highest priority.
Put the queue to ldisc data path into a workqueue and trigger it whenever
new data has been put into the transmission queue. Change
gsm_dlci_data_sweep() accordingly to fill up the transmission queue until
TX_THRESH_HI. This solves the locking issue, keeps latency low and provides
good performance on high data load.
Note that now all packets from a DLCI are removed from the internal queue
if the associated DLCI was closed. This ensures that no data is sent by the
introduced write task to an already closed DLCI.
BUG: spinlock recursion on CPU#0, test_v24_loop/124
lock: serial8250_ports+0x3a8/0x7500, .magic: dead4ead, .owner: test_v24_loop/124, .owner_cpu: 0
CPU: 0 PID: 124 Comm: test_v24_loop Tainted: G O 5.18.0-rc2 #3
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
Call Trace:
<IRQ>
dump_stack_lvl+0x34/0x44
do_raw_spin_lock+0x76/0xa0
_raw_spin_lock_irqsave+0x72/0x80
uart_write_room+0x3b/0xc0
gsm_data_kick+0x14b/0x240 [n_gsm]
gsmld_write_wakeup+0x35/0x70 [n_gsm]
tty_wakeup+0x53/0x60
tty_port_default_wakeup+0x1b/0x30
serial8250_tx_chars+0x12f/0x220
serial8250_handle_irq.part.0+0xfe/0x150
serial8250_default_handle_irq+0x48/0x80
serial8250_interrupt+0x56/0xa0
__handle_irq_event_percpu+0x78/0x1f0
handle_irq_event+0x34/0x70
handle_fasteoi_irq+0x90/0x1e0
__common_interrupt+0x69/0x100
common_interrupt+0x48/0xc0
asm_common_interrupt+0x1e/0x40
RIP: 0010:__do_softirq+0x83/0x34e
Code: 2a 0a ff 0f b7 ed c7 44 24 10 0a 00 00 00 48 c7 c7 51 2a 64 82 e8 2d
e2 d5 ff 65 66 c7 05 83 af 1e 7e 00 00 fb b8 ff ff ff ff <49> c7 c2 40 61
80 82 0f bc c5 41 89 c4 41 83 c4 01 0f 84 e6 00 00
RSP: 0018:ffffc90000003f98 EFLAGS: 00000286
RAX: 00000000ffffffff RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff82642a51 RDI: ffffffff825bb5e7
RBP: 0000000000000200 R08: 00000008de3271a8 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000030 R14: 0000000000000000 R15: 0000000000000000
? __do_softirq+0x73/0x34e
irq_exit_rcu+0xb5/0x100
common_interrupt+0xa4/0xc0
</IRQ>
<TASK>
asm_common_interrupt+0x1e/0x40
RIP: 0010:_raw_spin_unlock_irqrestore+0x2e/0x50
Code: 00 55 48 89 fd 48 83 c7 18 53 48 89 f3 48 8b 74 24 10 e8 85 28 36 ff
48 89 ef e8 cd 58 36 ff 80 e7 02 74 01 fb bf 01 00 00 00 <e8> 3d 97 33 ff
65 8b 05 96 23 2b 7e 85 c0 74 03 5b 5d c3 0f 1f 44
RSP: 0018:ffffc9000020fd08 EFLAGS: 00000202
RAX: 0000000000000000 RBX: 0000000000000246 RCX: 0000000000000000
RDX: 0000000000000004 RSI: ffffffff8257fd74 RDI: 0000000000000001
RBP: ffff8880057de3a0 R08: 00000008de233000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000100 R14: 0000000000000202 R15: ffff8880057df0b8
? _raw_spin_unlock_irqrestore+0x23/0x50
gsmtty_write+0x65/0x80 [n_gsm]
n_tty_write+0x33f/0x530
? swake_up_all+0xe0/0xe0
file_tty_write.constprop.0+0x1b1/0x320
? n_tty_flush_buffer+0xb0/0xb0
new_sync_write+0x10c/0x190
vfs_write+0x282/0x310
ksys_write+0x68/0xe0
do_syscall_64+0x3b/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f3e5e35c15c
Code: 8b 7c 24 08 89 c5 e8 c5 ff ff ff 89 ef 89 44 24 08 e8 58 bc 02 00 8b
44 24 08 48 83 c4 10 5d c3 48 63 ff b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff
ff 76 10 48 8b 15 fd fc 05 00 f7 d8 64 89 02 48 83
RSP: 002b:00007ffcee77cd18 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007ffcee77cd70 RCX: 00007f3e5e35c15c
RDX: 0000000000000100 RSI: 00007ffcee77cd90 RDI: 0000000000000003
RBP: 0000000000000100 R08: 0000000000000000 R09: 7efefefefefefeff
R10: 00007f3e5e3bddeb R11: 0000000000000246 R12: 00007ffcee77ce8f
R13: 0000000000000001 R14: 000056214404e010 R15: 00007ffcee77cd90
</TASK>
Fixes: e1eaea46bb ("tty: n_gsm line discipline")
Signed-off-by: Daniel Starke <daniel.starke@siemens.com>
Link: https://lore.kernel.org/r/20220701122332.2039-1-daniel.starke@siemens.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The function may be used by the user directly and also by the n_gsm
internal functions. They can lead into a race condition which results in
interleaved frames if both are writing at the same time. The receiving side
is not able to decode those interleaved frames correctly.
Add a lock around the low side tty write to avoid race conditions and frame
interleaving between user originated writes and n_gsm writes.
Fixes: e1eaea46bb ("tty: n_gsm line discipline")
Signed-off-by: Daniel Starke <daniel.starke@siemens.com>
Link: https://lore.kernel.org/r/20220701061652.39604-9-daniel.starke@siemens.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In the current implementation control packets are re-transmitted even if
the control channel closed down during T2. This is wrong.
Check whether the control channel is open before re-transmitting any
packets. Note that control channel open/close is handled by T1 and not T2
and remains unaffected by this.
Fixes: e1eaea46bb ("tty: n_gsm line discipline")
Signed-off-by: Daniel Starke <daniel.starke@siemens.com>
Link: https://lore.kernel.org/r/20220701061652.39604-7-daniel.starke@siemens.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
n_gsm is based on the 3GPP 07.010 and its newer version is the 3GPP 27.010.
See https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=1516
The changes from 07.010 to 27.010 are non-functional. Therefore, I refer to
the newer 27.010 here. Chapter 5.4.6.3.6 states that FCoff stops the
transmission on all channels except the control channel. This is already
implemented in gsm_data_kick(). However, chapter 5.4.8.1 explains that this
shall result in the same behavior as software flow control on the ldisc in
advanced option mode. That means only flow control frames shall be sent
during flow off. The current implementation does not consider this case.
Change gsm_data_kick() to send only flow control frames if constipated to
abide the standard. gsm_read_ea_val() and gsm_is_flow_ctrl_msg() are
introduced as helper functions for this.
It is planned to use gsm_read_ea_val() in later code cleanups for other
functions, too.
Fixes: c01af4fec2 ("n_gsm : Flow control handling in Mux driver")
Signed-off-by: Daniel Starke <daniel.starke@siemens.com>
Link: https://lore.kernel.org/r/20220701061652.39604-5-daniel.starke@siemens.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The current implementation does not handle the situation that no data is in
the internal queue and needs to be sent out while the user tty fifo is
full.
Add a timer that moves more data from user tty down to the internal queue
which is then serialized on the ldisc. This timer is triggered if no data
was moved from a user tty to the internal queue within 10 * T1.
Fixes: e1eaea46bb ("tty: n_gsm line discipline")
Signed-off-by: Daniel Starke <daniel.starke@siemens.com>
Link: https://lore.kernel.org/r/20220701061652.39604-4-daniel.starke@siemens.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1) The function drains the fifo for the given user tty/DLCI without
considering 'TX_THRESH_HI' and different to gsm_dlci_data_output_framed(),
which moves only one packet from the user side to the internal transmission
queue. We can only handle one packet at a time here if we want to allow
DLCI priority handling in gsm_dlci_data_sweep() to avoid link starvation.
2) Furthermore, the additional header octet from convergence layer type 2
is not counted against MTU. It is part of the UI/UIH frame message which
needs to be limited to MTU. Hence, it is wrong not to consider this octet.
3) Finally, the waiting user tty is not informed about freed space in its
send queue.
Take at most one packet worth of data out of the DLCI fifo to fix 1).
Limit the max user data size per packet to MTU - 1 in case of convergence
layer type 2 to leave space for the control signal octet which is added in
the later part of the function. This fixes 2).
Add tty_port_tty_wakeup() to wake up the user tty if new write space has
been made available to fix 3).
Fixes: 268e526b93 ("tty/n_gsm: avoid fifo overflow in gsm_dlci_data_output")
Signed-off-by: Daniel Starke <daniel.starke@siemens.com>
Link: https://lore.kernel.org/r/20220701061652.39604-3-daniel.starke@siemens.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The current implementation registers/deregisters the user ttys at mux
attach/detach. That means that the user devices are available before any
control channel is open. However, user channel initialization requires an
open control channel. Furthermore, the user is not informed if the mux
restarts due to configuration changes.
Put the registration/deregistration procedure into separate function to
improve readability.
Move registration to mux activation and deregistration to mux cleanup to
keep the user devices only open as long as a control channel exists. The
user will be informed via the device driver if the mux was reconfigured in
a way that required a mux re-activation.
This makes it necessary to add T2 initialization to gsmld_open() for the
ldisc open code path (not the reconfiguration code path) to avoid deletion
of an uninitialized T2 at mux cleanup.
Fixes: d50f6dcaf2 ("tty: n_gsm: expose gsmtty device nodes at ldisc open time")
Signed-off-by: Daniel Starke <daniel.starke@siemens.com>
Link: https://lore.kernel.org/r/20220701061652.39604-2-daniel.starke@siemens.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
After setting up the control channel on both sides the responder side may
want to open a virtual tty to listen on until the initiator starts an
application on a user channel. The current implementation allows the
open() but no other operation, like termios. These fail with EINVAL.
The responder sided application has no means to detect an open by the
initiator sided application this way. And the initiator sided applications
usually expect the responder sided application to listen on the user
channel upon open.
Set the user channel into half-open state on responder side once a user
application opens the virtual tty to allow IO operations on it.
Furthermore, keep the user channel constipated until the initiator side
opens it to give the responder sided application the chance to detect the
new connection and to avoid data loss if the responder sided application
starts sending before the user channel is open.
Fixes: e1eaea46bb ("tty: n_gsm line discipline")
Signed-off-by: Daniel Starke <daniel.starke@siemens.com>
Link: https://lore.kernel.org/r/20220701061652.39604-1-daniel.starke@siemens.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Place dw8250_serial_out() before dw8250_serial_out38x() so that it can
be called from dw8250_serial_out38x() to do the actual write.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220628134234.53771-2-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Instead of open-coding, use BIT(), GENMASK(), and FIELD_GET() helpers.
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220630100536.41329-1-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Drop CONFIG_PM and CONFIG_PM_SLEEP ifdeffery while converting dw8250_pm_ops
to use new PM macros. Since we are using runtime PM, wrap dw8250_pm_ops into
pm_ptr().
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220630100507.31113-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
For the sake of better maintenance, sort included headers alphabetically.
While at it, split the serial group of headers which makes clear the
subsystem the driver belongs to.
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220630093816.28271-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If the earlycon parameter is given twice, the kernel will spit out a
WARN() in register_console() because it was already registered. The
non-dt variant setup_earlycon() already handles that gracefully. The dt
variant of_setup_earlycon() doesn't. Add the check there and add the
-EALREADY handling in early_init_dt_scan_chosen_stdout().
FWIW, this doesn't happen if CONFIG_ACPI_SPCR_TABLE is set. In that case
the registration is delayed until after earlycon parameter(s) are
parsed.
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20220628120705.200617-1-michael@walle.cc
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Accessing LSR requires port lock because it mutates lsr_saved_flags
in serial_lsr_in().
Fixes: 197eb5c416 ("serial: 8250_dw: Use serial_lsr_in() in dw8250_handle_irq()")
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/c5879db7-bee9-93f-526e-872a292442@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Internal loopback mode can be supported by setting
UCON register's Loopback Mode bit. The mode & bit can be supported
since s3c2410 and later SoCs. The prefix of LOOPBACK / BIT(5) naming
should be also changed to S3C2410_ in order to avoid confusion.
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Chanho Park <chanho61.park@samsung.com>
Link: https://lore.kernel.org/r/20220629004141.51484-1-chanho61.park@samsung.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Regarding Exynos Auto v9 SoC, it supports uarts up to 12. However, the
maximum number of the ports has been derived from
CONFIG_SERIAL_SAMSUNG_UARTS and tightly coupled with the config for
previous Samsung SoCs such as s3c24xx and s3c64xx. To overcome this
limitation, this changes the usage of the definition to UART_NR which is
widely used from other serial drivers. This also defines the value to 12
only for ARM64 SoCs to not affect the change to previous arm32 SoCs.
Instead of enumerating all the ports as predefined arrays, this
introduces s3c24xx_serial_init_port_default that is initializing the
structure as the default value.
Reviewed-by: Hector Martin <marcan@marcan.st>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Chanho Park <chanho61.park@samsung.com>
Link: https://lore.kernel.org/r/20220629005538.60132-1-chanho61.park@samsung.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add 9th bit multipoint addressing mode for DW UART. 9th bit addressing
can be used only when HW RS485 is available.
Updating RAR (receive address register) is bit tricky because busy
indication is not be available when DW UART is strictly 16550
compatible, which is the case with the hardware I was testing with. RAR
should not be updated while receive is in progress which is now
achieved by deasserting RE and waiting for one frame (in case rx would
be in progress, the driver seems to have no way of knowing it w/o busy
indication). Because of this complexity, it's better to avoid doing it
unless really needed.
Co-developed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Co-developed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Co-developed-by: Raymond Tan <raymond.tan@intel.com>
Co-developed-by: Lakshmi Sowjanya <lakshmi.sowjanya.d@intel.com>
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Raymond Tan <raymond.tan@intel.com>
Signed-off-by: Lakshmi Sowjanya <lakshmi.sowjanya.d@intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220624204210.11112-7-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add support for RS-485 multipoint addressing using 9th bit [*]. The
addressing mode is configured through ->rs485_config().
ADDRB in termios indicates 9th bit addressing mode is enabled. In this
mode, 9th bit is used to indicate an address (byte) within the
communication line. ADDRB can only be enabled/disabled through
->rs485_config() that is also responsible for setting the destination and
receiver (filter) addresses.
Add traps to detect unwanted changes to struct serial_rs485 layout using
static_assert().
[*] Technically, RS485 is just an electronic spec and does not itself
specify the 9th bit addressing mode but 9th bit seems at least
"semi-standard" way to do addressing with RS485.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220624204210.11112-6-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To be able to alter ADDRB within ->rs485_config(), take termios_rwsem
before calling ->rs485_config() and pass termios.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220624204210.11112-5-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Use 32-bit reads in order to not lose higher bits of DW UART regs. This
change does not fix any known issue as the high bits are not used for
anything related to 8250 driver (dw8250_readl_ext and dw8250_writel_ext
used within the dwlib are already doing
readl/writel/ioread32be/iowrite32be anyway).
This change is necessary to enables 9th bit address mode. DW UART
reports address frames with BIT(8) of LSR.
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220624204210.11112-4-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
DW flags address received as BIT(8) in LSR. In order to not lose that
on read, enlarge lsr_saved_flags to u16.
Adjust lsr/status variables and related call chains to use u16.
Technically, some of these type conversion would not be needed but it
doesn't hurt to be consistent.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220624204210.11112-2-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
