linux-stable.git/drivers/tty/serial, branch v4.4.63 Linux kernel stable tree tty/serial: atmel: RS485 half duplex w/DMA: enable RX after TX is done 2017-04-21T07:30:08+00:00 Richard Genoud richard.genoud@gmail.com 2016-12-06T12:05:33+00:00 990a142ee0d3b504a0a3c23a16e2cda41c5d45cf commit b389f173aaa1204d6dc1f299082a162eb0491545 upstream. When using RS485 in half duplex, RX should be enabled when TX is finished, and stopped when TX starts. Before commit 0058f0871efe7b01c6 ("tty/serial: atmel: fix RS485 half duplex with DMA"), RX was not disabled in atmel_start_tx() if the DMA was used. So, collisions could happened. But disabling RX in atmel_start_tx() uncovered another bug: RX was enabled again in the wrong place (in atmel_tx_dma) instead of being enabled when TX is finished (in atmel_complete_tx_dma), so the transmission simply stopped. This bug was not triggered before commit 0058f0871efe7b01c6 ("tty/serial: atmel: fix RS485 half duplex with DMA") because RX was never disabled before. Moving atmel_start_rx() in atmel_complete_tx_dma() corrects the problem. Reported-by: Gil Weber <webergil@gmail.com> Fixes: 0058f0871efe7b01c6 Tested-by: Gil Weber <webergil@gmail.com> Signed-off-by: Richard Genoud <richard.genoud@gmail.com> Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> Tested-by: Bryan Evenson <bevenson@melinkcorp.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit b389f173aaa1204d6dc1f299082a162eb0491545 upstream.

When using RS485 in half duplex, RX should be enabled when TX is
finished, and stopped when TX starts.

Before commit 0058f0871efe7b01c6 ("tty/serial: atmel: fix RS485 half
duplex with DMA"), RX was not disabled in atmel_start_tx() if the DMA
was used. So, collisions could happened.

But disabling RX in atmel_start_tx() uncovered another bug:
RX was enabled again in the wrong place (in atmel_tx_dma) instead of
being enabled when TX is finished (in atmel_complete_tx_dma), so the
transmission simply stopped.

This bug was not triggered before commit 0058f0871efe7b01c6
("tty/serial: atmel: fix RS485 half duplex with DMA") because RX was
never disabled before.

Moving atmel_start_rx() in atmel_complete_tx_dma() corrects the problem.

Reported-by: Gil Weber <webergil@gmail.com>
Fixes: 0058f0871efe7b01c6
Tested-by: Gil Weber <webergil@gmail.com>
Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Tested-by: Bryan Evenson <bevenson@melinkcorp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty/serial: atmel: fix TX path in atmel_console_write() 2017-04-08T07:53:31+00:00 Nicolas Ferre nicolas.ferre@microchip.com 2017-03-20T15:38:57+00:00 0a1757cfa5ba3b46f6ee7a74ddb7a5c0bd5d7c2f commit 497e1e16f45c70574dc9922c7f75c642c2162119 upstream. A side effect of 89d8232411a8 ("tty/serial: atmel_serial: BUG: stop DMA from transmitting in stop_tx") is that the console can be called with TX path disabled. Then the system would hang trying to push charecters out in atmel_console_putchar(). Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com> Fixes: 89d8232411a8 ("tty/serial: atmel_serial: BUG: stop DMA from transmitting in stop_tx") Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 497e1e16f45c70574dc9922c7f75c642c2162119 upstream.

A side effect of 89d8232411a8 ("tty/serial: atmel_serial: BUG: stop DMA
from transmitting in stop_tx") is that the console can be called with
TX path disabled. Then the system would hang trying to push charecters
out in atmel_console_putchar().

Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Fixes: 89d8232411a8 ("tty/serial: atmel_serial: BUG: stop DMA from transmitting in stop_tx")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty/serial: atmel: fix race condition (TX+DMA) 2017-04-08T07:53:31+00:00 Richard Genoud richard.genoud@gmail.com 2017-03-20T10:52:41+00:00 74b8fc017d7689d1a60c9e234b2cfe3550b7f414 commit 31ca2c63fdc0aee725cbd4f207c1256f5deaabde upstream. If uart_flush_buffer() is called between atmel_tx_dma() and atmel_complete_tx_dma(), the circular buffer has been cleared, but not atmel_port->tx_len. That leads to a circular buffer overflow (dumping (UART_XMIT_SIZE - atmel_port->tx_len) bytes). Tested-by: Nicolas Ferre <nicolas.ferre@microchip.com> Signed-off-by: Richard Genoud <richard.genoud@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 31ca2c63fdc0aee725cbd4f207c1256f5deaabde upstream.

If uart_flush_buffer() is called between atmel_tx_dma() and
atmel_complete_tx_dma(), the circular buffer has been cleared, but not
atmel_port->tx_len.
That leads to a circular buffer overflow (dumping (UART_XMIT_SIZE -
atmel_port->tx_len) bytes).

Tested-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
serial: 8250_pci: Detach low-level driver during PCI error recovery 2017-03-30T07:35:20+00:00 Sumit Semwal sumit.semwal@linaro.org 2017-03-25T16:18:19+00:00 ac601978a2aad7fbb617f0187268011b577a127f From: Gabriel Krisman Bertazi <krisman@linux.vnet.ibm.com> [ Upstream commit f209fa03fc9d131b3108c2e4936181eabab87416 ] During a PCI error recovery, like the ones provoked by EEH in the ppc64 platform, all IO to the device must be blocked while the recovery is completed. Current 8250_pci implementation only suspends the port instead of detaching it, which doesn't prevent incoming accesses like TIOCMGET and TIOCMSET calls from reaching the device. Those end up racing with the EEH recovery, crashing it. Similar races were also observed when opening the device and when shutting it down during recovery. This patch implements a more robust IO blockage for the 8250_pci recovery by unregistering the port at the beginning of the procedure and re-adding it afterwards. Since the port is detached from the uart layer, we can be sure that no request will make through to the device during recovery. This is similar to the solution used by the JSM serial driver. I thank Peter Hurley <peter@hurleysoftware.com> for valuable input on this one over one year ago. Signed-off-by: Gabriel Krisman Bertazi <krisman@linux.vnet.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <alexander.levin@verizon.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
From: Gabriel Krisman Bertazi <krisman@linux.vnet.ibm.com>

[ Upstream commit f209fa03fc9d131b3108c2e4936181eabab87416 ]

During a PCI error recovery, like the ones provoked by EEH in the ppc64
platform, all IO to the device must be blocked while the recovery is
completed.  Current 8250_pci implementation only suspends the port
instead of detaching it, which doesn't prevent incoming accesses like
TIOCMGET and TIOCMSET calls from reaching the device.  Those end up
racing with the EEH recovery, crashing it.  Similar races were also
observed when opening the device and when shutting it down during
recovery.

This patch implements a more robust IO blockage for the 8250_pci
recovery by unregistering the port at the beginning of the procedure and
re-adding it afterwards.  Since the port is detached from the uart
layer, we can be sure that no request will make through to the device
during recovery.  This is similar to the solution used by the JSM serial
driver.

I thank Peter Hurley <peter@hurleysoftware.com> for valuable input on
this one over one year ago.

Signed-off-by: Gabriel Krisman Bertazi <krisman@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
serial: samsung: Continue to work if DMA request fails 2017-03-18T11:09:58+00:00 Krzysztof Kozlowski krzk@kernel.org 2017-02-25T16:36:44+00:00 72ca0ab30680571295c97b6a0d87b56d1212c417 commit f98c7bce570bdbe344b74ff5daa7dfeef3f22929 upstream. If DMA is not available (even when configured in DeviceTree), the driver will fail the startup procedure thus making serial console not available. For example this causes boot failure on QEMU ARMv7 (Exynos4210, SMDKC210): [    1.302575] OF: amba_device_add() failed (-19) for /amba/pdma@12680000 ... [   11.435732] samsung-uart 13800000.serial: DMA request failed [   72.963893] samsung-uart 13800000.serial: DMA request failed [   73.143361] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000000 DMA is not necessary for serial to work, so continue with UART startup after emitting a warning. Fixes: 62c37eedb74c ("serial: samsung: add dma reqest/release functions") Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit f98c7bce570bdbe344b74ff5daa7dfeef3f22929 upstream.

If DMA is not available (even when configured in DeviceTree), the driver
will fail the startup procedure thus making serial console not
available.

For example this causes boot failure on QEMU ARMv7 (Exynos4210, SMDKC210):
    [    1.302575] OF: amba_device_add() failed (-19) for /amba/pdma@12680000
    ...
    [   11.435732] samsung-uart 13800000.serial: DMA request failed
    [   72.963893] samsung-uart 13800000.serial: DMA request failed
    [   73.143361] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000000

DMA is not necessary for serial to work, so continue with UART startup
after emitting a warning.

Fixes: 62c37eedb74c ("serial: samsung: add dma reqest/release functions")
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
serial: 8250_pci: Add MKS Tenta SCOM-0800 and SCOM-0801 cards 2017-03-15T01:57:11+00:00 Ian Abbott abbotti@mev.co.uk 2017-02-03T20:25:00+00:00 4b34572e98f1b0d0df4ea084347b89b5a20fbede commit 1c9c858e2ff8ae8024a3d75d2ed080063af43754 upstream. The MKS Instruments SCOM-0800 and SCOM-0801 cards (originally by Tenta Technologies) are 3U CompactPCI serial cards with 4 and 8 serial ports, respectively. The first 4 ports are implemented by an OX16PCI954 chip, and the second 4 ports are implemented by an OX16C954 chip on a local bus, bridged by the second PCI function of the OX16PCI954. The ports are jumper-selectable as RS-232 and RS-422/485, and the UARTs use a non-standard oscillator frequency of 20 MHz (base_baud = 1250000). Signed-off-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 1c9c858e2ff8ae8024a3d75d2ed080063af43754 upstream.

The MKS Instruments SCOM-0800 and SCOM-0801 cards (originally by Tenta
Technologies) are 3U CompactPCI serial cards with 4 and 8 serial ports,
respectively.  The first 4 ports are implemented by an OX16PCI954 chip,
and the second 4 ports are implemented by an OX16C954 chip on a local
bus, bridged by the second PCI function of the OX16PCI954.  The ports
are jumper-selectable as RS-232 and RS-422/485, and the UARTs use a
non-standard oscillator frequency of 20 MHz (base_baud = 1250000).

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty: serial: msm: Fix module autoload 2017-02-26T10:07:50+00:00 Javier Martinez Canillas javier@osg.samsung.com 2017-01-02T14:57:20+00:00 04fae8abfaef454d9ed299c9e83db63bb65b3c19 commit abe81f3b8ed2996e1712d26d38ff6b73f582c616 upstream. If the driver is built as a module, autoload won't work because the module alias information is not filled. So user-space can't match the registered device with the corresponding module. Export the module alias information using the MODULE_DEVICE_TABLE() macro. Before this patch: $ modinfo drivers/tty/serial/msm_serial.ko | grep alias $ After this patch: $ modinfo drivers/tty/serial/msm_serial.ko | grep alias alias: of:N*T*Cqcom,msm-uartdmC* alias: of:N*T*Cqcom,msm-uartdm alias: of:N*T*Cqcom,msm-uartC* alias: of:N*T*Cqcom,msm-uart Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com> Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit abe81f3b8ed2996e1712d26d38ff6b73f582c616 upstream.

If the driver is built as a module, autoload won't work because the module
alias information is not filled. So user-space can't match the registered
device with the corresponding module.

Export the module alias information using the MODULE_DEVICE_TABLE() macro.

Before this patch:

$ modinfo drivers/tty/serial/msm_serial.ko | grep alias
$

After this patch:

$ modinfo drivers/tty/serial/msm_serial.ko | grep alias
alias:          of:N*T*Cqcom,msm-uartdmC*
alias:          of:N*T*Cqcom,msm-uartdm
alias:          of:N*T*Cqcom,msm-uartC*
alias:          of:N*T*Cqcom,msm-uart

Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty/serial: atmel_serial: BUG: stop DMA from transmitting in stop_tx 2017-01-19T19:17:21+00:00 Richard Genoud richard.genoud@gmail.com 2016-12-13T16:27:56+00:00 075f493a974e390ba7664cef0b17994999705150 commit 89d8232411a85b9a6b12fd5da4d07d8a138a8e0c upstream. If we don't disable the transmitter in atmel_stop_tx, the DMA buffer continues to send data until it is emptied. This cause problems with the flow control (CTS is asserted and data are still sent). So, disabling the transmitter in atmel_stop_tx is a sane thing to do. Tested on at91sam9g35-cm(DMA) Tested for regressions on sama5d2-xplained(Fifo) and at91sam9g20ek(PDC) Signed-off-by: Richard Genoud <richard.genoud@gmail.com> Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 89d8232411a85b9a6b12fd5da4d07d8a138a8e0c upstream.

If we don't disable the transmitter in atmel_stop_tx, the DMA buffer
continues to send data until it is emptied.
This cause problems with the flow control (CTS is asserted and data are
still sent).

So, disabling the transmitter in atmel_stop_tx is a sane thing to do.

Tested on at91sam9g35-cm(DMA)
Tested for regressions on sama5d2-xplained(Fifo) and at91sam9g20ek(PDC)

Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sc16is7xx: Drop bogus use of IRQF_ONESHOT 2017-01-09T07:07:49+00:00 Josh Cartwright joshc@ni.com 2016-10-13T15:44:33+00:00 d78006d2345f87889918a8a7aa3764628ff84263 commit 04da73803c05dc1150ccc31cbf93e8cd56679c09 upstream. The use of IRQF_ONESHOT when registering an interrupt handler with request_irq() is non-sensical. Not only that, it also prevents the handler from being threaded when it otherwise should be w/ IRQ_FORCED_THREADING is enabled. This causes the following deadlock observed by Sean Nyekjaer on -rt: Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM [..] rt_spin_lock_slowlock from queue_kthread_work queue_kthread_work from sc16is7xx_irq sc16is7xx_irq [sc16is7xx] from handle_irq_event_percpu handle_irq_event_percpu from handle_irq_event handle_irq_event from handle_level_irq handle_level_irq from generic_handle_irq generic_handle_irq from mxc_gpio_irq_handler mxc_gpio_irq_handler from mx3_gpio_irq_handler mx3_gpio_irq_handler from generic_handle_irq generic_handle_irq from __handle_domain_irq __handle_domain_irq from gic_handle_irq gic_handle_irq from __irq_svc __irq_svc from rt_spin_unlock rt_spin_unlock from kthread_worker_fn kthread_worker_fn from kthread kthread from ret_from_fork Fixes: 9e6f4ca3e567 ("sc16is7xx: use kthread_worker for tx_work and irq") Reported-by: Sean Nyekjaer <sean.nyekjaer@prevas.dk> Signed-off-by: Josh Cartwright <joshc@ni.com> Cc: linux-rt-users@vger.kernel.org Cc: Jakub Kicinski <moorray3@wp.pl> Cc: linux-serial@vger.kernel.org Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Julia Cartwright <julia@ni.com> Acked-by: Jakub Kicinski <kubakici@wp.pl> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 04da73803c05dc1150ccc31cbf93e8cd56679c09 upstream.

The use of IRQF_ONESHOT when registering an interrupt handler with
request_irq() is non-sensical.

Not only that, it also prevents the handler from being threaded when it
otherwise should be w/ IRQ_FORCED_THREADING is enabled.  This causes the
following deadlock observed by Sean Nyekjaer on -rt:

Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM
[..]
   rt_spin_lock_slowlock from queue_kthread_work
   queue_kthread_work from sc16is7xx_irq
   sc16is7xx_irq [sc16is7xx] from handle_irq_event_percpu
   handle_irq_event_percpu from handle_irq_event
   handle_irq_event from handle_level_irq
   handle_level_irq from generic_handle_irq
   generic_handle_irq from mxc_gpio_irq_handler
   mxc_gpio_irq_handler from mx3_gpio_irq_handler
   mx3_gpio_irq_handler from generic_handle_irq
   generic_handle_irq from __handle_domain_irq
   __handle_domain_irq from gic_handle_irq
   gic_handle_irq from __irq_svc
   __irq_svc from rt_spin_unlock
   rt_spin_unlock from kthread_worker_fn
   kthread_worker_fn from kthread
   kthread from ret_from_fork

Fixes: 9e6f4ca3e567 ("sc16is7xx: use kthread_worker for tx_work and irq")
Reported-by: Sean Nyekjaer <sean.nyekjaer@prevas.dk>
Signed-off-by: Josh Cartwright <joshc@ni.com>
Cc: linux-rt-users@vger.kernel.org
Cc: Jakub Kicinski <moorray3@wp.pl>
Cc: linux-serial@vger.kernel.org
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Julia Cartwright <julia@ni.com>
Acked-by: Jakub Kicinski <kubakici@wp.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sparc: serial: sunhv: fix a double lock bug 2016-11-21T09:06:40+00:00 Dan Carpenter dan.carpenter@oracle.com 2016-07-15T11:17:33+00:00 4e90b688013526340fef9f11ae0184888fd563d1 [ Upstream commit 344e3c7734d5090b148c19ac6539b8947fed6767 ] We accidentally take the "port->lock" twice in a row. This old code was supposed to be deleted. Fixes: e58e241c1788 ('sparc: serial: Clean up the locking for -rt') Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 344e3c7734d5090b148c19ac6539b8947fed6767 ]

We accidentally take the "port->lock" twice in a row.  This old code
was supposed to be deleted.

Fixes: e58e241c1788 ('sparc: serial: Clean up the locking for -rt')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>