Commit Graph

5630 Commits

Author SHA1 Message Date
Fabien Dessenne
f4e68d58cf tty: fix NULL pointer issue when tty_port ops is not set
Unlike 'client_ops' which is initialized to 'default_client_ops', the
port operations 'ops' may be left to NULL.
Check the 'ops' value before checking the 'ops->x' value.

Signed-off-by: Fabien Dessenne <fabien.dessenne@st.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-03-28 01:21:21 +09:00
Wentao Wang
3ec8002951 Disable kgdboc failed by echo space to /sys/module/kgdboc/parameters/kgdboc
Echo "" to /sys/module/kgdboc/parameters/kgdboc will fail with "No such
device” error.

This is caused by function "configure_kgdboc" who init err to ENODEV
when the config is empty (legal input) the code go out with ENODEV
returned.

Fixes: 2dd4531686 ("kgdboc: Fix restrict error")
Signed-off-by: Wentao Wang <witallwang@gmail.com>
Cc: stable <stable@vger.kernel.org>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-03-28 00:27:48 +09:00
Razvan Stefanescu
69646d7a36 tty/serial: atmel: RS485 HD w/DMA: enable RX after TX is stopped
In half-duplex operation, RX should be started after TX completes.

If DMA is used, there is a case when the DMA transfer completes but the
TX FIFO is not emptied, so the RX cannot be restarted just yet.

Use a boolean variable to store this state and rearm TX interrupt mask
to be signaled again that the transfer finished. In interrupt transmit
handler this variable is used to start RX. A warning message is generated
if RX is activated before TX fifo is cleared.

Fixes: b389f173aa ("tty/serial: atmel: RS485 half duplex w/DMA: enable
RX after TX is done")
Signed-off-by: Razvan Stefanescu <razvan.stefanescu@microchip.com>
Acked-by: Richard Genoud <richard.genoud@gmail.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-03-28 00:27:48 +09:00
Razvan Stefanescu
f304098313 tty/serial: atmel: Add is_half_duplex helper
Use a helper function to check that a port needs to use half duplex
communication, replacing several occurrences of multi-line bit checking.

Fixes: b389f173aa ("tty/serial: atmel: RS485 half duplex w/DMA: enable RX after TX is done")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Razvan Stefanescu <razvan.stefanescu@microchip.com>
Acked-by: Richard Genoud <richard.genoud@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-03-28 00:27:48 +09:00
Hoan Nguyen An
93bcefd4c6 serial: sh-sci: Fix setting SCSCR_TIE while transferring data
We disable transmission interrupt (clear SCSCR_TIE) after all data has been transmitted
(if uart_circ_empty(xmit)). While transmitting, if the data is still in the tty buffer,
re-enable the SCSCR_TIE bit, which was done at sci_start_tx().
This is unnecessary processing, wasting CPU operation if the data transmission length is large.
And further, transmit end, FIFO empty bits disabling have also been performed in the step above.

Signed-off-by: Hoan Nguyen An <na-hoan@jinso.co.jp>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-03-19 15:37:44 +01:00
Petr Štetiar
72ff51d8dd serial: ar933x_uart: Fix build failure with disabled console
Andrey has reported on OpenWrt's bug tracking system[1], that he
currently can't use ar93xx_uart as pure serial UART without console
(CONFIG_SERIAL_8250_CONSOLE and CONFIG_SERIAL_AR933X_CONSOLE undefined),
because compilation ends with following error:

 ar933x_uart.c: In function 'ar933x_uart_console_write':
 ar933x_uart.c:550:14: error: 'struct uart_port' has no
                               member named 'sysrq'

So this patch moves all the code related to console handling behind
series of CONFIG_SERIAL_AR933X_CONSOLE ifdefs.

1. https://bugs.openwrt.org/index.php?do=details&task_id=2152

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Andrey Batyiev <batyiev@gmail.com>
Reported-by: Andrey Batyiev <batyiev@gmail.com>
Tested-by: Andrey Batyiev <batyiev@gmail.com>
Signed-off-by: Petr Štetiar <ynezz@true.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-03-19 15:37:44 +01:00
Nathan Chancellor
c5cbc78acf tty: serial: qcom_geni_serial: Initialize baud in qcom_geni_console_setup
When building with -Wsometimes-uninitialized, Clang warns:

drivers/tty/serial/qcom_geni_serial.c:1079:6: warning: variable 'baud'
is used uninitialized whenever 'if' condition is false
[-Wsometimes-uninitialized]

It's not wrong; when options is NULL, baud has no default value. Use
9600 as that is a sane default.

Link: https://github.com/ClangBuiltLinux/linux/issues/395
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-03-19 15:37:44 +01:00
Mao Wenan
ac0cdb3d99 sc16is7xx: missing unregister/delete driver on error in sc16is7xx_init()
Add the missing uart_unregister_driver() and i2c_del_driver() before return
from sc16is7xx_init() in the error handling case.

Signed-off-by: Mao Wenan <maowenan@huawei.com>
Reviewed-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-03-19 15:37:44 +01:00
Kangjie Lu
6734330654 tty: mxs-auart: fix a potential NULL pointer dereference
In case ioremap fails, the fix returns -ENOMEM to avoid NULL
pointer dereferences.
Multiple places use port.membase.

Signed-off-by: Kangjie Lu <kjlu@umn.edu>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-03-19 15:37:43 +01:00
Kangjie Lu
c85be04106 tty: atmel_serial: fix a potential NULL pointer dereference
In case dmaengine_prep_dma_cyclic fails, the fix returns a proper
error code to avoid NULL pointer dereference.

Signed-off-by: Kangjie Lu <kjlu@umn.edu>
Fixes: 34df42f59a ("serial: at91: add rx dma support")
Acked-by: Richard Genoud <richard.genoud@gmail.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-03-19 15:37:43 +01:00
Aditya Pakki
3a10e3dd52 serial: max310x: Fix to avoid potential NULL pointer dereference
of_match_device can return a NULL pointer when matching device is not
found. This patch avoids a scenario causing NULL pointer derefernce.

Signed-off-by: Aditya Pakki <pakki001@umn.edu>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-03-19 15:37:43 +01:00
Aditya Pakki
32f4717983 serial: mvebu-uart: Fix to avoid a potential NULL pointer dereference
of_match_device on failure to find a matching device can return a NULL
pointer. The patch checks for such a scenrio and passes the error upstream.

Signed-off-by: Aditya Pakki <pakki001@umn.edu>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-03-19 15:37:43 +01:00
Linus Torvalds
31ef489a02 Merge tag 'dmaengine-5.1-rc1' of git://git.infradead.org/users/vkoul/slave-dma
Pull dmaengine updates from Vinod Koul:

 - dmatest updates for modularizing common struct and code

 - remove SG support for VDMA xilinx IP and updates to driver

 - Update to dw driver to support Intel iDMA controllers multi-block
   support

 - tegra updates for proper reporting of residue

 - Add Snow Ridge ioatdma device id and support for IOATDMA v3.4

 - struct_size() usage and useless LIST_HEAD cleanups in subsystem.

 - qDMA controller driver for Layerscape SoCs

 - stm32-dma PM Runtime support

 - And usual updates to imx-sdma, sprd, Documentation, fsl-edma,
   bcm2835, qcom_hidma etc

* tag 'dmaengine-5.1-rc1' of git://git.infradead.org/users/vkoul/slave-dma: (81 commits)
  dmaengine: imx-sdma: fix consistent dma test failures
  dmaengine: imx-sdma: add a test for imx8mq multi sdma devices
  dmaengine: imx-sdma: add clock ratio 1:1 check
  dmaengine: dmatest: move test data alloc & free into functions
  dmaengine: dmatest: add short-hand `buf_size` var in dmatest_func()
  dmaengine: dmatest: wrap src & dst data into a struct
  dmaengine: ioatdma: support latency tolerance report (LTR) for v3.4
  dmaengine: ioatdma: add descriptor pre-fetch support for v3.4
  dmaengine: ioatdma: disable DCA enabling on IOATDMA v3.4
  dmaengine: ioatdma: Add Snow Ridge ioatdma device id
  dmaengine: sprd: Change channel id to slave id for DMA cell specifier
  dt-bindings: dmaengine: sprd: Change channel id to slave id for DMA cell specifier
  dmaengine: mv_xor: Use correct device for DMA API
  Documentation :dmaengine: clarify DMA desc. pointer after submission
  Documentation: dmaengine: fix dmatest.rst warning
  dmaengine: k3dma: Add support for dma-channel-mask
  dmaengine: k3dma: Delete axi_config
  dmaengine: k3dma: Upgrade k3dma driver to support hisi_asp_dma hardware
  Documentation: bindings: dma: Add binding for dma-channel-mask
  Documentation: bindings: k3dma: Extend the k3dma driver binding to support hisi-asp
  ...
2019-03-14 09:11:54 -07:00
Linus Torvalds
2901752c14 Merge tag 'pci-v5.1-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci
Pull PCI updates from Bjorn Helgaas:

 - Use match_string() instead of reimplementing it (Andy Shevchenko)

 - Enable SERR# forwarding for all bridges (Bharat Kumar Gogada)

 - Use Latency Tolerance Reporting if already enabled by platform (Bjorn
   Helgaas)

 - Save/restore LTR info for suspend/resume (Bjorn Helgaas)

 - Fix DPC use of uninitialized data (Dongdong Liu)

 - Probe bridge window attributes only once at enumeration-time to fix
   device accesses during rescan (Bjorn Helgaas)

 - Return BAR size (not "size -1 ") from pci_size() to simplify code (Du
   Changbin)

 - Use config header type (not class code) identify bridges more
   reliably (Honghui Zhang)

 - Work around Intel Denverton incorrect Trace Hub BAR size reporting
   (Alexander Shishkin)

 - Reorder pciehp cached state/hardware state updates to avoid missed
   interrupts (Mika Westerberg)

 - Turn ibmphp semaphores into completions or mutexes (Arnd Bergmann)

 - Mark expected switch fall-through (Mathieu Malaterre)

 - Use of_node_name_eq() for node name comparisons (Rob Herring)

 - Add ACS and pciehp quirks for HXT SD4800 (Shunyong Yang)

 - Consolidate Rohm Vendor ID definitions (Andy Shevchenko)

 - Use u32 (not __u32) for things not exposed to userspace (Logan
   Gunthorpe)

 - Fix locking semantics of bus and slot reset interfaces (Alex
   Williamson)

 - Update PCIEPORTBUS Kconfig help text (Hou Zhiqiang)

 - Allow portdrv to claim subtractive decode Ports so PCIe services will
   work for them (Honghui Zhang)

 - Report PCIe links that become degraded at run-time (Alexandru
   Gagniuc)

 - Blacklist Gigabyte X299 Root Port power management to fix Thunderbolt
   hotplug (Mika Westerberg)

 - Revert runtime PM suspend/resume callbacks that broke PME on network
   cable plug (Mika Westerberg)

 - Disable Data Link State Changed interrupts to prevent wakeup
   immediately after suspend (Mika Westerberg)

 - Extend altera to support Stratix 10 (Ley Foon Tan)

 - Allow building altera driver on ARM64 (Ley Foon Tan)

 - Replace Douglas with Tom Joseph as Cadence PCI host/endpoint
   maintainer (Lorenzo Pieralisi)

 - Add DT support for R-Car RZ/G2E (R8A774C0) (Fabrizio Castro)

 - Add dra72x/dra74x/dra76x SoC compatible strings (Kishon Vijay Abraham I)

 - Enable x2 mode support for dra72x/dra74x/dra76x SoC (Kishon Vijay
   Abraham I)

 - Configure dra7xx PHY to PCIe mode (Kishon Vijay Abraham I)

 - Simplify dwc (remove unnecessary header includes, name variables
   consistently, reduce inverted logic, etc) (Gustavo Pimentel)

 - Add i.MX8MQ support (Andrey Smirnov)

 - Add message to help debug dwc MSI-X mask bit errors (Gustavo
   Pimentel)

 - Work around imx7d PCIe PLL erratum (Trent Piepho)

 - Don't assert qcom reset GPIO during probe (Bjorn Andersson)

 - Skip dwc MSI init if MSIs have been disabled (Lucas Stach)

 - Use memcpy_fromio()/memcpy_toio() instead of plain memcpy() in PCI
   endpoint framework (Wen Yang)

 - Add interface to discover supported endpoint features to replace a
   bitfield that wasn't flexible enough (Kishon Vijay Abraham I)

 - Implement the new supported-feature interface for designware-plat,
   dra7xx, rockchip, cadence (Kishon Vijay Abraham I)

 - Fix issues with 64-bit BAR in endpoints (Kishon Vijay Abraham I)

 - Add layerscape endpoint mode support (Xiaowei Bao)

 - Remove duplicate struct hv_vp_set in favor of struct hv_vpset (Maya
   Nakamura)

 - Rework hv_irq_unmask() to use cpumask_to_vpset() instead of
   open-coded reimplementation (Maya Nakamura)

 - Align Hyper-V struct retarget_msi_interrupt arguments (Maya Nakamura)

 - Fix mediatek MMIO size computation to enable full size of available
   MMIO space (Honghui Zhang)

 - Fix mediatek DMA window size computation to allow endpoint DMA access
   to full DRAM address range (Honghui Zhang)

 - Fix mvebu prefetchable BAR regression caused by common bridge
   emulation that assumed all bridges had prefetchable windows (Thomas
   Petazzoni)

 - Make advk_pci_bridge_emul_ops static (Wei Yongjun)

 - Configure MPS settings for VMD root ports (Jon Derrick)

* tag 'pci-v5.1-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci: (92 commits)
  PCI: Update PCIEPORTBUS Kconfig help text
  PCI: Fix "try" semantics of bus and slot reset
  PCI/LINK: Report degraded links via link bandwidth notification
  dt-bindings: PCI: altera: Add altr,pcie-root-port-2.0
  PCI: altera: Enable driver on ARM64
  PCI: altera: Add Stratix 10 PCIe support
  PCI/PME: Fix possible use-after-free on remove
  PCI: aardvark: Make symbol 'advk_pci_bridge_emul_ops' static
  PCI: dwc: skip MSI init if MSIs have been explicitly disabled
  PCI: hv: Refactor hv_irq_unmask() to use cpumask_to_vpset()
  PCI: hv: Replace hv_vp_set with hv_vpset
  PCI: hv: Add __aligned(8) to struct retarget_msi_interrupt
  PCI: mediatek: Enlarge PCIe2AHB window size to support 4GB DRAM
  PCI: mediatek: Fix memory mapped IO range size computation
  PCI: dwc: Remove superfluous shifting in definitions
  PCI: dwc: Make use of GENMASK/FIELD_PREP
  PCI: dwc: Make use of BIT() in constant definitions
  PCI: dwc: Share code for dw_pcie_rd/wr_other_conf()
  PCI: dwc: Make use of IS_ALIGNED()
  PCI: imx6: Add code to request/control "pcie_aux" clock for i.MX8MQ
  ...
2019-03-09 14:57:08 -08:00
Linus Torvalds
be37f21a08 Merge tag 'audit-pr-20190305' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit
Pull audit updates from Paul Moore:
 "A lucky 13 audit patches for v5.1.

  Despite the rather large diffstat, most of the changes are from two
  bug fix patches that move code from one Kconfig option to another.

  Beyond that bit of churn, the remaining changes are largely cleanups
  and bug-fixes as we slowly march towards container auditing. It isn't
  all boring though, we do have a couple of new things: file
  capabilities v3 support, and expanded support for filtering on
  filesystems to solve problems with remote filesystems.

  All changes pass the audit-testsuite.  Please merge for v5.1"

* tag 'audit-pr-20190305' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit:
  audit: mark expected switch fall-through
  audit: hide auditsc_get_stamp and audit_serial prototypes
  audit: join tty records to their syscall
  audit: remove audit_context when CONFIG_ AUDIT and not AUDITSYSCALL
  audit: remove unused actx param from audit_rule_match
  audit: ignore fcaps on umount
  audit: clean up AUDITSYSCALL prototypes and stubs
  audit: more filter PATH records keyed on filesystem magic
  audit: add support for fcaps v3
  audit: move loginuid and sessionid from CONFIG_AUDITSYSCALL to CONFIG_AUDIT
  audit: add syscall information to CONFIG_CHANGE records
  audit: hand taken context to audit_kill_trees for syscall logging
  audit: give a clue what CONFIG_CHANGE op was involved
2019-03-07 12:20:11 -08:00
Rajan Vaja
f694936c3b tty: xilinx_uartps: Correct return value in probe
Existing driver checks for alternate clock if devm_clk_get() fails
and returns error code for last clock failure. If xilinx_uartps is
called before clock driver, devm_clk_get() returns -EPROBE_DEFER.
In this case, probe should not check for alternate clock as main
clock is already present in DTS and return -EPROBE_DEFER only.

This patch fixes it by not checking for alternate clock when main
clock get returns -EPROBE_DEFER.

Signed-off-by: Rajan Vaja <rajan.vaja@xilinx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-03-01 18:07:34 +01:00
Lanqing Liu
5b9cea15a3 serial: sprd: Modify the baud rate calculation formula
When the source clock is not divisible by the expected baud rate and
the remainder is not less than half of the expected baud rate, the old
formular will round up the frequency division coefficient. This will
make the actual baud rate less than the expected value and can not meet
the external transmission requirements.

Thus this patch modifies the baud rate calculation formula to support
the serial controller output the maximum baud rate.

Signed-off-by: Lanqing Liu <lanqing.liu@unisoc.com>
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-02-26 12:35:02 +01:00
Lubomir Rintel
f4817843e3 serial: 8250_of: assume reg-shift of 2 for mrvl,mmp-uart
There are two other drivers that bind to mrvl,mmp-uart and both of them
assume register shift of 2 bits. There are device trees that lack the
property and rely on that assumption.

If this driver wins the race to bind to those devices, it should behave
the same as the older deprecated driver.

Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-02-26 12:30:45 +01:00
Lubomir Rintel
fe9ed6d248 serial: 8250_pxa: honor the port number from devicetree
Like the other OF-enabled drivers, use the port number from the firmware if
the devicetree specifies an alias:

  aliases {
      ...
      serial2 = &uart2; /* Should be ttyS2 */
  }

This is how the deprecated pxa.c driver behaved, switching to 8250_pxa
messes up the numbering.

Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-02-26 12:30:44 +01:00
Gustavo A. R. Silva
d56f00fd53 tty: hvc_xen: Mark expected switch fall-through
In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

This patch fixes the following warning:

drivers/tty/hvc/hvc_xen.c: In function ‘xencons_backend_changed’:
drivers/tty/hvc/hvc_xen.c:493:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
   if (dev->state == XenbusStateClosed)
      ^
drivers/tty/hvc/hvc_xen.c:496:2: note: here
  case XenbusStateClosing:
  ^~~~

Warning level 3 was used: -Wimplicit-fallthrough=3

Notice that, in this particular case, the code comment is modified
in accordance with what GCC is expecting to find.

This patch is part of the ongoing efforts to enable
-Wimplicit-fallthrough

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-02-26 12:30:44 +01:00
Gustavo A. R. Silva
3e913eebdf tty: n_gsm: Mark expected switch fall-throughs
In preparation to enabling -Wimplicit-fallthrough, mark switch
cases where we are expecting to fall through.

This patch fixes the following warnings:

drivers/tty/n_gsm.c: In function ‘gsm_dlci_data’:
drivers/tty/n_gsm.c:1582:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
   if (tty) {
      ^
drivers/tty/n_gsm.c:1587:2: note: here
  case 1:
  ^~~~
drivers/tty/n_gsm.c: In function ‘gsm1_receive’:
  CC [M]  drivers/scsi/snic/snic_disc.o
  CC [M]  drivers/net/wireless/realtek/rtlwifi/pci.o
  CC      drivers/usb/early/xhci-dbc.o
drivers/tty/n_gsm.c:1981:12: warning: this statement may fall through [-Wimplicit-fallthrough=]
   gsm->fcs = INIT_FCS;
            ^
drivers/tty/n_gsm.c:1983:2: note: here
  case GSM_ADDRESS: /* Address continuation */
  ^~~~

Warning level 3 was used: -Wimplicit-fallthrough=3

Notice that, in this particular case, the code comment is modified
in accordance with what GCC is expecting to find.

This patch is part of the ongoing efforts to enable
-Wimplicit-fallthrough.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-02-26 12:30:44 +01:00
Jeffrey Hugo
be24c27018 tty: serial: msm_serial: Remove __init from msm_console_setup()
Due to the complexities of modern Qualcomm SoCs, about a half dozen drivers
must successfully probe before the clocks for the console are present, and
the console can successfully probe.  Depending on several random factors
such as probe order and modules vs builtin, msm_serial may not be able to
successfully probe for some, at which point, __init annotated functions
may become unmapped.  If this occurs, msm_console_setup() will be called
from the probe path, but will no longer exist, resulting in a kernel
panic.

Resolve this issue by removing the __init annotation from
msm_console_setup().

Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-02-19 13:42:08 +01:00
Stuart Menefy
5086e0a409 tty: serial: samsung: Enable baud clock during initialisation
The Exynos 5260, like the 5433, appears to require baud clock as
well as pclk to be running before accessing any of the registers,
otherwise an external abort is raised.

The serial driver already enables baud clock when required, but only
if it knows which clock is baud clock. On older SoCs baud clock may be
selected from a number of possible clocks so to support this the driver
only selects which clock to use for baud clock when a port is opened,
at which point the desired baud rate is known and the best clock can be
selected.

The result is that there are a number of circumstances in which
registers are accessed without first explicitly enabling baud clock:
 - while the driver is being initialised
 - the initial parts of opening a port for the first time
 - when resuming if the port hasn't been already opened

The 5433 overcomes this currently by marking the baud clock as
CLK_IGNORE_UNUSED, so the clock is always enabled, however
for the 5260 I've been trying to avoid this.

This change adds code to pick the first available clock to use
as baud clock and enables it while initialising the driver.

This code wouldn't be sufficient on a SoC which supports
multiple possible baud clock sources _and_ requires the
correct baud clock to be enabled before accessing any of the
serial port registers (in particular the register which selects
which clock to use as the baud clock).  As far as I know
such hardware doesn't exist.

Signed-off-by: Stuart Menefy <stuart.menefy@mathembedded.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-02-19 13:42:08 +01:00
Anssi Hannula
7abab16051 serial: uartps: Fix stuck ISR if RX disabled with non-empty FIFO
If RX is disabled while there are still unprocessed bytes in RX FIFO,
cdns_uart_handle_rx() called from interrupt handler will get stuck in
the receive loop as read bytes will not get removed from the RX FIFO
and CDNS_UART_SR_RXEMPTY bit will never get set.

Avoid the stuck handler by checking first if RX is disabled. port->lock
protects against race with RX-disabling functions.

This HW behavior was mentioned by Nathan Rossi in 43e98facc4a3 ("tty:
xuartps: Fix RX hang, and TX corruption in termios call") which fixed a
similar issue in cdns_uart_set_termios().
The behavior can also be easily verified by e.g. setting
CDNS_UART_CR_RX_DIS at the beginning of cdns_uart_handle_rx() - the
following loop will then get stuck.

Resetting the FIFO using RXRST would not set RXEMPTY either so simply
issuing a reset after RX-disable would not work.

I observe this frequently on a ZynqMP board during heavy RX load at 1M
baudrate when the reader process exits and thus RX gets disabled.

Fixes: 61ec901698 ("tty/serial: add support for Xilinx PS UART")
Signed-off-by: Anssi Hannula <anssi.hannula@bitwise.fi>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-02-19 13:42:07 +01:00
Chengguang Xu
b289c496e5 tty: serial: remove redundant likely annotation
unlikely has already included in IS_ERR(),
so just remove redundant likely annotation.

Signed-off-by: Chengguang Xu <cgxu519@gmx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-02-19 13:42:07 +01:00