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Serial core handles serial_rs485 assignment.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220606100433.13793-34-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Serial core handles serial_rs485 sanitization and copying rs485 struct.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220606100433.13793-29-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Serial core handles serial_rs485 sanitization and copying rs485 struct.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220606100433.13793-28-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Serial core handles serial_rs485 sanitization and copying rs485 struct.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220606100433.13793-27-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Serial core handles serial_rs485 sanitization and rs485 struct
assignment. As serial_rs485 is already clear for the non-RS485 case by
serial core, there no need to clear flags in the driver.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220606100433.13793-26-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Add information on supported serial_rs485 features.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220606100433.13793-12-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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8250_of uses em485, fill in rs485_supported accordingly.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220606100433.13793-11-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Add information on supported serial_rs485 features.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220606100433.13793-10-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Add information on supported serial_rs485 features.
Differentiate based on which port is in question.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220606100433.13793-9-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Add information on supported serial_rs485 features.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220606100433.13793-8-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Add information on supported serial_rs485 features. When the driver is
using em485, take advantage of serial8250_em485_supported.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220606100433.13793-7-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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bcm2835aux uses em485, fill in rs485_supported accordingly.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220606100433.13793-6-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Create serial8250_em485_supported for the serial_rs485 features
supported by the em485 framework.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220606100433.13793-5-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Preparing to move serial_rs485 struct sanitization into serial core,
each driver has to provide what fields/flags it supports. This
information is pointed into by rs485_supported.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220606100433.13793-4-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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A few serial drivers make a call to rs485_config() themselves (all
these seem to relate to init). Convert them all to use a common helper
which makes it easy to make adjustments on tasks related to it as
serial_rs485 struct sanitization is going to be added.
In pci_fintek_setup() (in 8250_pci.c), the rs485_config() call was made
with NULL, however, it can be changed to pass uart_port's rs485 struct.
No other callers should pass NULL into rs485_config() so the NULL check
can now be eliminated.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220606100433.13793-2-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Make sure LSR flags are preserved in dw8250_tx_wait_empty(). This
function is called from a low-level out function and therefore cannot
call serial_lsr_in() as it would lead to infinite recursion.
It is borderline if the flags need to be saved here at all since this
code relates to writing LCR register which usually implies no important
characters should be arriving.
Fixes: 914eaf935ec7 ("serial: 8250_dw: Allow TX FIFO to drain before writing to UART_LCR")
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220608095431.18376-7-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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dw8250_handle_irq() reads LSR under a few conditions, convert both to
use serial_lsr_in() in order to preserve LSR flags properly across
reads.
Fixes: 424d79183af0 ("serial: 8250_dw: Avoid "too much work" from bogus rx timeout interrupt")
Fixes: aa63d786cea2 ("serial: 8250: dw: Add support for DMA flow controlling devices")
Cc: Douglas Anderson <dianders@chromium.org>
Cc: Phil Edworthy <phil.edworthy@renesas.com>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220608095431.18376-6-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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serial8250_rx_chars() has max_count based character limit. If it
triggers, the function returns the old LSR value (and it has never
returned only flags which were not handled). Adjust the comment to
match behavior and warn about which flags can be depended on.
I'd have moved LSR read before LSR read and used serial_lsr_in() also
here but I came across an old discussion about the topic. That
discussion generated commit d22f8f10683c ("serial: 8250: Fix lost rx
state") so I left the code as it is (it works as long as the callers
only use a subset of the LSR flags which holds true today) and changed
the comment instead.
Link: https://www.spinics.net/lists/linux-serial/msg16220.html
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220608095431.18376-5-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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serial8250_handle_irq() assumes it's the first to read LSR register.
However, there are 8250 drivers which perform LSR read in their own irq
handler prior to calling serial8250_handle_irq(). As not all flags are
preserved across LSR reads, use serial_lsr_in() helper to get all the
preserved flags.
This commit might fix other commits too besides the ones for DW UART
mentioned below. It's just not clear to me which of the other devices
clear some of the LSR flags on read. AFAIK, nobody has complained about
this problem (either against DW or other devices) so it might not have
that bad impact in the end.
Fixes: 424d79183af0 ("serial: 8250_dw: Avoid "too much work" from bogus rx timeout interrupt")
Fixes: aa63d786cea2 ("serial: 8250: dw: Add support for DMA flow controlling devices")
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220608095431.18376-4-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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LSR register readers need to be careful in order to not lose bits that
are not preserved across reads. Create a helper that takes care of
storing the non-preserved bits into lsr_save_flags.
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220608095431.18376-3-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Not all LSR register flags are preserved across reads. Therefore, LSR
readers must store the non-preserved bits into lsr_save_flags.
This fix was initially mixed into feature commit f6f586102add ("serial:
8250: Handle UART without interrupt on TEMT using em485"). However,
that feature change had a flaw and it was reverted to make room for
simpler approach providing the same feature. The embedded fix got
reverted with the feature change.
Re-add the lsr_save_flags fix and properly mark it's a fix.
Link: https://lore.kernel.org/all/1d6c31d-d194-9e6a-ddf9-5f29af829f3@linux.intel.com/T/#m1737eef986bd20cf19593e344cebd7b0244945fc
Fixes: e490c9144cfa ("tty: Add software emulated RS485 support for 8250")
Co-developed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220608095431.18376-2-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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As either start_tx_rs485() or start_tx() calls __start_tx() as the last
line of their logic, it makes sense to just move that call into
start_tx(). When start_tx_rs485() wants to defer tx using timer, return
false so start_tx() can return based on it.
Reorganize em485 code in serial8250_start_tx() so that the return can be
shared for the cases where tx start is deferred.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220607084154.8172-2-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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There seems to be little reason for __do_stop_tx() to exits on its own.
It is rather simple and is only called from __stop_tx(). Thus, move its
logic into __stop_tx().
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220607084154.8172-1-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Pull tty and serial driver updates from Greg KH:
"Here is the big set of tty and serial driver updates for 5.19-rc1.
Lots of tiny cleanups in here, the major stuff is:
- termbit cleanups and unification by Ilpo. A much needed change that
goes a long way to making things simpler for all of the different
arches
- tty documentation cleanups and movements to their own place in the
documentation tree
- old tty driver cleanups and fixes from Jiri to bring some existing
drivers into the modern world
- RS485 cleanups and unifications to make it easier for individual
drivers to support this mode instead of having to duplicate logic
in each driver
- Lots of 8250 driver updates and additions
- new device id additions
- n_gsm continued fixes and cleanups
- other minor serial driver updates and cleanups
All of these have been in linux-next for weeks with no reported issues"
* tag 'tty-5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (166 commits)
tty: Rework receive flow control char logic
pcmcia: synclink_cs: Don't allow CS5-6
serial: stm32-usart: Correct CSIZE, bits, and parity
serial: st-asc: Sanitize CSIZE and correct PARENB for CS7
serial: sifive: Sanitize CSIZE and c_iflag
serial: sh-sci: Don't allow CS5-6
serial: txx9: Don't allow CS5-6
serial: rda-uart: Don't allow CS5-6
serial: digicolor-usart: Don't allow CS5-6
serial: uartlite: Fix BRKINT clearing
serial: cpm_uart: Fix build error without CONFIG_SERIAL_CPM_CONSOLE
serial: core: Do stop_rx in suspend path for console if console_suspend is disabled
tty: serial: qcom-geni-serial: Remove uart frequency table. Instead, find suitable frequency with call to clk_round_rate.
dt-bindings: serial: renesas,em-uart: Add RZ/V2M clock to access the registers
serial: 8250_fintek: Check SER_RS485_RTS_* only with RS485
Revert "serial: 8250_mtk: Make sure to select the right FEATURE_SEL"
serial: msm_serial: disable interrupts in __msm_console_write()
serial: meson: acquire port->lock in startup()
serial: 8250_dw: Use dev_err_probe()
serial: 8250_dw: Use devm_add_action_or_reset()
...
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Pull ARMv4T/v5 multiplatform support from Arnd Bergmann:
"This series has been 12 years in the making, it mostly finishes the
work that was started with the founding of Linaro to clean up platform
support in the kernel.
The largest change here is a cleanup of the omap1 platform, which is
the final ARM machine type to get converted to the common-clk
subsystem. All the omap1 specific drivers are now made independent of
the mach/*.h headers to allow the platform to be part of a generic
ARMv4/v5 multiplatform kernel.
The last bit that enables this support is still missing here while we
wait for some last dependencies to make it into the mainline kernel
through other subsystems.
The s3c24xx, ixp4xx, iop32x, ep93xx and dove platforms were all almost
at the point of allowing multiplatform kernels, this work gets
completed here along with a few additional cleanup. At the same time,
the s3c24xx and s3c64xx are now deprecated and expected to get removed
in the future.
The PXA and OMAP1 bits are in a separate branch because of
dependencies. Once both branches are merged, only the three Intel
StrongARM platforms (RiscPC, Footbridge/NetWinder and StrongARM1100)
need separate kernels, and there are no plans to include these"
* tag 'arm-multiplatform-5.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: (61 commits)
ARM: ixp4xx: Consolidate Kconfig fixing issue
ARM: versatile: Add missing of_node_put in dcscb_init
ARM: config: Refresh IXP4xx config after multiplatform
ARM: omap1: add back omap_set_dma_priority() stub
ARM: omap: fix missing declaration warnings
ARM: omap: fix address space warnings from sparse
ARM: spear: remove include/mach/ subdirectory
ARM: davinci: remove include/mach/ subdirectory
ARM: omap2: remove include/mach/ subdirectory
integrator: remove empty ap_init_early()
ARM: s3c: fix include path
MAINTAINERS: omap1: Add Janusz as an additional maintainer
ARM: omap1: htc_herald: fix typos in comments
ARM: OMAP1: fix typos in comments
ARM: OMAP1: clock: Remove noop code
ARM: OMAP1: clock: Remove unused code
ARM: OMAP1: clock: Fix UART rate reporting algorithm
ARM: OMAP1: clock: Fix early UART rate issues
ARM: OMAP1: Prepare for conversion of OMAP1 clocks to CCF
ARM: omap1: fix build with no SoC selected
...
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SER_RS485_RTS_ON_SEND and SER_RS485_RTS_AFTER_SEND relate to behavior
within RS485 operation. The driver checks if they have the same value
which is not possible to realize with the hardware. The check is taken
regardless of SER_RS485_ENABLED flag and -EINVAL is returned when the
check fails, which creates problems.
This check makes it unnecessarily complicated to turn RS485 mode off as
simple zeroed serial_rs485 struct will trigger that equal values check.
In addition, the driver itself memsets its rs485 structure to zero when
RS485 is disabled but if userspace would try to make an TIOCSRS485
ioctl() call with the very same struct, it would end up failing with
-EINVAL which doesn't make much sense.
Resolve the problem by moving the check inside SER_RS485_ENABLED block.
Fixes: 7ecc77011c6f ("serial: 8250_fintek: Return -EINVAL on invalid configuration")
Cc: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/035c738-8ea5-8b17-b1d7-84a7b3aeaa51@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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It was found that some MediaTek SoCs are incompatible with this
change. Also, this register was mistakenly understood as it was
related to the 16550A register layout selection but, at least
on some IPs, if not all, it's related to something else unknown.
This reverts commit 6f81fdded0d024c7d4084d434764f30bca1cd6b1.
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Fixes: 6f81fdded0d0 ("serial: 8250_mtk: Make sure to select the right FEATURE_SEL")
Reported-by: "kernelci.org bot" <bot@kernelci.org>
Link: https://lore.kernel.org/r/20220510122620.150342-1-angelogioacchino.delregno@collabora.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Simplify the error path in ->probe() a bit by using dev_err_probe().
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220509172129.37770-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Slightly simplify ->probe() and drop a few goto labels by using
devm_add_action_or_reset() for clock and reset cleanup.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220509172129.37770-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The of_irq.h and of_platform.h are not used by the driver. On the
other hand, the mod_devicetable.h missed. Drop the former two and
add the latter one.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220509161911.37164-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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CMSPAR is defined by all architectures since commit 6bf08cb246b5
("[PATCH] Add CMSPAR to termbits.h for powerpc and alpha").
Reviewed-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220513082906.11096-2-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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We need the tty fixes in here as well, as we need to revert one of them :(
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The XON1/XOFF1 character registers are at offset 0xa0 and 0xa8
respectively, so we cannot use the definition in serial_port.h.
Fixes: bdbd0a7f8f03 ("serial: 8250-mtk: modify baudrate setting")
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220427132328.228297-4-angelogioacchino.delregno@collabora.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Set the FEATURE_SEL at probe time to make sure that BIT(0) is enabled:
this guarantees that when the port is configured as AP UART, the
right register layout is interpreted by the UART IP.
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220427132328.228297-3-angelogioacchino.delregno@collabora.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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On MediaTek SoCs, the UART IP is 16550A compatible, but there are some
specific quirks: we are declaring a register shift of 2, but this is
only valid for the majority of the registers, as there are some that
are out of the standard layout.
Specifically, this driver is using definitions from serial_reg.h, where
we have a UART_EFR register defined as 2: this results in a 0x8 offset,
but there we have the FCR register instead.
The right offset for the EFR register on MediaTek UART is at 0x98,
so, following the decimal definition convention in serial_reg.h and
accounting for the register left shift of two, add and use the correct
register address for this IP, defined as decimal 38, so that the final
calculation results in (0x26 << 2) = 0x98.
Fixes: bdbd0a7f8f03 ("serial: 8250-mtk: modify baudrate setting")
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220427132328.228297-2-angelogioacchino.delregno@collabora.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Oxford Semiconductor PCIe (Tornado) 950 serial port devices are driven
by a fixed 62.5MHz clock input derived from the 100MHz PCI Express clock.
We currently drive the device using its default oversampling rate of 16
and the clock prescaler disabled, consequently yielding the baud base of
3906250. This base is inadequate for some of the high-speed baud rates
such as 460800bps, for which the closest rate possible can be obtained
by dividing the baud base by 8, yielding the baud rate of 488281.25bps,
which is off by 5.9638%. This is enough for data communication to break
with the remote end talking actual 460800bps, where missed stop bits
have been observed.
We can do better however, by taking advantage of a reduced oversampling
rate, which can be set to any integer value from 4 to 16 inclusive by
programming the TCR register, and by using the clock prescaler, which
can be set to any value from 1 to 63.875 in increments of 0.125 in the
CPR/CPR2 register pair. The prescaler has to be explicitly enabled
though by setting bit 7 in the MCR or otherwise it is bypassed (in the
enhanced mode that we enable) as if the value of 1 was used.
Make use of these features then as follows:
- Set the baud base to 15625000, reflecting the minimum oversampling
rate of 4 with the clock prescaler and divisor both set to 1.
- Override the `set_mctrl' and set the MCR shadow there so as to have
MCR[7] always set and have the 8250 core propagate these settings.
- Override the `get_divisor' handler and determine a good combination of
parameters by using a lookup table with predetermined value pairs of
the oversampling rate and the clock prescaler and finding a pair that
divides the input clock such that the quotient, when rounded to the
nearest integer, deviates the least from the exact result. Calculate
the clock divisor accordingly.
Scale the resulting oversampling rate (only by powers of two) if
possible so as to maximise it, reducing the divisor accordingly, and
avoid a divisor overflow for very low baud rates by scaling the
oversampling rate and/or the prescaler even if that causes some
accuracy loss.
Also handle the historic spd_cust feature so as to allow one to set
all the three parameters manually to arbitrary values, by keeping the
low 16 bits for the divisor and then putting TCR in bits 19:16 and
CPR/CPR2 in bits 28:20, sanitising the bit pattern supplied such as
to clamp CPR/CPR2 values between 0.000 and 0.875 inclusive to 33.875.
This preserves compatibility with any existing setups, that is where
requesting a custom divisor that only has any bits set among the low
16 the oversampling rate of 16 and the clock prescaler of 33.875 will
be used as with the original 8250.
Finally abuse the `frac' argument to store the determined bit patterns
for the TCR, CPR and CPR2 registers.
- Override the `set_divisor' handler so as to set the TCR, CPR and CPR2
registers from the `frac' value supplied. Set the divisor as usual.
With the baud base set to 15625000 and the unsigned 16-bit UART_DIV_MAX
limitation imposed by `serial8250_get_baud_rate' standard baud rates
below 300bps become unavailable in the regular way, e.g. the rate of
200bps requires the baud base to be divided by 78125 and that is beyond
the unsigned 16-bit range. The historic spd_cust feature can still be
used to obtain such rates if so required.
See Documentation/tty/device_drivers/oxsemi-tornado.rst for more details.
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2204181519450.9383@angie.orcam.me.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Make ICR access helpers available outside 8250_port.c, however retain
them as ordinary static functions so as not to regress code generation.
This is because `serial_icr_write' is currently automatically inlined by
GCC, however `serial_icr_read' is not. Making them both static inline
would grow code produced, e.g.:
$ i386-linux-gnu-size --format=gnu 8250_port-{old,new}.o
text data bss total filename
15065 3378 0 18443 8250_port-old.o
15289 3378 0 18667 8250_port-new.o
and:
$ riscv64-linux-gnu-size --format=gnu 8250_port-{old,new}.o
text data bss total filename
16980 5306 0 22286 8250_port-old.o
17124 5306 0 22430 8250_port-new.o
while making them external would needlessly add a new module interface
and lose the benefit from `serial_icr_write' getting inlined outside
8250_port.o.
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2204181517500.9383@angie.orcam.me.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The EndRun PTP/1588 dual serial port device is based on the Oxford
Semiconductor OXPCIe952 UART device with the PCI vendor:device ID set
for EndRun Technologies and uses the same sequence to determine the
number of ports available. Despite that we have duplicate code
specific to the EndRun device.
Remove redundant code then and factor out OxSemi Tornado device
detection.
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2204181516220.9383@angie.orcam.me.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The 8250 PXA driver never used Runtime PM, so there was never a need to
include <linux/pm_runtime.h>.
Fixes: ab28f51c77cd4618 ("serial: rewrite pxa2xx-uart to use 8250_core")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/9fd96fba9bbbbdeb16af0dc07ae9dee21c8e297c.1651494971.git.geert+renesas@glider.be
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The last calls into Runtime PM were moved to 8250_port.c a long time
ago.
Fixes: b6830f6df8914faa ("serial: 8250: Split base port operations from universal driver")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/2545eaa7fc552013a5d04c4df027255204e64834.1651494971.git.geert+renesas@glider.be
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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dw8250_platform_data is only used on DT platforms for now.
Fixes: 4a218b277fdb ("serial: 8250: dw: Create a generic platform data structure")
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220502115621.77985-1-heikki.krogerus@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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We need the tty/serial fixes in here as well.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This patch enables support for SW half-duplex mode using em485.
Cc: Eric Tremblay <etremblay@distech-controls.com>
Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Tested-by: Vicente Bergas <vicencb@gmail.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220426122448.38997-3-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The Synopsys DesignWare UART can be configured to have HW support for
the RS485 protocol from IP version 4.0 onward. Add support for
hardware-controlled half duplex and full duplex modes.
HW will take care of managing DE and RE, the driver just gives it
permission to use either by setting both to 1.
To ask for full duplex mode, userspace sets SER_RS485_RX_DURING_TX flag
and HW will take care of the rest.
Set delay_rts_before_send and delay_rts_after_send to zero for now. The
granularity of that ABI is too coarse to be useful.
Co-developed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Co-developed-by: Raymond Tan <raymond.tan@intel.com>
Signed-off-by: Raymond Tan <raymond.tan@intel.com>
Co-developed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220426122448.38997-2-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Add UART_CAP_NOTEMT for UARTs that lack interrupt on TEMT but want to
use em485. Em485 framework needs to ensure not only FIFO is empty but
also that tx shift register is empty.
This approach uses Uwe Kleine-König's suggestion on simply
using/incrementing stop_tx timer rather than adding another timer. When
UART_CAP_NOTEMT is set and THRE is present w/o TEMT, stop tx timer is
reused to wait for the emptying of the shift register.
This change does not add the UART_CAP_NOTEMT define as it already exist
but is currently no-op. See 7a107b2c6b81 (Revert "serial: 8250: Handle
UART without interrupt on TEMT using em485") for further details.
Vicente Bergas reported that RTS is deasserted roughly one bit too
early losing stop bit tx. To address this problem, stop_delay now
accounts for one extra bit using rough formula /7 (assumes worst-case
of 2+5 bits). I suspect this glitch had to do with when THRE is getting
asserted. If FIFO is emptied already during the tx of the stop bit,
perhaps it leads to HW asserting THRE early for the normal frame time
formula to work accurately.
Suggested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Eric Tremblay <etremblay@distech-controls.com>
Tested-by: Vicente Bergas <vicencb@gmail.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220425143410.12703-4-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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8250 DMA tx complete path lacks calls to normal 8250 stop handling. It
does not use THRE to detect true completion of the tx and also doesn't
call __stop_tx. This leads to problems with em485 that needs to handle
RTS timing.
Instead of handling tx stop internally within 8250 dma code, enable
THRE when tx'able data runs out and tweak serial8250_handle_irq to call
only __stop_tx when uart is using DMA.
It also seems bit early to call serial8250_rpm_put_tx from there while
tx is still underway(?).
Tested-by: Vicente Bergas <vicencb@gmail.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220425143410.12703-3-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Renesas RZ/N1 SoC features a slightly modified DW UART.
On this SoC, the CPR register value is known but not synthetized in
hardware. We hence need to provide a CPR value in the platform
data. This version of the controller also relies on acting as flow
controller when using DMA, so we need to provide the
"is dma flow controller" quirk.
Co-developed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/r/20220422180615.9098-10-miquel.raynal@bootlin.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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DW based controllers like the one on Renesas RZ/N1 must be programmed as
flow controllers when using DMA.
* Table 11.45 of the system manual, "Flow Control Combinations", states
that using UART with DMA requires setting the DMA in the peripheral
flow controller mode regardless of the direction.
* Chapter 11.6.1.3 of the system manual, "Basic Interface Definitions",
explains that the burst size in the above case must be configured in
the peripheral's register DEST/SRC_BURST_SIZE.
Experiments shown that upon Rx timeout, the DMA transaction needed to be
manually cleared as well.
Co-developed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/r/20220422180615.9098-9-miquel.raynal@bootlin.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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These accessors should be used instead of the regular readl/writel()
helpers. In order to use them also from 8250_dw.c in this directory,
move the helpers to 8250_dwlib.h
There is no functional change.
There is no need for declaring `struct uart_port` or even UPIO_MEM32BE
which both are already included in the 8250_dwlib.h header by 8250.h.
Suggested-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/r/20220422180615.9098-8-miquel.raynal@bootlin.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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In a next change we are going to need the same Rx timeout condition as
we already have in the IRQ handling code. Let's just create a boolean to
clarify what this operation does before reusing it.
There is no functional change.
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/r/20220422180615.9098-7-miquel.raynal@bootlin.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Ilpo Järvinen
Linus Torvalds
AngeloGioacchino Del Regno
Andy Shevchenko
Greg Kroah-Hartman
Maciej W. Rozycki
Geert Uytterhoeven
Heikki Krogerus
Phil Edworthy
Miquel Raynal