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* serial: 8250: Move Alpha-specific quirk out of the coreLukas Wunner2021-12-301-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | struct uart_8250_port contains mcr_mask and mcr_force members whose sole purpose is to work around an Alpha-specific quirk. This code doesn't belong in the core where it is executed by everyone else, so move it to a proper ->set_mctrl callback which is used on the affected Alpha machine only. The quirk was introduced in January 1995: https://git.kernel.org/pub/scm/linux/kernel/git/history/history.git/diff/drivers/char/serial.c?h=1.1.83 The members in struct uart_8250_port were added in 2002: https://git.kernel.org/history/history/c/4524aad27854 The quirk applies to non-PCI Alphas and arch/alpha/Kconfig specifies "select FORCE_PCI if !ALPHA_JENSEN". So apparently the only affected machine is the EISA-based Jensen that Linus was working on back then: https://lore.kernel.org/all/CAHk-=wj1JWZ3sCrGz16nxEj7=0O+srMg6Ah3iPTDXSPKEws_SA@mail.gmail.com/ Up until now the quirk is not applied unless CONFIG_PCI is disabled. If users forget to do that or run a generic Alpha kernel, the serial ports aren't usable on Jensen. Avoid by confining the quirk to CONFIG_ALPHA_JENSEN instead of !CONFIG_PCI. On generic Alpha kernels, auto-detect at runtime whether the quirk needs to be applied. Cc: Russell King <rmk+kernel@armlinux.org.uk> Cc: Ulrich Teichert <krypton@ulrich-teichert.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Lukas Wunner <lukas@wunner.de> Link: https://lore.kernel.org/r/b83d069cb516549b8a5420e097bb6bdd806f36fc.1640695609.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty/serial: make port of serial8250_register_8250_port constJiri Slaby2021-05-201-1/+1
| | | | | | | | | | After the previous patch, we can make port passed to serial8250_find_match_or_unused const. And then we can make const also port of serial8250_register_8250_port. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20210519072153.3859-2-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: serial: 8250: 8250_port: Move prototypes to shared locationLee Jones2020-11-131-0/+5
| | | | | | | | | | | | | | | Fixes the following W=1 kernel build warning(s): drivers/tty/serial/8250/8250_port.c:349:14: warning: no previous prototype for ‘au_serial_in’ [-Wmissing-prototypes] drivers/tty/serial/8250/8250_port.c:359:6: warning: no previous prototype for ‘au_serial_out’ [-Wmissing-prototypes] Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jirislaby@kernel.org> Cc: Mike Hudson <Exoray@isys.ca> Cc: linux-serial@vger.kernel.org Signed-off-by: Lee Jones <lee.jones@linaro.org> Link: https://lore.kernel.org/r/20201112105857.2078977-3-lee.jones@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: Add 8250 port clock update methodSerge Semin2020-07-291-0/+2
| | | | | | | | | | | | | | | | | | | | | Some platforms can be designed in a way so the UART port reference clock might be asynchronously changed at some point. In Baikal-T1 SoC this may happen due to the reference clock being shared between two UART ports, on the Allwinner SoC the reference clock is derived from the CPU clock, so any CPU frequency change should get to be known/reflected by/in the UART controller as well. But it's not enough to just update the uart_port->uartclk field of the corresponding UART port, the 8250 controller reference clock divisor should be altered so to preserve current baud rate setting. All of these things is done in a coherent way by calling the serial8250_update_uartclk() method provided in this patch. Though note that it isn't supposed to be called from within the UART port callbacks because the locks using to the protect the UART port data are already taken in there. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Link: https://lore.kernel.org/r/20200723003357.26897-2-Sergey.Semin@baikalelectronics.ru Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250_port: Don't use power management for kernel consoleAndy Shevchenko2020-03-171-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Doing any kind of power management for kernel console is really bad idea. First of all, it runs in poll and atomic mode. This fact attaches a limitation on the functions that might be called. For example, pm_runtime_get_sync() might sleep and thus can't be used. This call needs, for example, to bring the device to powered on state on the system, where the power on sequence may require on-atomic operations, such as Intel Cherrytrail with ACPI enumerated UARTs. That said, on ACPI enabled platforms it might even call firmware for a job. On the other hand pm_runtime_get() doesn't guarantee that device will become powered on fast enough. Besides that, imagine the case when console is about to print a kernel Oops and it's powered off. In such an emergency case calling the complex functions is not the best what we can do, taking into consideration that user wants to see at least something of the last kernel word before it passes away. Here we modify the 8250 console code to prevent runtime power management. Note, there is a behaviour change for OMAP boards. It will require to detach kernel console to become idle. Link: https://lists.openwall.net/linux-kernel/2018/09/29/65 Suggested-by: Russell King <rmk+kernel@armlinux.org.uk> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20200217114016.49856-6-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: Generalize rs485 software emulationLukas Wunner2020-03-071-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit e490c9144cfa ("tty: Add software emulated RS485 support for 8250") introduced support to use RTS as an rs485 Transmit Enable signal. So far the only drivers taking advantage of it are 8250_omap.c and 8250_of.c. We're about to make use of the feature in 8250_bcm2835aux.c as well. The bcm2835aux differs from omap chips by inverting the meaning of RTS in the MCR register. Moreover, omap achieves half-duplex mode by disabling the RX interrupt and clearing the RX FIFO when TX stops. The bcm2835aux requires disabling the receiver instead. Support these behavioral differences by generalizing the rs485 emulation: Introduce ->rs485_start_tx() and ->rs485_stop_tx() callbacks in struct uart_8250_port, provide generic implementations containing the existing code and use them as callbacks in 8250_omap.c and 8250_of.c. start_tx_rs485() is idempotent in that it recognizes whether RTS is already asserted. Achieve the same by introducing a tx_stopped flag in struct uart_8250_em485. This may even perform a little better on arches where memory access is faster than mmio access. Signed-off-by: Lukas Wunner <lukas@wunner.de> Cc: Matwey V. Kornilov <matwey@sai.msu.ru> Link: https://lore.kernel.org/r/5ac0464ae4414708e723a1e0d52b0c1b2bd41b9b.1582895077.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty/serial: Migrate 8250_fsl to use has_sysrqDmitry Safonov2019-12-181-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | The SUPPORT_SYSRQ ifdeffery is not nice as: - May create misunderstanding about sizeof(struct uart_port) between different objects - Prevents moving functions from serial_core.h - Reduces readability (well, it's ifdeffery - it's hard to follow) In order to remove SUPPORT_SYSRQ, has_sysrq variable has been added. Initialise it in driver's probe and remove ifdeffery. In contrast to 8250/8250_of, legacy_serial on powerpc does fill (struct plat_serial8250_port). The reason is likely that it's done on device_initcall(), not on probe. So, 8250_core is not yet probed. Propagate value from platform_device on 8250 probe - in case powepc legacy driver it's initialized on initcall, in case 8250_of it will be initialized later on of_platform_serial_setup(). Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: linuxppc-dev@lists.ozlabs.org Signed-off-by: Dmitry Safonov <dima@arista.com> Link: https://lore.kernel.org/r/20191213000657.931618-6-dima@arista.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty/serial/8250: use mctrl_gpio helpersYegor Yefremov2019-06-211-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | This patch permits the usage for GPIOs to control the CTS/RTS/DTR/DSR/DCD/RI signals. Changed by Stefan: Only call mctrl_gpio_init(), if the device has no ACPI companion device to not break existing ACPI based systems. Also only use the mctrl_gpio_ functions when "gpios" is available. Use MSR / MCR <-> TIOCM wrapper functions. Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com> Signed-off-by: Stefan Roese <sr@denx.de> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com> Tested-by: Yegor Yefremov <yegorslists@googlemail.com> Cc: Mika Westerberg <mika.westerberg@linux.intel.com> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Giulio Benetti <giulio.benetti@micronovasrl.com> Cc: Yegor Yefremov <yegorslists@googlemail.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152Thomas Gleixner2019-05-301-5/+1
| | | | | | | | | | | | | | | | | | | | | Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: Rate limit serial port rx interrupts during input overrunsDarwin Dingel2018-12-171-0/+4
| | | | | | | | | | | | | | | | | | | When a serial port gets faulty or gets flooded with inputs, its interrupt handler starts to work double time to get the characters to the workqueue for the tty layer to handle them. When this busy time on the serial/tty subsystem happens during boot, where it is also busy on the userspace trying to initialise, some processes can continuously get preempted and will be on hold until the interrupts subside. The fix is to backoff on processing received characters for a specified amount of time when an input overrun is seen (received a new character before the previous one is processed). This only stops receive and will continue to transmit characters to serial port. After the backoff period is done, it receive will be re-enabled. This is optional and will only be enabled by setting 'overrun-throttle-ms' in the dts. Signed-off-by: Darwin Dingel <darwin.dingel@alliedtelesis.co.nz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: export serial8250_do_set_divisor()Jisheng Zhang2018-07-121-0/+3
| | | | | | | | | Some drivers could call serial8250_do_set_divisor() to complete its own set_divisor routine. Export this symbol for code reusing. Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial/8250: export serial8250_read_charJeremy Kerr2018-04-231-0/+1
| | | | | | | | | | | | | | | | | Currently, we export serial8250_rx_chars, which does a whole bunch of reads from the 8250 data register, without any form of flow control between reads. An upcoming change to the aspeed vuart driver implements more fine-grained flow control in the interrupt handler, requiring character-at-a-time control over the rx path. This change exports serial8250_read_char to allow this. Signed-off-by: Jeremy Kerr <jk@ozlabs.org> Tested-by: Eddie James <eajames@linux.vnet.ibm.com> Tested-by: Joel Stanley <joel@jms.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: Use hrtimers for rs485 delaysRafael Gago2017-08-281-3/+4
| | | | | | | | | | Previously the timers where based on the classic timers, giving a too coarse resolution on systems with configs of less than 1000 HZ. This patch changes the rs485 timers to hrtimers. Signed-off-by: Rafael Gago Castano <rgc@hms.se> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: Expose set_ldisc functionEd Blake2016-11-161-0/+4
| | | | | | | | Expose set_ldisc() function so that it can be overridden with a platform specific implementation. Signed-off-by: Ed Blake <ed.blake@imgtec.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: Add IrDA to UART capabilitiesEd Blake2016-11-161-2/+2
| | | | | | | | | Add an IrDA UART capability flag and change the type of uart_8250_port.capabilities to be u32 rather than unsigned short to accommodate the additional flag. Signed-off-by: Ed Blake <ed.blake@imgtec.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Revert "tty/serial/8250: use mctrl_gpio helpers"Andy Shevchenko2016-08-311-1/+0
| | | | | | | | | | | | | | | | Serial console is broken in v4.8-rcX. Mika and I independently bisected down to commit 4ef03d328769 ("tty/serial/8250: use mctrl_gpio helpers"). Since neither author nor anyone else didn't propose a solution we better revert it for now. This reverts commit 4ef03d328769eddbfeca1f1c958fdb181a69c341. Link: https://lkml.kernel.org/r/20160809130229.GN1729@lahna.fi.intel.com Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Tested-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty/serial/8250: use mctrl_gpio helpersYegor Yefremov2016-06-251-0/+1
| | | | | | | | This patch permits the usage for GPIOs to control the CTS/RTS/DTR/DSR/DCD/RI signals. Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: export get_mctrl functionWan Ahmad Zainie2016-04-301-0/+2
| | | | | | | | | | Exposes get_mctrl() function so that it can be overriden with platform specific implementation. Signed-off-by: Wan Ahmad Zainie <wan.ahmad.zainie.wan.mohamad@intel.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: Add software emulated RS485 support for 8250Matwey V. Kornilov2016-02-061-0/+8
| | | | | | | | | | | | | | | | Implementation of software emulation of RS485 direction handling is based on omap_serial driver. Before and after transmission RTS is set to the appropriate value. Note that before calling serial8250_em485_init() the caller has to ensure that UART will interrupt when shift register empty. Otherwise, emultaion cannot be used. Both serial8250_em485_init() and serial8250_em485_destroy() are idempotent functions. Signed-off-by: Matwey V. Kornilov <matwey@sai.msu.ru> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty/early: make serial8250_early_{in,out} static againVineet Gupta2015-07-231-2/+0
| | | | | | | | | | | | | | | | | | | | | Commit ed71871bed719 ("tty/8250_early: Turn serial_in/serial_out into weak symbols") made these routines weak to allow platform specific Big endian override However recent updates to core, specifically ebc5e20082 ("serial: of_serial: Support big-endian register accesses") and 6e63be3fee14 ("serial: earlycon: Add support for big-endian MMIO accesses") means that round about way to overide the early serial accessors is no longer needed. Cc: Jiri Slaby <jslaby@suse.cz> Cc: Peter Hurley <peter@hurleysoftware.com> Cc: Rob Herring <robh@kernel.org> Cc: Kevin Cernekee <cernekee@gmail.com> Acked-by: Noam Camus <noamc@ezchip.com> Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Reviewed-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: Split base port operations from universal driverPeter Hurley2015-07-231-0/+5
| | | | | | | | | | | | | | | | | | | | | | | Refactor base port operations into new file; 8250_port.c. Legacy irq handling, RSA port support, port storage for universal driver, driver definition, module parameters and linkage remain in 8250_core.c The source file split and resulting modules is diagrammed below: 8250_core.c ====> 8250_core.c __ \ \ \ +-- 8250.ko (alias 8250_core) \ 8250_pnp.c __/ (universal driver) \ => 8250_port.c __ \ +-- 8250_base.ko 8250_dma.c __/ (port operations) Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: include <linux/serial_reg.h> from serial_8250.hMasahiro Yamada2015-05-311-0/+1
| | | | | | | | | | The header file, include/linux/serial_8250.h, contains references to UART_LSR_BRK_ERROR_BITS and UART_MSR_ANY_DELTA that are defined in <linux/serial_reg.h>. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: serial: 8250: export early_serial8250_setup functionEddie Huang2015-05-101-0/+2
| | | | | | | | | 8250-like uart driver may call early_serial8250_setup to reuse 8250_early.c character output function. Signed-off-by: Eddie Huang <eddie.huang@mediatek.com> Tested-by: Sascha Hauer <s.hauer@pengutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: Decouple RSA probePeter Hurley2015-03-261-0/+2
| | | | | | | | | | | | | | Prepare for 8250 split; separate RSA probe and resource management from base port operations. Override base port operations for the config_port(), request_port() and release_port() methods to implement the optional RSA probe and resource management only in the universal/legacy 8250 driver. Introduce 'probe' flags for 8250 ports, which allows drivers higher up the driver stack to enable optional probes. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: Separate legacy irq handling from core port operationsPeter Hurley2015-03-261-0/+15
| | | | | | | | | | | | | | | Prepare for 8250 split; decouple irq setup/teardown and handler from core port operations. Introduce setup_irq() and release_irq() 8250 driver methods; the 8250 core will use these methods to install and remove irq handling for the given 8250 port. Refactor irq chain linking/unlinking from 8250 core into univ8250_setup_irq()/univ8250_release_irq() for the universal 8250 driver. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250_early: Remove setup_early_serial8250_console()Peter Hurley2015-03-261-1/+0
| | | | | | | | | | | setup_earlycon() will now match and register the desired earlycon from the param string (as if 'earlycon=...' had been set on the command line). Use setup_earlycon() from existing arch call sites which start an earlycon directly. Acked-by: Rob Herring <robh@kernel.org> Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* console: Add extensible console matchingPeter Hurley2015-03-261-2/+0
| | | | | | | | | | | | | | | | | | Add match() method to struct console which allows the console to perform console command line matching instead of (or in addition to) default console matching (ie., by fixed name and index). The match() method returns 0 to indicate a successful match; normal console matching occurs if no match() method is defined or the match() method returns non-zero. The match() method is expected to set the console index if required. Re-implement earlycon-to-console-handoff with direct matching of "console=uart|uart8250,..." to the 8250 ttyS console. Acked-by: Rob Herring <robh@kernel.org> Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: Use canary to restart console after suspendPeter Hurley2015-02-021-0/+3
| | | | | | | | | | | | | | | | | | | | | | | When using no_console_suspend, the serial console may be powered off anyway during system sleep. Upon resume, the port may be in its default power-on state, but is expected to continue console i/o before the device has received its pm callback. The resultant garbage i/o can cause all kinds of havoc on the remote end. Use the scratch register as a canary to discover if the console has been powered-off. Write a non-zero value to the scratch register at port suspend and reprogram the port before any console i/o if the scratch register != canary before port resume. This workaround is disabled for omap_8250 (which uses different divisor programming). Credit to Doug Anderson <dianders@chromium.org> for the idea of using the scratch register canary to discover port power-down. Cc: Doug Anderson <dianders@chromium.org> Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: omap_8250: Fix RTS handlingPeter Hurley2015-01-091-0/+1
| | | | | | | | | | | | | | | | | | | The OMAP3 UART ignores MCR[1] (ie., UART_MCR_RTS) when in autoRTS mode (UPF_HARD_FLOW + CRTSCTS). This makes it impossible for either the serial core or userspace to manually flow control the sender. Disable autoRTS mode when RTS is lowered and restore the previous mode when RTS is raised. Note that the OMAP3 UART provides no mechanism for switching from autoRTS mode without corrupting incoming data; to access the necessary register, the line control settings must be set to 8-e-2 and thus any data received during that time will be interpreted with those settings. This corruption has been observed in practice. Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial/8250: Remove obsolete handling of rs485 ioctlsRicardo Ribalda Delgado2014-11-061-3/+0
| | | | | | | | | | | | | | | | | There is no more users for this functions. All the 8250 drivers are using the rs485 handler on serial_core instead. Reviewed-by: Alan Cox <alan@linux.intel.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Alan Cox <alan@linux.intel.com> Cc: Tony Lindgren <tony@atomide.com> Cc: Peter Hurley <peter@hurleysoftware.com> Cc: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: serial: 8250: use 32bit variable for rpm_tx_activeSebastian Andrzej Siewior2014-09-291-1/+1
| | | | | | | | | | | | | | | | | | The kbuild test robot wrote me: | make.cross ARCH=powerpc |>> ERROR: ".__xchg_called_with_bad_pointer" [drivers/tty/serial/8250/8250.ko] undefined! The generic implementation of xchg() on arm and x86 works for variables of size one bye (char). According to the report powerpc does not support xchg() for one byte sized variables and looking further it seems also to be the same case for sparc and tile (or for 10 out of 26 architectures which provide a custom implementation). For that reason I increase the size of the variable from one to four bytes to get it work on powerpc (and the others). Reported-By: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: serial: 8250_core: add run time pmSebastian Andrzej Siewior2014-09-261-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | While comparing the OMAP-serial and the 8250 part of this I noticed that the latter does not use run time-pm. Here are the pieces. It is basically a get before first register access and a last_busy + put after last access. This has to be enabled from userland _and_ UART_CAP_RPM is required for this. The runtime PM can usually work transparently in the background however there is one exception to this: After serial8250_tx_chars() completes there still may be unsent bytes in the FIFO (depending on CPU speed vs baud rate + flow control). Even if the TTY-buffer is empty we do not want RPM to disable the device because it won't send the remaining bytes. Instead we leave serial8250_tx_chars() with RPM enabled and wait for the FIFO empty interrupt. Once we enter serial8250_tx_chars() with an empty buffer we know that the FIFO is empty and since we are not going to send anything, we can disable the device. That xchg() is to ensure that serial8250_tx_chars() can be called multiple times and only the first invocation will actually invoke the runtime PM function. So that the last invocation of __stop_tx() will disable runtime pm. NOTE: do not enable RPM on the device unless you know what you do! If the device goes idle, it won't be woken up by incomming RX data _unless_ there is a wakeup irq configured which is usually the RX pin configure for wakeup via the reset module. The RX activity will then wake up the device from idle. However the first character is garbage and lost. The following bytes will be received once the device is up in time. On the beagle board xm (omap3) it takes approx 13ms from the first wakeup byte until the first byte that is received properly if the device was in core-off. v5…v8: - drop RPM from serial8250_set_mctrl() it will be used in restore path which already has RPM active and holds dev->power.lock v4…v5: - add a wrapper around rpm function and introduce UART_CAP_RPM to ensure RPM put is invoked after the TX FIFO is empty. v3…v4: - added runtime to the console code - removed device_may_wakeup() from serial8250_set_sleep() Cc: mika.westerberg@linux.intel.com Reviewed-by: Tony Lindgren <tony@atomide.com> Tested-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: serial: 8250_core: allow to overwrite & export serial8250_startup()Sebastian Andrzej Siewior2014-09-081-0/+2
| | | | | | | | | | | | | The OMAP version of the 8250 can actually use 1:1 serial8250_startup(). However it needs to be extended by a wake up irq which should to be requested & enabled at ->startup() time and disabled at ->shutdown() time. v2…v3: properly copy callbacks v1…v2: add shutdown callback Acked-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial/8250: Add support for RS485 IOCTLsRicardo Ribalda Delgado2014-09-081-0/+3
| | | | | | | | | | | | | | | | | | This patch allow the users of the 8250 infrastructure to define a handler for RS485 configration. If no handler is defined the 8250 driver will work as usual. Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> Acked-by: Alan Cox <alan@linux.intel.com> -- v2:Change suggested by Alan "One Thousand Gnomes": - Move rs485 structure further down on the uart_8250_port structure drivers/tty/serial/8250/8250_core.c | 39 +++++++++++++++++++++++++++++++++++++ include/linux/serial_8250.h | 3 +++ 2 files changed, 42 insertions(+) Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial/uart/8250: Add tunable RX interrupt trigger I/F of FIFO buffersYoshihiro YUNOMAE2014-07-171-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add tunable RX interrupt trigger I/F of FIFO buffers. Serial devices are used as not only message communication devices but control or sending communication devices. For the latter uses, normally small data will be exchanged, so user applications want to receive data unit as soon as possible for real-time tendency. If we have a sensor which sends a 1 byte data each time and must control a device based on the sensor feedback, the RX interrupt should be triggered for each data. According to HW specification of serial UART devices, RX interrupt trigger can be changed, but the trigger is hard-coded. For example, RX interrupt trigger in 16550A can be set to 1, 4, 8, or 14 bytes for HW, but current driver sets the trigger to only 8bytes. This patch makes some devices change RX interrupt trigger from userland. <How to use> - Read current setting # cat /sys/class/tty/ttyS0/rx_trig_bytes 8 - Write user setting # echo 1 > /sys/class/tty/ttyS0/rx_trig_bytes # cat /sys/class/tty/ttyS0/rx_trig_bytes 1 <Support uart devices> - 16550A and Tegra (1, 4, 8, or 14 bytes) - 16650V2 (8, 16, 24, or 28 bytes) - 16654 (8, 16, 56, or 60 bytes) - 16750 (1, 16, 32, or 56 bytes) <Change log> Changes in V9: - Use attr_group instead of dev_spec_attr_group of uart_port structure Changes in V8: - Divide this patch from V7's patch based on Greg's comment Changes in V7: - Add Documentation - Change I/F name from rx_int_trig to rx_trig_bytes because the name rx_int_trig is hard to understand how users specify the value Changes in V6: - Move FCR_RX_TRIG_* definition in 8250.h to include/uapi/linux/serial_reg.h, rename those to UART_FCR_R_TRIG_*, and use UART_FCR_TRIGGER_MASK to UART_FCR_R_TRIG_BITS() - Change following function names: convert_fcr2val() => fcr_get_rxtrig_bytes() convert_val2rxtrig() => bytes_to_fcr_rxtrig() - Fix typo in serial8250_do_set_termios() - Delete the verbose error message pr_info() in bytes_to_fcr_rxtrig() - Rename *rx_int_trig/rx_trig* to *rxtrig* for several functions or variables (but UI remains rx_int_trig) - Change the meaningless variable name 'val' to 'bytes' following functions: fcr_get_rxtrig_bytes(), bytes_to_fcr_rxtrig(), do_set_rxtrig(), do_serial8250_set_rxtrig(), and serial8250_set_attr_rxtrig() - Use up->fcr in order to get rxtrig_bytes instead of rx_trig_raw in fcr_get_rxtrig_bytes() - Use conf_type->rxtrig_bytes[0] instead of switch statement for support check in register_dev_spec_attr_grp() - Delete the checking whether a user changed FCR or not when minimum buffer is needed in serial8250_do_set_termios() Changes in V5.1: - Fix FCR_RX_TRIG_MAX_STATE definition Changes in V5: - Support Tegra, 16650V2, 16654, and 16750 - Store default FCR value to up->fcr when the port is first created - Add rx_trig_byte[] in uart_config[] for each device and use rx_trig_byte[] in convert_fcr2val() and convert_val2rxtrig() Changes in V4: - Introduce fifo_bug flag in uart_8250_port structure This is enabled only when parity is enabled and UART_BUG_PARITY is enabled for up->bugs. If this flag is enabled, user cannot set RX trigger. - Return -EOPNOTSUPP when it does not support device at convert_fcr2val() and at convert_val2rxtrig() - Set the nearest lower RX trigger when users input a meaningless value at convert_val2rxtrig() - Check whether p->fcr is existing at serial8250_clear_and_reinit_fifos() - Set fcr = up->fcr in the begging of serial8250_do_set_termios() Changes in V3: - Change I/F from ioctl(2) to sysfs(rx_int_trig) Changed in V2: - Use _IOW for TIOCSFIFORTRIG definition - Pass the interrupt trigger value itself Signed-off-by: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: introduce up_to_u8250p() helperAndy Shevchenko2014-07-171-0/+5
| | | | | | | It helps to cast struct uart_port to struct uart_8250_port at runtime. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: Add support for dmaengineHeikki Krogerus2013-01-151-0/+4
| | | | | | | | | Add support for dmaengine API. The drivers can implement the struct uart_8250_dma member in struct uart_8250_port and 8250.c can take care of the rest. Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty/8250_early: Turn serial_in/serial_out into weak symbols.Noam Camus2012-11-161-0/+2
| | | | | | | | | | | | | | | | | | Allows overriding default methods serial_in/serial_out. In such platform specific replacement it is possible to use other regshift, biased register offset, any other manipulation that is not covered with common default methods. Overriding default methods may be useful for platforms which got serial peripheral with registers represented in big endian. In this situation and assuming that 32 bit operations / alignment is required then it may be useful to swab words before/after accessing the serial registers. Signed-off-by: Noam Camus <noamc@ezchip.com> Acked-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* 8250: three way resolve of the 8250 diffsAlan Cox2012-07-171-2/+30
| | | | | | | | This resolves the differences between the original 8250 patch, the revised 8250 patch and the independant clean up of the octeon driver (to use platform devices properly yay!) Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* 8250: use the 8250 register interface not the legacy oneAlan Cox2012-07-121-1/+0
| | | | | | | | The old interface just copies bits over and calls the newer one. In addition we can now pass more information. Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Merge branch 'delete-mca' of ↵Linus Torvalds2012-05-231-1/+0
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux Pull the MCA deletion branch from Paul Gortmaker: "It was good that we could support MCA machines back in the day, but realistically, nobody is using them anymore. They were mostly limited to 386-sx 16MHz CPU and some 486 class machines and never more than 64MB of RAM. Even the enthusiast hobbyist community seems to have dried up close to ten years ago, based on what you can find searching various websites dedicated to the relatively short lived hardware. So lets remove the support relating to CONFIG_MCA. There is no point carrying this forward, wasting cycles doing routine maintenance on it; wasting allyesconfig build time on validating it, wasting I/O on git grep'ping over it, and so on." Let's see if anybody screams. It generally has compiled, and James Bottomley pointed out that there was a MCA extension from NCR that allowed for up to 4GB of memory and PPro-class machines. So in *theory* there may be users out there. But even James (technically listed as a maintainer) doesn't actually have a system, and while Alan Cox claims to have a machine in his cellar that he offered to anybody who wants to take it off his hands, he didn't argue for keeping MCA support either. So we could bring it back. But somebody had better speak up and talk about how they have actually been using said MCA hardware with modern kernels for us to do that. And David already took the patch to delete all the networking driver code (commit a5e371f61ad3: "drivers/net: delete all code/drivers depending on CONFIG_MCA"). * 'delete-mca' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux: MCA: delete all remaining traces of microchannel bus support. scsi: delete the MCA specific drivers and driver code serial: delete the MCA specific 8250 support. arm: remove ability to select CONFIG_MCA
| * serial: delete the MCA specific 8250 support.Paul Gortmaker2012-05-171-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | The support for CONFIG_MCA is being removed, since the 20 year old hardware simply isn't capable of meeting today's software demands on CPU and memory resources. This commit removes the MCA specific 8250 UART code. Cc: Alan Cox <alan@linux.intel.com> Cc: linux-serial@vger.kernel.org Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
* | serial8250: Introduce serial8250_register_8250_port()Magnus Damm2012-05-021-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Introduce yet another 8250 registration function. This time it is serial8250_register_8250_port() and it allows us to register 8250 hardware instances using struct uart_8250_port. The new function makes it possible to register 8250 hardware that makes use of 8250 specific callbacks such as ->dl_read() and ->dl_write(). Signed-off-by: Magnus Damm <damm@opensource.se> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | tegra, serial8250: add ->handle_break() uart_port opDan Williams2012-04-181-0/+1
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The "KT" serial port has another use case for a "received break" quirk, so before adding another special case to the 8250 core take this opportunity to push such quirks out of the core and into a uart_port op. Stephen says: "If the callback function is to no longer live in 8250.c itself, arch/arm/mach-tegra/devices.c isn't logically a good place to put it, and that file will be going away once we get rid of all the board files and move solely to device tree." ...so since 8250_pci.c houses all the quirks for pci serial devices this quirk is similarly housed in of_serial.c. Once the open firmware conversion completes the infrastructure details (include/linux/of_serial.h, and the export) can all be removed to make this self contained to of_serial.c. Cc: Nhan H Mai <nhan.h.mai@intel.com> Cc: Colin Cross <ccross@android.com> Cc: Olof Johansson <olof@lixom.net> [stephen: kill CONFIG_SERIAL_TEGRA in favor just using CONFIG_ARCH_TEGRA] Cc: Grant Likely <grant.likely@secretlab.ca> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Sudhakar Mamillapalli <sudhakar@fb.com> Reported-by: Alan Cox <alan@lxorguk.ukuu.org.uk> Acked-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-by: Stephen Warren <swarren@wwwdotorg.org> Tested-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: add irq handler for Freescale 16550 errata.Paul Gortmaker2011-12-091-0/+1
| | | | | | | | | | | | | | | | | | | | | | | Sending a break on the SOC UARTs found in some MPC83xx/85xx/86xx chips seems to cause a short lived IRQ storm (/proc/interrupts typically shows somewhere between 300 and 1500 events). Unfortunately this renders SysRQ over the serial console completely inoperable. The suggested workaround in the errata is to read the Rx register, wait one character period, and then read the Rx register again. We achieve this by tracking the old LSR value, and on the subsequent interrupt event after a break, we don't read LSR, instead we just read the RBR again and return immediately. The "fsl,ns16550" is used in the compatible field of the serial device to mark UARTs known to have this issue. Thanks to Scott Wood for providing the errata data which led to a much cleaner fix. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Acked-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* serial: export the key functions for an 8250 IRQ handlerPaul Gortmaker2011-12-091-0/+4
| | | | | | | | | | | | | | | | | For drivers that need to construct their own IRQ handler, the three components are seen in the current handle_port -- i.e. Rx, Tx and modem_status. Make these exported symbols so that "almost" 8250 UARTs can construct their own IRQ handler with these shared components, while working around their own unique errata issues. The function names are given a serial8250 prefix, since they are now entering the global namespace. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Acked-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* Revert "tty: serial8250: add helpers for the DesignWare 8250"Greg Kroah-Hartman2011-08-241-8/+0
| | | | | | | | | | | This reverts commit 6b1a98d1c4851235d9b6764b3f7b7db7909fc760. It causes a build error that needs to be resolved differently. Cc: Alan Cox <alan@linux.intel.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Jamie Iles <jamie@jamieiles.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* tty: serial8250: add helpers for the DesignWare 8250Jamie Iles2011-08-231-0/+8
| | | | | | | | | | | | | The Synopsys DesignWare 8250 is an 8250 that has an extra interrupt that gets raised when writing to the LCR when busy. To handle this we need special serial_out, serial_in and handle_irq methods. Add a new function serial8250_use_designware_io() that configures a uart_port with these accessors. Cc: Alan Cox <alan@linux.intel.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Jamie Iles <jamie@jamieiles.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* tty: serial8250: allow platforms to override irq handlerJamie Iles2011-08-231-0/+2
| | | | | | | | | | | | Some ports (e.g. Synopsys DesignWare 8250) have special requirements for handling the interrupts. Allow these platforms to specify their own interrupt handler that will override the default. serial8250_handle_irq() is provided so that platforms can extend the IRQ handler rather than completely replacing it. Signed-off-by: Jamie Iles <jamie@jamieiles.com> Acked-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* serial: abstraction for 8250 legacy portsAlan Cox2010-10-221-0/+4
| | | | | | | | | | | | | Not every platform that has generic legacy 8250 ports manages to have them clocked the right way or without errata. Provide a generic interface to allow platforms to override the default behaviour in a manner that dumps the complexity in *their* code not the 8250 driver. Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Dirk Brandewie <dirk.brandewie@gmail.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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