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path: root/drivers/tty/serial/8250/8250_port.c
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* Clearing FIFOs in RS485 emulation mode causes subsequent transmits to breakDaniel Jedrychowski2017-01-19
| | | | | | | | | | | | | | | | | | | | | | | | | commit 2bed8a8e70729f996af92042d3ad0f11870acc1f upstream. When in RS485 emulation mode, __do_stop_tx_rs485() calls serial8250_clear_fifos(). This not only clears the FIFOs, but also sets all bits in their control register (UART_FCR) to 0. One of the effects of this is the disabling of the FIFOs, which turns them into single-byte holding registers. The rest of the driver doesn't know this, which results in the lions share of characters passed into a write call to be dropped. (I can supply logic analyzer screenshots if necessary) This fix replaces the serial8250_clear_fifos() call to serial8250_clear_and_reinit_fifos() - this prevents the "dropped characters" issue from manifesting again while retaining the requirement of clearing the RX FIFO after transmission if the SER_RS485_RX_DURING_TX flag is disabled. Signed-off-by: Daniel Jedrychowski <avistel@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: serial: 8250: 8250_core: NXP SC16C2552 workaroundSteve Shih2016-10-27
| | | | | | | | | | NXP SC16C2552 requires that we always write a reset to the RX FIFO and TX FIFO whenever we enable the FIFOs Cc: xe-kernel@external.cisco.com Signed-off-by: Steve Shih <sshih@cisco.com> Signed-off-by: David Singleton <davsingl@cisco.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: Set Altera 16550 TX FIFO ThresholdThor Thayer2016-09-27
| | | | | | | | | | The Altera 16550 soft IP UART requires 2 additional registers for TX FIFO threshold support. These 2 registers enable the TX FIFO Low Watermark and set the TX FIFO Low Watermark. Set the TX FIFO threshold to the FIFO size - tx_loadsz. Signed-off-by: Thor Thayer <tthayer@opensource.altera.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty/serial/8250: Touch NMI watchdog in wait_for_xmitrJiri Olsa2016-09-22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | First loop in wait_for_xmitr could also trigger NMI watchdog in case reading from the port is slow: PID: 0 TASK: ffffffff819c1460 CPU: 0 COMMAND: "swapper/0" #0 [ffff88019f405e58] crash_nmi_callback at ffffffff8104d382 #1 [ffff88019f405e68] nmi_handle at ffffffff8168ead9 #2 [ffff88019f405eb0] do_nmi at ffffffff8168ec53 #3 [ffff88019f405ef0] end_repeat_nmi at ffffffff8168df13 [exception RIP: delay_tsc+50] RIP: ffffffff81325642 RSP: ffff88019f403bb0 RFLAGS: 00000083 RAX: 00000000000005c8 RBX: ffffffff81f83000 RCX: 0000024e4fb88a8b RDX: 0000024e4fb89053 RSI: 0000000000000000 RDI: 00000000000007d1 RBP: ffff88019f403bb0 R8: 000000000000000a R9: 0000000000000000 R10: 0000000000000000 R11: ffff88019f403ad6 R12: 000000000000250f R13: 0000000000000020 R14: ffffffff81d360c7 R15: 0000000000000047 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 --- <NMI exception stack> --- #4 [ffff88019f403bb0] delay_tsc at ffffffff81325642 #5 [ffff88019f403bb8] __const_udelay at ffffffff813255a8 #6 [ffff88019f403bc8] wait_for_xmitr at ffffffff81404390 #7 [ffff88019f403bf0] serial8250_console_putchar at ffffffff8140455c #8 [ffff88019f403c10] uart_console_write at ffffffff813ff00a #9 [ffff88019f403c40] serial8250_console_write at ffffffff814044ae #10 [ffff88019f403c88] call_console_drivers.constprop.15 at ffffffff81086b01 #11 [ffff88019f403cb0] console_unlock at ffffffff8108842f #12 [ffff88019f403ce8] vprintk_emit at ffffffff81088834 #13 [ffff88019f403d58] vprintk_default at ffffffff81088ba9 #14 [ffff88019f403d68] printk at ffffffff8167f034 Adding touch_nmi_watchdog call to the first loop as well. Reported-by: Chunyu Hu <chuhu@redhat.com> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Merge 4.8-rc5 into tty-nextGreg Kroah-Hartman2016-09-05
|\ | | | | | | | | | | We want the fixes in here for merge issues. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * Revert "tty/serial/8250: use mctrl_gpio helpers"Andy Shevchenko2016-08-31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | serial: 8250_port: unify check of em485 variableAndy Shevchenko2016-09-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Unify the check of em485 variable to be either (em485) or (!em485) instead of the explicit comparison to NULL. While here, remove redundant check in __do_stop_tx_rs485() and __stop_tx_rs485() since the functions ain't called with NULL value of em485 variable. Cc: "Matwey V. Kornilov" <matwey@sai.msu.ru> Tested-by: Yegor Yefremov <yegorslists@googlemail.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | serial: 8250_port: fix runtime PM use in __do_stop_tx_rs485()Andy Shevchenko2016-09-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are calls to serial8250_rpm_{get|put}() in __do_stop_tx_rs485() that are certainly placed in a wrong location. I dunno how it had been tested with runtime PM enabled because it is obvious "sleep in atomic context" error. Besides that serial8250_rpm_get() is called immediately after an IO just happened. It implies that the device is already powered on, see implementation of serial8250_em485_rts_after_send() and serial8250_clear_fifos() for the details. There is no bug have been seen due to, as I can guess, use of auto suspend mode when scheduled transaction to suspend is invoked quite lately than it's needed for a few writes to the port. It might be possible to trigger a warning if stop_tx_timer fires when device is suspended. Refactor the code to use runtime PM only in case of timer function. Fixes: 0c66940d584d ("tty/serial/8250: fix RS485 half-duplex RX") Cc: "Matwey V. Kornilov" <matwey@sai.msu.ru> Tested-by: Yegor Yefremov <yegorslists@googlemail.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | serial: 8250: enable AFE on ports where FIFO is 16 bytesAndy Shevchenko2016-08-31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Intel Quark has 16550A compatible UART with autoflow feature enabled. It has only 16 bytes of FIFO. Currently serial8250_do_set_termios() prevents to enable autoflow since the minimum requirement of 32 bytes of FIFO size. Drop a FIFO size limitation to allow autoflow control be enabled on such UARTs. While here, comment out UART_CAP_AFE for PORT_AR7 since it wasn't working and it will be not a good idea to use it in conjunction with trigger level of 1 byte. Suggested-by: Peter Hurley <peter@hurleysoftware.com> Reviewed-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Tested-by: Bryan O'Donoghue <pure.logic@nexus-software.ie> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | serial: 8250_mtk: support big baud rate.Eddie Huang2016-08-31
|/ | | | | | | | | mediatek can support baud rate up to 4M. the 'uart_get_baud_rate' function will limit the max baud rate. Modify max baud to remove the limit. Signed-off-by: Long Cheng <long.cheng@mediatek.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty/serial/8250: use mctrl_gpio helpersYegor Yefremov2016-06-25
| | | | | | | | 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>
* tty/serial/8250: make UART_MCR register access consistentYegor Yefremov2016-06-25
| | | | | | | | | | | | | | | | Introduce serial8250_out_MCR() and serial8250_in_MCR() routines, that replace following calls: serial_out(port, UART_MCR, val) serial_port_out(up, UART_MCR, val) serial_in(port, UART_MCR) This patch is needed in order to integrate reading/writing of MCR signals via SERIAL_MCTRL_GPIO infrastructure later. Reviewed-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: 8250, remove shadow and unused variablesJiri Slaby2016-06-25
| | | | | | | | | | | | | | | | | | The compiler complains about variables that are set, but never used: * intX variables in exar_handle_irq drivers/tty/serial/8250/8250_port.c:1864:34: warning: variable ‘int3’ set but not used [-Wunused-but-set-variable] * val variable in pci_quatech_wqopr drivers/tty/serial/8250/8250_pci.c:1139:10: warning: variable ‘val’ set but not used [-Wunused-but-set-variable] And about a shadow variable: * tmout in wait_for_xmitr is defined twice with the same type. Both of them are also initialized before use. Remove all of them. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Cc: Matt Schulte <matts@commtech-fastcom.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: 8250, kill DEBUG_INTRJiri Slaby2016-06-25
| | | | | | | | | | | | | | Convert DEBUG_INTR to pr_debug: * defined semantics (DEBUG, DYNAMIC_DEBUG) * KERN_DEBUG level instead of KERN_DEFAULT * emit __func__ and \n * verified 'fmt' even when !DEBUG I wonder if anybody ever used that or whether we should just drop the lines. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: Integrate Fintek into 8250_baseRicardo Ribalda Delgado2016-04-30
| | | | | | | | | | | | | | | | | | | | | The 8250_fintek driver advertises as the PNP0501 driver; however this conflicts with the standard 16550A uart PNP0501. The conflict causes the 8250_fintek driver to load with _every_ PNP0501, but never probe, and causing the entire 8250 driver stack to unload if the 8250_fintek driver is unloaded (modprobe doesn't know that 8250_pnp rather than 8250_fintek claimed the resource). This patch merges the Fintek driver into 8250_base. On autoconfig_16550 the device is probed to verify if it is a FINTEK device or not. This custom probing can be disabled completely via configuration. When a Fintek device is not probed it will behave as a standard 16550A device, with no RS485 capabilities. Reported-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> Reviewed-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: Extract IIR logic steering from rx dmaPeter Hurley2016-04-30
| | | | | | | | | | | | | | | | Using fake IIR values to perform rx dma operations unnecessarily conflates separate operations, stopping in-progress dma with starting new dma. Introduce serial8250_rx_dma_flush() to handle stopping in-progress dma [omap8250 already has equivalent omap_8250_rx_dma_flush()]. Replace rx_dma(UART_IIR_RX_TIMEOUT) with the equivalent *_rx_dma_flush(), and rx_dma(0) with the equivalent *_rx_dma(). Handle IIR steering in the irq handler with handle_rx_dma() helper. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: Reduce expr in 8250 irq handlerPeter Hurley2016-04-30
| | | | | | | | If !up->dma == F, then up->dma == T and can be elided from the (up->dma && up->dma->tx_err) sub-expression. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: Eliminate needless local in irq handlersPeter Hurley2016-04-30
| | | | | | | | dma_err is not used other than for boolean evaluation; substitute the actual operation directly. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: export get_mctrl functionWan Ahmad Zainie2016-04-30
| | | | | | | | | | 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/serial/8250: fix RS485 half-duplex RXYegor Yefremov2016-04-19
| | | | | | | | | | | | When in half-duplex mode RX will be disabled before TX, but not enabled after deactivating transmitter. This patch enables UART_IER_RLSI and UART_IER_RDI interrupts after TX is over. Cc: Matwey V. Kornilov <matwey@sai.msu.ru> Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com> Fixes: e490c9144cfa ("tty: Add software emulated RS485 support for 8250") Acked-by: Matwey V. Kornilov <matwey@sai.msu.ru> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: convert drivers to use up_to_u8250p()Andy Shevchenko2016-03-07
| | | | | | | | up_to_u8250p() casts struct uart_port * to struct uart_8250_port *. Update code to use it instead of open coded variant. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: serial: Use GFP_ATOMIC instead of GFP_KERNEL in serial8250_em485_init()Matwey V. Kornilov2016-03-07
| | | | | | | | | | | | serial8250_em485_init() is supposed to be protected with p->port.lock spinlock. This may lead to issues when kmalloc sleeps, so it is better to use GFP_ATOMIC in this spinlocked context. Fixes: e490c9144cfa ("tty: Add software emulated RS485 support for 8250") Reported-by: Ильяс Гасанов <torso.nafi@gmail.com> Signed-off-by: Matwey V. Kornilov <matwey@sai.msu.ru> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: serial: 8250: Fix indentation warningsAnton Wuerfel2016-02-07
| | | | | | | | | | | | | Checkpatch complains about incorrect indentation of switch/case statements. This patch fixes the corresponding warnings. Additionally some indentation is changed to match the correct format specified in the Linux Kernel Coding Style. Signed-off-by: Anton Würfel <anton.wuerfel@fau.de> Signed-off-by: Phillip Raffeck <phillip.raffeck@fau.de> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: linux-kernel@i4.cs.fau.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: serial: 8250: Suitably replace printkPhillip Raffeck2016-02-07
| | | | | | | | | | | | This patch replaces printk by the corresponding variant of dev_* in order to fix checkpatch warnings. If no suitable device pointer is present, the corresponding pr_* variant is used. Signed-off-by: Phillip Raffeck <phillip.raffeck@fau.de> Signed-off-by: Anton Würfel <anton.wuerfel@fau.de> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: linux-kernel@i4.cs.fau.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: serial: 8250: Fix multiline comment styleAnton Wuerfel2016-02-07
| | | | | | | | | | | Checkpatch outputs some warnings about incorrect comment style, which is fixed by this patch. Signed-off-by: Anton Würfel <anton.wuerfel@fau.de> Signed-off-by: Phillip Raffeck <phillip.raffeck@fau.de> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: linux-kernel@i4.cs.fau.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: serial: 8250: Replace spaces with tabsAnton Wuerfel2016-02-07
| | | | | | | | | | | | Indentation is changed to match the correct format of using tabs instead of spaces wherever possible. Signed-off-by: Anton Würfel <anton.wuerfel@fau.de> Signed-off-by: Phillip Raffeck <phillip.raffeck@fau.de> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Peter Hurley <peter@hurleysoftware.com> Cc: linux-kernel@i4.cs.fau.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: serial: 8250: Fix whitespace errorsAnton Wuerfel2016-02-07
| | | | | | | | | | | | This patch fixes whitespace errors reported by checkpatch to increase readability. Main focus is on missing spaces after commas in function headers and macros (like foo,bar edited to foo, bar). Signed-off-by: Anton Würfel <anton.wuerfel@fau.de> Signed-off-by: Phillip Raffeck <phillip.raffeck@fau.de> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: linux-kernel@i4.cs.fau.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* 8250: use callbacks to access UART_DLL/UART_DLMSebastian Frias2016-02-07
| | | | | | | | | | | | | Some UART HW has a single register combining UART_DLL/UART_DLM (this was probably forgotten in the change that introduced the callbacks, commit b32b19b8ffc05cbd3bf91c65e205f6a912ca15d9) Fixes: b32b19b8ffc0 ("[SERIAL] 8250: set divisor register correctly ...") Signed-off-by: Sebastian Frias <sf84@laposte.net> Reviewed-by: Peter Hurley <peter@hurleysoftware.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: Add software emulated RS485 support for 8250Matwey V. Kornilov2016-02-07
| | | | | | | | | | | | | | | | 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: Move serial8250_stop_rx() in front of serial8250_start_tx()Matwey V. Kornilov2016-02-07
| | | | | | | | | | Software RS485 emultaion is to be added in the following commit. serial8250_start_tx() will need to refer serial8250_stop_rx(). Move serial8250_stop_rx() in front of serial8250_start_tx() in order to avoid function forward declaration. Signed-off-by: Matwey V. Kornilov <matwey@sai.msu.ru> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: Unfold < 80 char linesPeter Hurley2016-01-28
| | | | | Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: Wait for irq to complete before shutdownPeter Hurley2016-01-28
| | | | | | | | After masking all interrupts, wait for the irq handler to complete before continuing shutdown. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: Remove low_latency workaroundPeter Hurley2016-01-28
| | | | | | | | | | | | | | | The defunct low_latency input steering executed flush_to_ldisc() directly from interrupt context so dropping the port lock was necessary to avoid deadlock. That steering was removed by commit a9c3f68f3cd8d55f809fbdb0c138ed061ea1bd25 Author: Peter Hurley <peter@hurleysoftware.com> Date: Sat Feb 22 07:31:21 2014 -0500 tty: Fix low_latency BUG Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: Fix lost rx statePeter Hurley2016-01-28
| | | | | | | | | | When max_count is reached, the rx loop exits. However, UART_LSR has already been read so those char flags are lost, and subsequent rx status will be for the wrong byte until the rx fifo drains. Reported-by: George Spelvin <linux@horizon.com> Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: Refactor serial8250_rx_chars() inner loopPeter Hurley2016-01-28
| | | | | | | | Factor the read/process one char inner loop to a separate helper function serial8250_read_char(). No functional change. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: support 16-bit register interface for consoleMasahiro Yamada2015-12-13
| | | | | | | | | | | | Currently, 8-bit (MMIO) and 32-bit (MMIO32) register interfaces are supported for the 8250 console, but the 16-bit (MMIO16) is not. The 8250 UART device on my board is connected to a 16-bit bus and my main motivation is to use earlycon with it. (Refer to arch/arm/boot/dts/uniphier-support-card.dtsi) 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>
* Merge 4.3-rc5 into tty-nextGreg Kroah-Hartman2015-10-12
|\ | | | | | | | | | | | | We want the tty fixes and reverts in here as well so that people can properly test and use it. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * serial: 8250: add uart_config entry for PORT_RT2880Mans Rullgard2015-10-04
| | | | | | | | | | | | | | | | | | | | | | This adds an entry to the uart_config table for PORT_RT2880 enabling rx/tx FIFOs. The UART is actually a Palmchip BK-3103 which is found in several devices from Alchemy/RMI, Ralink, and Sigma Designs. Signed-off-by: Mans Rullgard <mans@mansr.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | serial: 8250: Refactor serial console restore-from-suspendPeter Hurley2015-10-04
| | | | | | | | | | | | | | | | | | | | Move h/w reinit of serial console restore-from-suspend into standalone helper function. No functional change. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | serial: 8250: Tolerate clock variance for max baud rateJames Hogan2015-10-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When the UART clock is set slightly under 1.8432MHz, the 8250 driver core doesn't permit the 115200 baud rate since it calculates the maximum frequency to pass to uart_get_baud_rate by simply dividing the uart clock by 16 which yields a value slightly under 115200, even though the frequency is close enough for the UART to operate reliably. Therefore add some tolerance in the calculation of the maximum baud rate. 1% tolerance allows for marginally slower uart clk than nominal without introducing transmission errors. Signed-off-by: James Hogan <james.hogan@imgtec.com> [pjh: Forward-port & refactor original patch; change tolerance to 1%] Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | serial: 8250: simplify ralink/alchemy register remap selectionMans Rullgard2015-10-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some SoCs, including Ralink/Mediatek and Alchemy Au1xxx, have a 16550-like UART with a non-standard register layout. These are supported by a simple mapping table in 8250_port.c Rather than list every SoC type using this access mode in the ifdefs there, allow selecting the SERIAL_8250_RT288X Kconfig option with any system and default it to y for the known cases needing it. The help text is reworded accordingly. This change simplifies adding support for other SoCs also using the same UART. The name of the option is a little misleading, but not knowing the true origin of this UART, it is as good a choice as any. Signed-off-by: Mans Rullgard <mans@mansr.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | serial: 8250: Fix autoconfig_irq() to avoid race conditionsTaichi Kageyama2015-10-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The following race conditions can happen when a serial port is used as console. Case1: CPU_B is used to detect an interrupt from a serial port, but it can have interrupts disabled during the waiting time. Case2: CPU_B clears UART_IER just after CPU_A sets UART_IER and then a serial port may not make an interrupt. Case3: CPU_A sets UART_IER just after CPU_B clears UART_IER. This is an unexpected behavior for serial8250_console_write(). CPU_A [autoconfig_irq] | CPU_B [serial8250_console_write] ----------------------------|--------------------------------------- | probe_irq_on() | spin_lock_irqsave(&port->lock,) serial_outp(,UART_IER,0x0f) | serial_out(,UART_IER,0) udelay(20); | uart_console_write() probe_irq_off() | | spin_unlock_irqrestore(&port->lock,) Case1 and 2 can make autoconfig_irq() failed. In these cases, the console doesn't work in interrupt mode and "input overrun" (which can make operation mistakes) can happen on some systems. Especially in the Case1, It is known that the problem happens with high rate every boot once it occurs because the boot sequence is always almost same. port mutex makes sure that the autoconfig operation is exclusive of any other concurrent HW access except by the console operation. console lock is required in autoconfig_irq(). Signed-off-by: Taichi Kageyama <t-kageyama@cp.jp.nec.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Reviewed-by: Peter Hurley <peter@hurleysoftware.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | serial: don't register CIR serial portsMaciej S. Szmigiero2015-10-04
|/ | | | | | | | | | | | | | | | | | | | | | | | | CIR type serial ports aren't real serial ports. This is just a way to prevent legacy 8250 serial driver from probing and eventually binding some resources. Since in current state such ports aren't providing any real functionality and it is not possible to change their type via setserial/ioctl(TIOCSSERIAL) (due to UPF_FIXED_PORT flag set on them) it is simpler and cleaner to not register them at all with serial core. Print a short message in this case so it is known to user what has happened. This way checks for PORT_8250_CIR in serial port callbacks can be removed too, since they won't ever be called. Signed-off-by: Maciej Szmigiero <mail@maciej.szmigiero.name> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: serial: Add missing module license for 8250_base.koJonathan McDowell2015-09-22
| | | | | | | | | | | | The split of the 8250 driver into a 8250_base/8250.ko resulted in a lack of a license for the 8250_base.ko module. This caused the module to fail to load and the kernel to be tainted. Add the appropriate MODULE_LICENSE to 8250_port.c, which is always compiled into 8250_base.ko Signed-off-by: Jonathan McDowell <noodles@earth.li> Reported-by: Mikael Pettersson <mikpelinux@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: Do XR17V35X specific wakeup in serial8250_do_startupJoerg Roedel2015-07-23
| | | | | | | | | | | | | | | | | | The XR17V35X UART needs the ECB bit set in its XR_EFR register to enable access to IER [7:5], ISR [5:4], FCR[5:4], MCR[7:5], and MSR [7:0]. Also reset the IER register to mask interrupts after access to all bits of this register has been enabled. This makes my 8-port XR17V35X working with the in-kernel serial driver. Cc: Joe Schultz <jschultz@xes-inc.com> Signed-off-by: Joerg Roedel <jroedel@suse.de> Reviewed-by: Peter Hurley <peter@hurleysoftware.com> Reviewed-by: Michael Welling <mwelling@ieee.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: Defer interrupt enable until fifos enabledPeter Hurley2015-07-23
| | | | | | | | | | | | | An already-active sender can swamp the interrupt handler with "too much work" if the rx interrupts are enabled when the fifo is disabled and operating in single-byte mode. Defer rx and line status interrupt enable until after the fifos are enabled in set_termios(), but at least initialize the shadow IER value with the interrupts which will be enabled. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: Split base port operations from universal driverPeter Hurley2015-07-23
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>
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