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path: root/drivers/serial/8250.c
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2006-02-23[SERIAL] Add comment about early_serial_setup()Russell King
early_serial_setup() must not be called after console initialisation. Add a comment prior to the function explicitly stating this. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-02-15[SERIAL] Fix typo in commentRalf Baechle
Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-02-08[SERIAL] 8250 serial console update uart_8250_port ierKumar Gala
On some embedded PowerPC (MPC834x) systems an extra byte would some times be required to flush data out of the fifo. serial8250_console_write() was updating the IER in hardware without also updating the copy in uart_8250_port. This causes issues functions like serial8250_start_tx() and __stop_tx() to misbehave. Signed-off-by: Kumar Gala <galak@kernel.crashing.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-01-21[SERIAL] Remove UPF_AUTOPROBE and UPF_BOOT_ONLYMCARussell King
The functionality UPF_BOOT_ONLYMCA provided has been replaced by the 8250_mca module, which only registers MCA ports if MCA is present. UPF_AUTOPROBE has no functional effect - in fact, it's never tested. Only ibmasm set the flag. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-01-21[SERIAL] 8250 serial console fixesAlan Cox
This patch resolves most of the problems with an SMP serial console race with output via the tty path. At the end of the serial console print we force enable the tx int in case we clobbered the tx interrupt status racing between the console and tty output. That way the extra tx interrupt causes the transmit path to restart not hang. It also makes the serial console printk use the FIFO. This is neccessary because some remote management devices fake serial console with FIFO and are confused into sending one packet per character over ethernet when we stall rather than filling the FIFO. In order to preserve existing reliability semantics the function waits for the serial queue to completely empty before returning. Both of these problems were identified by a Red Hat partner. Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-01-18[SERIAL] Fix serial8250 driver initialisation orderingRussell King
Commit 7493a314cb83797ce612a577475aacaedc553fed changed the ordering of the registration of the platform device driver vs the 8250 drivers internal initialisation. This led to the probe function being called before the driver had finished its internal initialisation, causing mayhem. Revert the ordering change. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-01-13[SERIAL] serial8250: convert to the new platform device interfaceDmitry Torokhov
Do not use platform_device_register_simple() as it is going away. Also set up driver's owner to create link driver->module in sysfs. Signed-off-by: Dmitry Torokhov <dtor@mail.ru> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-01-12[SERIAL] turn serial semaphores into mutexesArjan van de Ven
Turn several drivers/serial/ semaphores-used-as-mutex into mutexes Signed-off-by: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-01-10[PATCH] TTY layer buffering revampAlan Cox
The API and code have been through various bits of initial review by serial driver people but they definitely need to live somewhere for a while so the unconverted drivers can get knocked into shape, existing drivers that have been updated can be better tuned and bugs whacked out. This replaces the tty flip buffers with kmalloc objects in rings. In the normal situation for an IRQ driven serial port at typical speeds the behaviour is pretty much the same, two buffers end up allocated and the kernel cycles between them as before. When there are delays or at high speed we now behave far better as the buffer pool can grow a bit rather than lose characters. This also means that we can operate at higher speeds reliably. For drivers that receive characters in blocks (DMA based, USB and especially virtualisation) the layer allows a lot of driver specific code that works around the tty layer with private secondary queues to be removed. The IBM folks need this sort of layer, the smart serial port people do, the virtualisers do (because a virtualised tty typically operates at infinite speed rather than emulating 9600 baud). Finally many drivers had invalid and unsafe attempts to avoid buffer overflows by directly invoking tty methods extracted out of the innards of work queue structs. These are no longer needed and all go away. That fixes various random hangs with serial ports on overflow. The other change in here is to optimise the receive_room path that is used by some callers. It turns out that only one ldisc uses receive room except asa constant and it updates it far far less than the value is read. We thus make it a variable not a function call. I expect the code to contain bugs due to the size alone but I'll be watching and squashing them and feeding out new patches as it goes. Because the buffers now dynamically expand you should only run out of buffering when the kernel runs out of memory for real. That means a lot of the horrible hacks high performance drivers used to do just aren't needed any more. Description: tty_insert_flip_char is an old API and continues to work as before, as does tty_flip_buffer_push() [this is why many drivers dont need modification]. It does now also return the number of chars inserted There are also tty_buffer_request_room(tty, len) which asks for a buffer block of the length requested and returns the space found. This improves efficiency with hardware that knows how much to transfer. and tty_insert_flip_string_flags(tty, str, flags, len) to insert a string of characters and flags For a smart interface the usual code is len = tty_request_buffer_room(tty, amount_hardware_says); tty_insert_flip_string(tty, buffer_from_card, len); More description! At the moment tty buffers are attached directly to the tty. This is causing a lot of the problems related to tty layer locking, also problems at high speed and also with bursty data (such as occurs in virtualised environments) I'm working on ripping out the flip buffers and replacing them with a pool of dynamically allocated buffers. This allows both for old style "byte I/O" devices and also helps virtualisation and smart devices where large blocks of data suddenely materialise and need storing. So far so good. Lots of drivers reference tty->flip.*. Several of them also call directly and unsafely into function pointers it provides. This will all break. Most drivers can use tty_insert_flip_char which can be kept as an API but others need more. At the moment I've added the following interfaces, if people think more will be needed now is a good time to say int tty_buffer_request_room(tty, size) Try and ensure at least size bytes are available, returns actual room (may be zero). At the moment it just uses the flipbuf space but that will change. Repeated calls without characters being added are not cumulative. (ie if you call it with 1, 1, 1, and then 4 you'll have four characters of space. The other functions will also try and grow buffers in future but this will be a more efficient way when you know block sizes. int tty_insert_flip_char(tty, ch, flag) As before insert a character if there is room. Now returns 1 for success, 0 for failure. int tty_insert_flip_string(tty, str, len) Insert a block of non error characters. Returns the number inserted. int tty_prepare_flip_string(tty, strptr, len) Adjust the buffer to allow len characters to be added. Returns a buffer pointer in strptr and the length available. This allows for hardware that needs to use functions like insl or mencpy_fromio. Signed-off-by: Alan Cox <alan@redhat.com> Cc: Paul Fulghum <paulkf@microgate.com> Signed-off-by: Hirokazu Takata <takata@linux-m32r.org> Signed-off-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: John Hawkes <hawkes@sgi.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-07[SERIAL] Make the number of UARTs registered configurable.Dave Jones
Also add a nr_uarts module option to the 8250 code to override this, up to a maximum of CONFIG_SERIAL_8250_NR_UARTS This should appease people who complain about a proliferation of /dev/ttyS & /sysfs nodes whilst at the same time allowing a single kernel image to support the rarer occasions of lots of devices. Signed-off-by: Dave Jones <davej@redhat.com>
2006-01-04[SERIAL] Remove _INLINE_Russell King
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-01-04[SERIAL] Move interrupt-time spinlocking inside serial8250_handle_port()Russell King
All call sites for serial8250_handle_port() acquired the port spinlock and released it afterwards. This is a needless duplication of code. Move the spinlocking inside serial8250_handle_port(). Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-01-04[SERIAL] Use uart_match_port() to find a matching port in find_port()Russell King
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-01-04[Serial] Don't miss modem status changesRussell King
Reading the MSR register on 8250-compatible UARTs results in any modem status interrupts being cleared. To avoid missing any status changes, arrange for get_mctrl() to read the current status via check_modem_status(), which will process any pending state changes for us. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-11-28[SERIAL] mark several serial tables constArjan van de Ven
This patch marks a few serial data structures const, moving them to .rodata where they won't false-share cachelines with things that get written to. Signed-off-by: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-11-12[SERIAL] don't disable xscale serial ports after autoconfigLennert Buytenhek
xscale-type UARTs have an extra bit (UUE) in the IER register that has to be written as 1 to enable the UART. At the end of autoconfig() in drivers/serial/8250.c, the IER register is unconditionally written as zero, which turns off the UART, and makes any subsequent printch() hang the box. Since other 8250-type UARTs don't have this enable bit and are thus always 'enabled' in this sense, it can't hurt to enable xscale-type serial ports all the time as well. The attached patch changes the autoconfig() exit path to see if the port has an UUE enable bit, and if yes, to write UUE=1 instead of just putting a zero into IER, using the same test as is used at the beginning of serial8250_console_write(). Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-11-09[DRIVER MODEL] Convert platform drivers to use struct platform_driverRussell King
This allows us to eliminate the casts in the drivers, and eventually remove the use of the device_driver function pointer methods for platform device drivers. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-11-07[PATCH] serial console: touch NMI watchdogAndrew Morton
Large console spews from IRQ or local_irq_disable() sections can cause the NMI watchdog to go off. Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-06[SERIAL] Support Au1x00 8250 UARTs using the generic 8250 driver.Pantelis Antoniou
The offsets of the registers are in a different place, and some parts cannot handle a full set of modem control signals. Signed-off-by: Pantelis Antoniou <pantelis@embeddedalley.ocm> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-10-29Create platform_device.h to contain all the platform device details.Russell King
Convert everyone who uses platform_bus_type to include linux/platform_device.h. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-10-28[PATCH] DRIVER MODEL: Get rid of the obsolete tri-level suspend/resume callbacksRussell King
In PM v1, all devices were called at SUSPEND_DISABLE level. Then all devices were called at SUSPEND_SAVE_STATE level, and finally SUSPEND_POWER_DOWN level. However, with PM v2, to maintain compatibility for platform devices, I arranged for the PM v2 suspend/resume callbacks to call the old PM v1 suspend/resume callbacks three times with each level in order so that existing drivers continued to work. Since this is obsolete infrastructure which is no longer necessary, we can remove it. Here's an (untested) patch to do exactly that. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-09-09[SERIAL] Spelling fix in 8250.cRussell King
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-09-08[SERIAL] Use an enum for serial8250 platform device IDsRussell King
Rather than hard-coding the platform device IDs, enumerate them. We don't particularly care about the actual ID we get, just as long as they're unique. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-08-31[ARM] 2866/1: add i.MX set_mctrl / get_mctrl functionsSascha Hauer
Patch from Sascha Hauer This patch adds support for setting and getting RTS / CTS via set_mtctrl / get_mctrl functions. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-08-31[SERIAL] Clean up and fix tty transmission start/stopingRussell King
The start_tx and stop_tx methods were passed a flag to indicate whether the start/stop was from the tty start/stop callbacks, and some drivers used this flag to decide whether to ask the UART to immediately stop transmission (where the UART supports such a feature.) There are other cases when we wish this to occur - when CTS is lowered, or if we change from soft to hard flow control and CTS is inactive. In these cases, this flag was false, and we would allow the transmitter to drain before stopping. There is really only one case where we want to let the transmitter drain before disabling, and that's when we run out of characters to send. Hence, re-jig the start_tx and stop_tx methods to eliminate this flag, and introduce new functions for the special "disable and allow transmitter to drain" case. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-06-30[PATCH] Serial: Fix small CONFIG_SERIAL_8250_NR_UARTSRussell King
If CONFIG_SERIAL_8250_NR_UARTS is smaller than the array size in asm/serial.h, we trampled on memory which wasn't ours. Take our big boots away by limiting the number of ports initialised to the smaller of ...NR_UARTS and the array size. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-06-29[PATCH] Serial: Split 8250 port table (part 2)Russell King
Remove legacy ISA serial ports for Accent, Boca, Fourport, Hub6 and MCA from the architecture specific serial.h include. The only ports which remain in asm-*/serial.h are the platform specific entries. These should really be converted by platform maintainers to use a platform device, such as can be found in arch/arm/mach-footbridge/isa.c Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-06-29[PATCH] Serial: Disable OX950 transmitter for flow controlRussell King
Disable the transmitter whenever we want to prevent characters being transmitted by flow control. However, if we run out of characters to send and want to only disable the TX interrupt, allow that scenario. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-06-29[PATCH] Serial: Adjust serial lockingRussell King
This patch changes the way serial ports are locked when getting modem status. This change is necessary because we will need to atomically read the modem status and take action depending on the CTS status. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-06-27[PATCH] Serial: Split 8250 port tableRussell King
Add separate files for the different 8250 ISA-based serial boards. Looking across all the various architectures, it seems reasonable that we can key the availability of the configuration options for these beasts to the bus-related symbols (iow, CONFIG_ISA). We also standardise the base baud/uart clock rate for these boards - I'm sure that isn't architecture specific, but is solely dependent on the crystal fitted on the board (which should be the same no matter what type of machine its fitted into.) Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-06-24[PATCH] Serial: Eliminate magic numbersRussell King
Use the existing macros instead. Signed-off-by: Yoichi Yuasa <yuasa@hh.iij4u.or.jp> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-06-23[PATCH] Serial: Bugs are not capabilitiesRussell King
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-06-23[PATCH] Serial: Mobility's 16550A ports need a helping handRussell King
The Mobility 16550A serial ports don't behave the same as standard 16550A ports, and need a helping hand to get them going once the transmitter has drained and been disabled. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-06-23[PATCH] Serial: Convert 8250 revision-based bug fixes to bug bitmaskRussell King
For some 8250 port types, we used to check the type of the port, and then determine whether the chip revision means the device is buggy. Instead, introduce a bit array, and set the appropriate bit(s) when we discover a buggy device. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-05-21When we detect that a 16550 was in fact part of a NatSemi SuperIO chipDavid Woodhouse
with high-speed mode enabled, we switch it to high-speed mode so that baud_base becomes 921600. However, we also need to multiply the baud divisor by 8 at the same time, in case it's already in use as a console. Signed-off-by: David Woodhouse Acked-by: Tom Rini Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-05-09[PATCH] Serial: Add uart_insert_char()Russell King
Add uart_insert_char(), which handles inserting characters into the flip buffer. This helper function handles the correct semantics for handling overrun in addition to inserting normal characters. Signed-off-by: Russell King <rmk@arm.linux.org.uk>
2005-05-01[PATCH] make lots of things staticAdrian Bunk
Another large rollup of various patches from Adrian which make things static where they were needlessly exported. Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-16[PATCH] serial: fix comments in 8250.cRussell King
Fix the formatting of some comments in 8250.c, and add a note that the register_serial / unregister_serial shouldn't be used in new code. We do this here in preference to adding to linux/serial.h, since that is used by a number of non-8250 drivers which pretend to be 8250. It is not known whether it would be appropriate to do so. Signed-off-by: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-16Linux-2.6.12-rc2Linus Torvalds
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!