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path: root/drivers/serial/amba-pl011.c
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2006-03-20[SERIAL] kernel console should send CRLF not LFCRRussell King1-15/+5
Glen Turner reported that writing LFCR rather than the more traditional CRLF causes issues with some terminals. Since this aflicts many serial drivers, extract the common code to a library function (uart_console_write) and arrange for each driver to supply a "putchar" function. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-01-10[PATCH] TTY layer buffering revampAlan Cox1-9/+0
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[ARM] Move asm/hardware/clock.h to linux/clk.hRussell King1-1/+1
This is needs to be visible to other architectures using the AMBA bus and peripherals. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-01-07[ARM] Move AMBA include files to include/linux/amba/Russell King1-2/+2
Since the ARM AMBA bus is used on MIPS as well as ARM, we need to make the bus available for other architectures to use. Move the AMBA include files from include/asm-arm/hardware/ to include/linux/amba/ Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-01-03[ARM] Remove clk_use()/clk_unuse()Russell King1-7/+0
It seems that clk_use() and clk_unuse() are additional complexity which isn't required anymore. Remove them from the clock framework to avoid the additional confusion which they cause, and update all ARM machine types except for OMAP. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-12-27[SERIAL] Fix AMBA PL011 sysrq character handlingRussell King1-1/+1
We only want the received character without the status bits for sysrq handling. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-11-19[SERIAL] Fix status reporting with PL011 serial driverRussell King1-23/+22
The receiver status register reports latched error conditions, which must be cleared by writing to it. However, the data register reports unlatched conditions which are associated with the current character. Use the data register to interpret error status rather than the RSR. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-10-28[ARM] 3/4: Remove asm/hardware.h from Versatile and Integrator io.hRussell King1-0/+1
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-09-14[ARM] 2907/1: GCC 4 serial driver compile fixesVincent Sanders1-1/+1
Patch from Vincent Sanders When building the ARM platforms several serial drivers fail to compile with GCC 4.01 due to extern/static ambiguity. Signed-off-by: Vincent Sanders <vince@arm.linux.org.uk> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-08-31[SERIAL] Clean up and fix tty transmission start/stopingRussell King1-4/+4
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>
2005-05-09[PATCH] Serial: Add uart_insert_char()Russell King1-12/+2
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>
2005-04-26[PATCH] Serial: Ensure error paths are marked with unlikely()Russell King1-1/+1
Ensure ARM serial driver error paths are marked with the unlikely() compiler hint. Signed-off-by: Russell King <rmk@arm.linux.org.uk>
2005-04-16Linux-2.6.12-rc2v2.6.12-rc2Linus Torvalds1-0/+869
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!