| Age | Commit message (Collapse) | Author |
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The serial drivers are really just tty drivers, so move them to
drivers/tty/ to make things a bit neater overall.
This is part of the tty/serial driver movement proceedure as proposed by
Arnd Bergmann and approved by everyone involved a number of months ago.
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Rogier Wolff <R.E.Wolff@bitwizard.nl>
Cc: Michael H. Warfield <mhw@wittsend.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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ST Micro variants has some specific dma burst threshold compensation,
which allows them to make better use of a DMA controller. Add support
to set this up.
Based on a patch from Linus Walleij.
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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Add DMA engine support for transmit to the PL011 driver. Based on a
patch from Linus Walliej, with the following changes:
- remove RX DMA support. As PL011 doesn't give us receive timeout
interrupts, we only get notified of received data when the RX DMA
has completed. This rather sucks for interactive use of the TTY.
- remove abuse of completions. Completions are supposed to be for
events, not to tell what condition buffers are in. Replace it with
a simple 'queued' bool.
- fix locking - it is only safe to access the circular buffer with the
port lock held.
- only map the DMA buffer when required - if we're ever behind an IOMMU
this helps keep IOMMU usage down, and also ensures that we're legal
when we change the scatterlist entry length.
- fix XON/XOFF sending - we must send XON/XOFF characters out as soon
as possible - waiting for up to 4095 characters in the DMA buffer
to be sent first is not acceptable.
- fix XON/XOFF receive handling - we need to stop DMA when instructed
to by the TTY layer, and restart it again when instructed to. There
is a subtle problem here: we must not completely empty the circular
buffer with DMA, otherwise we will not be notified of XON.
- change the 'enable_dma' flag into a 'using DMA' flag, and track
whether we can use TX DMA by whether the channel pointer is non-NULL.
This gives us more control over whether we use DMA in the driver.
- we don't need to have the TX DMA buffer continually allocated for
each port - instead, allocate it when the port starts up, and free
it when it's shut down. Update the 'using DMA' flag if we get
the buffer, and adjust the TTY FIFO size appropriately.
- if we're going to use PIO to send characters, use the existing IRQ
based functionality rather than reimplementing it. This also ensures
we call uart_write_wakeup() at the appropriate time, otherwise we'll
stall.
- use DMA engine helper functions for type safety.
- fix init when built as a module - we can't have to initcall functions,
so we must settle on one. This means we can eliminate the deferred
DMA initialization.
- there is no need to terminate transfers on a failed prep_slave_sg()
call - nothing has been setup, so nothing needs to be terminated.
This avoids a potential deadlock in the DMA engine code
(tasklet->callback->failed prepare->terminate->tasklet_disable
which then ends up waiting for the tasklet to finish running.)
- Dan says that the submission callback should not return an error:
| dma_submit_error() is something I should have removed after commit
| a0587bcf "ioat1: move descriptor allocation from submit to prep" all
| errors should be notified by prep failing to return a descriptor
| handle. Negative dma_cookie_t values are only returned by the
| dma_async_memcpy* calls which translate a prep failure into -ENOMEM.
So remove the error handling at that point. This also solves the
potential deadlock mentioned in the previous comment.
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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As the DMA support introduces a separate interrupt-time callback, our
interrupt handler will not be the only handler which takes the port
lock, so we need to ensure that IRQs are disabled. We must use the
_irqsave variant so we don't inadvertently enable interrupts.
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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With DMA support, we need to tell the TTY subsystem that the DMA buffer
is the size of the FIFO, otherwise things like tty_wait_until_sent()
will time out too early. Keep (and use) the hardware value separately
from the port->fifosize.
This was part of a larger patch from Linus Walleij, with a little
modification.
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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Rather than copying all vendor data into the port structure, copy
just that which is frequently used, and keep a pointer to the
remaining vendor data structure. This makes it easier to add
vendor quirks in the future.
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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The error flags weren't being cleared upon UART startup, which
can cause problems when we add DMA support. It's good practice
to ensure that these flags are cleared anyway, so let's do so.
This was part of a larger patch from Linus Walleij.
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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Include the revision number of the PL011 primecell in the boot-time
port printk to allow proper identification of the peripheral.
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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Found in the Versatile build:
WARNING: drivers/built-in.o(.data+0x14c): Section mismatch in reference from the variable pl061_gpio_driver to the (unknown reference) .init.data:(unknown)
The variable pl061_gpio_driver references
the (unknown reference) __initdata (unknown)
WARNING: drivers/built-in.o(.data+0x40f8): Section mismatch in reference from the variable pl011_driver to the (unknown reference) .init.data:(unknown)
The variable pl011_driver references
the (unknown reference) __initdata (unknown)
WARNING: drivers/built-in.o(.data+0x5ab4): Section mismatch in reference from the variable pl031_driver to the (unknown reference) .init.data:(unknown)
The variable pl031_driver references
the (unknown reference) __initdata (unknown)
Basically, amba_id structures must not be __initdata. Also fix:
WARNING: drivers/built-in.o(.data+0x138): Section mismatch in reference from the variable pl061_gpio_driver to the function .init.text:pl061_probe()
The variable pl061_gpio_driver references
the function __init pl061_probe()
which is an incorrectly annotated probe function. Fix it to reflect
the other AMBA bus probe functions by removing the __init attributation.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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Implementation of the ST-Ericsson baudrate extension in the PL011
block. In this modified variant it is possible to change the
sampling factor from 16 to 8, and thanks to this we can get higher
baudrates while still using the same peripheral clock.
Also replace the simple division to determine the baud divisor
with DIV_ROUND_CLOSEST() rather than a simple integer division.
Cc: Alessandro Rubini <rubini@unipv.it>
Cc: Jerzy Kasenberg <jerzy.kasenberg@tieto.com>
Signed-off-by: Marcin Mielczarczyk <marcin.mielczarczyk@tieto.com>
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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In the ST-Ericsson version of the PL011 the TX and RX have different
control registers.
Cc: Alessandro Rubini <rubini@unipv.it>
Signed-off-by: Marcin Mielczarczyk <marcin.mielczarczyk@tieto.com>
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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The design of the kdb shell requires that every device that can
provide input to kdb have a polling routine that exits immediately if
there is no character available. This is required in order to get the
page scrolling mechanism working.
Changing the kernel debugger I/O API to require all polling character
routines to exit immediately if there is no data allows the kernel
debugger to process multiple input channels.
NO_POLL_CHAR will be the return code to the polling routine when ever
there is no character available.
CC: linux-serial@vger.kernel.org
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
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implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
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Enable/disable automatic hardware flow control as requested by the
termios. The controller does not allow us to control the RTS line when
auto-RTS is enabled, so we enable auto-RTS only if the kernel has not
disabled RTS.
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Rabin Vincent <rabin.vincent@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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This is used by various drivers not just serial and can be extracted
as commonality
Signed-off-by: Alan Cox <alan@linux.intel.com>
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We moved this into uart_state, now move the fields out of the separate
structure and kill it off.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Add suspend/resume functions to the AMBA pl011 serial driver.
Signed-off-by: Leo Chen <leochen@broadcom.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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I found the PrimeCell/AMBA Bus drivers distrusting the resource
passed in as part of the struct amba_device abstraction. This
patch removes all hard coded resource sizes found in the PrimeCell
drivers and move the responsibility of this definition back to
the platform/board device definition, which already exist and
appear to be correct for all in-tree users of these drivers.
We do this using the resource_size() inline function which was
also replicated in the only driver using the resource size, so
that has been changed too. The KMI_SIZE was left in kmi.h in case
someone likes it. Test-compiled against Versatile and Integrator
defconfigs, seems to work but I don't posess these boards and
cannot test them.
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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in Nomadik
The Nomadik 8815 SoC has a slightly modified version of the PL011 block.
The patch uses the different ID value as a key to select a vendor
structure that is used to keep track of the differences, as suggested
by Russell King.
Signed-off-by: Alessandro Rubini <rubini@unipv.it>
Acked-by: Andrea Gallo <andrea.gallo@stericsson.com>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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Signed-off-by: Alessandro Rubini <rubini@unipv.it>"
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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The second argument of the probe method points to the amba_id
structure, so it's better passed with the correct type. None of the
current in-tree drivers uses the pointer, so they have only been
checked for a clean compile.
Change suggested by Russell King.
Signed-off-by: Alessandro Rubini <rubini@unipv.it>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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clocks
Where devices only have one consumer, passing a consumer clock ID
has no real benefit, and it only encourages wrong implementations of
the clk API. Remove it.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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The below is the patch to replace blindly all possible places,
including Jack's fixes.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
(Reviewed and checked rather than blindly added)
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This patch removes CVS keywords that weren't updated for a long time in
comments, printk's and MODULE_DESCRIPTION's (no printk's or
MODULE_DESCRIPTION's are completely removed).
While doing this I also found and fixed a missing \n in a printk
in m32r_sio.c
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Implement the serial polling hooks for the pl011 uart for use with
kgdboc.
This patch was specifically tested on the ARM Versatile AB reference
platform.
[ mingo@elte.hu: minor cleanups. ]
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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amba-pl011, rename BIT macro
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Transform some calls to kmalloc/memset to a single kzalloc (or kcalloc).
Here is a short excerpt of the semantic patch performing
this transformation:
@@
type T2;
expression x;
identifier f,fld;
expression E;
expression E1,E2;
expression e1,e2,e3,y;
statement S;
@@
x =
- kmalloc
+ kzalloc
(E1,E2)
... when != \(x->fld=E;\|y=f(...,x,...);\|f(...,x,...);\|x=E;\|while(...) S\|for(e1;e2;e3) S\)
- memset((T2)x,0,E1);
@@
expression E1,E2,E3;
@@
- kzalloc(E1 * E2,E3)
+ kcalloc(E1,E2,E3)
[akpm@linux-foundation.org: get kcalloc args the right way around]
Signed-off-by: Yoann Padioleau <padator@wanadoo.fr>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Acked-by: Russell King <rmk@arm.linux.org.uk>
Cc: Bryan Wu <bryan.wu@analog.com>
Acked-by: Jiri Slaby <jirislaby@gmail.com>
Cc: Dave Airlie <airlied@linux.ie>
Acked-by: Roland Dreier <rolandd@cisco.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Acked-by: Dmitry Torokhov <dtor@mail.ru>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Mauro Carvalho Chehab <mchehab@infradead.org>
Acked-by: Pierre Ossman <drzeus-list@drzeus.cx>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: "David S. Miller" <davem@davemloft.net>
Acked-by: Greg KH <greg@kroah.com>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The -rt patch triggered a lockdep warning in the amba serial drivers, which never
shows up on UP kernels. On SMP systems this would trigger as well.
Release the port lock before calling tty_flip_buffer_push() and reacquire it after
the call. This matches the code in the 8250 serial driver.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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Using console=ttyAM1 or console=ttyAMA1 resulted in an oops during
boot due to trying to drive the console before that port had been
registered. Fix this by checking whether the port is present before
allowing console setup to proceed.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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This is the grungy swap all the occurrences in the right places patch that
goes with the updates. At this point we have the same functionality as
before (except that sgttyb() returns speeds not zero) and are ready to
begin turning new stuff on providing nobody reports lots of bugs
If you are a tty driver author converting an out of tree driver the only
impact should be termios->ktermios name changes for the speed/property
setting functions from your upper layers.
If you are implementing your own TCGETS function before then your driver
was broken already and its about to get a whole lot more painful for you so
please fix it 8)
Also fill in c_ispeed/ospeed on init for most devices, although the current
code will do this for you anyway but I'd like eventually to lose that extra
paranoia
[akpm@osdl.org: bluetooth fix]
[mp3@de.ibm.com: sclp fix]
[mp3@de.ibm.com: warning fix for tty3270]
[hugh@veritas.com: fix tty_ioctl powerpc build]
[jdike@addtoit.com: uml: fix ->set_termios declaration]
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Martin Peschke <mp3@de.ibm.com>
Acked-by: Peter Oberparleiter <oberpar@de.ibm.com>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Maintain a per-CPU global "struct pt_regs *" variable which can be used instead
of passing regs around manually through all ~1800 interrupt handlers in the
Linux kernel.
The regs pointer is used in few places, but it potentially costs both stack
space and code to pass it around. On the FRV arch, removing the regs parameter
from all the genirq function results in a 20% speed up of the IRQ exit path
(ie: from leaving timer_interrupt() to leaving do_IRQ()).
Where appropriate, an arch may override the generic storage facility and do
something different with the variable. On FRV, for instance, the address is
maintained in GR28 at all times inside the kernel as part of general exception
handling.
Having looked over the code, it appears that the parameter may be handed down
through up to twenty or so layers of functions. Consider a USB character
device attached to a USB hub, attached to a USB controller that posts its
interrupts through a cascaded auxiliary interrupt controller. A character
device driver may want to pass regs to the sysrq handler through the input
layer which adds another few layers of parameter passing.
I've build this code with allyesconfig for x86_64 and i386. I've runtested the
main part of the code on FRV and i386, though I can't test most of the drivers.
I've also done partial conversion for powerpc and MIPS - these at least compile
with minimal configurations.
This will affect all archs. Mostly the changes should be relatively easy.
Take do_IRQ(), store the regs pointer at the beginning, saving the old one:
struct pt_regs *old_regs = set_irq_regs(regs);
And put the old one back at the end:
set_irq_regs(old_regs);
Don't pass regs through to generic_handle_irq() or __do_IRQ().
In timer_interrupt(), this sort of change will be necessary:
- update_process_times(user_mode(regs));
- profile_tick(CPU_PROFILING, regs);
+ update_process_times(user_mode(get_irq_regs()));
+ profile_tick(CPU_PROFILING);
I'd like to move update_process_times()'s use of get_irq_regs() into itself,
except that i386, alone of the archs, uses something other than user_mode().
Some notes on the interrupt handling in the drivers:
(*) input_dev() is now gone entirely. The regs pointer is no longer stored in
the input_dev struct.
(*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking. It does
something different depending on whether it's been supplied with a regs
pointer or not.
(*) Various IRQ handler function pointers have been moved to type
irq_handler_t.
Signed-Off-By: David Howells <dhowells@redhat.com>
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
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Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
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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>
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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>
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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>
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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>
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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>
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We only want the received character without the status bits for
sysrq handling.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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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>
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Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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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>
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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>
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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>
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Ensure ARM serial driver error paths are marked with the
unlikely() compiler hint.
Signed-off-by: Russell King <rmk@arm.linux.org.uk>
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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!
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