Commit Graph

16 Commits

Author SHA1 Message Date
Jeff Garzik
c7bec5aba5 Various drivers' irq handlers: kill dead code, needless casts
- Eliminate casts to/from void*

- Eliminate checks for conditions that never occur.  These typically
  fall into two classes:

	1) Checking for 'dev_id == NULL', then it is never called with
	NULL as an argument.

	2) Checking for invalid irq number, when the only caller (the
	system) guarantees the irq handler is called with the proper
	'irq' number argument.

Signed-off-by: Jeff Garzik <jeff@garzik.org>
2006-10-06 15:00:58 -04:00
David Howells
7d12e780e0 IRQ: Maintain regs pointer globally rather than passing to IRQ handlers
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)
2006-10-05 15:10:12 +01:00
Thomas Gleixner
40663cc7f1 [PATCH] irq-flags: serial: Use the new IRQF_ constants
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-02 13:58:53 -07:00
Paul Fulghum
817d6d3bce [PATCH] remove TTY_DONT_FLIP
Remove TTY_DONT_FLIP tty flag.  This flag was introduced in 2.1.X kernels
to prevent the N_TTY line discipline functions read_chan() and
n_tty_receive_buf() from running at the same time.  2.2.15 introduced
tty->read_lock to protect access to the N_TTY read buffer, which is the
only state requiring protection between these two functions.

The current TTY_DONT_FLIP implementation is broken for SMP, and is not
universally honored by drivers that send data directly to the line
discipline receive_buf function.

Because TTY_DONT_FLIP is not necessary, is broken in implementation, and is
not universally honored, it is removed.

Signed-off-by: Paul Fulghum <paulkf@microgate.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-28 14:59:05 -07:00
Adrian Bunk
2a08b4e904 fix the email address of Wendy Xiong
Replace a bouncing version of the email address of Wendy Xiong with a
working one.

Signed-off-by: Adrian Bunk <bunk@stusta.de>
2006-04-01 01:04:20 +02:00
Jesper Juhl
a58e00e7da [PATCH] Decrease number of pointer derefs in jsm_tty.c
Decrease the number of pointer derefs in drivers/serial/jsm/jsm_tty.c

Benefits of the patch:
 - Fewer pointer dereferences should make the code slightly faster.
 - Size of generated code is smaller
 - Improved readability

Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Acked-by: "V. ANANDA KRISHNAN" <mansarov@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-31 12:19:01 -08:00
Adrian Bunk
1374ae8b9a [PATCH] drivers/serial/jsm/: cleanups
- jsm_driver.c: remove the now unused jsm_rawreadok module_param
- jsm_tty.c: remove a now unused variable

Is there any problem with removing the now useless jsm_rawreadok
module_param?

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Cc: V. Ananda Krishnan <mansarov@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-03 08:32:08 -08:00
V. Ananda Krishnan
0a577ce34f [PATCH] jsm: update for tty buffering revamp
Signed-off-by: V. Ananda Krishnan <mansarov@us.ibm.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-03 08:32:07 -08:00
V. Ananda Krishnan
bb3c190e8d [PATCH] jsm: fix for high baud rates problem
Scott Kilau <Scott_Kilau@digi.com>

Digi serial port console doesn't work when baud rates are set higher than
38400.  So the lookup table and code in jsm_neo.c has been modified and
tested.  Please let me have the feed-back.

Signed-off-by: V.Ananda Krishnan <mansarov@us.ibm.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-01 08:53:14 -08:00
Russell King
b129a8ccd5 [SERIAL] Clean up and fix tty transmission start/stoping
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>
2005-08-31 10:12:14 +01:00
V. ANANDA KRISHNAN
c223695634 [PATCH] jsm: warning fixes
- updates the version

- fix mixing of declarations and code.  The mixing of declarations and
  code displays warnings when used against RedHat RHEL4.0 distro (compiler
  version is 3.4.3-22.1) and hence I separated them out.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-07-27 16:25:52 -07:00
V. ANANDA KRISHNAN
9539c1d495 [PATCH] jsm: use dynamic major number allocation
The jsm driver uses a static number of 253.  The major number 253 is a
reserved for "LOCAL/EXPERIMENTAL USE" by both char and block devices.  So
take advantage of the dynamic allocation of major number by the kernel.

Signed-off-by: V. Ananda Krishnan <mansarov@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-07-27 16:25:52 -07:00
Olaf Hering
6d283d2716 [PATCH] Serial: Remove linux/version.h
changing CONFIG_LOCALVERSION rebuilds too much, for no appearent reason.

Signed-off-by: Olaf Hering <olh@suse.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-07-16 09:59:00 +01:00
Adrian Bunk
408b664a7d [PATCH] make lots of things static
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>
2005-05-01 08:59:29 -07:00
Christoph Hellwig
614a7d6a76 [PATCH] fix up newly added jsm driver
- plug various leaks and use after frees in the remove and
   initialization failure path (some still left)
 - remove useless global list of boards and use pci_set_drvdata instead
 - unobsfucate init path by merging functions together
 - kill various totally useless state variables
 - .. probably more I forgot

Note that the tty part still generates lots of sparse warnings and there's
still a totally useless layer of function pointer indirections, but maybe
someone else will fix that bit up.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-16 15:25:44 -07:00
Linus Torvalds
1da177e4c3 Linux-2.6.12-rc2
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!
2005-04-16 15:20:36 -07:00