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  1. 02 Nov, 2005 33 commits
  3. 01 Nov, 2005 7 commits
    • Deepak Saxena's avatar
      [ARM] 3081/1: Remove GTWX5715 from ixp4xx_defconfig · 73ee723e
      Deepak Saxena authored 
      Patch from Deepak Saxena

CONFIG_MACH_GTWX5715 hardcodes the machine type in head-xscale.S so we
can no longer boot on any other machine types. The proper fix would be
to remove the hardcoding, but that machine is an off-the-shelf system
and most users won't have access to the bootloader. :(
Signed-off-by: default avatarDeepak Saxena <dsaxena@plexity.net>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
      73ee723e
    • Dan Williams's avatar
      [ARM] 3079/1: Fix typo in i2c-iop3xx.c (invalid pointer passed to release_mem_region) · fbd9a6d7
      Dan Williams authored 
      Patch from Dan Williams

* If request_irq fails then a call to release_mem_region will be made with an invalid pointer.
* Two formatting fixes
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
Signed-off-by: default avatarDeepak Saxena <dsaxena@plexity.net>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
      fbd9a6d7
    • Lennert Buytenhek's avatar
      [ARM] 3052/1: add ixp2000 microcode loader · d01e8897
      Lennert Buytenhek authored 
      Patch from Lennert Buytenhek

This patch adds a microcode loader for the ixp2000 architecture.

The ixp2000 is an xscale-based CPU with a number of additional small
CPUs ('microengines') on die that can be programmed to do various
things.  Depending on the ixp2000 model, there are between 2 and 16
microengines.

This code provides an API that allows configuring the microengines,
loading code into them, and starting and stopping them and reading
out a number of status registers, and is used by the microengine
network driver that was recently announced to netdev.
Signed-off-by: default avatarLennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: default avatarDeepak Saxena <dsaxena@plexity.net>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
      d01e8897
    • Nicolas Pitre's avatar
      [ARM] 2948/1: new preemption safe copy_{to|from}_user implementation · fadab094
      Nicolas Pitre authored 
      Patch from Nicolas Pitre

This patch provides a preemption safe implementation of copy_to_user
and copy_from_user based on the copy template also used for memcpy.
It is enabled unconditionally when CONFIG_PREEMPT=y.  Otherwise if the
configured architecture is not ARMv3 then it is enabled as well as it
gives better performances at least on StrongARM and XScale cores.  If
ARMv3 is not too affected or if it doesn't matter too much then
uaccess.S could be removed altogether.
Signed-off-by: default avatarNicolas Pitre <nico@cam.org>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
      fadab094
    • Nicolas Pitre's avatar
      [ARM] 2947/1: copy template with new memcpy/memmove · 75494230
      Nicolas Pitre authored 
      Patch from Nicolas Pitre

This patch provides a new implementation for optimized memory copy
functions on ARM.  It is made of two levels: a template that consists of
the core copy code and separate files that define macros to be used with
the core code depending on the type of copy needed. This allows for best
performances while sharing the same core for implementing memcpy(),
copy_from_user() and copy_to_user() for instance.

Two reasons for this work:

1) the current copy_to_user/copy_from_user implementation assumes no
   task switch will ever occur in the middle of each copied page making
   it completely unsafe with CONFIG_PREEMPT=y.

2) current copy implementations are measurably suboptimal and optimizing
   different implementations separately is a pain and more opportunities
   for bugs.

The reason for (1) is the fact that copy inside user pages are performed
with the ldm instruction which has no mean for testing user protections
and could possibly race with process preemption bypassing the COW mechanism
for example.  This is a longstanding issue that we said ought to be fixed
for about two years now.  The solution is to substitute those ldm insns
with a series of ldrt or strt insns to enforce user memory protection.
At least on StrongARM and XScale cores the ldm is not faster than the
equivalent ldr/str insns with a warm i-cache so there is no measurable
performance degradation with that change. The fact that the copy code is
a template makes it pretty easy to reuse the same core code as for memcpy
and benefit from the same performance optimizations.

Now (2) is best demonstrated with actual throughput measurements.
First, here is a summary of memcopy tests performed on a StrongARM core:

	PTR alignment	buffer size	kernel version	this version
	------------------------------------------------------------
	  aligned	     32		 59.73		107.43
	unaligned	     32		 61.31		 74.72
	  aligned	    100		132.47		136.15
	unaligned	    100	    	103.84		123.76
	  aligned	   4096		130.67		130.80
	unaligned	   4096	    	130.68		130.64
	  aligned	1048576		 68.03		68.18
	unaligned	1048576		 68.03		68.18

The buffer size is in bytes and the measured speed in MB/s.  The copy
was performed repeatedly with given buffer and throughput averaged over
3 seconds.

Here we can see that the current kernel version has a higher entry cost
that shows up with small buffers.  As buffer size grows both implementation
converge to the same throughput.

Now here's the exact same test performed on an XScale core (PXA255):

	PTR alignment	buffer size	kernel version	this version
	------------------------------------------------------------
	  aligned	     32		 46.99		 77.58
	unaligned	     32		 53.61		 59.59
	  aligned	    100		107.19		136.59
	unaligned	    100		 83.61		 97.58
	  aligned	   4096		129.13		129.98
	unaligned	   4096		128.36		128.53
	  aligned	1048576		 53.76		 59.41
	unaligned	1048576		 33.67		 56.96

Again we can see the entry setup cost being higher for the current kernel
before getting to the main copy loop.  Then throughput results converge
as long as the buffer remains in the cache. Then the 1MB case shows more
differences probably due to better pld placement and/or less instruction
interlocks in this proposed implementation.

Disclaimer: The PXA system was running with slower clocks than the
StrongARM system so trying to infer any conclusion by comparing those
separate sets of results side by side would be completely inappropriate.

So...  What this patch does is to replace both memcpy and memmove with
an implementation based on the provided copy code template.  The memmove
code is kept separate since it is used only if the memory areas involved
do overlap in which case the code is a transposition of the template but
with the copy occurring in the opposite direction (trying to fit that
mode into the template turned it into a mess not worth it for memmove
alone).  And obviously both memcpy and memmove were tested with all kinds
of pointer alignments and buffer sizes to exercise all code paths for
correctness.

The next patch will provide the now trivial replacement implementation
copy_to_user and copy_from_user.
Signed-off-by: default avatarNicolas Pitre <nico@cam.org>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
      75494230
    • Nicolas Pitre's avatar
      [ARM] 2946/2: split --arch_clear_user() out of lib/uaccess.S · a0c6fdb9
      Nicolas Pitre authored 
      Patch from Nicolas Pitre

Required for future enhancement patches.
Signed-off-by: default avatarNicolas Pitre <nico@cam.org>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
      a0c6fdb9
    • David Brownell's avatar
      [ARM] 3078/1: lubbock platform updates, mostly mmc detection · 85eb226c
      David Brownell authored 
      Patch from David Brownell

Lubbock updates:

  * Provide an address for the SMC91x chip that doesn't generate
    a boot-time warning (matching the EEPROM).

  * Update MMC support to (a) detect card insert/remove, and
    (b) report the readonly switch setting for SD cards.

Previously, MMC/SD cards had to be present at boot time else they
couldn't be detected.
Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
      85eb226c
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