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linux/arch/arm/mach-pxa/Kconfig
Lennert Buytenhek afe4b25e7d [ARM] 3881/4: xscale: clean up cp0/cp1 handling
XScale cores either have a DSP coprocessor (which contains a single
40 bit accumulator register), or an iWMMXt coprocessor (which contains
eight 64 bit registers.)

Because of the small amount of state in the DSP coprocessor, access to
the DSP coprocessor (CP0) is always enabled, and DSP context switching
is done unconditionally on every task switch.  Access to the iWMMXt
coprocessor (CP0/CP1) is enabled only when an iWMMXt instruction is
first issued, and iWMMXt context switching is done lazily.

CONFIG_IWMMXT is supposed to mean 'the cpu we will be running on will
have iWMMXt support', but boards are supposed to select this config
symbol by hand, and at least one pxa27x board doesn't get this right,
so on that board, proc-xscale.S will incorrectly assume that we have a
DSP coprocessor, enable CP0 on boot, and we will then only save the
first iWMMXt register (wR0) on context switches, which is Bad.

This patch redefines CONFIG_IWMMXT as 'the cpu we will be running on
might have iWMMXt support, and we will enable iWMMXt context switching
if it does.'  This means that with this patch, running a CONFIG_IWMMXT=n
kernel on an iWMMXt-capable CPU will no longer potentially corrupt iWMMXt
state over context switches, and running a CONFIG_IWMMXT=y kernel on a
non-iWMMXt capable CPU will still do DSP context save/restore.

These changes should make iWMMXt work on PXA3xx, and as a side effect,
enable proper acc0 save/restore on non-iWMMXt capable xsc3 cores such
as IOP13xx and IXP23xx (which will not have CONFIG_CPU_XSCALE defined),
as well as setting and using HWCAP_IWMMXT properly.

Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-12-03 17:52:22 +00:00

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if ARCH_PXA
menu "Intel PXA2xx Implementations"
choice
prompt "Select target board"
config ARCH_LUBBOCK
bool "Intel DBPXA250 Development Platform"
select PXA25x
select SA1111
config MACH_LOGICPD_PXA270
bool "LogicPD PXA270 Card Engine Development Platform"
select PXA27x
config MACH_MAINSTONE
bool "Intel HCDDBBVA0 Development Platform"
select PXA27x
config ARCH_PXA_IDP
bool "Accelent Xscale IDP"
select PXA25x
config PXA_SHARPSL
bool "SHARP Zaurus SL-5600, SL-C7xx and SL-Cxx00 Models"
select SHARP_SCOOP
select SHARP_PARAM
help
Say Y here if you intend to run this kernel on a
Sharp Zaurus SL-5600 (Poodle), SL-C700 (Corgi),
SL-C750 (Shepherd), SL-C760 (Husky), SL-C1000 (Akita),
SL-C3000 (Spitz), SL-C3100 (Borzoi) or SL-C6000x (Tosa)
handheld computer.
config MACH_TRIZEPS4
bool "Keith und Koep Trizeps4 DIMM-Module"
select PXA27x
endchoice
if PXA_SHARPSL
choice
prompt "Select target Sharp Zaurus device range"
config PXA_SHARPSL_25x
bool "Sharp PXA25x models (SL-5600, SL-C7xx and SL-C6000x)"
select PXA25x
config PXA_SHARPSL_27x
bool "Sharp PXA270 models (SL-Cxx00)"
select PXA27x
endchoice
endif
if MACH_TRIZEPS4
choice
prompt "Select base board for Trizeps 4 module"
config MACH_TRIZEPS4_CONXS
bool "ConXS Eval Board"
config MACH_TRIZEPS4_ANY
bool "another Board"
endchoice
endif
endmenu
config MACH_POODLE
bool "Enable Sharp SL-5600 (Poodle) Support"
depends PXA_SHARPSL_25x
select SHARP_LOCOMO
select PXA_SSP
config MACH_CORGI
bool "Enable Sharp SL-C700 (Corgi) Support"
depends PXA_SHARPSL_25x
select PXA_SHARP_C7xx
config MACH_SHEPHERD
bool "Enable Sharp SL-C750 (Shepherd) Support"
depends PXA_SHARPSL_25x
select PXA_SHARP_C7xx
config MACH_HUSKY
bool "Enable Sharp SL-C760 (Husky) Support"
depends PXA_SHARPSL_25x
select PXA_SHARP_C7xx
config MACH_AKITA
bool "Enable Sharp SL-1000 (Akita) Support"
depends PXA_SHARPSL_27x
select PXA_SHARP_Cxx00
select MACH_SPITZ
select I2C
select I2C_PXA
config MACH_SPITZ
bool "Enable Sharp Zaurus SL-3000 (Spitz) Support"
depends PXA_SHARPSL_27x
select PXA_SHARP_Cxx00
config MACH_BORZOI
bool "Enable Sharp Zaurus SL-3100 (Borzoi) Support"
depends PXA_SHARPSL_27x
select PXA_SHARP_Cxx00
config MACH_TOSA
bool "Enable Sharp SL-6000x (Tosa) Support"
depends PXA_SHARPSL_25x
config PXA25x
bool
help
Select code specific to PXA21x/25x/26x variants
config PXA27x
bool
help
Select code specific to PXA27x variants
config PXA_SHARP_C7xx
bool
select PXA_SSP
select SHARPSL_PM
help
Enable support for all Sharp C7xx models
config PXA_SHARP_Cxx00
bool
select PXA_SSP
select SHARPSL_PM
help
Enable common support for Sharp Cxx00 models
config PXA_SSP
tristate
help
Enable support for PXA2xx SSP ports
endif