linux-stable.git/arch/arm/kernel/sleep.S, branch v3.2 Linux kernel stable tree ARM: pm: convert some assembly to C 2011-09-20T22:33:44+00:00 Russell King rmk+kernel@arm.linux.org.uk 2011-09-01T10:52:33+00:00 abda1bd5f4e04054ce083c298fcd68a743e9df03 Convert some of the sleep.S guts to C code, which makes it easier to use our macros and to add L2 cache handling. We provide a helper function, __cpu_suspend_save(), which deals with saving the common state, setting up for resume, and flushing caches. The remainder left as assembly code is the saving of the CPU general purpose registers, and allocating space on the stack to save the CPU specific registers and resume state. Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Tested-by: Shawn Guo <shawn.guo@linaro.org> Tested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> 
Convert some of the sleep.S guts to C code, which makes it easier to
use our macros and to add L2 cache handling.  We provide a helper
function, __cpu_suspend_save(), which deals with saving the common
state, setting up for resume, and flushing caches.

The remainder left as assembly code is the saving of the CPU general
purpose registers, and allocating space on the stack to save the CPU
specific registers and resume state.

Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Tested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: pm: get rid of cpu_resume_turn_mmu_on 2011-09-20T22:33:42+00:00 Russell King rmk+kernel@arm.linux.org.uk 2011-08-31T22:26:18+00:00 62b2d07c0ea9db40a1787d2d0ab49f03c3e0613c We don't require cpu_resume_turn_mmu_on as we can combine the ldr instruction with the following code provided we ensure that cpu_resume_mmu is aligned for older CPUs. Note that we also align to a 32-byte boundary to ensure that the code can't cross a section boundary. Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Tested-by: Shawn Guo <shawn.guo@linaro.org> Tested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> 
We don't require cpu_resume_turn_mmu_on as we can combine the ldr
instruction with the following code provided we ensure that
cpu_resume_mmu is aligned for older CPUs.  Note that we also align
to a 32-byte boundary to ensure that the code can't cross a section
boundary.

Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Tested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: pm: only use preallocated page table during resume 2011-09-20T22:33:38+00:00 Russell King rmk+kernel@arm.linux.org.uk 2011-08-27T21:39:09+00:00 de8e71ca4f2e17329f6718ae88d5c8336cb249ee Only use the preallocated page table during the resume, not while suspending. This avoids the overhead of having to switch unnecessarily to the resume page table in the suspend path. Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Tested-by: Shawn Guo <shawn.guo@linaro.org> Tested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> 
Only use the preallocated page table during the resume, not while
suspending.  This avoids the overhead of having to switch unnecessarily
to the resume page table in the suspend path.

Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Tested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: pm: preallocate a page table for suspend/resume 2011-09-20T22:33:36+00:00 Russell King rmk+kernel@arm.linux.org.uk 2011-08-26T19:28:52+00:00 e8ce0eb5e2254b85415e4b58e73f24a5d13846a1 Preallocate a page table and setup an identity mapping for the MMU enable code. This means we don't have to "borrow" a page table to do this, avoiding complexities with L2 cache coherency. Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Tested-by: Shawn Guo <shawn.guo@linaro.org> Tested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> 
Preallocate a page table and setup an identity mapping for the MMU
enable code.  This means we don't have to "borrow" a page table to
do this, avoiding complexities with L2 cache coherency.

Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Tested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: pm: force non-zero return value from __cpu_suspend when aborting 2011-09-20T22:33:28+00:00 Russell King rmk+kernel@arm.linux.org.uk 2011-08-27T10:17:36+00:00 f5fa68d9674156ddaafa12a058ccc93c8866d5f9 Ensure that the return value from __cpu_suspend is non-zero when aborting. Zero indicates a successful suspend occurred. Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Tested-by: Shawn Guo <shawn.guo@linaro.org> Tested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> 
Ensure that the return value from __cpu_suspend is non-zero when
aborting.  Zero indicates a successful suspend occurred.

Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Tested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: pm: allow suspend finisher to return error codes 2011-07-02T08:54:01+00:00 Russell King rmk+kernel@arm.linux.org.uk 2011-07-02T08:54:01+00:00 29cb3cd208dd0e4471bb80bec4facc49ceb199fa There are SoCs where attempting to enter a low power state is ignored, and the CPU continues executing instructions with all state preserved. It is over-complex at that point to disable the MMU just to call the resume path. Instead, allow the suspend finisher to return error codes to abort suspend in this circumstance, where the cpu_suspend internals will then unwind the saved state on the stack. Also omit the tlb flush as no changes to the page tables will have happened. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> 
There are SoCs where attempting to enter a low power state is ignored,
and the CPU continues executing instructions with all state preserved.
It is over-complex at that point to disable the MMU just to call the
resume path.

Instead, allow the suspend finisher to return error codes to abort
suspend in this circumstance, where the cpu_suspend internals will then
unwind the saved state on the stack.  Also omit the tlb flush as no
changes to the page tables will have happened.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: pm: hide 1st and 2nd arguments to cpu_suspend from platform code 2011-06-24T08:54:39+00:00 Russell King rmk+kernel@arm.linux.org.uk 2011-06-22T16:41:48+00:00 2c74a0cefa463a7a483b07ba4d2ea8e4ec7b996c The first and second arguments shouldn't concern platform code, so hide them from each platforms caller. Tested-by: Kevin Hilman <khilman@ti.com> Acked-by: Jean Pihet <j-pihet@ti.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> 
The first and second arguments shouldn't concern platform code, so
hide them from each platforms caller.

Tested-by: Kevin Hilman <khilman@ti.com>
Acked-by: Jean Pihet <j-pihet@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: pm: move cpu_init() call into core code 2011-06-24T07:48:43+00:00 Russell King rmk+kernel@arm.linux.org.uk 2011-06-21T15:32:58+00:00 14cd8fd574bce1cfbe510ccb1f73c7c1024d770f As we have core code dealing with CPU suspend/resume, we can re-initialize the CPUs exception banked registers via that code rather than having platforms deal with that level of detail. So, move the call to cpu_init() out of platform code into core code. Tested-by: Kevin Hilman <khilman@ti.com> Acked-by: Jean Pihet <j-pihet@ti.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> 
As we have core code dealing with CPU suspend/resume, we can
re-initialize the CPUs exception banked registers via that code rather
than having platforms deal with that level of detail.  So, move the
call to cpu_init() out of platform code into core code.

Tested-by: Kevin Hilman <khilman@ti.com>
Acked-by: Jean Pihet <j-pihet@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: pm: convert cpu_suspend() to a normal function 2011-06-24T07:48:43+00:00 Russell King rmk+kernel@arm.linux.org.uk 2011-06-13T14:58:34+00:00 e8856a8797e76e6883ae81f8f9ecbb231cc535df cpu_suspend() has a weird calling method which makes it only possible to call from assembly code: it returns with a modified stack pointer to finish the suspend, but on resume, it 'returns' via a provided pointer. We can make cpu_suspend() appear to be a normal function merely by swapping the resume pointer argument and the link register. Do so, and update all callers to take account of this more traditional behaviour. Acked-by: Frank Hofmann <frank.hofmann@tomtom.com> Tested-by: Kevin Hilman <khilman@ti.com> Acked-by: Jean Pihet <j-pihet@ti.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> 
cpu_suspend() has a weird calling method which makes it only possible to
call from assembly code: it returns with a modified stack pointer to
finish the suspend, but on resume, it 'returns' via a provided pointer.

We can make cpu_suspend() appear to be a normal function merely by
swapping the resume pointer argument and the link register.

Do so, and update all callers to take account of this more traditional
behaviour.

Acked-by: Frank Hofmann <frank.hofmann@tomtom.com>
Tested-by: Kevin Hilman <khilman@ti.com>
Acked-by: Jean Pihet <j-pihet@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: pm: rejig suspend follow-on function calling convention 2011-06-24T07:47:36+00:00 Russell King rmk+kernel@arm.linux.org.uk 2011-06-13T14:28:40+00:00 3799bbe57843d279008c9ec3406838966cad5f15 Save the suspend function pointer onto the stack for use when returning. Allocate r2 to pass an argument to the suspend function. Acked-by: Frank Hofmann <frank.hofmann@tomtom.com> Tested-by: Kevin Hilman <khilman@ti.com> Acked-by: Jean Pihet <j-pihet@ti.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> 
Save the suspend function pointer onto the stack for use when returning.
Allocate r2 to pass an argument to the suspend function.

Acked-by: Frank Hofmann <frank.hofmann@tomtom.com>
Tested-by: Kevin Hilman <khilman@ti.com>
Acked-by: Jean Pihet <j-pihet@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>