From mboxrd@z Thu Jan 1 00:00:00 1970 From: linux@arm.linux.org.uk (Russell King - ARM Linux) Date: Thu, 16 Jun 2011 22:31:28 +0100 Subject: [RFC PATCH v5] ARM hibernation / suspend-to-disk (fwd) In-Reply-To: References: <20110613122601.GC12325@n2100.arm.linux.org.uk> <20110613164452.GE13643@n2100.arm.linux.org.uk> Message-ID: <20110616213128.GC32629@n2100.arm.linux.org.uk> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wed, Jun 15, 2011 at 02:35:26PM +0100, Frank Hofmann wrote: > this change is perfect; with this, the hibernation support code turns > into the attached. Should I assume that's an ack for all the patches? > That's both better and simpler to perform a full suspend/resume cycle > (via resetting in the cpu_suspend "finisher") after the snapshot image > has been created, instead of shoehorning a return into this. It's now not soo difficult to have an error code returned from the finisher function - the only thing we have to make sure is that the cpu_do_suspend helper just saves state and does not make any state changes. We can then do this, which makes it possible for the finisher to return, and we propagate its return value. We also ensure that a path through from cpu_resume will result in a zero return value from cpu_suspend. This isn't an invitation for people to make the S2RAM path return after they time out waiting for suspend to happen - that's potentially dangerous because in that case the suspend may happen while we're resuming devices which wouldn't be nice. diff -u b/arch/arm/kernel/sleep.S b/arch/arm/kernel/sleep.S --- b/arch/arm/kernel/sleep.S +++ b/arch/arm/kernel/sleep.S @@ -12,7 +12,6 @@ * r1 = v:p offset * r2 = suspend function arg0 * r3 = suspend function - * Note: does not return until system resumes */ ENTRY(cpu_suspend) stmfd sp!, {r4 - r11, lr} @@ -26,7 +25,7 @@ #endif mov r6, sp @ current virtual SP sub sp, sp, r5 @ allocate CPU state on stack - mov r0, sp @ save pointer + mov r0, sp @ save pointer to CPU save block add ip, ip, r1 @ convert resume fn to phys stmfd sp!, {r1, r6, ip} @ save v:p, virt SP, phys resume fn ldr r5, =sleep_save_sp @@ -55,10 +54,17 @@ #else bl __cpuc_flush_kern_all #endif + adr lr, BSYM(cpu_suspend_abort) ldmfd sp!, {r0, pc} @ call suspend fn ENDPROC(cpu_suspend) .ltorg +cpu_suspend_abort: + ldmia sp!, {r1 - r3} @ pop v:p, virt SP, phys resume fn + mov sp, r2 + ldmfd sp!, {r4 - r11, pc} +ENDPROC(cpu_suspend_abort) + /* * r0 = control register value * r1 = v:p offset (preserved by cpu_do_resume) @@ -88,6 +94,7 @@ cpu_resume_after_mmu: str r5, [r2, r4, lsl #2] @ restore old mapping mcr p15, 0, r0, c1, c0, 0 @ turn on D-cache + mov r0, #0 @ return zero on success ldmfd sp!, {r4 - r11, pc} ENDPROC(cpu_resume_after_mmu)