ARM: pm: convert cpu_suspend() to a normal function

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>

8 files changed, 31 insertions, 40 deletions

diff --git a/arch/arm/include/asm/system.h b/arch/arm/include/asm/system.h
index 832888d0c20c..50be6055df89 100644
--- a/arch/arm/include/asm/system.h
+++ b/arch/arm/include/asm/system.h
@@ -106,6 +106,8 @@ extern void __show_regs(struct pt_regs *);
 
 extern int cpu_architecture(void);
 extern void cpu_init(void);
+extern void cpu_suspend(int, long, unsigned long, void (*)(unsigned long));
+extern void cpu_resume(void);
 
 void arm_machine_restart(char mode, const char *cmd);
 extern void (*arm_pm_restart)(char str, const char *cmd);
diff --git a/arch/arm/kernel/sleep.S b/arch/arm/kernel/sleep.S
index b924bcc32dcd..e0626779fe92 100644
--- a/arch/arm/kernel/sleep.S
+++ b/arch/arm/kernel/sleep.S
@@ -11,13 +11,11 @@
  * Save CPU state for a suspend
  *  r1 = v:p offset
  *  r2 = suspend function arg0
- *  r3 = virtual return function
- * Note: sp is decremented to allocate space for CPU state on stack
- * r0-r3,ip,lr corrupted
+ *  r3 = suspend function
+ * Note: does not return until system resumes
  */
 ENTRY(cpu_suspend)
-        stmfd   sp!, {r3}
-        stmfd   sp!, {r4 - r11}
+        stmfd   sp!, {r4 - r11, lr}
 #ifdef MULTI_CPU
         ldr     r10, =processor
         ldr     r5, [r10, #CPU_SLEEP_SIZE] @ size of CPU sleep state
@@ -33,7 +31,7 @@ ENTRY(cpu_suspend)
         stmfd   sp!, {r1, r6, ip}       @ save v:p, virt SP, phys resume fn
         ldr     r5, =sleep_save_sp
         add     r6, sp, r1              @ convert SP to phys
-        stmfd   sp!, {r2, lr}           @ save suspend func arg and pointer
+        stmfd   sp!, {r2, r3}           @ save suspend func arg and pointer
 #ifdef CONFIG_SMP
         ALT_SMP(mrc p15, 0, lr, c0, c0, 5)
         ALT_UP(mov lr, #0)
diff --git a/arch/arm/mach-exynos4/sleep.S b/arch/arm/mach-exynos4/sleep.S
index 6b62425417a6..d9a2287b4641 100644
--- a/arch/arm/mach-exynos4/sleep.S
+++ b/arch/arm/mach-exynos4/sleep.S
@@ -42,16 +42,15 @@
 ENTRY(s3c_cpu_save)
 
         stmfd   sp!, { r3 - r12, lr }
-        ldr     r3, =resume_with_mmu
+        adr     r3, BSYM(exynos4_finish_suspend)
         bl      cpu_suspend
+        ldmfd   sp!, { r3 - r12, pc }
 
+exynos4_finish_suspend:
         ldr     r0, =pm_cpu_sleep
         ldr     r0, [ r0 ]
         mov     pc, r0
 
-resume_with_mmu:
-        ldmfd   sp!, { r3 - r12, pc }
-
         .ltorg
 
         /*
diff --git a/arch/arm/mach-pxa/sleep.S b/arch/arm/mach-pxa/sleep.S
index 613ddfa2c295..3a67887e6dbd 100644
--- a/arch/arm/mach-pxa/sleep.S
+++ b/arch/arm/mach-pxa/sleep.S
@@ -35,9 +35,11 @@ ENTRY(pxa3xx_cpu_suspend)
 #endif
         stmfd   sp!, {r2 - r12, lr}     @ save registers on stack
         mov     r1, r0
-        ldr     r3, =pxa_cpu_resume     @ resume function
+        adr     r3, BSYM(pxa3xx_finish_suspend)
         bl      cpu_suspend
+        b       pxa_cpu_resume
 
+pxa3xx_finish_suspend:
         mov     r0, #0x06               @ S2D3C4 mode
         mcr     p14, 0, r0, c7, c0, 0   @ enter sleep
 
@@ -60,9 +62,11 @@ ENTRY(pxa27x_cpu_suspend)
 #endif
         stmfd   sp!, {r2 - r12, lr}             @ save registers on stack
         mov     r2, r0                          @ save sleep mode
-        ldr     r3, =pxa_cpu_resume             @ resume function
+        adr     r3, BSYM(pxa27x_finish_suspend)
         bl      cpu_suspend
+        b       pxa_cpu_resume
 
+pxa27x_finish_suspend:
         @ Put the processor to sleep
         @ (also workaround for sighting 28071)
 
@@ -110,8 +114,11 @@ ENTRY(pxa27x_cpu_suspend)
 ENTRY(pxa25x_cpu_suspend)
         stmfd   sp!, {r2 - r12, lr}             @ save registers on stack
         mov     r2, r0                          @ save sleep mode
-        ldr     r3, =pxa_cpu_resume             @ resume function
+        adr     r3, BSYM(pxa25x_finish_suspend)
         bl      cpu_suspend
+        b       pxa_cpu_resume
+
+pxa25x_finish_suspend:
         @ prepare value for sleep mode
         mov     r1, r0                          @ sleep mode
 
diff --git a/arch/arm/mach-s3c64xx/sleep.S b/arch/arm/mach-s3c64xx/sleep.S
index 1f87732b2320..dc4f58202101 100644
--- a/arch/arm/mach-s3c64xx/sleep.S
+++ b/arch/arm/mach-s3c64xx/sleep.S
@@ -36,18 +36,15 @@
 
 ENTRY(s3c_cpu_save)
         stmfd   sp!, { r4 - r12, lr }
-        ldr     r3, =resume_with_mmu
+        adr     r3, BSYM(s3c64xx_finish_suspend)
         bl      cpu_suspend
+        ldmfd   sp!, { r4 - r12, pc }
 
+s3c64xx_finish_suspend:
         @@ call final suspend code
         ldr     r0, =pm_cpu_sleep
         ldr     pc, [r0]
         
-        @@ return to the caller, after the MMU is turned on.
-        @@ restore the last bits of the stack and return.
-resume_with_mmu:
-        ldmfd   sp!, { r4 - r12, pc }   @ return, from sp from s3c_cpu_save
-
         /* Sleep magic, the word before the resume entry point so that the
          * bootloader can check for a resumeable image. */
 
diff --git a/arch/arm/mach-s5pv210/sleep.S b/arch/arm/mach-s5pv210/sleep.S
index a3d649466fb1..1182fc848a79 100644
--- a/arch/arm/mach-s5pv210/sleep.S
+++ b/arch/arm/mach-s5pv210/sleep.S
@@ -41,16 +41,15 @@
 ENTRY(s3c_cpu_save)
 
         stmfd   sp!, { r3 - r12, lr }
-        ldr     r3, =resume_with_mmu
+        adr     r3, BSYM(s5pv210_finish_suspend)
         bl      cpu_suspend
+        ldmfd   sp!, { r3 - r12, pc }
 
+s5pv210_finish_suspend:
         ldr     r0, =pm_cpu_sleep
         ldr     r0, [ r0 ]
         mov     pc, r0
 
-resume_with_mmu:
-        ldmfd   sp!, { r3 - r12, pc }
-
         .ltorg
 
         /* sleep magic, to allow the bootloader to check for an valid
diff --git a/arch/arm/mach-sa1100/sleep.S b/arch/arm/mach-sa1100/sleep.S
index 122ab3c66923..f3fe39773f8b 100644
--- a/arch/arm/mach-sa1100/sleep.S
+++ b/arch/arm/mach-sa1100/sleep.S
@@ -31,9 +31,11 @@
 ENTRY(sa1100_cpu_suspend)
         stmfd   sp!, {r4 - r12, lr}             @ save registers on stack
         mov     r1, r0
-        ldr     r3, =sa1100_cpu_resume          @ return function
+        adr     r3, BSYM(sa1100_finish_suspend)
         bl      cpu_suspend
+        ldmfd   sp!, {r4 - r12, pc}             @ return to caller
 
+sa1100_finish_suspend:
         @ disable clock switching
         mcr     p15, 0, r1, c15, c2, 2
 
@@ -139,12 +141,3 @@ sa1110_sdram_controller_fix:
         str     r13, [r12]
 
 20:     b       20b                     @ loop waiting for sleep
-
-/*
- * cpu_sa1100_resume()
- *
- * entry point from bootloader into kernel during resume
- */
-        .align 5
-sa1100_cpu_resume:
-        ldmfd   sp!, {r4 - r12, pc}             @ return to caller
diff --git a/arch/arm/plat-s3c24xx/sleep.S b/arch/arm/plat-s3c24xx/sleep.S
index fd7032f84ae7..f822e6282dd4 100644
--- a/arch/arm/plat-s3c24xx/sleep.S
+++ b/arch/arm/plat-s3c24xx/sleep.S
@@ -49,21 +49,17 @@
 
 ENTRY(s3c_cpu_save)
         stmfd   sp!, { r4 - r12, lr }
-        ldr     r3, =resume_with_mmu
+        adr     r3, BSYM(s3c24xx_finish_suspend)
         bl      cpu_suspend
+        ldmfd   sp!, { r4 - r12, pc }
 
+s3c24xx_finish_suspend:
         @@ jump to final code to send system to sleep
         ldr     r0, =pm_cpu_sleep
         @@ldr   pc, [ r0 ]
         ldr     r0, [ r0 ]
         mov     pc, r0
         
-        @@ return to the caller, after having the MMU
-        @@ turned on, this restores the last bits from the
-        @@ stack
-resume_with_mmu:
-        ldmfd   sp!, { r4 - r12, pc }
-
         .ltorg
 
         /* sleep magic, to allow the bootloader to check for an valid