ARM: pm: convert some assembly to C

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>

3 files changed, 46 insertions, 39 deletions

diff --git a/arch/arm/include/asm/proc-fns.h b/arch/arm/include/asm/proc-fns.h
index 633d1cb84d87..9e92cb205e65 100644
--- a/arch/arm/include/asm/proc-fns.h
+++ b/arch/arm/include/asm/proc-fns.h
@@ -81,6 +81,10 @@ extern void cpu_dcache_clean_area(void *, int);
 extern void cpu_do_switch_mm(unsigned long pgd_phys, struct mm_struct *mm);
 extern void cpu_set_pte_ext(pte_t *ptep, pte_t pte, unsigned int ext);
 extern void cpu_reset(unsigned long addr) __attribute__((noreturn));
+
+/* These three are private to arch/arm/kernel/suspend.c */
+extern void cpu_do_suspend(void *);
+extern void cpu_do_resume(void *);
 #else
 #define cpu_proc_init                   processor._proc_init
 #define cpu_proc_fin                    processor._proc_fin
@@ -89,6 +93,10 @@ extern void cpu_reset(unsigned long addr) __attribute__((noreturn));
 #define cpu_dcache_clean_area           processor.dcache_clean_area
 #define cpu_set_pte_ext                 processor.set_pte_ext
 #define cpu_do_switch_mm                processor.switch_mm
+
+/* These three are private to arch/arm/kernel/suspend.c */
+#define cpu_do_suspend                  processor.do_suspend
+#define cpu_do_resume                   processor.do_resume
 #endif
 
 extern void cpu_resume(void);
diff --git a/arch/arm/kernel/sleep.S b/arch/arm/kernel/sleep.S
index c9a43caaea80..020e99c845e7 100644
--- a/arch/arm/kernel/sleep.S
+++ b/arch/arm/kernel/sleep.S
@@ -8,54 +8,35 @@
         .text
 
 /*
- * Save CPU state for a suspend
- *  r0 = phys addr of temporary page tables
- *  r1 = v:p offset
- *  r2 = suspend function arg0
- *  r3 = suspend function
+ * Save CPU state for a suspend.  This saves the CPU general purpose
+ * registers, and allocates space on the kernel stack to save the CPU
+ * specific registers and some other data for resume.
+ *  r0 = suspend function arg0
+ *  r1 = suspend function
  */
 ENTRY(__cpu_suspend)
         stmfd   sp!, {r4 - r11, lr}
-        mov     r4, r0
 #ifdef MULTI_CPU
         ldr     r10, =processor
-        ldr     r5, [r10, #CPU_SLEEP_SIZE] @ size of CPU sleep state
-        ldr     ip, [r10, #CPU_DO_RESUME] @ virtual resume function
+        ldr     r4, [r10, #CPU_SLEEP_SIZE] @ size of CPU sleep state
 #else
-        ldr     r5, =cpu_suspend_size
-        ldr     ip, =cpu_do_resume
+        ldr     r4, =cpu_suspend_size
 #endif
-        mov     r6, sp                  @ current virtual SP
-        sub     sp, sp, r5              @ allocate CPU state on stack
-        mov     r0, sp                  @ save pointer to CPU save block
-        add     ip, ip, r1              @ convert resume fn to phys
-        stmfd   sp!, {r4, r6, ip}       @ save phys pgd, virt SP, phys resume fn
-        ldr     r5, =sleep_save_sp
-        add     r6, sp, r1              @ convert SP to phys
-        stmfd   sp!, {r2, r3}           @ save suspend func arg and pointer
+        mov     r5, sp                  @ current virtual SP
+        add     r4, r4, #12             @ Space for pgd, virt sp, phys resume fn
+        sub     sp, sp, r4              @ allocate CPU state on stack
+        stmfd   sp!, {r0, r1}           @ save suspend func arg and pointer
+        add     r0, sp, #8              @ save pointer to save block
+        mov     r1, r4                  @ size of save block
+        mov     r2, r5                  @ virtual SP
+        ldr     r3, =sleep_save_sp
 #ifdef CONFIG_SMP
         ALT_SMP(mrc p15, 0, lr, c0, c0, 5)
         ALT_UP(mov lr, #0)
         and     lr, lr, #15
-        str     r6, [r5, lr, lsl #2]    @ save phys SP
-#else
-        str     r6, [r5]                @ save phys SP
-#endif
-#ifdef MULTI_CPU
-        mov     lr, pc
-        ldr     pc, [r10, #CPU_DO_SUSPEND] @ save CPU state
-#else
-        bl      cpu_do_suspend
-#endif
-
-        @ flush data cache
-#ifdef MULTI_CACHE
-        ldr     r10, =cpu_cache
-        mov     lr, pc
-        ldr     pc, [r10, #CACHE_FLUSH_KERN_ALL]
-#else
-        bl      __cpuc_flush_kern_all
+        add     r3, r3, lr, lsl #2
 #endif
+        bl      __cpu_suspend_save
         adr     lr, BSYM(cpu_suspend_abort)
         ldmfd   sp!, {r0, pc}           @ call suspend fn
 ENDPROC(__cpu_suspend)
diff --git a/arch/arm/kernel/suspend.c b/arch/arm/kernel/suspend.c
index ed4160b64e66..2d60f1903206 100644
--- a/arch/arm/kernel/suspend.c
+++ b/arch/arm/kernel/suspend.c
@@ -8,10 +8,29 @@
 
 static pgd_t *suspend_pgd;
 
-extern int __cpu_suspend(int, long, unsigned long, int (*)(unsigned long));
+extern int __cpu_suspend(unsigned long, int (*)(unsigned long));
 extern void cpu_resume_mmu(void);
 
 /*
+ * This is called by __cpu_suspend() to save the state, and do whatever
+ * flushing is required to ensure that when the CPU goes to sleep we have
+ * the necessary data available when the caches are not searched.
+ */
+void __cpu_suspend_save(u32 *ptr, u32 ptrsz, u32 sp, u32 *save_ptr)
+{
+        *save_ptr = virt_to_phys(ptr);
+
+        /* This must correspond to the LDM in cpu_resume() assembly */
+        *ptr++ = virt_to_phys(suspend_pgd);
+        *ptr++ = sp;
+        *ptr++ = virt_to_phys(cpu_do_resume);
+
+        cpu_do_suspend(ptr);
+
+        flush_cache_all();
+}
+
+/*
  * Hide the first two arguments to __cpu_suspend - these are an implementation
  * detail which platform code shouldn't have to know about.
  */
@@ -29,8 +48,7 @@ int cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
          * resume (indicated by a zero return code), we need to switch
          * back to the correct page tables.
          */
-        ret = __cpu_suspend(virt_to_phys(suspend_pgd),
-                            PHYS_OFFSET - PAGE_OFFSET, arg, fn);
+        ret = __cpu_suspend(arg, fn);
         if (ret == 0) {
                 cpu_switch_mm(mm->pgd, mm);
                 local_flush_tlb_all();