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>

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);

arch/arm/kernel/sleep.S

@@ -8,54 +8,35 @@
 	.text
 
 /*
- * Save CPU state for a suspend
+ * Save CPU state for a suspend.  This saves the CPU general purpose
- *  r0 = phys addr of temporary page tables
+ * registers, and allocates space on the kernel stack to save the CPU
- *  r1 = v:p offset
+ * specific registers and some other data for resume.
- *  r2 = suspend function arg0
+ *  r0 = suspend function arg0
- *  r3 = suspend function
+ *  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	r4, [r10, #CPU_SLEEP_SIZE] @ size of CPU sleep state
-	ldr	ip, [r10, #CPU_DO_RESUME] @ virtual resume function
 #else
-	ldr	r5, =cpu_suspend_size
+	ldr	r4, =cpu_suspend_size
-	ldr	ip, =cpu_do_resume
 #endif
-	mov	r6, sp			@ current virtual SP
+	mov	r5, sp			@ current virtual SP
-	sub	sp, sp, r5		@ allocate CPU state on stack
+	add	r4, r4, #12		@ Space for pgd, virt sp, phys resume fn
-	mov	r0, sp			@ save pointer to CPU save block
+	sub	sp, sp, r4		@ allocate CPU state on stack
-	add	ip, ip, r1		@ convert resume fn to phys
+	stmfd	sp!, {r0, r1}		@ save suspend func arg and pointer
-	stmfd	sp!, {r4, r6, ip}	@ save phys pgd, virt SP, phys resume fn
+	add	r0, sp, #8		@ save pointer to save block
-	ldr	r5, =sleep_save_sp
+	mov	r1, r4			@ size of save block
-	add	r6, sp, r1		@ convert SP to phys
+	mov	r2, r5			@ virtual SP
-	stmfd	sp!, {r2, r3}		@ save suspend func arg and pointer
+	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
+	add	r3, r3, lr, lsl #2
-#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
 #endif
+	bl	__cpu_suspend_save
 	adr	lr, BSYM(cpu_suspend_abort)
 	ldmfd	sp!, {r0, pc}		@ call suspend fn
 ENDPROC(__cpu_suspend)

arch/arm/kernel/suspend.c

@@ -8,9 +8,28 @@
 
 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),
+	ret = __cpu_suspend(arg, fn);
-			    PHYS_OFFSET - PAGE_OFFSET, arg, fn);
 	if (ret == 0) {
 		cpu_switch_mm(mm->pgd, mm);
 		local_flush_tlb_all();