[PATCH 6/7] ARM: pm: convert some assembly to C

Russell King - ARM Linux
2011-09-19T17:48:48Z

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>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---
arch/arm/include/asm/proc-fns.h | 8 ++++++
arch/arm/kernel/sleep.S | 53 ++++++++++++--------------------------
arch/arm/kernel/suspend.c | 24 +++++++++++++++--
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 633d1cb..9e92cb2 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 c9a43ca..020e99c 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 ed4160b..2d60f19 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();
--
1.7.4.4