sh: hibernation support

Add Suspend-to-disk / swsusp / CONFIG_HIBERNATION support
to the SuperH architecture.

To suspend, use "swapon /dev/sda2; echo disk > /sys/power/state"
To resume, pass "resume=/dev/sda2" on the kernel command line.

The patch "pm: rework includes, remove arch ifdefs V2" is
needed to allow the generic swsusp code to build properly.

Hibernation is not enabled with this patch though, a patch
setting ARCH_HIBERNATION_POSSIBLE will be submitted later.

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/include/asm/sections.h

@@ -3,6 +3,7 @@
 
 #include <asm-generic/sections.h>
 
+extern void __nosave_begin, __nosave_end;
 extern long __machvec_start, __machvec_end;
 extern char __uncached_start, __uncached_end;
 extern char _ebss[];

arch/sh/include/asm/suspend.h

@@ -0,0 +1,13 @@
+#ifndef _ASM_SH_SUSPEND_H
+#define _ASM_SH_SUSPEND_H
+
+static inline int arch_prepare_suspend(void) { return 0; }
+
+#include <asm/ptrace.h>
+
+struct swsusp_arch_regs {
+	struct pt_regs user_regs;
+	unsigned long bank1_regs[8];
+};
+
+#endif /* _ASM_SH_SUSPEND_H */

arch/sh/kernel/Makefile_32

@@ -30,5 +30,6 @@ obj-$(CONFIG_KPROBES)		+= kprobes.o
 obj-$(CONFIG_GENERIC_GPIO)	+= gpio.o
 obj-$(CONFIG_DYNAMIC_FTRACE)	+= ftrace.o
 obj-$(CONFIG_DUMP_CODE)		+= disassemble.o
+obj-$(CONFIG_HIBERNATION)	+= swsusp.o
 
 EXTRA_CFLAGS += -Werror

arch/sh/kernel/asm-offsets.c

@@ -12,8 +12,10 @@
 #include <linux/types.h>
 #include <linux/mm.h>
 #include <linux/kbuild.h>
+#include <linux/suspend.h>
 
 #include <asm/thread_info.h>
+#include <asm/suspend.h>
 
 int main(void)
 {
@@ -25,5 +27,11 @@ int main(void)
 	DEFINE(TI_PRE_COUNT,	offsetof(struct thread_info, preempt_count));
 	DEFINE(TI_RESTART_BLOCK,offsetof(struct thread_info, restart_block));
 
+#ifdef CONFIG_HIBERNATION
+	DEFINE(PBE_ADDRESS, offsetof(struct pbe, address));
+	DEFINE(PBE_ORIG_ADDRESS, offsetof(struct pbe, orig_address));
+	DEFINE(PBE_NEXT, offsetof(struct pbe, next));
+	DEFINE(SWSUSP_ARCH_REGS_SIZE, sizeof(struct swsusp_arch_regs));
+#endif
 	return 0;
 }

arch/sh/kernel/cpu/sh3/Makefile

@@ -4,6 +4,8 @@
 
 obj-y	:= ex.o probe.o entry.o setup-sh3.o
 
+obj-$(CONFIG_HIBERNATION)		+= swsusp.o
+
 # CPU subtype setup
 obj-$(CONFIG_CPU_SUBTYPE_SH7705)	+= setup-sh7705.o
 obj-$(CONFIG_CPU_SUBTYPE_SH7706)	+= setup-sh770x.o

arch/sh/kernel/cpu/sh3/entry.S

@@ -216,7 +216,7 @@ ENTRY(sh_bios_handler)
 ! r9 trashed
 ! BL=0 on entry, on exit BL=1 (depending on r8).
 
-restore_regs:
+ENTRY(restore_regs)
 	mov.l	@r15+, r0
 	mov.l	@r15+, r1
 	mov.l	@r15+, r2
@@ -362,8 +362,10 @@ general_exception:
 	 nop
 
 	! Save registers / Switch to bank 0
+	mov.l	k4, k2		! keep vector in k2
+	mov.l	1f, k4		! SR bits to clear in k4
 	bsr	save_regs	! needs original pr value in k3
-	 mov	k4, k2		! keep vector in k2
+	 nop
 
 	bra	handle_exception_special
 	 nop
@@ -471,6 +473,7 @@ handle_exception:
 
 	! Save registers / Switch to bank 0
 	mov.l	5f, k2		! vector register address
+	mov.l	1f, k4		! SR bits to clear in k4
 	bsr	save_regs	! needs original pr value in k3
 	 mov.l	@k2, k2		! read out vector and keep in k2
 
@@ -495,10 +498,10 @@ handle_exception_special:
 ! k0 contains original stack pointer*
 ! k1 trashed
 ! k3 passes original pr*
-! k4 trashed
+! k4 passes SR bitmask
 ! BL=1 on entry, on exit BL=0.
 
-save_regs:
+ENTRY(save_regs)
 	mov	#-1, r1
 	mov.l	k1, @-r15	! set TRA (default: -1)
 	sts.l	macl, @-r15
@@ -518,8 +521,16 @@ save_regs:
 	mov.l	r8, @-r15
 
 	mov.l	0f, k3		! SR bits to set in k3
-	mov.l	1f, k4		! SR bits to clear in k4
 
+	! fall-through
+
+! save_low_regs()
+! - modify SR for bank switch
+! - save r7, r6, r5, r4, r3, r2, r1, r0 on the stack
+! k3 passes bits to set in SR
+! k4 passes bits to clear in SR
+
+ENTRY(save_low_regs)
 	stc	sr, r8
 	or	k3, r8
 	and	k4, r8
@@ -565,6 +576,7 @@ ENTRY(handle_interrupt)
 	 PREF(k0)
 
 	! Save registers / Switch to bank 0
+	mov.l	1f, k4		! SR bits to clear in k4
 	bsr	save_regs	! needs original pr value in k3
 	 mov	#-1, k2		! default vector kept in k2
 

arch/sh/kernel/cpu/sh3/swsusp.S

@@ -0,0 +1,147 @@
+/*
+ * arch/sh/kernel/cpu/sh3/swsusp.S
+ *
+ * Copyright (C) 2009 Magnus Damm
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+#include <linux/sys.h>
+#include <linux/errno.h>
+#include <linux/linkage.h>
+#include <asm/asm-offsets.h>
+#include <asm/page.h>
+
+#define k0	r0
+#define k1	r1
+#define k2	r2
+#define k3	r3
+#define k4	r4
+
+! swsusp_arch_resume()
+! - copy restore_pblist pages
+! - restore registers from swsusp_arch_regs_cpu0
+
+ENTRY(swsusp_arch_resume)
+	mov.l	1f, r15
+	mov.l	2f, r4
+	mov.l	@r4, r4
+
+swsusp_copy_loop:
+	mov	r4, r0
+	cmp/eq	#0, r0
+	bt	swsusp_restore_regs
+
+	mov.l	@(PBE_ADDRESS, r4), r2
+	mov.l	@(PBE_ORIG_ADDRESS, r4), r5
+
+	mov	#(PAGE_SIZE >> 10), r3
+	shll8	r3
+	shlr2	r3 /* PAGE_SIZE / 16 */
+swsusp_copy_page:
+	dt	r3
+	mov.l	@r2+,r1   /*  16n+0 */
+	mov.l	r1,@r5
+	add	#4,r5
+	mov.l	@r2+,r1	  /*  16n+4 */
+	mov.l	r1,@r5
+	add	#4,r5
+	mov.l	@r2+,r1   /*  16n+8 */
+	mov.l	r1,@r5
+	add	#4,r5
+	mov.l	@r2+,r1   /*  16n+12 */
+	mov.l	r1,@r5
+	bf/s	swsusp_copy_page
+	 add	#4,r5
+
+	bra	swsusp_copy_loop
+	 mov.l	@(PBE_NEXT, r4), r4
+
+swsusp_restore_regs:
+	! BL=0: R7->R0 is bank0
+	mov.l	3f, r8
+	mov.l	4f, r5
+	jsr	@r5
+	 nop
+
+	! BL=1: R7->R0 is bank1
+	lds	k2, pr
+	ldc	k3, ssr
+
+	mov.l	@r15+, r0
+	mov.l	@r15+, r1
+	mov.l	@r15+, r2
+	mov.l	@r15+, r3
+	mov.l	@r15+, r4
+	mov.l	@r15+, r5
+	mov.l	@r15+, r6
+	mov.l	@r15+, r7
+
+	rte
+	 nop
+	! BL=0: R7->R0 is bank0
+
+	.align	2
+1:	.long	swsusp_arch_regs_cpu0
+2:	.long	restore_pblist
+3:	.long	0x20000000 ! RB=1
+4:	.long	restore_regs
+
+! swsusp_arch_suspend()
+! - prepare pc for resume, return from function without swsusp_save on resume
+! - save registers in swsusp_arch_regs_cpu0
+! - call swsusp_save write suspend image
+
+ENTRY(swsusp_arch_suspend)
+	sts	pr, r0		! save pr in r0
+	mov	r15, r2		! save sp in r2
+	mov	r8, r5		! save r8 in r5
+	stc	sr, r1
+	ldc	r1, ssr		! save sr in ssr
+	mov.l	1f, r1
+	ldc	r1, spc		! setup pc value for resuming
+	mov.l	5f, r15		! use swsusp_arch_regs_cpu0 as stack
+	mov.l	6f, r3
+	add	r3, r15		! save from top of structure
+
+	! BL=0: R7->R0 is bank0
+	mov.l	2f, r3		! get new SR value for bank1
+	mov	#0, r4
+	mov.l	7f, r1
+	jsr	@r1		! switch to bank1 and save bank1 r7->r0
+	 not	r4, r4
+
+	! BL=1: R7->R0 is bank1
+	stc	r2_bank, k0	! fetch old sp from r2_bank0
+	mov.l	3f, k4		! SR bits to clear in k4
+	mov.l	8f, k1
+	jsr	@k1		! switch to bank0 and save all regs
+	 stc	r0_bank, k3	! fetch old pr from r0_bank0
+
+	! BL=0: R7->R0 is bank0
+	mov	r2, r15		! restore old sp
+	mov	r5, r8		! restore old r8
+	stc	ssr, r1
+	ldc	r1, sr		! restore old sr
+	lds	r0, pr		! restore old pr
+	mov.l	4f, r0
+	jmp	@r0
+	 nop
+
+swsusp_call_save:
+	mov	r2, r15		! restore old sp
+	mov	r5, r8		! restore old r8
+	lds	r0, pr		! restore old pr
+	rts
+	 mov	#0, r0
+
+	.align	2
+1:	.long	swsusp_call_save
+2:	.long	0x20000000 ! RB=1
+3:	.long	0xdfffffff ! RB=0
+4:	.long	swsusp_save
+5:	.long	swsusp_arch_regs_cpu0
+6:	.long	SWSUSP_ARCH_REGS_SIZE
+7:	.long	save_low_regs
+8:	.long	save_regs

arch/sh/kernel/cpu/sh4/Makefile

@@ -5,6 +5,7 @@
 obj-y	:= probe.o common.o
 common-y	+= $(addprefix ../sh3/, entry.o ex.o)
 
+obj-$(CONFIG_HIBERNATION)		+= $(addprefix ../sh3/, swsusp.o)
 obj-$(CONFIG_SH_FPU)			+= fpu.o softfloat.o
 obj-$(CONFIG_SH_STORE_QUEUES)		+= sq.o
 

arch/sh/kernel/swsusp.c

@@ -0,0 +1,38 @@
+/*
+ * swsusp.c - SuperH hibernation support
+ *
+ * Copyright (C) 2009 Magnus Damm
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/mm.h>
+#include <linux/sched.h>
+#include <linux/suspend.h>
+#include <asm/suspend.h>
+#include <asm/sections.h>
+#include <asm/tlbflush.h>
+#include <asm/page.h>
+#include <asm/fpu.h>
+
+struct swsusp_arch_regs swsusp_arch_regs_cpu0;
+
+int pfn_is_nosave(unsigned long pfn)
+{
+	unsigned long begin_pfn = __pa(&__nosave_begin) >> PAGE_SHIFT;
+	unsigned long end_pfn = PAGE_ALIGN(__pa(&__nosave_end)) >> PAGE_SHIFT;
+
+	return (pfn >= begin_pfn) && (pfn < end_pfn);
+}
+
+void save_processor_state(void)
+{
+	init_fpu(current);
+}
+
+void restore_processor_state(void)
+{
+	local_flush_tlb_all();
+}