LoongArch: Add suspend (ACPI S3) support

Add suspend (Suspend To RAM, aka ACPI S3) support for LoongArch.

Signed-off-by: Huacai Chen <[email protected]>

Author: chenhuacai

arch/loongarch/Kconfig

@@ -56,6 +56,7 @@ config LOONGARCH
 	select ARCH_WANTS_NO_INSTR
 	select BUILDTIME_TABLE_SORT
 	select COMMON_CLK
+	select CPU_PM
 	select EFI
 	select GENERIC_CLOCKEVENTS
 	select GENERIC_CMOS_UPDATE
@@ -517,6 +518,10 @@ config ARCH_MMAP_RND_BITS_MAX
 
 menu "Power management options"
 
+config ARCH_SUSPEND_POSSIBLE
+	def_bool y
+
+source "kernel/power/Kconfig"
 source "drivers/acpi/Kconfig"
 
 endmenu

arch/loongarch/Makefile

@@ -104,6 +104,9 @@ endif
 libs-y += arch/loongarch/lib/
 libs-$(CONFIG_EFI_STUB) += $(objtree)/drivers/firmware/efi/libstub/lib.a
 
+# suspend and hibernation support
+drivers-$(CONFIG_PM)	+= arch/loongarch/power/
+
 ifeq ($(KBUILD_EXTMOD),)
 prepare: vdso_prepare
 vdso_prepare: prepare0

arch/loongarch/include/asm/acpi.h

@@ -35,4 +35,14 @@ extern struct list_head acpi_wakeup_device_list;
 
 #define ACPI_TABLE_UPGRADE_MAX_PHYS ARCH_LOW_ADDRESS_LIMIT
 
+extern int loongarch_acpi_suspend(void);
+extern int (*acpi_suspend_lowlevel)(void);
+extern void loongarch_suspend_enter(void);
+
+static inline unsigned long acpi_get_wakeup_address(void)
+{
+	extern void loongarch_wakeup_start(void);
+	return (unsigned long)loongarch_wakeup_start;
+}
+
 #endif /* _ASM_LOONGARCH_ACPI_H */

arch/loongarch/include/asm/bootinfo.h

@@ -32,6 +32,7 @@ struct loongson_system_configuration {
 	int cores_per_node;
 	int cores_per_package;
 	unsigned long cores_io_master;
+	unsigned long suspend_addr;
 	const char *cpuname;
 };
 

arch/loongarch/include/asm/loongson.h

@@ -136,4 +136,7 @@ typedef enum {
 #define ls7a_writel(val, addr)	*(volatile unsigned int   *)TO_UNCACHE(addr) = (val)
 #define ls7a_writeq(val, addr)	*(volatile unsigned long  *)TO_UNCACHE(addr) = (val)
 
+void enable_gpe_wakeup(void);
+void enable_pci_wakeup(void);
+
 #endif /* __ASM_LOONGSON_H */

arch/loongarch/include/asm/time.h

@@ -12,6 +12,7 @@
 extern u64 cpu_clock_freq;
 extern u64 const_clock_freq;
 
+extern void save_counter(void);
 extern void sync_counter(void);
 
 static inline unsigned int calc_const_freq(void)

arch/loongarch/kernel/acpi.c

@@ -140,6 +140,12 @@ static void __init acpi_process_madt(void)
 	loongson_sysconf.nr_cpus = num_processors;
 }
 
+#ifndef CONFIG_SUSPEND
+int (*acpi_suspend_lowlevel)(void);
+#else
+int (*acpi_suspend_lowlevel)(void) = loongarch_acpi_suspend;
+#endif
+
 void __init acpi_boot_table_init(void)
 {
 	/*

arch/loongarch/kernel/smp.c

@@ -16,6 +16,7 @@
 #include <linux/smp.h>
 #include <linux/threads.h>
 #include <linux/export.h>
+#include <linux/syscore_ops.h>
 #include <linux/time.h>
 #include <linux/tracepoint.h>
 #include <linux/sched/hotplug.h>

arch/loongarch/kernel/time.c

@@ -115,12 +115,17 @@ static unsigned long __init get_loops_per_jiffy(void)
 	return lpj;
 }
 
-static long init_timeval;
+static long init_offset __nosavedata;
+
+void save_counter(void)
+{
+	init_offset = drdtime();
+}
 
 void sync_counter(void)
 {
 	/* Ensure counter begin at 0 */
-	csr_write64(-init_timeval, LOONGARCH_CSR_CNTC);
+	csr_write64(init_offset, LOONGARCH_CSR_CNTC);
 }
 
 static int get_timer_irq(void)
@@ -219,7 +224,7 @@ void __init time_init(void)
 	else
 		const_clock_freq = calc_const_freq();
 
-	init_timeval = drdtime() - csr_read64(LOONGARCH_CSR_CNTC);
+	init_offset = -(drdtime() - csr_read64(LOONGARCH_CSR_CNTC));
 
 	constant_clockevent_init();
 	constant_clocksource_init();

arch/loongarch/power/Makefile

@@ -0,0 +1,3 @@
+obj-y	+= platform.o
+
+obj-$(CONFIG_SUSPEND)		+= suspend.o suspend_asm.o