LoongArch: Add hibernation (ACPI S4) support

Add hibernation (Suspend to Disk, aka ACPI S4) support for LoongArch.

Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

1 files changed, 62 insertions, 0 deletions

diff --git a/arch/loongarch/power/hibernate.c b/arch/loongarch/power/hibernate.c
new file mode 100644
index 000000000000..1e0590542f98
--- /dev/null
+++ b/arch/loongarch/power/hibernate.c
@@ -0,0 +1,62 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <asm/fpu.h>
+#include <asm/loongson.h>
+#include <asm/sections.h>
+#include <asm/tlbflush.h>
+#include <linux/suspend.h>
+
+static u32 saved_crmd;
+static u32 saved_prmd;
+static u32 saved_euen;
+static u32 saved_ecfg;
+static u64 saved_pcpu_base;
+struct pt_regs saved_regs;
+
+void save_processor_state(void)
+{
+	saved_crmd = csr_read32(LOONGARCH_CSR_CRMD);
+	saved_prmd = csr_read32(LOONGARCH_CSR_PRMD);
+	saved_euen = csr_read32(LOONGARCH_CSR_EUEN);
+	saved_ecfg = csr_read32(LOONGARCH_CSR_ECFG);
+	saved_pcpu_base = csr_read64(PERCPU_BASE_KS);
+
+	if (is_fpu_owner())
+		save_fp(current);
+}
+
+void restore_processor_state(void)
+{
+	csr_write32(saved_crmd, LOONGARCH_CSR_CRMD);
+	csr_write32(saved_prmd, LOONGARCH_CSR_PRMD);
+	csr_write32(saved_euen, LOONGARCH_CSR_EUEN);
+	csr_write32(saved_ecfg, LOONGARCH_CSR_ECFG);
+	csr_write64(saved_pcpu_base, PERCPU_BASE_KS);
+
+	if (is_fpu_owner())
+		restore_fp(current);
+}
+
+int pfn_is_nosave(unsigned long pfn)
+{
+	unsigned long nosave_begin_pfn = PFN_DOWN(__pa(&__nosave_begin));
+	unsigned long nosave_end_pfn = PFN_UP(__pa(&__nosave_end));
+
+	return	(pfn >= nosave_begin_pfn) && (pfn < nosave_end_pfn);
+}
+
+extern int swsusp_asm_suspend(void);
+
+int swsusp_arch_suspend(void)
+{
+	enable_pci_wakeup();
+	return swsusp_asm_suspend();
+}
+
+extern int swsusp_asm_resume(void);
+
+int swsusp_arch_resume(void)
+{
+	/* Avoid TLB mismatch during and after kernel resume */
+	local_flush_tlb_all();
+	return swsusp_asm_resume();
+}