1 files changed, 74 insertions, 0 deletions
diff --git a/arch/mips/include/asm/mach-loongson64/cpucfg-emul.h b/arch/mips/include/asm/mach-loongson64/cpucfg-emul.h
new file mode 100644
index 000000000000..d64af19c210d
--- /dev/null
+++ b/arch/mips/include/asm/mach-loongson64/cpucfg-emul.h
@@ -0,0 +1,74 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_MACH_LOONGSON64_CPUCFG_EMUL_H_
+#define _ASM_MACH_LOONGSON64_CPUCFG_EMUL_H_
+
+#include <asm/cpu-info.h>
+
+#ifdef CONFIG_CPU_LOONGSON3_CPUCFG_EMULATION
+
+#include <loongson_regs.h>
+
+#define LOONGSON_FPREV_MASK 0x7
+
+void loongson3_cpucfg_synthesize_data(struct cpuinfo_mips *c);
+
+static inline bool loongson3_cpucfg_emulation_enabled(struct cpuinfo_mips *c)
+{
+	/* All supported cores have non-zero LOONGSON_CFG1 data. */
+	return c->loongson3_cpucfg_data[0] != 0;
+}
+
+static inline u32 loongson3_cpucfg_read_synthesized(struct cpuinfo_mips *c,
+	__u64 sel)
+{
+	switch (sel) {
+	case LOONGSON_CFG0:
+		return c->processor_id;
+	case LOONGSON_CFG1:
+	case LOONGSON_CFG2:
+	case LOONGSON_CFG3:
+		return c->loongson3_cpucfg_data[sel - 1];
+	case LOONGSON_CFG4:
+	case LOONGSON_CFG5:
+		/* CPUCFG selects 4 and 5 are related to the input clock
+		 * signal.
+		 *
+		 * Unimplemented for now.
+		 */
+		return 0;
+	case LOONGSON_CFG6:
+		/* CPUCFG select 6 is for the undocumented Safe Extension. */
+		return 0;
+	case LOONGSON_CFG7:
+		/* CPUCFG select 7 is for the virtualization extension.
+		 * We don't know if the two currently known features are
+		 * supported on older cores according to the public
+		 * documentation, so leave this at zero.
+		 */
+		return 0;
+	}
+
+	/*
+	 * Return 0 for unrecognized CPUCFG selects, which is real hardware
+	 * behavior observed on Loongson 3A R4.
+	 */
+	return 0;
+}
+#else
+static inline void loongson3_cpucfg_synthesize_data(struct cpuinfo_mips *c)
+{
+}
+
+static inline bool loongson3_cpucfg_emulation_enabled(struct cpuinfo_mips *c)
+{
+	return false;
+}
+
+static inline u32 loongson3_cpucfg_read_synthesized(struct cpuinfo_mips *c,
+	__u64 sel)
+{
+	return 0;
+}
+#endif
+
+#endif /* _ASM_MACH_LOONGSON64_CPUCFG_EMUL_H_ */