From 7764a8481c411c2bf06d9588a6f782e899e3d75b Mon Sep 17 00:00:00 2001
From: Simon Glass <sjg@chromium.org>
Date: Tue, 22 Sep 2020 12:45:12 -0600
Subject: [PATCH] x86: acpi: Add PCT and PTC tables

These are needed for the CPU tables. Add them into an x86-specific file
since we do not support them on sandbox, or include tests.

Signed-off-by: Simon Glass <sjg@chromium.org>
---
 arch/x86/include/asm/acpigen.h | 35 +++++++++++++
 arch/x86/lib/Makefile          |  2 +-
 arch/x86/lib/acpigen.c         | 96 ++++++++++++++++++++++++++++++++++
 3 files changed, 132 insertions(+), 1 deletion(-)
 create mode 100644 arch/x86/include/asm/acpigen.h
 create mode 100644 arch/x86/lib/acpigen.c

diff --git a/arch/x86/include/asm/acpigen.h b/arch/x86/include/asm/acpigen.h
new file mode 100644
index 0000000000..c531dd61d5
--- /dev/null
+++ b/arch/x86/include/asm/acpigen.h
@@ -0,0 +1,35 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Generation of x86-specific ACPI tables
+ *
+ * Copyright 2020 Google LLC
+ */
+
+#ifndef __ASM_ACPIGEN_H__
+#define __ASM_ACPIGEN_H__
+
+struct acpi_ctx;
+
+/**
+ * acpigen_write_empty_pct() - Write an empty PCT
+ *
+ * See ACPI v6.3 section 8.4.6.1: _PCT (Performance Control)
+ *
+ * This writes an empty table so that CPU performance works as expected
+ *
+ * @ctx: ACPI context pointer
+ */
+void acpigen_write_empty_pct(struct acpi_ctx *ctx);
+
+/**
+ * acpigen_write_empty_ptc() - Write an empty PTC
+ *
+ * See ACPI v6.3 section 8.4.5.1: _PTC (Processor Throttling Control)
+ *
+ * This writes an empty table so that CPU performance works as expected
+ *
+ * @ctx: ACPI context pointer
+ */
+void acpigen_write_empty_ptc(struct acpi_ctx *ctx);
+
+#endif /* __ASM_ACPI_H__ */
diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
index 1185a88c27..f04d275dd9 100644
--- a/arch/x86/lib/Makefile
+++ b/arch/x86/lib/Makefile
@@ -38,7 +38,7 @@ obj-y += sfi.o
 obj-y	+= acpi.o
 obj-$(CONFIG_HAVE_ACPI_RESUME) += acpi_s3.o
 ifndef CONFIG_QEMU
-obj-$(CONFIG_GENERATE_ACPI_TABLE) += acpi_table.o
+obj-$(CONFIG_GENERATE_ACPI_TABLE) += acpi_table.o acpigen.o
 endif
 obj-y	+= tables.o
 ifndef CONFIG_SPL_BUILD
diff --git a/arch/x86/lib/acpigen.c b/arch/x86/lib/acpigen.c
new file mode 100644
index 0000000000..ea2ec2a908
--- /dev/null
+++ b/arch/x86/lib/acpigen.c
@@ -0,0 +1,96 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2020 Google LLC
+ */
+
+#include <common.h>
+#include <acpi/acpigen.h>
+#include <acpi/acpi_table.h>
+#include <asm/acpigen.h>
+
+void acpigen_write_empty_pct(struct acpi_ctx *ctx)
+{
+	/*
+	 * Name (_PCT, Package (0x02)
+	 * {
+	 *	ResourceTemplate ()
+	 *	{
+	 *		Register (FFixedHW,
+	 *			0x00,               // Bit Width
+	 *			0x00,               // Bit Offset
+	 *			0x0000000000000000, // Address
+	 *			,)
+	 *	},
+	 *
+	 *	ResourceTemplate ()
+	 *	{
+	 *		Register (FFixedHW,
+	 *			0x00,               // Bit Width
+	 *			0x00,               // Bit Offset
+	 *			0x0000000000000000, // Address
+	 *			,)
+	 *	}
+	 * })
+	 */
+	static char stream[] = {
+		/* 00000030    "0._PCT.," */
+		0x08, 0x5f, 0x50, 0x43, 0x54, 0x12, 0x2c,
+		/* 00000038    "........" */
+		0x02, 0x11, 0x14, 0x0a, 0x11, 0x82, 0x0c, 0x00,
+		/* 00000040    "........" */
+		0x7f, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+		/* 00000048    "....y..." */
+		0x00, 0x00, 0x00, 0x00, 0x79, 0x00, 0x11, 0x14,
+		/* 00000050    "........" */
+		0x0a, 0x11, 0x82, 0x0c, 0x00, 0x7f, 0x00, 0x00,
+		/* 00000058    "........" */
+		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+		0x00, 0x79, 0x00
+	};
+	acpigen_emit_stream(ctx, stream, ARRAY_SIZE(stream));
+}
+
+void acpigen_write_empty_ptc(struct acpi_ctx *ctx)
+{
+	/*
+	 * Name (_PTC, Package (0x02)
+	 * {
+	 *	ResourceTemplate ()
+	 *	{
+	 *		Register (FFixedHW,
+	 *			0x00,               // Bit Width
+	 *			0x00,               // Bit Offset
+	 *			0x0000000000000000, // Address
+	 *			,)
+	 *	},
+	 *
+	 *	ResourceTemplate ()
+	 *	{
+	 *		Register (FFixedHW,
+	 *			0x00,               // Bit Width
+	 *			0x00,               // Bit Offset
+	 *			0x0000000000000000, // Address
+	 *			,)
+	 *	}
+	 * })
+	 */
+	struct acpi_gen_regaddr addr = {
+		.space_id    = ACPI_ADDRESS_SPACE_FIXED,
+		.bit_width   = 0,
+		.bit_offset  = 0,
+		.access_size = 0,
+		.addrl       = 0,
+		.addrh       = 0,
+	};
+
+	acpigen_write_name(ctx, "_PTC");
+	acpigen_write_package(ctx, 2);
+
+	/* ControlRegister */
+	acpigen_write_register_resource(ctx, &addr);
+
+	/* StatusRegister */
+	acpigen_write_register_resource(ctx, &addr);
+
+	acpigen_pop_len(ctx);
+}
-- 
2.39.5