x86: Start moving AMD node functionality out of AMD_NB

The "AMD Node" concept spans many families of systems and applies to
a number of subsystems and drivers.

Currently, the AMD Northbridge code is overloaded with AMD node
functionality. However, the node concept is broader than just
northbridges.

Start files to host common AMD node functions and definitions.  Include
a helper to find an AMD node device function based on the convention
described in AMD documentation.

Anything that needs node functionality should include this rather than
amd_nb.h. The AMD_NB code will be reduced to only northbridge-specific
code needed for legacy systems.

Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20241206161210.163701-5-yazen.ghannam@amd.com

1 files changed, 27 insertions, 0 deletions

diff --git a/arch/x86/include/asm/amd_node.h b/arch/x86/include/asm/amd_node.h
new file mode 100644
index 000000000000..622bd3038eeb
--- /dev/null
+++ b/arch/x86/include/asm/amd_node.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * AMD Node helper functions and common defines
+ *
+ * Copyright (c) 2024, Advanced Micro Devices, Inc.
+ * All Rights Reserved.
+ *
+ * Author: Yazen Ghannam <Yazen.Ghannam@amd.com>
+ *
+ * Note:
+ * Items in this file may only be used in a single place.
+ * However, it's prudent to keep all AMD Node functionality
+ * in a unified place rather than spreading throughout the
+ * kernel.
+ */
+
+#ifndef _ASM_X86_AMD_NODE_H_
+#define _ASM_X86_AMD_NODE_H_
+
+#include <linux/pci.h>
+
+#define MAX_AMD_NUM_NODES	8
+#define AMD_NODE0_PCI_SLOT	0x18
+
+struct pci_dev *amd_node_get_func(u16 node, u8 func);
+
+#endif /*_ASM_X86_AMD_NODE_H_*/