[tip: x86/misc] x86/amd_node: Add a smn_read_register() helper

[tip-bot2 for Mario Limonciello]

The following commit has been merged into the x86/misc branch of tip:

Commit-ID:     c893ee3f95f16fcb98da934d61483d0b7d8ed568
Gitweb:        https://git.kernel.org/tip/c893ee3f95f16fcb98da934d61483d0b7d8ed568
Author:        Mario Limonciello <mario.limonciello@xxxxxxx>
AuthorDate:    Mon, 17 Feb 2025 17:17:41 -06:00
Committer:     Borislav Petkov (AMD) <bp@xxxxxxxxx>
CommitterDate: Tue, 18 Feb 2025 18:14:29 +01:00

x86/amd_node: Add a smn_read_register() helper

Some of the ACP drivers will poll registers through SMN using
read_poll_timeout() which requires returning the result of the register read
as the argument.

Add a helper to do just that.

Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Link: https://lore.kernel.org/r/20250217231747.1656228-2-superm1@xxxxxxxxxx
---
 arch/x86/include/asm/amd_node.h | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/arch/x86/include/asm/amd_node.h b/arch/x86/include/asm/amd_node.h
index 002c3af..23fe617 100644
--- a/arch/x86/include/asm/amd_node.h
+++ b/arch/x86/include/asm/amd_node.h
@@ -46,4 +46,15 @@ static inline int __must_check amd_smn_hsmp_rdwr(u16 node, u32 address, u32 *val
 }
 #endif /* CONFIG_AMD_NODE */
 
+/* helper for use with read_poll_timeout */
+static inline int smn_read_register(u32 reg)
+{
+	int data, rc;
+
+	rc = amd_smn_read(0, reg, &data);
+	if (rc)
+		return rc;
+
+	return data;
+}
 #endif /*_ASM_X86_AMD_NODE_H_*/