platform/x86/amd/pmc: Use FCH_PM_BASE definition

The s2idle MMIO quirk uses a scratch register in the FCH.
Adjust the code to clarify that.

Signed-off-by: Mario Limonciello <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Hans de Goede <[email protected]>
Cc: Ilpo Järvinen <[email protected]>
Cc: Shyam Sundar S K <[email protected]>
Cc: Yazen Ghannam <[email protected]>
Cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]

Author: superm1

arch/x86/include/asm/amd/fch.h

@@ -7,5 +7,6 @@
 /* Register offsets from PM base: */
 #define FCH_PM_DECODEEN			0x00
 #define FCH_PM_DECODEEN_SMBUS0SEL	GENMASK(20, 19)
+#define FCH_PM_SCRATCH			0x80
 
 #endif /* _ASM_X86_AMD_FCH_H_ */

drivers/platform/x86/amd/pmc/pmc-quirks.c

@@ -11,6 +11,7 @@
 #include <linux/dmi.h>
 #include <linux/io.h>
 #include <linux/ioport.h>
+#include <asm/amd/fch.h>
 
 #include "pmc.h"
 
@@ -20,7 +21,7 @@ struct quirk_entry {
 };
 
 static struct quirk_entry quirk_s2idle_bug = {
-	.s2idle_bug_mmio = 0xfed80380,
+	.s2idle_bug_mmio = FCH_PM_BASE + FCH_PM_SCRATCH,
 };
 
 static struct quirk_entry quirk_spurious_8042 = {