[RFC PATCH 12/15] x86/acpi/cstate: Improve Intel family model checks

[Sohil Mehta <sohil.mehta@intel.com>]

Update the Intel family checks to consistently use Family 15 instead of
Family 0xF. Also, get rid of one of last usages of x86_model by using
the new VFM checks.

Update the incorrect comment since the check has changed since the
initial commit ee1ca48fae7e ("ACPI: Disable ARB_DISABLE on platforms
where it is not needed").

commit 3e2ada5867b7 ("ACPI: fix Compaq Evo N800c (Pentium 4m) boot hang
regression") removed the P4s and commit 03a05ed11529 ("ACPI: Use the
ARB_DISABLE for the CPU which model id is less than 0x0f.") got rid of
CORE_YONAH.

Signed-off-by: Sohil Mehta <sohil.mehta@intel.com>
---
 arch/x86/include/asm/intel-family.h | 3 +++
 arch/x86/kernel/acpi/cstate.c       | 8 ++++----
 2 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/intel-family.h b/arch/x86/include/asm/intel-family.h
index 76a184361930..73e458440fcb 100644
--- a/arch/x86/include/asm/intel-family.h
+++ b/arch/x86/include/asm/intel-family.h
@@ -179,6 +179,9 @@
 #define INTEL_XEON_PHI_KNL		IFM(6, 0x57) /* Knights Landing */
 #define INTEL_XEON_PHI_KNM		IFM(6, 0x85) /* Knights Mill */
 
+/* Notational marker denoting the last Family 6 model */
+#define INTEL_FAM6_LAST		        IFM(6, 0xFF)
+
 /* Family 5 */
 #define INTEL_FAM5_START		IFM(5, 0x00) /* Notational marker, also P5 A-step */
 #define INTEL_PENTIUM_75		IFM(5, 0x02) /* P54C - Need a better name */
diff --git a/arch/x86/kernel/acpi/cstate.c b/arch/x86/kernel/acpi/cstate.c
index f3ffd0a3a012..6d87d1ebe89b 100644
--- a/arch/x86/kernel/acpi/cstate.c
+++ b/arch/x86/kernel/acpi/cstate.c
@@ -13,6 +13,7 @@
 #include <linux/sched.h>
 
 #include <acpi/processor.h>
+#include <asm/cpu_device_id.h>
 #include <asm/mwait.h>
 #include <asm/special_insns.h>
 
@@ -46,12 +47,11 @@ void acpi_processor_power_init_bm_check(struct acpi_processor_flags *flags,
 	/*
 	 * On all recent Intel platforms, ARB_DISABLE is a nop.
 	 * So, set bm_control to zero to indicate that ARB_DISABLE
-	 * is not required while entering C3 type state on
-	 * P4, Core and beyond CPUs
+	 * is not required while entering C3 type state.
 	 */
 	if (c->x86_vendor == X86_VENDOR_INTEL &&
-	    (c->x86 > 0xf || (c->x86 == 6 && c->x86_model >= 0x0f)))
-			flags->bm_control = 0;
+	    (c->x86 > 15 || (c->x86_vfm >= INTEL_CORE2_MEROM && c->x86_vfm <= INTEL_FAM6_LAST)))
+		flags->bm_control = 0;
 
 	if (c->x86_vendor == X86_VENDOR_CENTAUR) {
 		if (c->x86 > 6 || (c->x86 == 6 && c->x86_model == 0x0f &&
-- 
2.43.0