[PATCH v2 3/3] x86/acpi/cstate: add Zhaoxin processors support for cache flush policy in C3

From: Tony W Wang-oc
Date: Tue Jun 18 2019 - 04:42:33 EST


Same as Intel, Zhaoxin MP CPUs support C3 share cache and on all
recent Zhaoxin platforms ARB_DISABLE is a nop. So set related
flags correctly in the same way as Intel does.

Signed-off-by: Tony W Wang-oc <TonyWWang-oc@xxxxxxxxxxx>
---
arch/x86/kernel/acpi/cstate.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)

diff --git a/arch/x86/kernel/acpi/cstate.c b/arch/x86/kernel/acpi/cstate.c
index a5e5484..caf2edc 100644
--- a/arch/x86/kernel/acpi/cstate.c
+++ b/arch/x86/kernel/acpi/cstate.c
@@ -64,6 +64,21 @@ void acpi_processor_power_init_bm_check(struct acpi_processor_flags *flags,
c->x86_stepping >= 0x0e))
flags->bm_check = 1;
}
+
+ if (c->x86_vendor == X86_VENDOR_ZHAOXIN) {
+ /*
+ * All Zhaoxin CPUs that support C3 share cache.
+ * And caches should not be flushed by software while
+ * entering C3 type state.
+ */
+ flags->bm_check = 1;
+ /*
+ * On all recent Zhaoxin 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.
+ */
+ flags->bm_control = 0;
+ }
}
EXPORT_SYMBOL(acpi_processor_power_init_bm_check);

--
2.7.4