[PATCH 1/2] thermal/intel/intel_tcc_cooling: Detect TCC lock bit

[Zhang Rui <rui.zhang@intel.com>]

When MSR_IA32_TEMPERATURE_TARGET is locked, TCC Offset can not be
updated even if the PROGRAMMABE Bit is set.

Yield the driver on platforms with MSR_IA32_TEMPERATURE_TARGET locked.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
---
Note that this patch is made based on this patch series
https://patchwork.kernel.org/project/linux-pm/list/?series=693050
---
 drivers/thermal/intel/intel_tcc_cooling.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/thermal/intel/intel_tcc_cooling.c b/drivers/thermal/intel/intel_tcc_cooling.c
index ccd62358d4d0..f17fa5c81034 100644
--- a/drivers/thermal/intel/intel_tcc_cooling.c
+++ b/drivers/thermal/intel/intel_tcc_cooling.c
@@ -13,6 +13,7 @@
 #include <asm/cpu_device_id.h>
 
 #define TCC_PROGRAMMABLE	BIT(30)
+#define TCC_LOCKED		BIT(31)
 
 static struct thermal_cooling_device *tcc_cdev;
 
@@ -80,6 +81,15 @@ static int __init tcc_cooling_init(void)
 	if (!(val & TCC_PROGRAMMABLE))
 		return -ENODEV;
 
+	err = rdmsrl_safe(MSR_IA32_TEMPERATURE_TARGET, &val);
+	if (err)
+		return err;
+
+	if (val & TCC_LOCKED) {
+		pr_info("TCC Offset locked\n");
+		return -ENODEV;
+	}
+
 	pr_info("Programmable TCC Offset detected\n");
 
 	tcc_cdev =
-- 
2.25.1