IPS driver: verify BIOS provided limits

They're optional.  If not present or sane, we should use the CPU
defaults.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Matthew Garrett <mjg@redhat.com>

1 files changed, 23 insertions, 0 deletions

diff --git a/drivers/platform/x86/intel_ips.c b/drivers/platform/x86/intel_ips.c
index 71d04ef47b8c..c402cc417108 100644
--- a/drivers/platform/x86/intel_ips.c
+++ b/drivers/platform/x86/intel_ips.c
@@ -665,6 +665,27 @@ static bool mch_exceeded(struct ips_driver *ips)
 }
 
 /**
+ * verify_limits - verify BIOS provided limits
+ * @ips: IPS structure
+ *
+ * BIOS can optionally provide non-default limits for power and temp.  Check
+ * them here and use the defaults if the BIOS values are not provided or
+ * are otherwise unusable.
+ */
+static void verify_limits(struct ips_driver *ips)
+{
+        if (ips->mcp_power_limit < ips->limits->mcp_power_limit ||
+            ips->mcp_power_limit > 35000)
+                ips->mcp_power_limit = ips->limits->mcp_power_limit;
+
+        if (ips->mcp_temp_limit < ips->limits->core_temp_limit ||
+            ips->mcp_temp_limit < ips->limits->mch_temp_limit ||
+            ips->mcp_temp_limit > 150)
+                ips->mcp_temp_limit = min(ips->limits->core_temp_limit,
+                                          ips->limits->mch_temp_limit);
+}
+
+/**
  * update_turbo_limits - get various limits & settings from regs
  * @ips: IPS driver struct
  *
@@ -688,6 +709,7 @@ static void update_turbo_limits(struct ips_driver *ips)
         ips->mcp_temp_limit = thm_readw(THM_PTL);
         ips->mcp_power_limit = thm_readw(THM_MPPC);
 
+        verify_limits(ips);
         /* Ignore BIOS CPU vs GPU pref */
 }
 
@@ -1156,6 +1178,7 @@ static irqreturn_t ips_irq_handler(int irq, void *arg)
                                 STS_PTL_SHIFT;
                         ips->mcp_power_limit = (tc1 & STS_PPL_MASK) >>
                                 STS_PPL_SHIFT;
+                        verify_limits(ips);
                         spin_unlock(&ips->turbo_status_lock);
 
                         thm_writeb(THM_SEC, SEC_ACK);