1 files changed, 84 insertions, 25 deletions

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index d67974eb127a..ae2c0bb4b2e8 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -2964,24 +2964,10 @@ intel_enable_sagv(struct drm_i915_private *dev_priv)
         return 0;
 }
 
-static int
-intel_do_sagv_disable(struct drm_i915_private *dev_priv)
-{
-        int ret;
-        uint32_t temp = GEN9_SAGV_DISABLE;
-
-        ret = sandybridge_pcode_read(dev_priv, GEN9_PCODE_SAGV_CONTROL,
-                                     &temp);
-        if (ret)
-                return ret;
-        else
-                return temp & GEN9_SAGV_IS_DISABLED;
-}
-
 int
 intel_disable_sagv(struct drm_i915_private *dev_priv)
 {
-        int ret, result;
+        int ret;
 
         if (!intel_has_sagv(dev_priv))
                 return 0;
@@ -2993,25 +2979,23 @@ intel_disable_sagv(struct drm_i915_private *dev_priv)
         mutex_lock(&dev_priv->rps.hw_lock);
 
         /* bspec says to keep retrying for at least 1 ms */
-        ret = wait_for(result = intel_do_sagv_disable(dev_priv), 1);
+        ret = skl_pcode_request(dev_priv, GEN9_PCODE_SAGV_CONTROL,
+                                GEN9_SAGV_DISABLE,
+                                GEN9_SAGV_IS_DISABLED, GEN9_SAGV_IS_DISABLED,
+                                1);
         mutex_unlock(&dev_priv->rps.hw_lock);
 
-        if (ret == -ETIMEDOUT) {
-                DRM_ERROR("Request to disable SAGV timed out\n");
-                return -ETIMEDOUT;
-        }
-
         /*
          * Some skl systems, pre-release machines in particular,
          * don't actually have an SAGV.
          */
-        if (IS_SKYLAKE(dev_priv) && result == -ENXIO) {
+        if (IS_SKYLAKE(dev_priv) && ret == -ENXIO) {
                 DRM_DEBUG_DRIVER("No SAGV found on system, ignoring\n");
                 dev_priv->sagv_status = I915_SAGV_NOT_CONTROLLED;
                 return 0;
-        } else if (result < 0) {
-                DRM_ERROR("Failed to disable the SAGV\n");
-                return result;
+        } else if (ret < 0) {
+                DRM_ERROR("Failed to disable the SAGV (%d)\n", ret);
+                return ret;
         }
 
         dev_priv->sagv_status = I915_SAGV_DISABLED;
@@ -7890,6 +7874,81 @@ int sandybridge_pcode_write(struct drm_i915_private *dev_priv,
         return 0;
 }
 
+static bool skl_pcode_try_request(struct drm_i915_private *dev_priv, u32 mbox,
+                                  u32 request, u32 reply_mask, u32 reply,
+                                  u32 *status)
+{
+        u32 val = request;
+
+        *status = sandybridge_pcode_read(dev_priv, mbox, &val);
+
+        return *status || ((val & reply_mask) == reply);
+}
+
+/**
+ * skl_pcode_request - send PCODE request until acknowledgment
+ * @dev_priv: device private
+ * @mbox: PCODE mailbox ID the request is targeted for
+ * @request: request ID
+ * @reply_mask: mask used to check for request acknowledgment
+ * @reply: value used to check for request acknowledgment
+ * @timeout_base_ms: timeout for polling with preemption enabled
+ *
+ * Keep resending the @request to @mbox until PCODE acknowledges it, PCODE
+ * reports an error or an overall timeout of @timeout_base_ms+10 ms expires.
+ * The request is acknowledged once the PCODE reply dword equals @reply after
+ * applying @reply_mask. Polling is first attempted with preemption enabled
+ * for @timeout_base_ms and if this times out for another 10 ms with
+ * preemption disabled.
+ *
+ * Returns 0 on success, %-ETIMEDOUT in case of a timeout, <0 in case of some
+ * other error as reported by PCODE.
+ */
+int skl_pcode_request(struct drm_i915_private *dev_priv, u32 mbox, u32 request,
+                      u32 reply_mask, u32 reply, int timeout_base_ms)
+{
+        u32 status;
+        int ret;
+
+        WARN_ON(!mutex_is_locked(&dev_priv->rps.hw_lock));
+
+#define COND skl_pcode_try_request(dev_priv, mbox, request, reply_mask, reply, \
+                                   &status)
+
+        /*
+         * Prime the PCODE by doing a request first. Normally it guarantees
+         * that a subsequent request, at most @timeout_base_ms later, succeeds.
+         * _wait_for() doesn't guarantee when its passed condition is evaluated
+         * first, so send the first request explicitly.
+         */
+        if (COND) {
+                ret = 0;
+                goto out;
+        }
+        ret = _wait_for(COND, timeout_base_ms * 1000, 10);
+        if (!ret)
+                goto out;
+
+        /*
+         * The above can time out if the number of requests was low (2 in the
+         * worst case) _and_ PCODE was busy for some reason even after a
+         * (queued) request and @timeout_base_ms delay. As a workaround retry
+         * the poll with preemption disabled to maximize the number of
+         * requests. Increase the timeout from @timeout_base_ms to 10ms to
+         * account for interrupts that could reduce the number of these
+         * requests.
+         */
+        DRM_DEBUG_KMS("PCODE timeout, retrying with preemption disabled\n");
+        WARN_ON_ONCE(timeout_base_ms > 3);
+        preempt_disable();
+        ret = wait_for_atomic(COND, 10);
+        preempt_enable();
+
+out:
+        return ret ? ret : status;
+#undef COND
+}
+
 static int byt_gpu_freq(struct drm_i915_private *dev_priv, int val)
 {
         /*