drm/i915: Add more control to wait_for routines

This patch adds a little more control to a couple wait_for routines such
that we can avoid open-coding read/wait/timeout patterns which:
 - need the value of the register after the wait_for
 - run arbitrary operation for the read portion

This patch also chooses the correct sleep function (based on
timers-howto.txt) for the polling interval the caller specifies.

Changes in v2:
- Added to the series
Changes in v3:
- Rebased on drm-intel-next-queued and the new Wmin/max _wait_for
- Removed msleep option
Changes in v4:
- Removed ; for OP in _wait_for (Chris)
- Moved reg_value definition above ret (Chris)
Changes in v4:
- checkpatch whitespace fix
Changes in v5:
- None
Changes in v6:
- None

Suggested-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20180108195545.218615-3-seanpaul@chromium.org

1 files changed, 16 insertions, 7 deletions

diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
index 89547b614aa6..129c8ac77985 100644
--- a/drivers/gpu/drm/i915/intel_uncore.c
+++ b/drivers/gpu/drm/i915/intel_uncore.c
@@ -1767,12 +1767,14 @@ int __intel_wait_for_register_fw(struct drm_i915_private *dev_priv,
 }
 
 /**
- * intel_wait_for_register - wait until register matches expected state
+ * __intel_wait_for_register - wait until register matches expected state
  * @dev_priv: the i915 device
  * @reg: the register to read
  * @mask: mask to apply to register value
  * @value: expected value
- * @timeout_ms: timeout in millisecond
+ * @fast_timeout_us: fast timeout in microsecond for atomic/tight wait
+ * @slow_timeout_ms: slow timeout in millisecond
+ * @out_value: optional placeholder to hold registry value
  *
  * This routine waits until the target register @reg contains the expected
  * @value after applying the @mask, i.e. it waits until ::
@@ -1783,14 +1785,17 @@ int __intel_wait_for_register_fw(struct drm_i915_private *dev_priv,
  *
  * Returns 0 if the register matches the desired condition, or -ETIMEOUT.
  */
-int intel_wait_for_register(struct drm_i915_private *dev_priv,
+int __intel_wait_for_register(struct drm_i915_private *dev_priv,
 			    i915_reg_t reg,
 			    u32 mask,
 			    u32 value,
-			    unsigned int timeout_ms)
+			    unsigned int fast_timeout_us,
+			    unsigned int slow_timeout_ms,
+			    u32 *out_value)
 {
 	unsigned fw =
 		intel_uncore_forcewake_for_reg(dev_priv, reg, FW_REG_READ);
+	u32 reg_value;
 	int ret;
 
 	might_sleep();
@@ -1800,14 +1805,18 @@ int intel_wait_for_register(struct drm_i915_private *dev_priv,
 
 	ret = __intel_wait_for_register_fw(dev_priv,
 					   reg, mask, value,
-					   2, 0, NULL);
+					   fast_timeout_us, 0, &reg_value);
 
 	intel_uncore_forcewake_put__locked(dev_priv, fw);
 	spin_unlock_irq(&dev_priv->uncore.lock);
 
 	if (ret)
-		ret = wait_for((I915_READ_NOTRACE(reg) & mask) == value,
-			       timeout_ms);
+		ret = __wait_for(reg_value = I915_READ_NOTRACE(reg),
+				 (reg_value & mask) == value,
+				 slow_timeout_ms * 1000, 10, 1000);
+
+	if (out_value)
+		*out_value = reg_value;
 
 	return ret;
 }