On 30/06/16 12:30, Chris Wilson wrote:
We want to replace the inline wait_for() with an out-of-line hybrid
busy/sleep wait_for() in the hopes of speeding up the communication wit
the PCode unit.
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Mika Kuoppala <mika.kuoppala@xxxxxxxxx>
Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
---
drivers/gpu/drm/i915/intel_pm.c | 43 +++++++++++++++++++++++++++--------------
1 file changed, 28 insertions(+), 15 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index d7f8ba89d2a5..f84bf253d04a 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -7623,46 +7623,59 @@ int sandybridge_pcode_read(struct drm_i915_private *dev_priv, u32 mbox, u32 *val
{
WARN_ON(!mutex_is_locked(&dev_priv->rps.hw_lock));
- if (I915_READ(GEN6_PCODE_MAILBOX) & GEN6_PCODE_READY) {
+ /* GEN6_PCODE_* are outside of the forcewake domain, we can
+ * use te fw I915_READ variants to reduce the amount of work
+ * required when reading/writing.
+ */
+
+ if (I915_READ_FW(GEN6_PCODE_MAILBOX) & GEN6_PCODE_READY) {
DRM_DEBUG_DRIVER("warning: pcode (read) mailbox access failed\n");
return -EAGAIN;
}
- I915_WRITE(GEN6_PCODE_DATA, *val);
- I915_WRITE(GEN6_PCODE_DATA1, 0);
- I915_WRITE(GEN6_PCODE_MAILBOX, GEN6_PCODE_READY | mbox);
+ I915_WRITE_FW(GEN6_PCODE_DATA, *val);
+ I915_WRITE_FW(GEN6_PCODE_DATA1, 0);
+ I915_WRITE_FW(GEN6_PCODE_MAILBOX, GEN6_PCODE_READY | mbox);
- if (wait_for((I915_READ(GEN6_PCODE_MAILBOX) & GEN6_PCODE_READY) == 0,
- 500)) {
+ if (intel_wait_for_register(dev_priv,
+ GEN6_PCODE_MAILBOX, GEN6_PCODE_READY, 0,
+ 500)) {
Why not the _fw version?
Actually brings me to the point I glanced over in the previous patch -
why would intel_wait_for_register_fw be not suitable for long waits? It
looks like a concern for the calling code grabbing the fw outside it for
a long period and not for the function itself. This call site being a
case in point for that.
DRM_ERROR("timeout waiting for pcode read (%d) to finish\n", mbox);
return -ETIMEDOUT;
}
- *val = I915_READ(GEN6_PCODE_DATA);
- I915_WRITE(GEN6_PCODE_DATA, 0);
+ *val = I915_READ_FW(GEN6_PCODE_DATA);
+ I915_WRITE_FW(GEN6_PCODE_DATA, 0);
return 0;
}
-int sandybridge_pcode_write(struct drm_i915_private *dev_priv, u32 mbox, u32 val)
+int sandybridge_pcode_write(struct drm_i915_private *dev_priv,
+ u32 mbox, u32 val)
{
WARN_ON(!mutex_is_locked(&dev_priv->rps.hw_lock));
- if (I915_READ(GEN6_PCODE_MAILBOX) & GEN6_PCODE_READY) {
+ /* GEN6_PCODE_* are outside of the forcewake domain, we can
+ * use te fw I915_READ variants to reduce the amount of work
+ * required when reading/writing.
+ */
+
+ if (I915_READ_FW(GEN6_PCODE_MAILBOX) & GEN6_PCODE_READY) {
DRM_DEBUG_DRIVER("warning: pcode (write) mailbox access failed\n");
return -EAGAIN;
}
- I915_WRITE(GEN6_PCODE_DATA, val);
- I915_WRITE(GEN6_PCODE_MAILBOX, GEN6_PCODE_READY | mbox);
+ I915_WRITE_FW(GEN6_PCODE_DATA, val);
+ I915_WRITE_FW(GEN6_PCODE_MAILBOX, GEN6_PCODE_READY | mbox);
- if (wait_for((I915_READ(GEN6_PCODE_MAILBOX) & GEN6_PCODE_READY) == 0,
- 500)) {
+ if (intel_wait_for_register_fw(dev_priv,
+ GEN6_PCODE_MAILBOX, GEN6_PCODE_READY, 0,
+ 500)) {
Here you use the _fw variant.
DRM_ERROR("timeout waiting for pcode write (%d) to finish\n", mbox);
return -ETIMEDOUT;
}
- I915_WRITE(GEN6_PCODE_DATA, 0);
+ I915_WRITE_FW(GEN6_PCODE_DATA, 0);
return 0;
}
Regards,
Tvrtko
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