[Intel-gfx] [PATCH 3/5] drm/i915: Extract CSB status read

[Chris Wilson]

On Wed, Jan 06, 2016 at 03:09:41PM +0000, Michel Thierry wrote:
> On 1/5/2016 6:30 PM, Ben Widawsky wrote:
> >This is a useful thing to have around as a function because the mechanism may
> >change in the future.
> >
> >There is a net increase in LOC here, and it will continue to be the case on GEN8
> >and GEN9 - but future GENs may have an alternate mechanism for doing this.
> >
> >Signed-off-by: Ben Widawsky <benjamin.widawsky at intel.com>
> >---
> >  drivers/gpu/drm/i915/intel_lrc.c | 19 ++++++++++++++++---
> >  1 file changed, 16 insertions(+), 3 deletions(-)
> >
> >diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
> >index 14affaa..23839ff 100644
> >--- a/drivers/gpu/drm/i915/intel_lrc.c
> >+++ b/drivers/gpu/drm/i915/intel_lrc.c
> >@@ -496,6 +496,19 @@ static bool execlists_check_remove_request(struct intel_engine_cs *ring,
> >         return false;
> >  }
> >
> >+static void get_context_status(struct intel_engine_cs *ring,
> >+                              u8 read_pointer,
> >+                              u32 *status, u32 *context_id)
> >+{
> >+       struct drm_i915_private *dev_priv = ring->dev->dev_private;
> >+
> >+       if (WARN_ON(read_pointer >= GEN8_CSB_ENTRIES))
> >+               return;
> >+
> >+       *status = I915_READ(RING_CONTEXT_STATUS_BUF_LO(ring, read_pointer));
> >+       *context_id = I915_READ(RING_CONTEXT_STATUS_BUF_HI(ring, read_pointer));
> >+}
> >+
> >  /**
> >   * intel_lrc_irq_handler() - handle Context Switch interrupts
> >   * @ring: Engine Command Streamer to handle.
> >@@ -523,9 +536,9 @@ void intel_lrc_irq_handler(struct intel_engine_cs *ring)
> >         spin_lock(&ring->execlist_lock);
> >
> >         while (read_pointer < write_pointer) {
> >-               read_pointer++;
> >-               status = I915_READ(RING_CONTEXT_STATUS_BUF_LO(ring, read_pointer % GEN8_CSB_ENTRIES));
> >-               status_id = I915_READ(RING_CONTEXT_STATUS_BUF_HI(ring, read_pointer % GEN8_CSB_ENTRIES));
> >+
> >+               get_context_status(ring, ++read_pointer % GEN8_CSB_ENTRIES,
> >+                                  &status, &status_id);
> >
> >                 if (status & GEN8_CTX_STATUS_IDLE_ACTIVE)
> >                         continue;
> >--
> >2.6.4
> 
> Future GENs may need a completely new lrc_irq_handler anyway.
s/Future/Current/
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre