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.
Indeed, on my i5-2500s, __gen6_update_ring_freq improves from 6,080,661ns to 8172ns. v2: Missed using _fw variants for sandybridge_pcode_read() Signed-off-by: Chris Wilson <[email protected]> Cc: Mika Kuoppala <[email protected]> Cc: Ville Syrjälä <[email protected]> Cc: Tvrtko Ursulin <[email protected]> Reviewed-by: Tvrtko Ursulin <[email protected]> --- 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..870085ab5423 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_fw(dev_priv, + GEN6_PCODE_MAILBOX, GEN6_PCODE_READY, 0, + 500)) { 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)) { 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; } -- 2.8.1 _______________________________________________ Intel-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/intel-gfx
