From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932674Ab2CZO20 (ORCPT ); Mon, 26 Mar 2012 10:28:26 -0400 Received: from mail-qc0-f202.google.com ([209.85.216.202]:36658 "EHLO mail-qc0-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932554Ab2CZO05 (ORCPT ); Mon, 26 Mar 2012 10:26:57 -0400 From: Daniel Kurtz To: Keith Packard , David Airlie , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Daniel Vetter , Chris Wilson Cc: Benson Leung , Yufeng Shen , Daniel Kurtz Subject: [PATCH 11/11 v3] drm/i915/intel_i2c: reuse GMBUS2 value read in polling loop Date: Mon, 26 Mar 2012 22:26:50 +0800 Message-Id: <1332772010-19619-12-git-send-email-djkurtz@chromium.org> X-Mailer: git-send-email 1.7.7.3 In-Reply-To: <1332772010-19619-1-git-send-email-djkurtz@chromium.org> References: <1332772010-19619-1-git-send-email-djkurtz@chromium.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Save the GMBUS2 value read while polling for state changes, and then reuse this value when determining for which reason the loops were exited. This is a small optimization which saves a couple of bus accesses for memory mapped IO registers. Signed-off-by: Daniel Kurtz Reviewed-by: Chris Wilson --- drivers/gpu/drm/i915/intel_i2c.c | 17 +++++++++-------- 1 files changed, 9 insertions(+), 8 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_i2c.c b/drivers/gpu/drm/i915/intel_i2c.c index 9619bde..7674c89 100644 --- a/drivers/gpu/drm/i915/intel_i2c.c +++ b/drivers/gpu/drm/i915/intel_i2c.c @@ -214,6 +214,7 @@ gmbus_xfer(struct i2c_adapter *adapter, struct drm_i915_private *dev_priv = bus->dev_priv; int i, reg_offset; int ret = 0; + u32 gmbus2 = 0; mutex_lock(&dev_priv->gmbus_mutex); @@ -268,12 +269,12 @@ gmbus_xfer(struct i2c_adapter *adapter, do { u32 val, loop = 0; - if (wait_for(I915_READ(GMBUS2 + reg_offset) & + if (wait_for((gmbus2 = I915_READ(GMBUS2 + + reg_offset)) & (GMBUS_SATOER | GMBUS_HW_RDY), 50)) goto timeout; - if (I915_READ(GMBUS2 + reg_offset) & - GMBUS_SATOER) + if (gmbus2 & GMBUS_SATOER) goto clear_err; val = I915_READ(GMBUS3 + reg_offset); @@ -308,21 +309,21 @@ gmbus_xfer(struct i2c_adapter *adapter, I915_WRITE(GMBUS3 + reg_offset, val); POSTING_READ(GMBUS2 + reg_offset); - if (wait_for(I915_READ(GMBUS2 + reg_offset) & + if (wait_for((gmbus2 = I915_READ(GMBUS2 + + reg_offset)) & (GMBUS_SATOER | GMBUS_HW_RDY), 50)) goto timeout; - if (I915_READ(GMBUS2 + reg_offset) & - GMBUS_SATOER) + if (gmbus2 & GMBUS_SATOER) goto clear_err; } } - if (wait_for(I915_READ(GMBUS2 + reg_offset) & + if (wait_for((gmbus2 = I915_READ(GMBUS2 + reg_offset)) & (GMBUS_SATOER | GMBUS_HW_WAIT_PHASE), 50)) goto timeout; - if (I915_READ(GMBUS2 + reg_offset) & GMBUS_SATOER) + if (gmbus2 & GMBUS_SATOER) goto clear_err; } -- 1.7.7.3