Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752640AbdLEFQI (ORCPT ); Tue, 5 Dec 2017 00:16:08 -0500 Received: from mail-yb0-f193.google.com ([209.85.213.193]:45699 "EHLO mail-yb0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751473AbdLEFQA (ORCPT ); Tue, 5 Dec 2017 00:16:00 -0500 X-Google-Smtp-Source: AGs4zMZ+MM4g0q/rtMsFImfSGMEXepsnKA7h8/+tUlNQXMXycCTerqjqhmlnb2QdxhSWCD1Y0e8Y1g== From: Sean Paul To: dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org Cc: linux-kernel@vger.kernel.org, daniel.vetter@intel.com, seanpaul@google.com, Sean Paul , Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , David Airlie Subject: [PATCH v3 6/9] drm/i915: Make use of indexed write GMBUS feature Date: Tue, 5 Dec 2017 00:15:05 -0500 Message-Id: <20171205051513.8603-7-seanpaul@chromium.org> X-Mailer: git-send-email 2.15.0.531.g2ccb3012c9-goog In-Reply-To: <20171205051513.8603-1-seanpaul@chromium.org> References: <20171205051513.8603-1-seanpaul@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3970 Lines: 112 This patch enables the indexed write feature of the GMBUS to concatenate 2 consecutive messages into one. The criteria for an indexed write is that both messages are writes, the first is length == 1, and the second is length > 0. The first message is sent out by the GMBUS as the slave command, and the second one is sent via the GMBUS FIFO as usual. Changes in v3: - Added to series Suggested-by: Ville Syrjälä Signed-off-by: Sean Paul --- drivers/gpu/drm/i915/intel_i2c.c | 39 ++++++++++++++++++++++++++++++++++----- 1 file changed, 34 insertions(+), 5 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_i2c.c b/drivers/gpu/drm/i915/intel_i2c.c index 49fdf09f9919..7399009aee0a 100644 --- a/drivers/gpu/drm/i915/intel_i2c.c +++ b/drivers/gpu/drm/i915/intel_i2c.c @@ -373,7 +373,8 @@ gmbus_xfer_read(struct drm_i915_private *dev_priv, struct i2c_msg *msg, static int gmbus_xfer_write_chunk(struct drm_i915_private *dev_priv, - unsigned short addr, u8 *buf, unsigned int len) + unsigned short addr, u8 *buf, unsigned int len, + u32 gmbus1_index) { unsigned int chunk_size = len; u32 val, loop; @@ -386,7 +387,7 @@ gmbus_xfer_write_chunk(struct drm_i915_private *dev_priv, I915_WRITE_FW(GMBUS3, val); I915_WRITE_FW(GMBUS1, - GMBUS_CYCLE_WAIT | + gmbus1_index | GMBUS_CYCLE_WAIT | (chunk_size << GMBUS_BYTE_COUNT_SHIFT) | (addr << GMBUS_SLAVE_ADDR_SHIFT) | GMBUS_SLAVE_WRITE | GMBUS_SW_RDY); @@ -409,7 +410,8 @@ gmbus_xfer_write_chunk(struct drm_i915_private *dev_priv, } static int -gmbus_xfer_write(struct drm_i915_private *dev_priv, struct i2c_msg *msg) +gmbus_xfer_write(struct drm_i915_private *dev_priv, struct i2c_msg *msg, + u32 gmbus1_index) { u8 *buf = msg->buf; unsigned int tx_size = msg->len; @@ -419,7 +421,8 @@ gmbus_xfer_write(struct drm_i915_private *dev_priv, struct i2c_msg *msg) do { len = min(tx_size, GMBUS_BYTE_COUNT_MAX); - ret = gmbus_xfer_write_chunk(dev_priv, msg->addr, buf, len); + ret = gmbus_xfer_write_chunk(dev_priv, msg->addr, buf, len, + gmbus1_index); if (ret) return ret; @@ -430,6 +433,14 @@ gmbus_xfer_write(struct drm_i915_private *dev_priv, struct i2c_msg *msg) return 0; } +static int +gmbus_xfer_index_write(struct drm_i915_private *dev_priv, u8 cmd, + struct i2c_msg *msg) +{ + u8 gmbus1_index = GMBUS_CYCLE_INDEX | (cmd << GMBUS_SLAVE_INDEX_SHIFT); + return gmbus_xfer_write(dev_priv, msg, gmbus1_index); +} + /* * The gmbus controller can combine a 1 or 2 byte write with a read that * immediately follows it by using an "INDEX" cycle. @@ -444,6 +455,20 @@ gmbus_is_index_read(struct i2c_msg *msgs, int i, int num) (msgs[i + 1].flags & I2C_M_RD)); } +/* + * The gmbus controller can combine a 2-msg write into a single write that + * immediately follows it by using an "INDEX" cycle. + */ +static bool +gmbus_is_index_write(struct i2c_msg *msgs, int i, int num) +{ + return (i + 1 < num && + msgs[i].addr == msgs[i + 1].addr && + !(msgs[i].flags & I2C_M_RD) && + !(msgs[i + 1].flags & I2C_M_RD) && + (msgs[i].len == 1 || msgs[i + 1].len > 0)); +} + static int gmbus_xfer_index_read(struct drm_i915_private *dev_priv, struct i2c_msg *msgs) { @@ -489,10 +514,14 @@ do_gmbus_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num) if (gmbus_is_index_read(msgs, i, num)) { ret = gmbus_xfer_index_read(dev_priv, &msgs[i]); inc = 2; /* an index read is two msgs */ + } else if (gmbus_is_index_write(msgs, i, num)) { + ret = gmbus_xfer_index_write(dev_priv, msgs[i].buf[0], + &msgs[i + 1]); + inc = 2; /* an index write is two msgs */ } else if (msgs[i].flags & I2C_M_RD) { ret = gmbus_xfer_read(dev_priv, &msgs[i], 0); } else { - ret = gmbus_xfer_write(dev_priv, &msgs[i]); + ret = gmbus_xfer_write(dev_priv, &msgs[i], 0); } if (!ret) -- 2.15.0.531.g2ccb3012c9-goog