From patchwork Sat Dec 1 12:53:45 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Vetter X-Patchwork-Id: 1829121 Return-Path: X-Original-To: patchwork-intel-gfx@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) by patchwork2.kernel.org (Postfix) with ESMTP id C7FC0DF2EB for ; Sat, 1 Dec 2012 13:47:39 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id CDEF7E67F9 for ; Sat, 1 Dec 2012 05:47:39 -0800 (PST) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from mail-ee0-f49.google.com (mail-ee0-f49.google.com [74.125.83.49]) by gabe.freedesktop.org (Postfix) with ESMTP id 99274E639C for ; Sat, 1 Dec 2012 05:03:10 -0800 (PST) Received: by mail-ee0-f49.google.com with SMTP id c4so788916eek.36 for ; Sat, 01 Dec 2012 05:03:09 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=from:to:cc:subject:date:message-id:x-mailer:in-reply-to:references; bh=r/4viY7NwcgtOXrDDc/OblfagUblvQ01EDU7VHttdYQ=; b=O6xzSZiCloC+3KMD3eyIAyPZJwoqVkAJTu/Myz/tMYMm00MFdKgYaIaCqdouwfdlj6 159gJJih6gL9TYY6aPP+ZiFhO2NTxAg03gskkk/oM4lOs1nV7KfXQBf36wEEO5kgzP0t 4Ko4WHNiwPs517CRSh5BCVFTs+qS6vVAw2/mE= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=from:to:cc:subject:date:message-id:x-mailer:in-reply-to:references :x-gm-message-state; bh=r/4viY7NwcgtOXrDDc/OblfagUblvQ01EDU7VHttdYQ=; b=XZv7l3ArzEN96HAZdyDhwe4zs4V3tRlCduoeJJyEbratRcdSZdR89RqAcyUBIZUZAl I9IvBEuzgyqQBEK16Z4uXf0pvsGE3u3fhDHYM8wbDXBSVUYOVLj6/uqPk9c5n8rWn+TJ OKuzCO060HBEnFW9qWgTagthUatX6tWOrvkrlt2Nw0ZOzCsJh4AwJPiTMoJv73qom3hp q2XIZ5o7kNmxZzJaLA7bbVjJTly43S98W/izPLceAwZnjSzRnsFliNCjRwWp2KCQxx1b noI5CY9ci/1eTTENtOyQSGILW5fB8SnPB0lJsEYF6Qbvd/NevFS4KQ722mq1Ihmj73dx 4U1w== Received: by 10.14.203.2 with SMTP id e2mr15821945eeo.20.1354366989686; Sat, 01 Dec 2012 05:03:09 -0800 (PST) Received: from wespe.ffwll.local (178-83-130-250.dynamic.hispeed.ch. [178.83.130.250]) by mx.google.com with ESMTPS id f49sm17288642eep.12.2012.12.01.05.03.08 (version=TLSv1/SSLv3 cipher=OTHER); Sat, 01 Dec 2012 05:03:09 -0800 (PST) From: Daniel Vetter To: Intel Graphics Development Date: Sat, 1 Dec 2012 13:53:45 +0100 Message-Id: <1354366429-2324-7-git-send-email-daniel.vetter@ffwll.ch> X-Mailer: git-send-email 1.7.11.7 In-Reply-To: <1354366429-2324-1-git-send-email-daniel.vetter@ffwll.ch> References: <1354366429-2324-1-git-send-email-daniel.vetter@ffwll.ch> X-Gm-Message-State: ALoCoQlkJV09ZLppP2Ia7TYsqr7AEwQ/DxvqRRrjuvvh1MZEnInYeqNb5Xn3gbunWiz917cksPOP Cc: Daniel Vetter Subject: [Intel-gfx] [PATCH 06/10] drm/i915: use the gmbus irq for waits X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.13 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: intel-gfx-bounces+patchwork-intel-gfx=patchwork.kernel.org@lists.freedesktop.org Errors-To: intel-gfx-bounces+patchwork-intel-gfx=patchwork.kernel.org@lists.freedesktop.org We need two special things to properly wire this up: - Add another argument to gmbus_wait_hw_status to pass in the correct interrupt bit in gmbus4. - Since we can only get an irq for one of the two events we want, hand-roll the wait_event_timeout code so that we wake up every jiffie and can check for NAKs. This way we also subsume gmbus support for platforms without interrupts (or where those are not yet enabled). The important bit really is to only enable one gmbus interrupt source at the same time - with that piece of lore figured out, this seems to work flawlessly. Ben Widawsky rightfully complained the lack of measurements for the claimed benefits (especially since the first version was actually broken and fell back to bit-banging). Previously reading the 256 byte hdmi EDID takes about 72 ms here. With this patch it's down to 33 ms. Given that transfering the 256 bytes over i2c at wire speed takes 20.5ms alone, the reduction in additional overhead is rather nice. v2: Chris Wilson wondered whether GMBUS4 might contain some set bits when booting up an hence result in some spurious interrupts. Since we clear GMBUS4 after every wait and we do gmbus transfer really early in the setup sequence to detect displays the window is small, but still be paranoid and clear it properly. v3: Clarify the comment that gmbus irq generation can only support one kind of event, why it bothers us and how we work around that limit. Cc: Daniel Kurtz Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/i915_drv.h | 3 +++ drivers/gpu/drm/i915/i915_irq.c | 4 ++++ drivers/gpu/drm/i915/intel_i2c.c | 45 ++++++++++++++++++++++++++++++---------- 3 files changed, 41 insertions(+), 11 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index 9e05d98..8e9f292 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -632,6 +632,7 @@ typedef struct drm_i915_private { struct intel_gmbus gmbus[GMBUS_NUM_PORTS]; + /** gmbus_mutex protects against concurrent usage of the single hw gmbus * controller on different i2c buses. */ struct mutex gmbus_mutex; @@ -641,6 +642,8 @@ typedef struct drm_i915_private { */ uint32_t gpio_mmio_base; + wait_queue_head_t gmbus_wait_queue; + struct pci_dev *bridge_dev; struct intel_ring_buffer ring[I915_NUM_RINGS]; uint32_t next_seqno; diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c index 5062501..6fe62d0 100644 --- a/drivers/gpu/drm/i915/i915_irq.c +++ b/drivers/gpu/drm/i915/i915_irq.c @@ -530,7 +530,11 @@ static void gen6_queue_rps_work(struct drm_i915_private *dev_priv, static void gmbus_irq_handler(struct drm_device *dev) { + struct drm_i915_private *dev_priv = (drm_i915_private_t *) dev->dev_private; + DRM_DEBUG_DRIVER("GMBUS interrupt\n"); + + wake_up_all(&dev_priv->gmbus_wait_queue); } static irqreturn_t valleyview_irq_handler(int irq, void *arg) diff --git a/drivers/gpu/drm/i915/intel_i2c.c b/drivers/gpu/drm/i915/intel_i2c.c index a16eecd..8b71892 100644 --- a/drivers/gpu/drm/i915/intel_i2c.c +++ b/drivers/gpu/drm/i915/intel_i2c.c @@ -63,6 +63,7 @@ intel_i2c_reset(struct drm_device *dev) { struct drm_i915_private *dev_priv = dev->dev_private; I915_WRITE(dev_priv->gpio_mmio_base + GMBUS0, 0); + I915_WRITE(dev_priv->gpio_mmio_base + GMBUS4, 0); } static void intel_i2c_quirk_set(struct drm_i915_private *dev_priv, bool enable) @@ -204,20 +205,38 @@ intel_gpio_setup(struct intel_gmbus *bus, u32 pin) static int gmbus_wait_hw_status(struct drm_i915_private *dev_priv, - u32 gmbus2_status) + u32 gmbus2_status, + u32 gmbus4_irq_en) { - int ret; + int i; int reg_offset = dev_priv->gpio_mmio_base; - u32 gmbus2; + u32 gmbus2 = 0; + DEFINE_WAIT(wait); + + /* Important: The hw handles only the first bit, so set only one! Since + * we also need to check for NAKs besides the hw ready/idle signal, we + * need to wake up periodically and check that ourselves. */ + I915_WRITE(GMBUS4 + reg_offset, gmbus4_irq_en); - ret = wait_for((gmbus2 = I915_READ(GMBUS2 + reg_offset)) & - (GMBUS_SATOER | gmbus2_status), - 50); + for (i = 0; i < msecs_to_jiffies(50) + 1; i++) { + prepare_to_wait(&dev_priv->gmbus_wait_queue, &wait, + TASK_UNINTERRUPTIBLE); + + gmbus2 = I915_READ(GMBUS2 + reg_offset); + if (gmbus2 & (GMBUS_SATOER | gmbus2_status)) + break; + + schedule_timeout(1); + } + finish_wait(&dev_priv->gmbus_wait_queue, &wait); + + I915_WRITE(GMBUS4 + reg_offset, 0); if (gmbus2 & GMBUS_SATOER) return -ENXIO; - - return ret; + if (gmbus2 & gmbus2_status) + return 0; + return -ETIMEDOUT; } static int @@ -238,7 +257,8 @@ gmbus_xfer_read(struct drm_i915_private *dev_priv, struct i2c_msg *msg, int ret; u32 val, loop = 0; - ret = gmbus_wait_hw_status(dev_priv, GMBUS_HW_RDY); + ret = gmbus_wait_hw_status(dev_priv, GMBUS_HW_RDY, + GMBUS_HW_RDY_EN); if (ret) return ret; @@ -282,7 +302,8 @@ gmbus_xfer_write(struct drm_i915_private *dev_priv, struct i2c_msg *msg) I915_WRITE(GMBUS3 + reg_offset, val); - ret = gmbus_wait_hw_status(dev_priv, GMBUS_HW_RDY); + ret = gmbus_wait_hw_status(dev_priv, GMBUS_HW_RDY, + GMBUS_HW_RDY_EN); if (ret) return ret; } @@ -367,7 +388,8 @@ gmbus_xfer(struct i2c_adapter *adapter, if (ret == -ENXIO) goto clear_err; - ret = gmbus_wait_hw_status(dev_priv, GMBUS_HW_WAIT_PHASE); + ret = gmbus_wait_hw_status(dev_priv, GMBUS_HW_WAIT_PHASE, + GMBUS_HW_WAIT_EN); if (ret == -ENXIO) goto clear_err; if (ret) @@ -473,6 +495,7 @@ int intel_setup_gmbus(struct drm_device *dev) dev_priv->gpio_mmio_base = 0; mutex_init(&dev_priv->gmbus_mutex); + init_waitqueue_head(&dev_priv->gmbus_wait_queue); for (i = 0; i < GMBUS_NUM_PORTS; i++) { struct intel_gmbus *bus = &dev_priv->gmbus[i];