linux-kernel - [PATCH v4 03/78] drm/vc4: hvs: Boost the core clock during modeset

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Message-Id: <b04341887fb1acb9ed4adc28d109f9e21f146c7d.1594230107.git-series.maxime@cerno.tech>
Date:   Wed,  8 Jul 2020 19:41:11 +0200
From:   Maxime Ripard <maxime@...no.tech>
To:     Nicolas Saenz Julienne <nsaenzjulienne@...e.de>,
        Eric Anholt <eric@...olt.net>
Cc:     dri-devel@...ts.freedesktop.org,
        linux-rpi-kernel@...ts.infradead.org,
        bcm-kernel-feedback-list@...adcom.com,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Dave Stevenson <dave.stevenson@...pberrypi.com>,
        Tim Gover <tim.gover@...pberrypi.com>,
        Phil Elwell <phil@...pberrypi.com>,
        Maxime Ripard <maxime@...no.tech>
Subject: [PATCH v4 03/78] drm/vc4: hvs: Boost the core clock during modeset

In order to prevent timeouts and stalls in the pipeline, the core clock
needs to be maxed at 500MHz during a modeset on the BCM2711.

Reviewed-by: Eric Anholt <eric@...olt.net>
Signed-off-by: Maxime Ripard <maxime@...no.tech>
---
 drivers/gpu/drm/vc4/vc4_drv.h |  2 ++
 drivers/gpu/drm/vc4/vc4_hvs.c |  9 +++++++++
 drivers/gpu/drm/vc4/vc4_kms.c |  9 +++++++++
 3 files changed, 20 insertions(+)

diff --git a/drivers/gpu/drm/vc4/vc4_drv.h b/drivers/gpu/drm/vc4/vc4_drv.h
index e4cde1f9224b..6358f6ca8d56 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.h
+++ b/drivers/gpu/drm/vc4/vc4_drv.h
@@ -320,6 +320,8 @@ struct vc4_hvs {
 	void __iomem *regs;
 	u32 __iomem *dlist;
 
+	struct clk *core_clk;
+
 	/* Memory manager for CRTCs to allocate space in the display
 	 * list.  Units are dwords.
 	 */
diff --git a/drivers/gpu/drm/vc4/vc4_hvs.c b/drivers/gpu/drm/vc4/vc4_hvs.c
index 836d8799d79e..091fdf4908aa 100644
--- a/drivers/gpu/drm/vc4/vc4_hvs.c
+++ b/drivers/gpu/drm/vc4/vc4_hvs.c
@@ -19,6 +19,7 @@
  * each CRTC.
  */
 
+#include <linux/clk.h>
 #include <linux/component.h>
 #include <linux/platform_device.h>
 
@@ -540,6 +541,14 @@ static int vc4_hvs_bind(struct device *dev, struct device *master, void *data)
 	hvs->regset.regs = hvs_regs;
 	hvs->regset.nregs = ARRAY_SIZE(hvs_regs);
 
+	if (hvs->hvs5) {
+		hvs->core_clk = devm_clk_get(&pdev->dev, NULL);
+		if (IS_ERR(hvs->core_clk)) {
+			dev_err(&pdev->dev, "Couldn't get core clock\n");
+			return PTR_ERR(hvs->core_clk);
+		}
+	}
+
 	if (!hvs->hvs5)
 		hvs->dlist = hvs->regs + SCALER_DLIST_START;
 	else
diff --git a/drivers/gpu/drm/vc4/vc4_kms.c b/drivers/gpu/drm/vc4/vc4_kms.c
index 08318e69061b..210cc2408087 100644
--- a/drivers/gpu/drm/vc4/vc4_kms.c
+++ b/drivers/gpu/drm/vc4/vc4_kms.c
@@ -11,6 +11,8 @@
  * crtc, HDMI encoder).
  */
 
+#include <linux/clk.h>
+
 #include <drm/drm_atomic.h>
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_crtc.h>
@@ -149,6 +151,7 @@ vc4_atomic_complete_commit(struct drm_atomic_state *state)
 {
 	struct drm_device *dev = state->dev;
 	struct vc4_dev *vc4 = to_vc4_dev(dev);
+	struct vc4_hvs *hvs = vc4->hvs;
 	struct vc4_crtc *vc4_crtc;
 	int i;
 
@@ -160,6 +163,9 @@ vc4_atomic_complete_commit(struct drm_atomic_state *state)
 		vc4_hvs_mask_underrun(dev, vc4_crtc->channel);
 	}
 
+	if (vc4->hvs->hvs5)
+		clk_set_min_rate(hvs->core_clk, 500000000);
+
 	drm_atomic_helper_wait_for_fences(dev, state, false);
 
 	drm_atomic_helper_wait_for_dependencies(state);
@@ -182,6 +188,9 @@ vc4_atomic_complete_commit(struct drm_atomic_state *state)
 
 	drm_atomic_helper_commit_cleanup_done(state);
 
+	if (vc4->hvs->hvs5)
+		clk_set_min_rate(hvs->core_clk, 0);
+
 	drm_atomic_state_put(state);
 
 	up(&vc4->async_modeset);
-- 
git-series 0.9.1