linux-kernel - [PATCH v3 055/105] drm/vc4: hvs: Introduce a function to get the assigned FIFO

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Date:   Wed, 27 May 2020 17:48:25 +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 v3 055/105] drm/vc4: hvs: Introduce a function to get the assigned FIFO

At boot time, if we detect that a pixelvalve has been enabled, we need to
be able to retrieve the HVS channel it has been assigned to so that we can
disable that channel too. Let's create that function that returns the FIFO
or an error from a given output.

Signed-off-by: Maxime Ripard <maxime@...no.tech>
---
 drivers/gpu/drm/vc4/vc4_drv.h |  1 +-
 drivers/gpu/drm/vc4/vc4_hvs.c | 51 ++++++++++++++++++++++++++++++++++++-
 2 files changed, 52 insertions(+)

diff --git a/drivers/gpu/drm/vc4/vc4_drv.h b/drivers/gpu/drm/vc4/vc4_drv.h
index d51b695732e0..99001f8783aa 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.h
+++ b/drivers/gpu/drm/vc4/vc4_drv.h
@@ -880,6 +880,7 @@ void vc4_irq_reset(struct drm_device *dev);
 /* vc4_hvs.c */
 extern struct platform_driver vc4_hvs_driver;
 void vc4_hvs_stop_channel(struct drm_device *dev, unsigned int output);
+int vc4_hvs_get_fifo_from_output(struct drm_device *dev, unsigned int output);
 int vc4_hvs_atomic_check(struct drm_crtc *crtc, struct drm_crtc_state *state);
 void vc4_hvs_atomic_enable(struct drm_crtc *crtc, struct drm_crtc_state *old_state);
 void vc4_hvs_atomic_disable(struct drm_crtc *crtc, struct drm_crtc_state *old_state);
diff --git a/drivers/gpu/drm/vc4/vc4_hvs.c b/drivers/gpu/drm/vc4/vc4_hvs.c
index 1785c49534cf..56657959778f 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/bitfield.h>
 #include <linux/clk.h>
 #include <linux/component.h>
 #include <linux/platform_device.h>
@@ -196,6 +197,56 @@ static void vc4_hvs_update_gamma_lut(struct drm_crtc *crtc)
 	vc4_hvs_lut_load(crtc);
 }
 
+int vc4_hvs_get_fifo_from_output(struct drm_device *dev, unsigned int output)
+{
+	struct vc4_dev *vc4 = to_vc4_dev(dev);
+	u32 reg;
+	int ret;
+
+	switch (output) {
+	case 0:
+		return 0;
+
+	case 1:
+		return 1;
+
+	case 2:
+		reg = HVS_READ(SCALER_DISPECTRL);
+		ret = FIELD_GET(SCALER_DISPECTRL_DSP2_MUX_MASK, reg);
+		if (ret == 0)
+			return 2;
+
+		return 0;
+
+	case 3:
+		reg = HVS_READ(SCALER_DISPCTRL);
+		ret = FIELD_GET(SCALER_DISPCTRL_DSP3_MUX_MASK, reg);
+		if (ret == 3)
+			return -EPIPE;
+
+		return ret;
+
+	case 4:
+		reg = HVS_READ(SCALER_DISPEOLN);
+		ret = FIELD_GET(SCALER_DISPEOLN_DSP4_MUX_MASK, reg);
+		if (ret == 3)
+			return -EPIPE;
+
+		return ret;
+
+	case 5:
+		reg = HVS_READ(SCALER_DISPDITHER);
+		ret = FIELD_GET(SCALER_DISPDITHER_DSP5_MUX_MASK, reg);
+		if (ret == 3)
+			return -EPIPE;
+
+		return ret;
+
+	default:
+		return -EPIPE;
+	}
+}
+
 static int vc4_hvs_init_channel(struct vc4_dev *vc4, struct drm_crtc *crtc,
 				struct drm_display_mode *mode, bool oneshot)
 {
-- 
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