drm/vc4: crtc: Assign output to channel automatically

The HVS found in the BCM2711 has 6 outputs and 3 FIFOs, with each output
being connected to a pixelvalve, and some muxing between the FIFOs and
outputs.

Any output cannot feed from any FIFO though, and they all have a bunch of
constraints.

In order to support this, let's store the possible FIFOs each output can be
assigned to in the vc4_crtc_data, and use that information at atomic_check
time to iterate over all the CRTCs enabled and assign them FIFOs.

The channel assigned is then set in the vc4_crtc_state so that the rest of
the driver can use it.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Tested-by: Chanwoo Choi <cw00.choi@samsung.com>
Tested-by: Hoegeun Kwon <hoegeun.kwon@samsung.com>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Link: https://patchwork.freedesktop.org/patch/msgid/f9aba3814ef37156ff36f310118cdd3954dd3dc5.1599120059.git-series.maxime@cerno.tech

1 files changed, 4 insertions, 3 deletions

diff --git a/drivers/gpu/drm/vc4/vc4_drv.h b/drivers/gpu/drm/vc4/vc4_drv.h
index d1cf4c038180..9e81ad8331f1 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.h
+++ b/drivers/gpu/drm/vc4/vc4_drv.h
@@ -447,6 +447,9 @@ to_vc4_encoder(struct drm_encoder *encoder)
 }
 
 struct vc4_crtc_data {
+	/* Bitmask of channels (FIFOs) of the HVS that the output can source from */
+	unsigned int hvs_available_channels;
+
 	/* Which output of the HVS this pixelvalve sources from. */
 	int hvs_output;
 };
@@ -471,9 +474,6 @@ struct vc4_crtc {
 	/* Timestamp at start of vblank irq - unaffected by lock delays. */
 	ktime_t t_vblank;
 
-	/* Which HVS channel we're using for our CRTC. */
-	int channel;
-
 	u8 lut_r[256];
 	u8 lut_g[256];
 	u8 lut_b[256];
@@ -509,6 +509,7 @@ struct vc4_crtc_state {
 	struct drm_mm_node mm;
 	bool feed_txp;
 	bool txp_armed;
+	unsigned int assigned_channel;
 
 	struct {
 		unsigned int left;