gpu: host1x: Reserve VBLANK syncpoints at initialization

On T20-T148 chips, the bootloader can set up a boot splash
screen with DC configured to increment syncpoint 26/27
at VBLANK. Because of this we shouldn't allow these syncpoints
to be allocated until DC has been reset and will no longer
increment them in the background.

As such, on these chips, reserve those two syncpoints at
initialization, and only mark them free once the DC
driver has indicated it's safe to do so.

Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/gpu/host1x/dev.h

@@ -101,6 +101,12 @@ struct host1x_info {
 	bool has_hypervisor; /* has hypervisor registers */
 	unsigned int num_sid_entries;
 	const struct host1x_sid_entry *sid_table;
+	/*
+	 * On T20-T148, the boot chain may setup DC to increment syncpoints
+	 * 26/27 on VBLANK. As such we cannot use these syncpoints until
+	 * the display driver disables VBLANK increments.
+	 */
+	bool reserve_vblank_syncpts;
 };
 
 struct host1x {