linux-imx

drm/imx: dpu: crtc: Evade the first dumb frame for DPR/PRG errata

To workaround the errata TKT320950, DPR/PRG need to evade the first dumb frame
which is generated by DPU.  The way we achieve that is to bypass TCON(but set
the TCON sync signals and KA_CHUCK strobe signal up) before enabling the DPU
display controller, and then 1) enable the display controller, 2) wait for the
frame index starting to move and 3) finally switch TCON to operation mode.
Steps 1) to 3) should be done within a frame, so we disable local irq and
preemption to make sure we don't relinquish CPU during the procedure.

Signed-off-by: Liu Ying <victor.liu@nxp.com>