tegra: video: Don't power up the SOR twice

If U-Boot is the secondary boot loader, or has been run from itself, the
SOR may already be powered up. Powering it up again causes a hang, so
detect this situation and skip it.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Anatolij Gustschin <agust@denx.de>

diff --git a/drivers/video/tegra124/sor.c b/drivers/video/tegra124/sor.c
index 5e4140f..4324071 100644 (file)
--- a/drivers/video/tegra124/sor.c
+++ b/drivers/video/tegra124/sor.c
@@ -466,11 +466,20 @@ void tegra_dc_sor_set_lane_count(struct udevice *dev, u8 lane_count)
 static int tegra_dc_sor_power_up(struct udevice *dev, int is_lvds)
 {
        struct tegra_dc_sor_data *sor = dev_get_priv(dev);
+       u32 reg;
        int ret;
 
        if (sor->power_is_up)
                return 0;
 
+       /*
+        * If for some reason it is already powered up, don't do it again.
+        * This can happen if U-Boot is the secondary boot loader.
+        */
+       reg = tegra_sor_readl(sor, DP_PADCTL(sor->portnum));
+       if (reg & DP_PADCTL_PD_TXD_0_NO)
+               return 0;
+
        /* Set link bw */
        tegra_dc_sor_set_link_bandwidth(dev, is_lvds ?
                                        CLK_CNTRL_DP_LINK_SPEED_LVDS :