drm/msm/mdp5: fix reading hw revision on db410c platform

Since the commit commit c6122688f265 ("drm/msm/mdp5: stop overriding
drvdata") reading the MDP5 hw revision on db410c will crash the board
as the MDSS_GDSC is not enabled. Revert a part of the offending commit
(moving rpm enablement) and set priv->kms earlier. This make it possible
to use pm_runtime_get_sync() during read_mdp_hw_revision(), which will
power up both the MDP5 and MDSS devices.

Fixes: c6122688f265 ("drm/msm/mdp5: stop overriding drvdata")
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/512985/
Link: https://lore.kernel.org/r/20221125000213.252115-1-dmitry.baryshkov@linaro.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c b/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c
index b46f983..29ae5c9 100644 (file)
--- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c
+++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c
@@ -519,10 +519,9 @@ static void read_mdp_hw_revision(struct mdp5_kms *mdp5_kms,
        struct device *dev = &mdp5_kms->pdev->dev;
        u32 version;
 
-       /* Manually enable the MDP5, as pm runtime isn't usable yet. */
-       mdp5_enable(mdp5_kms);
+       pm_runtime_get_sync(dev);
        version = mdp5_read(mdp5_kms, REG_MDP5_HW_VERSION);
-       mdp5_disable(mdp5_kms);
+       pm_runtime_put_sync(dev);
 
        *major = FIELD(version, MDP5_HW_VERSION_MAJOR);
        *minor = FIELD(version, MDP5_HW_VERSION_MINOR);
@@ -839,6 +838,12 @@ static int mdp5_init(struct platform_device *pdev, struct drm_device *dev)
         */
        clk_set_rate(mdp5_kms->core_clk, 200000000);
 
+       /* set uninit-ed kms */
+       priv->kms = &mdp5_kms->base.base;
+
+       pm_runtime_enable(&pdev->dev);
+       mdp5_kms->rpm_enabled = true;
+
        read_mdp_hw_revision(mdp5_kms, &major, &minor);
 
        mdp5_kms->cfg = mdp5_cfg_init(mdp5_kms, major, minor);
@@ -887,12 +892,6 @@ static int mdp5_init(struct platform_device *pdev, struct drm_device *dev)
        if (ret)
                goto fail;
 
-       /* set uninit-ed kms */
-       priv->kms = &mdp5_kms->base.base;
-
-       pm_runtime_enable(&pdev->dev);
-       mdp5_kms->rpm_enabled = true;
-
        return 0;
 fail:
        if (mdp5_kms)