diff --git a/drivers/gpu/drm/ingenic/ingenic-drm-drv.c b/drivers/gpu/drm/ingenic/ingenic-drm-drv.c index 937d080f5d06a6b77f59d8ed671aad23396cf649..eadfe3a20bf19fab05fa9dc66595ea367ffbe3df 100644 --- a/drivers/gpu/drm/ingenic/ingenic-drm-drv.c +++ b/drivers/gpu/drm/ingenic/ingenic-drm-drv.c @@ -12,6 +12,7 @@ #include #include #include +#include #include #include #include @@ -71,6 +72,21 @@ struct ingenic_drm { bool panel_is_sharp; bool no_vblank; + + /* + * clk_mutex is used to synchronize the pixel clock rate update with + * the VBLANK. When the pixel clock's parent clock needs to be updated, + * clock_nb's notifier function will lock the mutex, then wait until the + * next VBLANK. At that point, the parent clock's rate can be updated, + * and the mutex is then unlocked. If an atomic commit happens in the + * meantime, it will lock on the mutex, effectively waiting until the + * clock update process finishes. Finally, the pixel clock's rate will + * be recomputed when the mutex has been released, in the pending atomic + * commit, or a future one. + */ + struct mutex clk_mutex; + bool update_clk_rate; + struct notifier_block clock_nb; }; static const u32 ingenic_drm_primary_formats[] = { @@ -119,6 +135,29 @@ static inline struct ingenic_drm *drm_crtc_get_priv(struct drm_crtc *crtc) return container_of(crtc, struct ingenic_drm, crtc); } +static inline struct ingenic_drm *drm_nb_get_priv(struct notifier_block *nb) +{ + return container_of(nb, struct ingenic_drm, clock_nb); +} + +static int ingenic_drm_update_pixclk(struct notifier_block *nb, + unsigned long action, + void *data) +{ + struct ingenic_drm *priv = drm_nb_get_priv(nb); + + switch (action) { + case PRE_RATE_CHANGE: + mutex_lock(&priv->clk_mutex); + priv->update_clk_rate = true; + drm_crtc_wait_one_vblank(&priv->crtc); + return NOTIFY_OK; + default: + mutex_unlock(&priv->clk_mutex); + return NOTIFY_OK; + } +} + static void ingenic_drm_crtc_atomic_enable(struct drm_crtc *crtc, struct drm_crtc_state *state) { @@ -284,8 +323,14 @@ static void ingenic_drm_crtc_atomic_flush(struct drm_crtc *crtc, if (drm_atomic_crtc_needs_modeset(state)) { ingenic_drm_crtc_update_timings(priv, &state->mode); + priv->update_clk_rate = true; + } + if (priv->update_clk_rate) { + mutex_lock(&priv->clk_mutex); clk_set_rate(priv->pix_clk, state->adjusted_mode.clock * 1000); + priv->update_clk_rate = false; + mutex_unlock(&priv->clk_mutex); } if (event) { @@ -1044,16 +1089,28 @@ static int ingenic_drm_bind(struct device *dev, bool has_components) if (soc_info->has_osd) regmap_write(priv->map, JZ_REG_LCD_OSDC, JZ_LCD_OSDC_OSDEN); + mutex_init(&priv->clk_mutex); + priv->clock_nb.notifier_call = ingenic_drm_update_pixclk; + + parent_clk = clk_get_parent(priv->pix_clk); + ret = clk_notifier_register(parent_clk, &priv->clock_nb); + if (ret) { + dev_err(dev, "Unable to register clock notifier\n"); + goto err_devclk_disable; + } + ret = drm_dev_register(drm, 0); if (ret) { dev_err(dev, "Failed to register DRM driver\n"); - goto err_devclk_disable; + goto err_clk_notifier_unregister; } drm_fbdev_generic_setup(drm, 32); return 0; +err_clk_notifier_unregister: + clk_notifier_unregister(parent_clk, &priv->clock_nb); err_devclk_disable: if (priv->lcd_clk) clk_disable_unprepare(priv->lcd_clk); @@ -1075,7 +1132,9 @@ static int compare_of(struct device *dev, void *data) static void ingenic_drm_unbind(struct device *dev) { struct ingenic_drm *priv = dev_get_drvdata(dev); + struct clk *parent_clk = clk_get_parent(priv->pix_clk); + clk_notifier_unregister(parent_clk, &priv->clock_nb); if (priv->lcd_clk) clk_disable_unprepare(priv->lcd_clk); clk_disable_unprepare(priv->pix_clk);