高通平台LCD之MDP code解析

LCD相关code所在目录：

        kernel/drvier/video/msm/mdss/ 

软件驱动主要分为三部分：

        MDP 驱动

        DSI 控制器驱动

        FrameBuffer驱动

执行probe 的先后顺序：

       MDP probe →  DSI probe → FB probe

MDP probe：对使用的硬件资源进行初始化，同时在fb设备中注册mdp的使用接口

（rc = mdss_fb_register_mdp_instance(&mdp5);）

接口定义如下：

struct msm_mdp_interface mdp5 = {

.init_fnc = mdss_mdp_overlay_init,

.fb_mem_get_iommu_domain = mdss_fb_mem_get_iommu_domain,

.fb_stride = mdss_mdp_fb_stride,

.check_dsi_status = mdss_check_dsi_ctrl_status,

.get_format_params = mdss_mdp_get_format_params,

};

DSI probe：解析模组厂提供的panel的dtsi文件，从文件中获得panel的mode，分辨率，帧率，command数据等。

FB probe：从DSI的数据结构中获取到panel的相关信息，多MDP进行初始化。

 if (mfd->mdp.init_fnc) {

                rc= mfd->mdp.init_fnc(mfd);

                if(rc) {

                        pr_err("init_fncfailed\n");

                        returnrc;

                }

        }

init_fnc 就是 MDP probe 注册的  mdss_mdp_overlay_init。

在 mdss_mdp_overlay_init 中，首先是对mdp interface 注册回调函数。

int mdss_mdp_overlay_init(struct msm_fb_data_type *mfd)

{

struct device *dev = mfd->fbi->dev;

struct msm_mdp_interface *mdp5_interface = &mfd->mdp;

struct mdss_overlay_private *mdp5_data = NULL;

struct irq_info *mdss_irq;

int rc;

mdp5_data = kzalloc(sizeof(struct mdss_overlay_private), GFP_KERNEL);

if (!mdp5_data) {

pr_err("fail to allocate mdp5 private data structure");

return -ENOMEM;

}

mdp5_data->mdata = dev_get_drvdata(mfd->pdev->dev.parent);

if (!mdp5_data->mdata) {

pr_err("unable to initialize overlay for fb%d\n", mfd->index);

rc = -ENODEV;

goto init_fail;

}

//注册回调函数

mdp5_interface->on_fnc = mdss_mdp_overlay_on;

mdp5_interface->off_fnc = mdss_mdp_overlay_off;

mdp5_interface->release_fnc = __mdss_mdp_overlay_release_all;

mdp5_interface->do_histogram = NULL;

if (mdp5_data->mdata->ncursor_pipes)

mdp5_interface->cursor_update = mdss_mdp_hw_cursor_pipe_update;

else

mdp5_interface->cursor_update = mdss_mdp_hw_cursor_update;

mdp5_interface->async_position_update =

mdss_mdp_async_position_update;

mdp5_interface->dma_fnc = mdss_mdp_overlay_pan_display;

mdp5_interface->ioctl_handler = mdss_mdp_overlay_ioctl_handler;

mdp5_interface->kickoff_fnc = mdss_mdp_overlay_kickoff;

mdp5_interface->mode_switch = mdss_mode_switch;

mdp5_interface->mode_switch_post = mdss_mode_switch_post;

mdp5_interface->pre_commit_fnc = mdss_mdp_overlay_precommit;

mdp5_interface->get_sync_fnc = mdss_mdp_rotator_sync_pt_get;

mdp5_interface->splash_init_fnc = mdss_mdp_splash_init;

mdp5_interface->configure_panel = mdss_mdp_update_panel_info;

mdp5_interface->input_event_handler = mdss_mdp_input_event_handler;

if (mfd->panel_info->type == WRITEBACK_PANEL) {

mdp5_interface->atomic_validate =

mdss_mdp_layer_atomic_validate_wfd;

mdp5_interface->pre_commit = mdss_mdp_layer_pre_commit_wfd;

mdp5_interface->is_config_same = mdss_mdp_wfd_is_config_same;

} else {

mdp5_interface->atomic_validate =

mdss_mdp_layer_atomic_validate;

mdp5_interface->pre_commit = mdss_mdp_layer_pre_commit;

}

INIT_LIST_HEAD(&mdp5_data->pipes_used);

INIT_LIST_HEAD(&mdp5_data->pipes_cleanup);

INIT_LIST_HEAD(&mdp5_data->pipes_destroy);

INIT_LIST_HEAD(&mdp5_data->bufs_pool);

INIT_LIST_HEAD(&mdp5_data->bufs_chunks);

INIT_LIST_HEAD(&mdp5_data->bufs_used);

INIT_LIST_HEAD(&mdp5_data->bufs_freelist);

INIT_LIST_HEAD(&mdp5_data->rot_proc_list);

mutex_init(&mdp5_data->list_lock);

mutex_init(&mdp5_data->ov_lock);

mutex_init(&mdp5_data->dfps_lock);

mdp5_data->hw_refresh = true;

mdp5_data->cursor_ndx[CURSOR_PIPE_LEFT] = MSMFB_NEW_REQUEST;

mdp5_data->cursor_ndx[CURSOR_PIPE_RIGHT] = MSMFB_NEW_REQUEST;

mfd->mdp.private1 = mdp5_data;

mfd->wait_for_kickoff = true;

rc = mdss_mdp_overlay_fb_parse_dt(mfd);

if (rc)

return rc;

/*

* disable BWC if primary panel is video mode on specific

* chipsets to workaround HW problem.

*/

if (mdss_has_quirk(mdp5_data->mdata, MDSS_QUIRK_BWCPANIC) &&

mfd->panel_info->type == MIPI_VIDEO_PANEL && (0 == mfd->index))

mdp5_data->mdata->has_bwc = false;

mfd->panel_orientation = mfd->panel_info->panel_orientation;

if ((mfd->panel_info->panel_orientation & MDP_FLIP_LR) &&

(mfd->split_mode == MDP_DUAL_LM_DUAL_DISPLAY))

mdp5_data->mixer_swap = true;

rc = sysfs_create_group(&dev->kobj, &mdp_overlay_sysfs_group);

if (rc) {

pr_err("vsync sysfs group creation failed, ret=%d\n", rc);

goto init_fail;

}

mdp5_data->vsync_event_sd = sysfs_get_dirent(dev->kobj.sd,

"vsync_event");

if (!mdp5_data->vsync_event_sd) {

pr_err("vsync_event sysfs lookup failed\n");

rc = -ENODEV;

goto init_fail;

}

mdp5_data->lineptr_event_sd = sysfs_get_dirent(dev->kobj.sd,

"lineptr_event");

if (!mdp5_data->lineptr_event_sd) {

pr_err("lineptr_event sysfs lookup failed\n");

rc = -ENODEV;

goto init_fail;

}

mdp5_data->hist_event_sd = sysfs_get_dirent(dev->kobj.sd,

"hist_event");

if (!mdp5_data->hist_event_sd) {

pr_err("hist_event sysfs lookup failed\n");

rc = -ENODEV;

goto init_fail;

}

mdp5_data->bl_event_sd = sysfs_get_dirent(dev->kobj.sd,

"bl_event");

if (!mdp5_data->bl_event_sd) {

pr_err("bl_event sysfs lookup failed\n");

rc = -ENODEV;

goto init_fail;

}

mdp5_data->ad_event_sd = sysfs_get_dirent(dev->kobj.sd,

"ad_event");

if (!mdp5_data->ad_event_sd) {

pr_err("ad_event sysfs lookup failed\n");

rc = -ENODEV;

goto init_fail;

}

mdp5_data->ad_bl_event_sd = sysfs_get_dirent(dev->kobj.sd,

"ad_bl_event");

if (!mdp5_data->ad_bl_event_sd) {

pr_err("ad_bl_event sysfs lookup failed\n");

rc = -ENODEV;

goto init_fail;

}

rc = sysfs_create_link_nowarn(&dev->kobj,

&mdp5_data->mdata->pdev->dev.kobj, "mdp");

if (rc)

pr_warn("problem creating link to mdp sysfs\n");

rc = sysfs_create_link_nowarn(&dev->kobj,

&mfd->pdev->dev.kobj, "mdss_fb");

if (rc)

pr_warn("problem creating link to mdss_fb sysfs\n");

if (mfd->panel_info->type == MIPI_VIDEO_PANEL) {

rc = sysfs_create_group(&dev->kobj,

&dynamic_fps_fs_attrs_group);

if (rc) {

pr_err("Error dfps sysfs creation ret=%d\n", rc);

goto init_fail;

}

}

if (mfd->panel_info->mipi.dms_mode ||

mfd->panel_info->type == MIPI_CMD_PANEL) {

rc = __vsync_retire_setup(mfd);

if (IS_ERR_VALUE(rc)) {

pr_err("unable to create vsync timeline\n");

goto init_fail;

}

}

mfd->mdp_sync_pt_data.async_wait_fences = true;

pm_runtime_set_suspended(&mfd->pdev->dev);

pm_runtime_enable(&mfd->pdev->dev);

kobject_uevent(&dev->kobj, KOBJ_ADD);

pr_debug("vsync kobject_uevent(KOBJ_ADD)\n");

mdss_irq = mdss_intr_line();

/* Adding event timer only for primary panel */

if ((mfd->index == 0) && (mfd->panel_info->type != WRITEBACK_PANEL)) {

mdp5_data->cpu_pm_hdl = add_event_timer(mdss_irq->irq, NULL,

(void *)mdp5_data);

if (!mdp5_data->cpu_pm_hdl)

pr_warn("%s: unable to add event timer\n", __func__);

}

//如果连续显示被打开，则会调用mdss_mdp_overlay_handoff函数，此时，mdp5_data->ctl 还没有被初始化，所以调用__mdss_mdp_overlay_ctl_init 函数，在这个函数中会执行mdss_mdp_ctl_init，在这函数里，会根据panel的type类型，注册不同的控制函数。

在这里我们看出start_fuc根据不同的type注册的函数不同，所以在probe 的时候，不同的DSI mode 在初始化时注册的函数也不同，

         当我们在显示过程中要对DSI mode 做切换的时候，需要从初始化的注册函数开始进行重新配置。

         在__mdss_mdp_overlay_ctl_init 函数中，还会对vsync_handler进行注册，以及Mixer 的malloc 内存分配等工作。

         在这之后还要初始化MDP 所需要的clk，以及必要的成员进行初始化。

         在对MDP 初始化完成之后，还要对lcd使用的背光进行注册。

if (mfd->panel_info->cont_splash_enabled) {

rc = mdss_mdp_overlay_handoff(mfd);

if (rc) {

/*

* Even though handoff failed, it is not fatal.

* MDP can continue, just that we would have a longer

* delay in transitioning from splash screen to boot

* animation

*/

pr_warn("Overlay handoff failed for fb%d. rc=%d\n",

mfd->index, rc);

rc = 0;

}

}

mdp5_data->dyn_pu_state = mfd->panel_info->partial_update_enabled;

if (mdss_mdp_pp_overlay_init(mfd))

pr_warn("Failed to initialize pp overlay data.\n");

return rc;

init_fail:

kfree(mdp5_data);

return rc;

}