RK3568平台（显示篇）DRM vop驱动程序分析

一.设备树配置

vopb: vop@ff900000 {compatible = "rockchip,rk3399-vop-big";reg = <0x0 0xff900000 0x0 0x2000>, <0x0 0xff902000 0x0 0x1000>;interrupts = <GIC_SPI 118 IRQ_TYPE_LEVEL_HIGH 0>;assigned-clocks = <&cru ACLK_VOP0>, <&cru HCLK_VOP0>;assigned-clock-rates = <400000000>, <100000000>;clocks = <&cru ACLK_VOP0>, <&cru DCLK_VOP0>, <&cru HCLK_VOP0>;clock-names = "aclk_vop", "dclk_vop", "hclk_vop";iommus = <&vopb_mmu>;power-domains = <&power RK3399_PD_VOPB>;resets = <&cru SRST_A_VOP0>, <&cru SRST_H_VOP0>, <&cru SRST_D_VOP0>;reset-names = "axi", "ahb", "dclk";status = "disabled";vopb_out: port {#address-cells = <1>;#size-cells = <0>;vopb_out_edp: endpoint@0 {reg = <0>;remote-endpoint = <&edp_in_vopb>;};vopb_out_mipi: endpoint@1 {reg = <1>;remote-endpoint = <&mipi_in_vopb>;};vopb_out_hdmi: endpoint@2 {reg = <2>;remote-endpoint = <&hdmi_in_vopb>;};vopb_out_mipi1: endpoint@3 {reg = <3>;remote-endpoint = <&mipi1_in_vopb>;};vopb_out_dp: endpoint@4 {reg = <4>;remote-endpoint = <&dp_in_vopb>;};};
};

vop具体实现文件：

drivers/gpu/drm/rockchip/rockchip_drm_vop.c；
drivers/gpu/drm/rockchip/rockchip_vop_reg.c；
drivers/gpu/drm/rockchip/rockchip_drm_vop.h;
drivers/gpu/drm/rockchip/rockchip_vop_reg.h；

二.驱动分析

const struct component_ops vop_component_ops = {.bind = vop_bind,.unbind = vop_unbind,
};

vop的驱动程序主要是从vop_bind开始，其定义在：drivers/gpu/drm/rockchip/rockchip_drm_vop.c

vop_bind函数涉及到对vop设备节点的解析，咱们以vopb设备节点为例进行分析；

static int vop_bind(struct device *dev, struct device *master, void *data)
{// 1. 获取platform_devicestruct platform_device *pdev = to_platform_device(dev);const struct vop_data *vop_data;struct drm_device *drm_dev = data;struct vop *vop;struct resource *res;int ret, irq;// 2. 得到rk3399_vop_bigvop_data = of_device_get_match_data(dev);if (!vop_data)return -ENODEV;/* Allocate vop struct and its vop_win array，初始化vop win */vop = devm_kzalloc(dev, struct_size(vop, win, vop_data->win_size),GFP_KERNEL);if (!vop)return -ENOMEM;vop->dev = dev;vop->data = vop_data;vop->drm_dev = drm_dev;// 设置驱动数据为vopdev_set_drvdata(dev, vop);// 3. 初始化vop winvop_win_init(vop);// 4. 获取第一个内存资源，即<0x0 0xff900000 0x0 0x2000>; VOP_BIG相关寄存器基地址res = platform_get_resource(pdev, IORESOURCE_MEM, 0);// 将VOP_BIG相关寄存器起始物理地址映射到虚拟地址，并返回虚拟地址vop->regs = devm_ioremap_resource(dev, res);if (IS_ERR(vop->regs))return PTR_ERR(vop->regs);vop->len = resource_size(res);// 5. 获取第二个内存资源，即<0x0 0xff902000 0x0 0x1000>; LUT相关寄存器基地址res = platform_get_resource(pdev, IORESOURCE_MEM, 1);if (res) {if (vop_data->lut_size != 1024 && vop_data->lut_size != 256) {DRM_DEV_ERROR(dev, "unsupported gamma LUT size %d\n", vop_data->lut_size);return -EINVAL;}// LUT相关寄存器起始物理地址映射到虚拟地址，并返回虚拟地址vop->lut_regs = devm_ioremap_resource(dev, res);if (IS_ERR(vop->lut_regs))return PTR_ERR(vop->lut_regs);}vop->regsbak = devm_kzalloc(dev, vop->len, GFP_KERNEL);if (!vop->regsbak)return -ENOMEM;// 6. 获取第1个IRQ编号 interrupts = <GIC_SPI 118 IRQ_TYPE_LEVEL_HIGH 0>;irq = platform_get_irq(pdev, 0);if (irq < 0) {DRM_DEV_ERROR(dev, "cannot find irq for vop\n");return irq;}vop->irq = (unsigned int)irq;// 初始化自旋锁和互斥锁spin_lock_init(&vop->reg_lock);spin_lock_init(&vop->irq_lock);mutex_init(&vop->vop_lock);// 7. 创建crtc对象，并和plane关联在一起ret = vop_create_crtc(vop);if (ret)return ret;// 电源管理相关pm_runtime_enable(&pdev->dev);// 8. vop初始化ret = vop_initial(vop);if (ret < 0) {DRM_DEV_ERROR(&pdev->dev,"cannot initial vop dev - err %d\n", ret);goto err_disable_pm_runtime;}// 9. 申请中断，中断处理函数设置为vop_isrret = devm_request_irq(dev, vop->irq, vop_isr,IRQF_SHARED, dev_name(dev), vop);if (ret)goto err_disable_pm_runtime;// 未设置if (vop->data->feature & VOP_FEATURE_INTERNAL_RGB) {vop->rgb = rockchip_rgb_init(dev, &vop->crtc, vop->drm_dev);if (IS_ERR(vop->rgb)) {ret = PTR_ERR(vop->rgb);goto err_disable_pm_runtime;}}// 10. dma初始化rockchip_drm_dma_init_device(drm_dev, dev);return 0;err_disable_pm_runtime:pm_runtime_disable(&pdev->dev);vop_destroy_crtc(vop);return ret;
}

这里我们以设备节点vopb为例，对这段代码进行分析，主要流程如下：

(1) 调用to_platform_device获取platform device，设备节点为vopb；

(2) 调用of_device_get_match_data获取与特定设备匹配的数据，这里获取到的数据为rk3399_vop_big;

(3) 调用vop_win_init初始化vop win；

(4) 首先调用platform_get_resource(pdev, IORESOURCE_MEM, 0)获取第一个内存资源，即：

<0x0 0xff900000 0x0 0x2000>

0xff900000为VOP_BIG相关寄存器基地址；

接着调用devm_ioremap_resource(dev, res)将VOP_BIG相关寄存器起始物理地址映射到虚拟地址，并返回虚拟地址；

(5) 调用platform_get_resource(pdev, IORESOURCE_MEM, 1)获取第二个内存资源，即：

<0x0 0xff902000 0x0 0x1000>

0xff902000为LUT相关寄存器基地址；

接着调用devm_ioremap_resource(dev, res)将LUT相关寄存器起始物理地址映射到虚拟地址，并返回虚拟地址；

(6) 调用platform_get_irq(pdev, 0) 获取第1个IRQ编号：

 interrupts = <GIC_SPI 118 IRQ_TYPE_LEVEL_HIGH 0>

(7) 调用vop_create_crtc(vop)初始化crtc对象，并和plane关联在一起；

(8) 调用vop_initial(vop)进行vop初始化；

(9) 调用devm_request_irq(dev, vop->irq, vop_isr, IRQF_SHARED, dev_name(dev), vop)申请中断，中断处理函数设置为vop_isr；

(10) 调用rockchip_drm_dma_init_device(drm_dev, dev)进行dma相关的初始化工作；

vop_bind函数里面比较重要的几个函数：

vo_win_init用于初始化vop win，那么什么是vop win，指定就是vop图层。

vop_create_crtc用于初始化crtc对象，crtc从Framebuffer中读取待显示的图像。

vop_initial用户vop初始化。

vo_win_init：初始化vop win。

/** Initialize the vop->win array elements.*/
static void vop_win_init(struct vop *vop)
{const struct vop_data *vop_data = vop->data;unsigned int i;// 遍历每一个图层for (i = 0; i < vop_data->win_size; i++) {// 获取第i个vop winstruct vop_win *vop_win = &vop->win[i];// 获取第i个vop win配置相关寄存器信息const struct vop_win_data *win_data = &vop_data->win[i];// 初始化成员vop_win->data = win_data;vop_win->vop = vop;// rk3399定义了win_yuv2yuv，因此初始化yuv2yuv_dataif (vop_data->win_yuv2yuv)vop_win->yuv2yuv_data = &vop_data->win_yuv2yuv[i];}
}

vop_create_crtc：用于初始化crtc对象。

static int vop_create_crtc(struct vop *vop)
{// 获取vop dataconst struct vop_data *vop_data = vop->data;// 获取device，对应的设备节点为vopbstruct device *dev = vop->dev;// 获取drm devicestruct drm_device *drm_dev = vop->drm_dev;struct drm_plane *primary = NULL, *cursor = NULL, *plane, *tmp;// 获取drm crtcstruct drm_crtc *crtc = &vop->crtc;struct device_node *port;int ret;int i;/** Create drm_plane for primary and cursor planes first, since we need* to pass them to drm_crtc_init_with_planes, which sets the* "possible_crtcs" to the newly initialized crtc.         * 1. 遍历每一个vop win，每个vop win内部包含一个drm_plane，对类型为primary和cursor plane* 进行初始化*/for (i = 0; i < vop_data->win_size; i++) {// 获取第i个vop winstruct vop_win *vop_win = &vop->win[i];// 获取第i个vop win dataconst struct vop_win_data *win_data = vop_win->data;// 只处理primary和cursor planeif (win_data->type != DRM_PLANE_TYPE_PRIMARY &&win_data->type != DRM_PLANE_TYPE_CURSOR)continue;// 进行plane的初始化，其中funcs被设置为vop_plane_funcsret = drm_universal_plane_init(vop->drm_dev,    // drm设备&vop_win->base,  // 要初始化的plane对象0,  // 可能的CRTCs的位掩码&vop_plane_funcs,  // plane的控制函数集合win_data->phy->data_formats,  // 支持的格式数组（DRM_FORMAT_*）win_data->phy->nformats,   // formats数组的长度win_data->phy->format_modifiers, win_data->type, // plane的类型NULL);if (ret) {DRM_DEV_ERROR(vop->dev, "failed to init plane %d\n",ret);goto err_cleanup_planes;}// 获取当前planeplane = &vop_win->base;// 设置plane的辅助函数helper_private为plane_helper_funcsdrm_plane_helper_add(plane, &plane_helper_funcs);// 如果vop win data配置了x_mir_en/y_mir_en，则调用drm_plane_create_rotation_property为plane附加rotation propertyvop_plane_add_properties(plane, win_data);// 保存primary planeif (plane->type == DRM_PLANE_TYPE_PRIMARY)primary = plane;// 保存cursor planeelse if (plane->type == DRM_PLANE_TYPE_CURSOR)cursor = plane;}// 2. 使用指定的primary and cursor planes初始化的crtc对象，其中crtc回调函数funcs设置为vop_crtc_funcsret = drm_crtc_init_with_planes(drm_dev, crtc, primary, cursor,&vop_crtc_funcs, NULL);if (ret)goto err_cleanup_planes;// 3. 设置crtc的辅助函数helper_private为vop_crtc_helper_funcsdrm_crtc_helper_add(crtc, &vop_crtc_helper_funcs);// 进入if (vop->lut_regs) {drm_mode_crtc_set_gamma_size(crtc, vop_data->lut_size);drm_crtc_enable_color_mgmt(crtc, 0, false, vop_data->lut_size);}/** Create drm_planes for overlay windows with possible_crtcs restricted* to the newly created crtc.* 4. 遍历每一个vop win，每个vop win内部包含一个drm_plane，对类型为overlay plane* 进行初始化*/for (i = 0; i < vop_data->win_size; i++) {// 获取第i个vop winstruct vop_win *vop_win = &vop->win[i];// 获取第i个vop win dataconst struct vop_win_data *win_data = vop_win->data;unsigned long possible_crtcs = drm_crtc_mask(crtc);// 只处理overlay planeif (win_data->type != DRM_PLANE_TYPE_OVERLAY)continue;// 进行plane的初始化，其中funcs被设置为vop_plane_funcsret = drm_universal_plane_init(vop->drm_dev, &vop_win->base,possible_crtcs,&vop_plane_funcs,win_data->phy->data_formats,win_data->phy->nformats,win_data->phy->format_modifiers,win_data->type, NULL);if (ret) {DRM_DEV_ERROR(vop->dev, "failed to init overlay %d\n",ret);goto err_cleanup_crtc;}// 设置plane的辅助函数helper_private为plane_helper_funcsdrm_plane_helper_add(&vop_win->base, &plane_helper_funcs);// 如果vop win data配置了x_mir_en/y_mir_en，则调用drm_plane_create_rotation_property为plane附加rotation propertyvop_plane_add_properties(&vop_win->base, win_data);}// 5. 从vopb节点的子节点列表中查找名为port的子节点，也就是vopb_out节点port = of_get_child_by_name(dev->of_node, "port");if (!port) {DRM_DEV_ERROR(vop->dev, "no port node found in %pOF\n",dev->of_node);ret = -ENOENT;goto err_cleanup_crtc;}// 6. 初始化工作队列drm_flip_work_init(&vop->fb_unref_work, "fb_unref",vop_fb_unref_worker);// 初始化完成量，init_completion(&vop->dsp_hold_completion);init_completion(&vop->line_flag_completion);// 设置port节点crtc->port = port;// 7. 对crtc进行自刷新相关的辅助函数初始化ret = drm_self_refresh_helper_init(crtc);if (ret)DRM_DEV_DEBUG_KMS(vop->dev,"Failed to init %s with SR helpers %d, ignoring\n",crtc->name, ret);return 0;err_cleanup_crtc:drm_crtc_cleanup(crtc);
err_cleanup_planes:list_for_each_entry_safe(plane, tmp, &drm_dev->mode_config.plane_list,head)drm_plane_cleanup(plane);return ret;err_cleanup_crtc:drm_crtc_cleanup(crtc);
err_cleanup_planes:list_for_each_entry_safe(plane, tmp, &drm_dev->mode_config.plane_list,head)drm_plane_cleanup(plane);return ret;
}

(1) 遍历每一个vop win，每个vop win内部包含一个drm_plane，对类型为primary和cursor plane进行初始化；具体是调用drm_universal_plane_init来初始化drm_plane，并且添加plane辅助函数、设置属性等；其中funcs被设置为vop_plane_funcs，定义在drivers/gpu/drm/rockchip/rockchip_drm_vop.c；

static const struct drm_plane_funcs vop_plane_funcs = {.update_plane   = drm_atomic_helper_update_plane,.disable_plane  = drm_atomic_helper_disable_plane,.destroy = vop_plane_destroy,.reset = drm_atomic_helper_plane_reset,.atomic_duplicate_state = drm_atomic_helper_plane_duplicate_state,.atomic_destroy_state = drm_atomic_helper_plane_destroy_state,.format_mod_supported = rockchip_mod_supported,
};

(2) 调用drm_crtc_init_with_planes使用指定的primary and cursor planes初始化的crtc对象，其中crtc回调函数funcs设置为vop_crtc_funcs，定义在drivers/gpu/drm/rockchip/rockchip_drm_vop.c；

static const struct drm_crtc_funcs vop_crtc_funcs = {.set_config = drm_atomic_helper_set_config,.page_flip = drm_atomic_helper_page_flip,.destroy = vop_crtc_destroy,.reset = vop_crtc_reset,.atomic_duplicate_state = vop_crtc_duplicate_state,.atomic_destroy_state = vop_crtc_destroy_state,.enable_vblank = vop_crtc_enable_vblank,.disable_vblank = vop_crtc_disable_vblank,.set_crc_source = vop_crtc_set_crc_source,.verify_crc_source = vop_crtc_verify_crc_source,
};

(3) 调用drm_crtc_helper_add设置crtc的辅助函数helper_private为vop_crtc_helper_funcs，定义在drivers/gpu/drm/rockchip/rockchip_drm_vop.c；

static const struct drm_crtc_helper_funcs vop_crtc_helper_funcs = {.mode_fixup = vop_crtc_mode_fixup,.atomic_check = vop_crtc_atomic_check,.atomic_begin = vop_crtc_atomic_begin,.atomic_flush = vop_crtc_atomic_flush,.atomic_enable = vop_crtc_atomic_enable,.atomic_disable = vop_crtc_atomic_disable,
};

(4) 遍历每一个vop win，每个vop win内部包含一个drm_plane，对类型为overlay plane进行初始化；

(5) 调用of_get_child_by_name从vopb节点的子节点列表中查找名为port的子节点，也就是vopb_out节点；

(6) 调用drm_flip_work_init(&vop->fb_unref_work, "fb_unref",vop_fb_unref_worker)初始化工作队列；

vop_initial

vop_initial用户vop初始化，定义在drivers/gpu/drm/rockchip/rockchip_drm_vop.c；

static int vop_initial(struct vop *vop)
{struct reset_control *ahb_rst;int i, ret;// 根据时钟名称hclk_vop获取时钟，设备节点属性clock-names、clocks，指定了名字为hclk_vop对应的时钟为<&cru HCLK_VOP0>vop->hclk = devm_clk_get(vop->dev, "hclk_vop");if (IS_ERR(vop->hclk)) {DRM_DEV_ERROR(vop->dev, "failed to get hclk source\n");return PTR_ERR(vop->hclk);}// 根据时钟名称aclk_vop获取时钟，设备节点属性clock-names、clocks，指定了名字为aclk_vop对应的时钟为<&cru ACLK_VOP0>vop->aclk = devm_clk_get(vop->dev, "aclk_vop");if (IS_ERR(vop->aclk)) {DRM_DEV_ERROR(vop->dev, "failed to get aclk source\n");return PTR_ERR(vop->aclk);}// 根据时钟名称dclk_vop获取时钟，设备节点属性clock-names、clocks，指定了名字为dclk_vop对应的时钟为<&cru DCLK_VOP0>vop->dclk = devm_clk_get(vop->dev, "dclk_vop");if (IS_ERR(vop->dclk)) {DRM_DEV_ERROR(vop->dev, "failed to get dclk source\n");return PTR_ERR(vop->dclk);}// 电源相关，，使能设备的runtime pm功能 暂且忽略ret = pm_runtime_resume_and_get(vop->dev);if (ret < 0) {DRM_DEV_ERROR(vop->dev, "failed to get pm runtime: %d\n", ret);return ret;}// dclk时钟准备，使其处于可用状态，但不启用它ret = clk_prepare(vop->dclk);if (ret < 0) {DRM_DEV_ERROR(vop->dev, "failed to prepare dclk\n");goto err_put_pm_runtime;}/* Enable both the hclk and aclk to setup the vop，hclk时钟准备和使能 */ret = clk_prepare_enable(vop->hclk);if (ret < 0) {DRM_DEV_ERROR(vop->dev, "failed to prepare/enable hclk\n");goto err_unprepare_dclk;}// aclk时钟准备和使能ret = clk_prepare_enable(vop->aclk);if (ret < 0) {DRM_DEV_ERROR(vop->dev, "failed to prepare/enable aclk\n");goto err_disable_hclk;}/** do hclk_reset, reset all vop registers. 获取ahb相应的reset句柄*/ahb_rst = devm_reset_control_get(vop->dev, "ahb");if (IS_ERR(ahb_rst)) {DRM_DEV_ERROR(vop->dev, "failed to get ahb reset\n");ret = PTR_ERR(ahb_rst);goto err_disable_aclk;}// 对传入的reset资源进行复位操作reset_control_assert(ahb_rst);// 睡眠，单位为微妙usleep_range(10, 20);// 对传入的reset资源进行解复位操作reset_control_deassert(ahb_rst);// 设置rk3399_vop_big.intr.clear所描述寄存器相应位的值VOP_INTR_SET_TYPE(vop, clear, INTR_MASK, 1);       // 设置rk3399_vop_big.intr.enable所描述寄存器相应位的值VOP_INTR_SET_TYPE(vop, enable, INTR_MASK, 0);// 备份vop相关寄存器的值for (i = 0; i < vop->len; i += sizeof(u32))vop->regsbak[i / 4] = readl_relaxed(vop->regs + i);// 设置rk3399_vop_big.misc.global_regdone_en所描述寄存器相应位的值VOP_REG_SET(vop, misc, global_regdone_en, 1);// 设置rk3399_vop_big.common.dsp_blank所描述寄存器相应位的值VOP_REG_SET(vop, common, dsp_blank, 0);// 遍历每一个vop winfor (i = 0; i < vop->data->win_size; i++) {// 获取第i个vop winstruct vop_win *vop_win = &vop->win[i];// 获取第i个vop win dataconst struct vop_win_data *win = vop_win->data;int channel = i * 2 + 1;// 设置rk3399_vop_big.win[i].phy.channel所描述寄存器相应位的值VOP_WIN_SET(vop, win, channel, (channel + 1) << 4 | channel);// 禁止当前vop winvop_win_disable(vop, vop_win);// 设置rk3399_vop_big.win[i].phy.gate所描述寄存器相应位的值VOP_WIN_SET(vop, win, gate, 1);}// 设置rk3399_vop_big.common.cfg_done所描述寄存器相应位的值，enable reg configvop_cfg_done(vop);/** do dclk_reset, let all config take affect. 获取dclk相应的reset句柄*/vop->dclk_rst = devm_reset_control_get(vop->dev, "dclk");if (IS_ERR(vop->dclk_rst)) {DRM_DEV_ERROR(vop->dev, "failed to get dclk reset\n");ret = PTR_ERR(vop->dclk_rst);goto err_disable_aclk;}// 对传入的reset资源进行复位操作reset_control_assert(vop->dclk_rst);// 睡眠，单位为微妙usleep_range(10, 20);// 对传入的reset资源进行解复位操作reset_control_deassert(vop->dclk_rst);// 禁止时钟hclkclk_disable(vop->hclk);// 禁止时钟aclkclk_disable(vop->aclk);// 使能标志位vop->is_enabled = false;pm_runtime_put_sync(vop->dev);return 0;err_disable_aclk:clk_disable_unprepare(vop->aclk);
err_disable_hclk:clk_disable_unprepare(vop->hclk);
err_unprepare_dclk:clk_unprepare(vop->dclk);
err_put_pm_runtime:pm_runtime_put_sync(vop->dev);return ret;
}

该函数主要做了两件事件：

• vop相关时钟初始化：aclk_vop、dclk_vop、hclk_vop；
• vop相关寄存器配置，底层通过vop_reg_set设置配置寄存器值；