大兴德艺网站建设,做固定背景网站,化妆品网站建设策划书,营销推广案例简介#xff1a; CSDN博客专家#xff0c;专注Android/Linux系统#xff0c;分享多mic语音方案、音视频、编解码等技术#xff0c;与大家一起成长#xff01; 优质专栏#xff1a;Audio工程师进阶系列【原创干货持续更新中……】#x1f680; 人生格言#xff1a; 人生… 简介 CSDN博客专家专注Android/Linux系统分享多mic语音方案、音视频、编解码等技术与大家一起成长 优质专栏Audio工程师进阶系列【原创干货持续更新中……】 人生格言 人生从来没有捷径只有行动才是治疗恐惧和懒惰的唯一良药. 更多原创,欢迎关注Android系统攻城狮 1.前言 本篇目的探究DRM基本接口的实现底层实现到底是如何与DRM驱动通信的 2.DRM基本接口实现解析
1.DRM之drmModeGetResources获取CRTC和Connector的id号
drm_public drmModeResPtr drmModeGetResources(int fd)
{struct drm_mode_card_res res, counts;drmModeResPtr r 0;retry:memclear(res);if (drmIoctl(fd, DRM_IOCTL_MODE_GETRESOURCES, res))return 0;counts res;if (res.count_fbs) {res.fb_id_ptr VOID2U64(drmMalloc(res.count_fbs*sizeof(uint32_t)));if (!res.fb_id_ptr)goto err_allocs;}if (res.count_crtcs) {res.crtc_id_ptr VOID2U64(drmMalloc(res.count_crtcs*sizeof(uint32_t)));if (!res.crtc_id_ptr)goto err_allocs;}if (res.count_connectors) {res.connector_id_ptr VOID2U64(drmMalloc(res.count_connectors*sizeof(uint32_t)));if (!res.connector_id_ptr)goto err_allocs;}if (res.count_encoders) {res.encoder_id_ptr VOID2U64(drmMalloc(res.count_encoders*sizeof(uint32_t)));if (!res.encoder_id_ptr)goto err_allocs;}if (drmIoctl(fd, DRM_IOCTL_MODE_GETRESOURCES, res))goto err_allocs;/* The number of available connectors and etc may have changed with a* hotplug event in between the ioctls, in which case the field is* silently ignored by the kernel.*/if (counts.count_fbs res.count_fbs ||counts.count_crtcs res.count_crtcs ||counts.count_connectors res.count_connectors ||counts.count_encoders res.count_encoders){drmFree(U642VOID(res.fb_id_ptr));drmFree(U642VOID(res.crtc_id_ptr));drmFree(U642VOID(res.connector_id_ptr));drmFree(U642VOID(res.encoder_id_ptr));goto retry;}/** return*/if (!(r drmMalloc(sizeof(*r))))goto err_allocs;r-min_width res.min_width;r-max_width res.max_width;r-min_height res.min_height;r-max_height res.max_height;r-count_fbs res.count_fbs;r-count_crtcs res.count_crtcs;r-count_connectors res.count_connectors;r-count_encoders res.count_encoders;r-fbs drmAllocCpy(U642VOID(res.fb_id_ptr), res.count_fbs, sizeof(uint32_t));r-crtcs drmAllocCpy(U642VOID(res.crtc_id_ptr), res.count_crtcs, sizeof(uint32_t));r-connectors drmAllocCpy(U642VOID(res.connector_id_ptr), res.count_connectors, sizeof(uint32_t));r-encoders drmAllocCpy(U642VOID(res.encoder_id_ptr), res.count_encoders, sizeof(uint32_t));if ((res.count_fbs !r-fbs) ||(res.count_crtcs !r-crtcs) ||(res.count_connectors !r-connectors) ||(res.count_encoders !r-encoders)){drmFree(r-fbs);drmFree(r-crtcs);drmFree(r-connectors);drmFree(r-encoders);drmFree(r);r 0;}err_allocs:drmFree(U642VOID(res.fb_id_ptr));drmFree(U642VOID(res.crtc_id_ptr));drmFree(U642VOID(res.connector_id_ptr));drmFree(U642VOID(res.encoder_id_ptr));return r;
}
核心要点1 1.调用drmIoctl(fd, DRM_IOCTL_MODE_GETRESOURCES, res)获取CRTC和Connector的id号。 2.drm_mode_card_res数据结构 struct drm_mode_card_res {__u64 fb_id_ptr;__u64 crtc_id_ptr;__u64 connector_id_ptr;__u64 encoder_id_ptr;__u32 count_fbs;__u32 count_crtcs;__u32 count_connectors;__u32 count_encoders;__u32 min_width;__u32 max_width;__u32 min_height;__u32 max_height;
};
2.DRM之drmModeGetConnector连接Connector显示器
static drmModeConnectorPtr
_drmModeGetConnector(int fd, uint32_t connector_id, int probe)
{struct drm_mode_get_connector conn, counts;drmModeConnectorPtr r NULL;struct drm_mode_modeinfo stack_mode;memclear(conn);conn.connector_id connector_id;if (!probe) {conn.count_modes 1;conn.modes_ptr VOID2U64(stack_mode);}if (drmIoctl(fd, DRM_IOCTL_MODE_GETCONNECTOR, conn))return 0;retry:counts conn;if (conn.count_props) {conn.props_ptr VOID2U64(drmMalloc(conn.count_props*sizeof(uint32_t)));if (!conn.props_ptr)goto err_allocs;conn.prop_values_ptr VOID2U64(drmMalloc(conn.count_props*sizeof(uint64_t)));if (!conn.prop_values_ptr)goto err_allocs;}if (conn.count_modes) {conn.modes_ptr VOID2U64(drmMalloc(conn.count_modes*sizeof(struct drm_mode_modeinfo)));if (!conn.modes_ptr)goto err_allocs;} else {conn.count_modes 1;conn.modes_ptr VOID2U64(stack_mode);}if (conn.count_encoders) {conn.encoders_ptr VOID2U64(drmMalloc(conn.count_encoders*sizeof(uint32_t)));if (!conn.encoders_ptr)goto err_allocs;}if (drmIoctl(fd, DRM_IOCTL_MODE_GETCONNECTOR, conn))goto err_allocs;/* The number of available connectors and etc may have changed with a* hotplug event in between the ioctls, in which case the field is* silently ignored by the kernel.*/if (counts.count_props conn.count_props ||counts.count_modes conn.count_modes ||counts.count_encoders conn.count_encoders) {drmFree(U642VOID(conn.props_ptr));drmFree(U642VOID(conn.prop_values_ptr));if (U642VOID(conn.modes_ptr) ! stack_mode)drmFree(U642VOID(conn.modes_ptr));drmFree(U642VOID(conn.encoders_ptr));goto retry;}if(!(r drmMalloc(sizeof(*r)))) {goto err_allocs;}r-connector_id conn.connector_id;r-encoder_id conn.encoder_id;r-connection conn.connection;r-mmWidth conn.mm_width;r-mmHeight conn.mm_height;/* convert subpixel from kernel to userspace */r-subpixel conn.subpixel 1;r-count_modes conn.count_modes;r-count_props conn.count_props;r-props drmAllocCpy(U642VOID(conn.props_ptr), conn.count_props, sizeof(uint32_t));r-prop_values drmAllocCpy(U642VOID(conn.prop_values_ptr), conn.count_props, sizeof(uint64_t));r-modes drmAllocCpy(U642VOID(conn.modes_ptr), conn.count_modes, sizeof(struct drm_mode_modeinfo));r-count_encoders conn.count_encoders;r-encoders drmAllocCpy(U642VOID(conn.encoders_ptr), conn.count_encoders, sizeof(uint32_t));r-connector_type conn.connector_type;r-connector_type_id conn.connector_type_id;if ((r-count_props !r-props) ||(r-count_props !r-prop_values) ||(r-count_modes !r-modes) ||(r-count_encoders !r-encoders)) {drmFree(r-props);drmFree(r-prop_values);drmFree(r-modes);drmFree(r-encoders);drmFree(r);r 0;}err_allocs:drmFree(U642VOID(conn.prop_values_ptr));drmFree(U642VOID(conn.props_ptr));if (U642VOID(conn.modes_ptr) ! stack_mode)drmFree(U642VOID(conn.modes_ptr));drmFree(U642VOID(conn.encoders_ptr));return r;
}
核心要点2 1.drmIoctl(fd, DRM_IOCTL_MODE_GETCONNECTOR, conn)连接CONNECTOR到显示器 2.drm_mode_get_connector数据结构 struct drm_mode_get_connector {__u64 encoders_ptr;__u64 modes_ptr;__u64 props_ptr;__u64 prop_values_ptr;__u32 count_modes;__u32 count_props;__u32 count_encoders;__u32 encoder_id;__u32 connector_id;__u32 connector_type;__u32 connector_type_id;__u32 connection;__u32 mm_width;__u32 mm_height;__u32 subpixel;__u32 pad;
};
3.DRM之modeset_create_fb添加framebuffer设备
static int modeset_create_fb(int fd, struct buffer_object *bo) {struct drm_mode_create_dumb create {};struct drm_mode_map_dumb map {};create.width bo-width;create.height bo-height;create.bpp 32;drmIoctl(fd, DRM_IOCTL_MODE_CREATE_DUMB, create);printf(create dumb w %d h %d\n, bo-width, bo-height);getchar();bo-pitch create.pitch;bo-size create.size;bo-handle create.handle;drmModeAddFB(fd, bo-width, bo-height, 24, 32, bo-pitch, bo-handle,bo-fb_id);printf(drmModeAddFB\n);getchar();map.handle create.handle;drmIoctl(fd, DRM_IOCTL_MODE_MAP_DUMB, map);printf(map dumb\n);getchar();bo-vaddr static_castunsigned char *(mmap64(0, create.size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, map.offset));memset(bo-vaddr, 0xff, bo-size);return 0;
}
核心要点3 1.drmIoctl(fd, DRM_IOCTL_MODE_CREATE_DUMB, create) 增加申请DUMB共享内存 2.drmModeAddFB(fd, bo-width, bo-height, 24, 32, bo-pitch, bo-handle,bo-fb_id); DRM_IOCTL(fd, DRM_IOCTL_MODE_ADDFB, f);添加一个FrameBuffer 3.bo-vaddr static_castunsigned char *(mmap64( 0, create.size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, map.offset));映射DRM图形buffer的共享内存到bo-vaddr地址。 memset(bo-vaddr, 0xff, bo-size);设置白色。 4.drm_mode_create_dumb和drm_mode_map_dumb数据结构 struct drm_mode_create_dumb {__u32 height;__u32 width;__u32 bpp;__u32 flags;__u32 handle;__u32 pitch;__u64 size;
};struct drm_mode_map_dumb {__u32 handle;__u32 pad;__u64 offset;
};
4.DRM之drmModeSetCrtcCRTC开始扫描framebuffer数据显示
drm_public int drmModeSetCrtc(int fd, uint32_t crtcId, uint32_t bufferId,uint32_t x, uint32_t y, uint32_t *connectors, int count,drmModeModeInfoPtr mode)
{struct drm_mode_crtc crtc;memclear(crtc);crtc.x x;crtc.y y;crtc.crtc_id crtcId;crtc.fb_id bufferId;crtc.set_connectors_ptr VOID2U64(connectors);crtc.count_connectors count;if (mode) {memcpy(crtc.mode, mode, sizeof(struct drm_mode_modeinfo));crtc.mode_valid 1;}return DRM_IOCTL(fd, DRM_IOCTL_MODE_SETCRTC, crtc);
}
核心要点4 1.DRM_IOCTL(fd, DRM_IOCTL_MODE_SETCRTC, crtc)CRTC对framebuffer的数据进行扫描 2.drm_mode_crtc数据结构 struct drm_mode_crtc {__u64 set_connectors_ptr;__u32 count_connectors;__u32 crtc_id;__u32 fb_id;__u32 x;__u32 y;__u32 gamma_size;__u32 mode_valid;struct drm_mode_modeinfo mode;
};
5.DRM之modeset_destroy_fb关闭framebuffer设备
static void modeset_destroy_fb(int fd, struct buffer_object *bo) {struct drm_mode_destroy_dumb destroy {};drmModeRmFB(fd, bo-fb_id);munmap(bo-vaddr, bo-size);destroy.handle bo-handle;drmIoctl(fd, DRM_IOCTL_MODE_DESTROY_DUMB, destroy);
}
核心要点5 1.drmIoctl(fd, DRM_IOCTL_MODE_DESTROY_DUMB, destroy);销毁DUMB共享内存 2.drm_mode_destroy_dumb数据结构 struct drm_mode_destroy_dumb {__u32 handle;
};
6.DRM之drmModeFreeConnector断开Connector连接
drm_public void drmModeFreeConnector(drmModeConnectorPtr ptr)
{if (!ptr)return;drmFree(ptr-encoders);drmFree(ptr-prop_values);drmFree(ptr-props);drmFree(ptr-modes);drmFree(ptr);
}
核心要点6 1.调用drmFree释放内存内部调用free()函数。 2.drmFree函数实现 drm_public void drmFree(void *pt)
{free(pt);
}
7.DRM之drmModeFreeResources释放资源
drm_public void drmModeFreeResources(drmModeResPtr ptr)
{if (!ptr)return;drmFree(ptr-fbs);drmFree(ptr-crtcs);drmFree(ptr-connectors);drmFree(ptr-encoders);drmFree(ptr);
}
核心要点7 1.调用drmFree释放资源本质和drmModeFreeConnector一样也是释放内存资源。 3.DRM基本接口总结
1.drmModeGetResources函数调用DRM驱动通过ioctl(DRM_IOCTL_MODE_GETRESOURCES)获取CRTC和Connector的id号。2.drmModeGetConnector函数调用ioctl(DRM_IOCTL_MODE_GETCONNECTOR)连接CONNECTOR到显示器3.modeset_create_fb函数调用ioctl(DRM_IOCTL_MODE_ADDFB)添加一个FrameBuffer4.drmModeSetCrtc函数调用ioctl(DRM_IOCTL_MODE_SETCRTC)CRTC对framebuffer的数据进行扫描5.modeset_destroy_fb函数调用ioctl(DRM_IOCTL_MODE_DESTROY_DUMB)销毁DUMB共享内存6.drmModeFreeConnector函数调用drmFree释放内存资源7.drmModeFreeResources函数调用drmFree释放内存资源
